It's the Rheo Thing

Open Access, Curation and Seredipity

2012-01-27T09:37:00.001-06:00

The issue of open access has raised itself up again this last week in the chemistry blogosphere. Rich Apodaca, author of the Depth-First blog, caused a stir when he came out in support of the Research Works Act, legislation that would at present prevent the NIH from requiring that research publications support by NIH grants cannot be placed in PubMed Central where they are freely accessible by anyone. (The bill of course, is written more broadly than that, but that would be the most obvious and immediate impact.)

But all this is prologue.

Rich made one argument that I strongly disagree with - that for a journal, the imprimatur provided by a journal is still valuable and needed.
"Any scientist who has been an active participant in scientific publication as an author, reviewer, and consumer recognizes that the only remaining value added by scientific publishers today is imprimatur. Imprimatur is the implied endorsement received by authors who publish in certain scientific journals, particularly in those that earned a high level of prestige during the pre-digital period of publication scarcity."
I disagree. The value of a "prestigious" journal is not the prestige, it is something far more valuable that we all are implicitly aware of, something that journal editors provide, something that gives the journal it's prestige and that is curation - deciding what is and isn't important. It is this step that provides the ultimate value of a journal. Without appropriate curation (lots more on that in a minute), the journal becomes a meaningless pile of data. Being peer-reviewed, it is accurate (more-or-less) but without guideposts.

As I said, we are all aware of this already, but just not explicitly. When that prestigious journal brag about how few papers they accept, what the journal really bragging about how much they curate. They are able to make great decisions about what their readers want to see and what they don't want to see. Effective curation over time leads to imprimatur. Without effective curation, your journal has papers which may or may not be of great value, but a landmark article in the Upper Midwest Journal of Photochemical Interactions in Northern Blots will never give that journal any prestige.

To me, if I was a journal that wanted to convince people that they should pay for it in this age when "information just want to be free" is the mantra, I would sell curation hard, very hard. All the other services that journals used to supply are now easily duplicated by all the disruptive technology available. Bur curation, and the ability to perform it well, is something valuable that still remains. It is what distinguishes Angewandte Chemie from Tetrahedron Letters. It needs to be recognized and it is worth paying for.
Let me go back to the subject of curation in a broader context.

As long as there has been mass media, there has been curation. It has never been possible for a mass media source to publish/broadcast everything so choices were made as to what was and wasn't going to be put out for consumption. In the past, those choices were made by a small group of people. If you were unhappy about their choices, there was little you could do. With the internet, curation initially appeared to have died, as everyone could have access to everything. But even with all those choices, mainstream media sites still remain popular destinations because of their ability to effectively curate. As with very selective journals, when the New York Times makes the statement "All the News That's Fit to Print", they are referring to their curation abilities.

Curation will never disappear. I would suggest that there is a basic human need for it. If it is lacking, someone, somewhere will create it. It is also fairly obvious that it is needed now more than ever. The information that we have access (or potential) access to is greater than ever before, and becoming greater with each passing day. Some of the most visited websites - the Drudge Report is a terrific example - are nothing more than curation sites. Matt Drudge decides what to link to on his page and doesn't provide any explicit editorial comment other than the headline for the link, and yet his sites has millions of hits per day because he has a great sense of what people want to see. If he ever loses this sense, his page will drop in it's importance.

Curation has also started appearing in our search engines. This is certainly a new concept, one that has never before occurred in our history. Early search engines on the Internet gave a haystack of results with little effort to prioritize the results. The searcher was expected to do find the good from the bad. Google became a dominant player because it was able to prioritize webpages - decide what was more important. But they didn't stop there. It is now becoming more well known that Google will further alter search results based on information it has gathered about your from past searches. A recent example of this was seen in the engineering sub-reddit, where an engineer posted a screenshot of what the Google image search showed for "pump" - quite a few high heeled shoes, more than he would have liked.

Here's what an identical search for me produced.
A lot less shoes. As you can see, all the technical searches that I perform at work are then used by Google to slant the search results towards what I am most likely interested in. (I imagine that the reddit engineer was searching on a computer often used by his girlfried.)

I've noticed over the years that my Google searches have become increasingly productive. I used to think that it was because I was becoming a better searcher - choosing better search terms - but now I am not so sure that Google isn't doing a better job of providing the results. Regardless, Google's efforts to provide relevant search results is a rather desirable outcome - in most situations. I'm looking for specific information and I don't have a lot of time, so not having to scroll down the page at all is invaluable
And yet, there are times where curation is that last thing that we need. With the more poignant search results, it becomes increasingly difficult to stumble upon something new, something that you find interesting, something that you didn't know you were looking for. I'm old enough to remember when libraries had card catalogs - collections of cards in drawers that could be searched to find a book in the library. Searches were typically possible by the title of the book, the author and by subject. The unintended beauty of the catalog was that you could be assured that the first card you looked was not the card you wanted, and so you then started flipping through more cards until you found the one you wanted. And sometimes in this search, you would find something that wanted without knowing that you wanted it - serendipity! Further, once you found the call number for the book, you had to wander the stacks to find it, which could lead to further unexpected results, although that was not as likely as books were generally arranged by subject. (Ethan Zuckerman notes that Harvard is considering enforcing serendipity by reorganizing all the books by size!)

Now when we find books via computer search (either from libraries or Amazon), serendipitous outcomes are pretty much impossible. Even if you misspell a word, the search algorithms will overcome that and give you the "intended" result. Can you have serendipitous search results with Google? A decade ago when their algorithms weren't so refined, you could have. Now you can't. There is no "random search" option, no "show me something new" option, no "tickle my brain" option. And this is not to pick on just Google. Twitter will only show you what you have indicated that you want to see. Same with Facebook and endless other sites.

Serendipitous results can be found, but ironically, you have to work at it. Reddit/Digg/StumbleUpon and similar sites are places where people send links that they think are interesting. Their main pages provide the top results, so you will certainly see something new, although it will be what is most popular, a description that makes me wonder about humanity's fate at times.

Wikipedia is another place where it is relatively easy to get off the beaten path if you start following the links in an article or the "see also" links. And serendipity is why I enjoy the journals Nature and Science - they have research from all fields of science, not just the polymers and rheology that I specialize in. (I do note the irony that these journals are also very well curated. More journals of such broad coverage in the future would be another route to enforce serendipity!)

Curation and serendipity are opposite sides of the coin, but paradoxically, we need both. Curation seems to have the upper hand at present and that trend will continue for the foreseeable futher, while serendipity is being forced to the side, something that we have to struggle to keep alive.

And finally getting back to the issues of open access that this post started with, curation is still the last valuable service performed by journal publishers that cannot be replace by technology - at present. Can algorithms be developed that can perform the curation for us? I wouldn't ever bet against that. In fact, I would expect to see it in my lifetime. But the real question is this: do we want that? (Sadly, I think the question might be better stated as: How can we prevent that?)

As a last comment, the blog entry by Ethan Zuckerman, Desperately Seeking Serendipity is a wonderful read about serendipity in cities and other geophysical structures. It is a long article, but well worth the time. Mind-opening.

Viewing History through an Oil Refinery

2012-01-26T10:55:00.003-06:00

It's probably a result of my education (but not my career path) in chemical engineering, but I love look looking at refineries and pictures of them. Hydrocarbon Processing" is my favorite trade journal to flip through because of the cover picture as well other photos inside. I am always amazed by the tangled pipeline, the endless columns, pumps,...such as I see at the Pine Bend Refinery located just south of town here:

When oil/petroleum refining was first developed, such complicated plants were not needed, and that was probably a great thing as no one would have been able to design such a complex monstrosity a hundred years ago. A distillation column, maybe a tank or two and some simple plumbing would have been enough. The outputs would have been just a crude - a cut for lamp oil, and maybe some gasoline, and then the tar at the bottom was probably just a waste pile until someone figured out that it would be good for roadway surface. But as the demands for these products became more rigorous, the demands on the refinery increased, and so did the equipment. More fractions could be taken, and the fractions needed higher purity. Things like sulfur became a concern, and so removing it required additional processes. Recycle lines were added along the way to increase productivity. The chemical industry was growing and was able to take undesired waste, but only if the waste was of a more consistent output. This continued until we have the huge plants that we see today. Yet at the heart of the plant is still the distillation column. The columns, plants and plant sites are all new, but the thought processes that justified the additional equipment, the history of the refining industry is still there for all to see.

Confusion over "Polymer"

2012-01-25T07:36:00.000-06:00

When I wrote yesterday's post about the confusion in the general public on the term "vinyl", I thought it would be a stand-alone topic. But late yesterday I found an article that is forcing a followup. Only in this case, the confusion is not in the general public, but with theoretical physicists. And in this case, the word is "polymer". As in the title of this paper: "Polymer Quantization on the Half-Line". Here's the abstract:

"We investigate polymer quantization on the half-line, constructing a one-parameter family of polymer Hamiltonians that are analogous to the Robin family of continuum boundary conditions for the half-line Schrodinger Hamiltonian. Applications include the free particle, the attractive Coulomb potential, the scale invariant potential and a black hole described in terms of Einstein-Rosen wormhole throat dynamics. The spectrum is analyzed by a combination of analytic and numerical techniques. In the continuum limit, the full Robin family of boundary conditions can be recovered via a suitable fine-tuning but the Dirichlet-type boundary condition emerges as generic."

"...a blackhole described in terms of Einstein-Rosen wormhold throat dynamics"? Not exactly the polymer science that I am aware of, although I bet you get an incredible extensional flowfield going into a blackhole. If any one can explain this use of "polymer" to me, I'd love to hear it, but I'm not holding my breath. I've sent the first author an email and will see if I get a response.

Confusion over "Vinyl"

2012-01-24T10:11:00.000-06:00

I recently had to clarify for someone what the term "vinyl" means. The confusion arises from the fact that it is commonly used by the general public, not just chemists. For the former group of people, the term refers to the polymer "polyvinyl chloride" (PVC), such as the vinyl drainpipes sold in hardware stores. For a chemist however, vinyl refers to a mono-substituted ethylene molecule, such as the vinyl chloride monomer (VCM) used to make PVC. [1]

You can see that the general public uses vinyl as a noun, while chemists use it as an adjective, a word to modify a noun, such a vinyl group, vinyl chloride, vinyl acetate, etc. But even for chemists, the use of "vinyl" for a mono-substituted ethylene group isn't consistent. α-olefins are a good counter example. 1-hexene is not ever referred to a vinyl butane [2]. I am unaware of any particular rules defining when to use and not use "vinyl", other than to state that it is not acceptable at all for IUPAC - they prefer the term "ethenyl".

The confusion that I referred to earlier came about with the term polyvinyl acetate (PVAc) and the perception that this polymer (the PVAc) would have some PVC in it, and in particular, chlorine. The "vinyl" in this case however, does not refer to VCM or PVC, but rather what chemists mean by the term vinyl - a mono-substituted ethylene group. In the case of PVAc, the substituent is an acetate group. There is no vinyl in polyvinyl acetate, there is no vinyl chloride in polyvinyl acetate, and there is no polyvinyl chloride in polyvinyl acetate.

A related monomer and polymer that I won't go into today are vinyl alcohol and polyvinyl alcohol. I've discussed them in the past, so you can look at this post if you want to find out about the monomer "vinyl alcohol" that doesn't exist, even though polyvinyl alcohol does.

[1] Di-substituted ethylene groups (assuming both substitution are identical substituents and are on the same end of the double bound) are called vinylidene groups, such as vinylidene fluoride, F₂C=CH-, entities that are far less common than vinyl groups.

[2] Or would "vinyl butyl" be more correct for this incorrect construction?

Free Access to Polymer Research

2012-01-20T09:21:00.000-06:00

I updated the page on "Free Access to Research in the Polymer Literature" (see the tab above). There are more sample issues, as well as a number of individual articles covering topics from branched polyethylenes to thiol-ene [*] prepared protein bioconjugates to solar photovoltaics. Something for everyone.

[*] Long time readers know that if there is thiol-ene article, I'm on top of it.

A Bad Day in the Operating Room

2012-01-19T09:05:00.000-06:00

This is an x-ray of a patient's lung. The small white stripes in the upper left are PMMA. How did PMMA get in his lungs you ask? Well, he was having back surgery. Still not obvious to you? O.k., here's the full story as explained by the article in the New England Journal of Medicine. The patient was having back surgery to fix spinal cord compression. The surgery involved injection methyl methacrylate (not polymerized) into the back, whereupon it does polymerize (with a nice little exotherm I might add). The procedure is called vertebroplasty. [*]

As is known to occasionally happen, some the the acrylate got into the bloodstream around the bone and was transported to the lungs. The plastic did interfere with the patient's breathing for a while (low O₂ levels in the blood) as well as some mild increases in blood pressure. The doctors that submitted this image to the journal noted that in extreme cases, serious illness and even death can occur as a result of these types of complications.

The Wikipedia article on the procedure has quite a discussion about the effectiveness of the procedure, or more properly, the lack of effectiveness. Combine this with the risks illustrated here and I can certainly state that I would not want this done to me. I like plastics a lot, but only outside of my body, and most certainly not in my lungs.

[*] It's great to have Wikipedia back, isn't it. I missed them yesterday, but their blackout did get me to sign a petition against the SOPA/PIPA bills and contact me representatives in Congress about the issue.

Criticisms of "Atom Economy"

2012-01-18T09:32:00.002-06:00

When I wrote about "atom economy" yesterday, I tried looking around for some serious criticism of the approach and didn't find much, so here are my thoughts.

Atom economy is defined by Barry Trost of Standford (subscription/pay-per-view) as the molecular weight of the product divided by the sum of the molecular weights of the reactants.

Chemists have in the past relied on yield percentages to measure the efficiency of a reaction. If there is 10 millimoles of A at the start of the reaction and it is transformed into 9 millimoles of B at the end, the efficiency is 90%. These yields are important, as many reactions are part of a multi-step synthesis. If a 5-step reaction has 90% yields for each step, the overall yield is 0.9⁵ = 59%.

With that 90% yield however, there may be a mountain of chemicals, solvents and catalysts left in the wake of the reaction and that shouldn't be ignored. In one of my earliest jobs working with coating solvent-dispersed adhesives, we were all very much aware that for every 3 gallons of adhesive brought into the plant, 2 gallons of solvent (plus a lot of heat) went out the roof of the building to the thermal oxidizer, so certainly a "big picture" approach to chemical reactions is needed. It;s just that I think atom economy is a lousy option.

The impact of atom economy is greatest for large volume, industrial situations, and not small academic labs. However, much of the research published on atom economy concerns academic research rather than industrial preparations. While in some cases, the difference between the two is mostly a matter of scale, in other cases, industrial processes are whole different than research lab processes. Worrying about the atom economy of a non-industrial reaction is a waste of time.
By focusing solely on the nature of the reaction and not the actual chemicals involved, atom economy overlooks process concerns such as ease of separation of the product, the hazardousness of the reaction and the byproducts, etc.
- It inherently favor reactions without any byproducts (additions and rearrangements) and disfavors all others (substitutions, condensations and eliminations).
- It also favors the upper rows of the periodic table. Lower rows, while often being more reactive, have greater atomic masses and are therefore disfavored by the calculation. Yet many preparations of fluorinated compounds are far more dangerous and hazardous than the chlorinated equivalents. Is this not a concern?
It is often unclear exactly what "the reaction" is. Taking the example again of (poly-)amide formation between an acyl ~~chloride~~ fluoride (lower MW in the reactant = GOOD!) and an amine. I'm not aware of any naturally-occurring acyl fluorides, so that material was prepared at some earlier point. Shouldn't that reaction be included in the overall calculation as well? And what if the amine also required preparatory reaction(s), shouldn't that be included in the atom efficiency calculation as well? How far back should this all be pushed? Is cradle-to-grave the proper approach? Or can we game this to a better starting point? (I find it rather ironic that the modern organic chemical industry itself is a "byproduct" of the petroleum industry. If the refiners had practiced better atom economy, modern organic chemistry would be much in arrears from where it is today.)

Just like yield percentages, atom economy looks at only one aspect of a reaction under the guise of being "green". A truly green approach however, requires some thought and critical analysis, not just a number that can be reported on a scorecard.

Amide Formation - A Case where Polymer Chemists Have it Easy

2012-01-17T09:21:00.001-06:00

At the end of last year, Nature had a review article (open access) on amide bond formation. As polymer people, we all know and love amide formation as the basis for polyamides, also known as nylons. Given the apparent ease with which many polyamide bonds can be made (watch the nylon rope trick video), I've never thought about amide formation as being a particularly challenging aspect of organic chemistry. I was wrong. Consider this quote from the article's introduction:

"The current methods for amide formation are remarkably general but at the same time widely regarded as expensive and inelegant. Not surprisingly, in 2007 the American Chemical Society Green Chemistry Institute (comprising members from major pharmaceutical industries worldwide) voted ‘amide formation avoiding poor atom economy [1] reagents’ as the top challenge for organic chemistry. Furthermore, even the best stoichiometric reagents often fail for the synthesis of sterically hindered amides [2]. The issues of waste and expense associated with amide formation are compounded when applied to peptide synthesis, and are responsible for the great cost of commercial therapeutic peptides. The chemical synthesis of proteins is largely prohibited by limitations inherent to traditional amide formation..."

(Footnotes are added by me and are located at the bottom of this article.)

In the nylon rope trick, the diacid is modified to form a diacyl chloride which then reacts with the diamine, in the process forming HCl. Fortunately, most commercial nylons are made from the straight diacid, or more correctly, the nylon copolymers such as nylon 6,6 are made this way. The diacid and the diamine form a isolatable, non-reactive salt which is then reacted at high temperature and pressure to induce polymerization. The nylon homopolymers, such as nylon 6, are made through a ring-opening polymerization of cyclic lactams. Most other organic compounds cannot tolerate the conditions or have an appropriate lactam, and so the search is ongoing for more and better techniques to create amides. Maybe some of these results will spill over into the polymer area, but I have my doubts. Just looking at some of the options

makes me thankful that we don't need to explore them.

[1] "Poor atom economy" refers to the molecular weight of the product divided by the molecular weight of all the reactants. It is a trendy way to quantify the efficiency of a reaction. I'll have quite a bit more to say about it tomorrow.

[2] All easy reactions fail for sterically hindered products. While polymaleic acid has been made, 2-olefins in general are still considered to be very difficult to polymerize.

Flying Cupcake Update

2012-01-16T14:11:00.000-06:00

Time magazine is reporting that a bakery in Rhode Island has risen to the challenge of TSA-stricken cupcakes and now sells cupcakes ensembles that include a cupcake with 3 ounces of frosting, a first class boarding pass, and a picture of Richard Nixon saying "I am not a gel!"

Ah! American Ingenuity at it's finest!

Previous discussion on this subject.

Gels and Cockroaches

2012-01-16T13:38:00.001-06:00

When last we met, we were talking about edible gels (or gel like materials) - cupcake frosting, and also cream cheese, peanut butter and other delicious foodstuffs. But not all gels are edible. A great example of the inedible sort, but one that also appears to be highly desired, is Du Pont Advion Cockroach Gel bait. I say highly desired as 13 tubes of it were reported as stolen over the weekend from the Manchester City Hall. Apparently nothing else was stolen, so either the thieves have the mother-of-all cockroach infestations in their homes, or they have some other nefarious activities in mind, although I can't imagine what.

If I had a cockroach problem, I'd gel up some linoleic acid. It's a very effective repellent - it's actually a necromone ("death hormone") that crushed cockroaches give off as a warning to others. So in other words, this cartoon drawing from the cockroach world is pretty unrealistic:

The coroner would be heading far away from the broken body.

The active ingredient of a linoleic gel is not only non-toxic, but also an essential oil for humans. However, despite all these advantages, you still wouldn't be able to take more than 3 ounces of this gel on a US plane.(Ever seen a cockroach on a plane? I can't imagine that they aren't there.)

The Dangers of a Flying Cupcake

2012-01-11T10:48:00.002-06:00

Or maybe more properly, the dangers of flying with a cupcake - one that is coated with lots of frosting.

The popular media has has a number of reports (1, 2, 3) of how "heavy handed" Transportation Security Agents (TSA) confiscated a women's cupcake as she attempted to pass through security with it. The frosting was considered by the TSA agent as a "gel", a restricted material, and the amount of frosting was judged to be in excess of the amount allowed on a plane in the US.

Although it certainly is fun to take potshots at the TSA and joke about how the agent was hungry and just wanted the cupcake for him or herself [*], rheologically speaking, the TSA was right on this one. Frosting is not a polymeric gel, but more of a "colloidal" gel with plenty of non-Newtonian behavior - certainly yield stress, but also likely shear thinning, and maybe even some thixotropy (I haven't measured the properties myself. If any readers have, feel free to add what you know in the comments box below.) And as the TSA commented regarding the incident, malevolent people are more likely to disguise their means as ordinary object and not give them a distinctive "explosive" appearance:

I submit the shoe-bomber and the underwear bomber as examples of potential explosives being disguised as commonplace objects. (Those particular examples didn't work, but that doesn't mean that a smarter/better chemist wouldn't succeed in the future.)

Unfortunately, this incident has come out as yet another example of a sweet innocent person vs. the evil TSA. While in many cases I do agree with that viewpoint, this is one where I clearly agree with the TSA.

[*] I can't imagine any agent eating anything that is confiscated from passengers. Would you really risk your health/life by eating something from an stranger? We're not talking about a box of donuts that's sitting in the breakroom.

Is the End Near for the Dow-Kuwaiti JV Disaster?

2012-01-09T13:28:00.000-06:00

One more post on Dow, since this is an update on a story that I commented on quite a bit (1, 2, 3, 4) when it originally happened.

As you may recall, back in 2008, Dow attempted to form a joint venture with Kuwaiti's Petrochemicals Industries Co (PIC), with the PIC paying Dow $9 billion for some capital assets as part of the deal. The Kuwaiti firm originally thought they had the money, but as oil prices fell that year, they came up short so they cancelled the deal. This really hurt Dow as Dow was already planning on using that money to help purchase Rohm & Haas. Dow was able to complete their purchase by selling other assets, but has since sued PIC for damages that apparently were specified in the original agreement. Dow is stating that they are "confident" that they will soon be rewarded $2.5 billion. We shall see. Knowing only what I've read, it seems like they should be owed something, but the law has a funny way of distorting justice and reality.

What You Want May not be What You Need

2012-01-09T10:09:00.002-06:00

Mark Rosenzweig has an commentary in the latest issue of Chemical Processing Magazine, entitled "There is a New Buzz on Campus" which discusses Dow Chemical's source of $25 million to a select group of American universities. The focus of the money is to finance a return to traditional research areas, rather than focus on the latest trends. To quote Dow:

"In the last two decades, there has been a shift in the U.S. academia from a focus on traditional skills of chemistry, materials science and chemical engineering toward bio-related areas. This shift can be primarily attributed to the greater availability of funding from both government and the private sector. The net impact is less research is being done in the fields that are less trendy, but key to the development of the industry as a whole, like catalysis, polymers, materials science and separations."

There is even a quote from William Banholzer, the Chief Technology Office of Dow (who has been in my crosshairs before for saying that all the polymers that can be invented have been invented):

"This unique and industry-leading investment will support breakthrough technologies and increase collaboration between Dow and leading universities, while helping to develop America's future pipeline of Ph.D.-level talent," notes William F. Banholzer, the company's chief technology officer and executive vice president of ventures, new business development and licensing. "It is vital that we support academic research to ensure universities can continue the tradition of excellence in chemical engineering, chemistry and materials science to help address the needs of the industry and our country."

Research grants always come with strings attached, some more obvious than others - it a variation of that old adage that whoever pays the piper requests the tune. Government funded research is increasing under public scrutiny, and so researchers are having to provide ever more information about the potential payoffs of their efforts - hence much of the hype that a new breakthrough will cure cancer AND reduce petroleum imports AND make your kids smarter. Dow's money will be no different - it's just that the tune will be changed. Dow is expecting these efforts to help their business which is based exclusively on large volume products with smaller margins [*], and the research will need that focus as well in order to be a "collaboration between Dow and leading universities". That's all fine and nice - I don't have a quibble with it, as that as how they have chosen to run their business, and researchers are free to apply for the money or not. No one is being forced to do anything.

But as I noted in my earlier blog post, Dow is clearly looking for large volume products that will be accepted in the marketplace quickly. Without these constraints, I find it quite surprising that Dow would be unable to take advantage of all the "trendy" research being generated these days. They specifically call out "bio" research as being so trendy (overlooking nanotechnology). Keep in mind that Dow was initially a joint-developer (with Cargill) of the polylactic acid Natureworks effort, a "bio"polymer if there ever was one, but sold out pretty early on - a move that in hindsight looks to have been a poor choice given the tremendous success of Natureworks.

Maybe Dow will be rewarded in this case with what they seek, but I have serious doubts that anything will be produced that they will want to invest further so as to have a large enough scale product quick enough to keep them happy.

[*] This is why Banholzer was so critical of any new polymers being invented. As far as Dow is concerned - looking for large volume materials - they have been. Or as was noted in the earlier blog post, large enough volume quickly enough.

Free Access to Articles in the Polymer Literature

2012-01-06T09:23:00.000-06:00

I'm going to try something new this year - keeping a separate page going that lists the current state of open access to polymer literature. (This is an idea I've been kicking around since my previous post on the subject back in October.) There is a tab at the top this page with what I have so far (heavy on the Elsevier journals since they were easy to tabulate), but I will keep adding to the page as new articles are available and remove them when they no longer are. As is often the case, publisher will provide free access for a limited time. And I am calling this "free access" rather than "open access" to denote the difference. Open access, in my mind, is for all eternity, or at least there are no plans to remove the access.

Any error and omissions are my own fault, although I am (naturally) going to skew the selection towards areas that I have interest in. An article on a new catalyst to convert a alkene into an alkyne? Nah. An article on a new catalyst to polymerize an alkene? Definitely.

Lastly, as I make significant changes to the page, I will put a short note here so that you don't have to keep looking at the other page. Granted, this assumes that you are using an RSS reader or you have this page bookmarked and read every post I create, which is scary thought.

How will the Law and Chemistry Interact? - The Sheri Sangji Case

2012-01-04T08:18:00.001-06:00

While there has been much excellent discussion of the Sheri Sangji case elsewhere (Jyllian Kelmsly has the best coverage of the unfortunate women killed in a UCLA lab when a large volume of a pyrophoric chemical was spilled in a hood containing hexane), I see a common underlying theme in all the commentary. Being chemists, we take a strongly scientific view of the matter, looking at the reported facts, filtering them through our collective chemistry culture and producing a "factual" answer. This is the way we operate on a daily basis at our jobs, as well we should. We do a great job at it, but now we are being cast aside. You see, now that the legal system has gotten involved, an entirely new perspective will enter the picture, one that is well removed from the "reality" that we experience in our hoods and on our benches. Or as Rees Kassen said in a recent Nature editorial "Our mistake is to think that science will be given a privileged voice on an issue. This is almost always wrong."

Consider these thoughts in no particular order:

While the Constitution guarantees Prof. Harran a jury of his peers, consider what the makeup of those "peers" will be. Does anyone think it will be 12 other chemicals professors? Or 12 chemists? Or even 1 from either of those groups? Or even a single technically educated person? No, there will not be anyone of such background on the jury. If there was, the jury would be effectively reduced to the that lone technical person, as everyone else would defer to their technical background and experience. Instead, the jury will be made up of 12 people from all walks of life. Some young, some old, probably an unemployed person or two who is just happy for the income and free lunch. Considering that only 30% of the population has a college degree, that means only 4 people on average will so educated. Look at some of the comments on the "Trending Topics" from Twitter to see the intelligence level that Professor Harran is facing. So it will not be enough for the prosecutor to state that there was also hexane in the hood at the time of the incident. As chemists, we all understand that hexane is very flammable. The jury will not. They will need to be told that a component of gasoline was also in the hood, but at the same time, the only "experience" most of them will have had with hexane on fire is seeing a car explode in a Hollywood movie - an entirely different matter. And while the judge will have a lay degree, he most likely knows nothing about chemistry either, so it would be pretty easy to snow him with some "less than totally accurate facts".
If the prosecutor had an easy case, he would have not waited until the statue of limitations nearly kicked in before filing the charges.
The way evidence is looked at in a trial is greatly removed from anything we ever see as chemists. As an example, know that until a few years ago, it was possible for a forensics lab to produce a one-sentence report against you stating for example, "The substance was cocaine"! It was assumed that appropriate analytical techniques were used, that the instruments were calibrated, that the results were interpreted correctly...Compare that with any peer-reviewed paper, or even a lab report that students turn it. There was nothing you could to about it except pay for testing the substance yourself, and then you would have competing reports and arguments about who was right and allusions that you found someone biased in your favor and... Remember that the constitution guarantees us the right to confront our accusers, but until the Melendez-Dias case reached the Supreme Court, that was not possible. The Melendez-Dias case opened the door at least to allowing the defense to actually question chemistry reports Regardless, the law takes an entirely different approach to evidence than chemists do.
Any comments being made know by the UCLA lawyers or the Prosecutor's office are just PR blurbs. None of the people making the statements are going to be the lawyers arguing at the trial, so ignore what is being said.

At the same time, we as chemists/scientists/engineers need to approach the legal system in the same way that we perform our jobs. As the trial proceeds, we can't be content to just read what is being reported in the mainstream press or the chemical press or blogs or...The real answers will be in the primary literature and the raw data - the actual proceedings that occur in court. Only by accessing that information will be able to truly understand what occurred in the trial.

I make no predictions of the outcome as I see difficulties on both sides and no clear cut "justice" as an outcome. Cases like this are why we are taught to pray to "save us from the time of trial".

Mt. Stupid

2011-12-30T07:25:00.000-06:00

From Saturday Morning Breakfast Cartoon on December 28, 2011 (Note that this particular comic is safe for work, but that is not always the case with SMBC):

Here's hoping that 2012 finds us all climbing the ultimate steep slope on the right hand side and never interacting with anyone living on Mount Stupid.

And with that, I'll be taking a few days off of well-earned vacation now that our corporate move is winding down.

A Bullet to the Head

2011-12-29T09:51:00.000-06:00

There was a report earlier this year of a Chinese man that had had bullet lodged in his brain for 23 years, but now the New England Journal of Medicine has a report that trumps that - a Russian man with a bullet lodge in his brain for 82 years! Take a look:

According to the doctors,

"The patient revealed that at the age of 3 he had been accidentally shot with a pistol by his older brother. The bullet had struck him just inferior to the nose, and he had lost consciousness for several hours, recovering completely without specific therapy. In his adult life, he had achieved professional success as an engineer, even winning the Soviet State Prize for his accomplishments."

82 years is a record unlikely to be broken. Isn't it strange that he was shot and that no medical evaluation was even made at that time?

PEO Crystals - The Snowflakes of Polymers

2011-12-29T07:00:00.000-06:00

While polymer single crystals have always showed a myriad of shapes, articles on the crystallization of polyethylene oxide (PEO) has always been the most exciting to read. That polymer, more than any other is able to crystallize into a seemingly endless variety of forms depending on reaction conditions. This is largely because of the flexibility of the ether linkages in the backbone. There is minimal hindrance to axial rotations and so getting some type of crystal to form is pretty much a given. It's just that no two crystals seem to be the same, much like snowflakes. Consider these 8 examples:

The above AFM photograph comes from a research letter (open access) published in the new ACS journal Macro Letters. As with all crystallization, you have the competing effects of nucleation and growth occurring. The relative rates determine the shape of the final crystal. Working through a wide range of supercooling conditions and molecular weights, the researchers were able to create a "morphology" diagram - a map of what conditions will lead to what outcomes. Here's a look at it:

where the letters in this figure corresponds to the different morphs in the previous diagram. The general trends is that as the supercooling (or molecular weight) increases, the fiberous nature of the crystals increases as well.

It's a short article with lots more detail in it - I highly recommend reading it if you have an interest in polymer crystallization.

Zhang, G., Zhai, X., Ma, Z., Jin, L., Zheng, P., Wang, W., Cheng, S., & Lotz, B. (2011). Morphology Diagram of Single-Layer Crystal Patterns in Supercooled Poly(ethylene oxide) Ultrathin Films: Understanding Macromolecular Effect of Crystal Pattern Formation and Selection ACS Macro Letters, 217-221 DOI: 10.1021/mz2001109

Chemistry vs. Physics &. Biology

2011-12-28T09:29:00.002-06:00

Of the three physical sciences listed above, physics and biology seem to have a lot in common, with chemistry being the odd-man out.

Physics and biology both have "dissident" scientists who disagree with some of the key fundamentals in the science. You don't have to spend too much time in physics forums to run across people who think that all of quantum mechanics and/or relativity is wrong, and that they have a better explanation that doesn't require ideas that clash with our everyday experiences. Biologists have to deal with all the people, including scientists, who deny evolution. Fortunately, chemistry seems to be immune to "dissident" thought. I can't think of a single example where a fundamental chemical idea is challenged.
Physics and biology have both done a better job of selling themselves to the general public than chemistry has. Physicists are able to get funding for particle accelerators that may not ever be able to produce results applicable to the "real world", and yet many in the general public are well aware of the search for the Higgs Boson. Astrophysicists are similarly able to get funding for ever larger telescopes and space telescopes. As long as they produce the occasional breathtaking picture of nebula and galaxies, the general public is happy. As for biologists, they were able to get billions for sequencing the human genome, although they at least held out the promise of "personalized medicine" and the discovery of the gene that causes disease X, Y and Z (with the soon to follow cure for these diseases). Has there ever been a large scale chemistry project, let alone one that captured the public's imagination? I can't think of any.
Chemistry seems to more feared by the public than physics or biology is. I'll admit that this is a personal perception that might be heavily tainted by my experiences, but it seems to me that there is more chemophobia than there is fear of anything that physicists or biologist work with. Certainly there is fear of radiation and certain microbiological organisms, but these fears are limited to rather thin facets of life - nuclear power plants & weapons for physics, and food safety & infections/disease for biologists, whereas chemophobia can exist with practically everything that people touch in their lives. If a physicist is working with optics, that's o.k. If a biologist is working with fish, that's o.k. [*] If a chemist is working at all, it's with chemicals and that's bad no matter what.

While I am glad that we don't have to deal with the crackpots, it sure would be nice to have a few large-scale projects that the public is all to happy to pay for, one that will improve their perception of chemistry and reduce the amount of chemophobia in the world today.

[*]as long as they are not genetically modified fish. (I realize this is a small concern in the US and a bigger concern in Europe.)

The Two Sides of Plastic Man

2011-12-27T08:31:00.000-06:00

Throughout history, "Plastic Man" has taken many forms. The oldest version is the ~~comic book~~ graphic novel hero. Being plastic, he was able to assume a vast array of shapes such as

or even this

All this fame and glory earned him a spot on US postal stamps back in 2006:

and apparently even had his own Saturday morning cartoon show in 1979

(I never saw it - at that point I was too deep into upperclassman chemical engineering classes to watch TV.)

But,like all Superheroes, "Plastic Man" had his dark side, as can be seen in this video from Sonny [*] and Cher from 1968:

The Kinks also had their own song "Plastic Man" the following year with entirely different music and lyrics (that Heaven for small favors), but equally disparaging:

From Superhero to Superzero - the life of Plastic Man

[*] This man went on to be come the Mayor of Palm Springs and then later, a US Congressman, believe it or not.

Aspen Research has Left the Building

2011-12-21T13:21:00.002-06:00

Yesterday the last truck arrived with all the goodies from our old building. We are now officially moved and located at our lovely new building, 8401 Jefferson Highway in Maple Grove, Minnesota. Having left the city of White Bear Lake, we no longer have to explain that we are so far north that we have white bears. "Maple Grove" is just another generic suburban name that needs no explanation (Wikipedia lists over a dozen cities in the US and Canada with the name. I've never seen a disambigulation page listing further diambigulations, have you?) Now it's just a matter of hooking everything back up, reclaiming the chair and desks and file cabinets and ... that others are squatting on, and away we go. The computer network is fine (YES!), the offices are nicely finished (the nicest cubicles I've ever seen) and significantly bigger than what we had before. How small were our old cubicles you say? Let's just say that Aspen Research was a leading the charge on nanotechnology 20 years ago.

With the whole operation of unpacking everything and putting it all in new places, you do get to look at all the stuff anew and rediscover some things, decide other things are no longer worth keeping and yet other items are going to be dealt with differently than before. It's all good.

Not Hiring Someone You Should Have

2011-12-20T10:04:00.000-06:00

When a decision is being made to hire a new employee, I see 4 potential outcomes based on two factors. The first is obviously whether or not to hire the person, and the other is whether or not the person should be hired. A simple diagram of this situation is this:

The people in the upper left hand corner we all know about - the ones who got hired and are working out well, and the same goes for the lower left corner - the ones who got hired and are not working out well [*]. The right hand side of the chart however, is more of a mystery. When a decision made to not hire someone, there is no feedback. Very seldom do you ever find out if you made the correct decision or not.

This discussion however, was all made on the basis of a single person making the decision or equivalently, an entire team being in agreement on the decision. If that is not the case, then it is possible for some people to explore more of the right hand side of the box. I can recall one case where I recommended against hiring an individual, the manager did it anyway and it turned out to be the correct move. Through that, I was able to explore some of the upper right hand corner, although it was just me and not my manager. While it is good, that's one of those situations that can really haunt you, that you would have let someone good get away. I never have claimed to have great insight on hiring, and that case certainly proved it.

[*] It's been my experience that large corporations have a very difficult time getting rid of these people, which is why I called that box a "really bad decision". Even if the person is ultimately let go or leaves on their own, it still is wasted time and effort for all involved.

The Supreme Leader's Contributions to Polymer Science & Engineering

2011-12-19T08:59:00.000-06:00

With the passing of North Korea's Supreme Leader Kim Jong Il, I thought that we should review the many contributions that the master of all trades gave to the field of polymer science. After all, anyone who can shoot 38-under par (including 5 aces) in his first time on a golf course, write 6 operas in two years and personally design the Juche Tower

certainly must have made immense contributions to polymer science.

Sure enough, he did. A quick search for with the terms "Kim Jong Il" and "plastics" yields a treasure trove of results, although you first have to get past all the articles about his son having plastic surgery so as to look more like his grandfather. But here's some paydirt - the Supreme Leader in an undated photo touring a plastics factory:

A press release from just a few months ago further elaborates the man's involvement with the Raknang Plastic Goods Factory:

"He set forth the tasks to be implemented by the factory.

An important duty facing the factory is to produce more plastic goods conducive to improving the standard of people's living in reliance on the existing production foundation and bring their quality to the highest level, he said, and went on:

It is necessary to direct great efforts to the technical control and the management of equipment and, at the same time, steadily raise the level of technical skill of the producers.

When making a product, it is essential to produce goods liked by people, products impeccable on any market and having world competitive power and increase their varieties to meet different demands and taste of customers."

Extremely insightful, wouldn't you say? We can all learn from this great man. I am sure as well that he was able to provide pointers are to removing mold lines and the blush issues that keep creeping up from time to time (such as increasing the cooling water temperature by 10 degrees).

But was this man limited to just knowledge of injection molding? Of course not - he was skilled in extrusion and fiber spinning too: Back in February, he toured a factory making vinalon, a fabric made from polyvinyl alcohol,

and the press reported:

"He expressed great satisfaction over the fact that the workers of the complex and their helpers have successfully wound up in a short span of time the huge project equivalent to the construction of a large chemical base by their own efforts and with their own technology in hearty response to the intention of the Party to develop the economy their own way and improve the people's standard of living by depending on the nation's economic foundation.

It is an astonishing miracle that the builders have constructed a precious structure of eternal value by their own efforts under so hard conditions by valiantly overcoming bottlenecks and difficulties lying in their way and dedicating their all to the project, he said. He extended high appreciation and thanks to them for having performed the laudable feats for the country and people."

(emphasis added).

Do you see that? Eternal value! Those of us outside of North Korea build machines that will last for a few decades at most before being discarded, but Kim Jong Il was able to devise machinery that would last forever. Truly this was the Supreme Leader. His only shortcoming was having a human body.

The Real Danger in Polycarbonate (it's not BPA!) and a Solution for it

2011-12-16T07:44:00.002-06:00

Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will kill you. But for PC, that is only half the story.

Polycarbonate is normally made by copolymerizing BPA and phosgene. Phosgene is the real bad guy that needs to be feared with all your being. Phosgene has a long track record of killing people, beginning in World War I when it was used as a chemical weapon, and it's potential use was feared in World War II [*]

While industrial accidents with phosgene have been relatively rare, they do occur. Some recent examples are a leak that led to the death of a DuPont worker last year in West Virginia, and leaks in Thailand and China that in both cases also had a death, along with hundreds of injuries. BPA never did this to anyone.

But not content to continue living with these problems, that creative bunch of people known as polymer chemists (Ouch! Sorry, I twisted my arm patting myself on the back) have devised phosphate-free routes to prepare PC, typically using diphenylcarbonate (DPC) as a replacement for the phosgene. BPA is still in the picture, but the DPC is a much safer option than phosgene. Shell Chemical has been a large driver in this effort and is building a pilot plant in Singapore to supply this material. The DPC is made in part with carbon monoxide which is nowhere near as toxic as phosgene.

It's also interesting to note that despite the economic downturn and all the people avoiding PC like an elephants avoiding mice, PC production is still growing at 4 - 5% a year.

[*] Phosgene is a great example of something being quite deadly but not having a wretched smell.

Isolating Thixotropy from Shear Thinning

2011-12-14T09:50:00.001-06:00

With non-Newtonian fluids, the viscosity is no longer constant. Depending on the flow conditions (and the material of course), the viscosity will decrease as the shear rate increases (shear thinning) or it will increase (shear thickening). In some cases as well, there is a time dependency - the viscosity at a given flow condition can decrease over time (thixotropy) or increase (rheopexy).

What I've just describer however, are ideal models that don't exist in reality. As far as I am aware, a purely shear-thinning material does not exist. Sure, most thermoplastics do show shear-thinning behavior, but it is over a range of shear rates, rather than ALL shear rates. (At low shear rates, the viscosity becomes constant and is given the name of zero-shear viscosity, and a some materials will also show a constant, high shear rate viscosity). The same is true for shear thickening materials - such behavior is observed over a range of shear rates and not in other subranges. And it becomes a bigger mess when time-dependent behavior is added. I've never seen a thixotropic material that wasn't also shear-thinning.

It would be a great help for educational purposes if we could find such materials that show only these isolated ideals of non-Newtonian behavior, particularly with the time dependent phenomenon. I think all educators have students that struggle with the difference between shear-thinning and thixotropy. A material showing only thixotropic behavior would be a great aid in demonstrating the difference.

Lastly, there is one set of fluids I am aware of that are able to isolate one subset of non-Newtonian behavior and those are Boger fluids - they have a constant viscosity like a Newtonian liquid, but show large amounts of elasticity.

A Derivation of the Cox-Merz Rule

2011-12-13T07:00:00.000-06:00

For reasons I've never understood, the most common search term that consistently, year-in, year-out brings people to this blog is "Cox-Merz rule" or some variation thereof. So I'm going to add fuel to the fire with some new research results about this important rheological relationship.

The Cox-Merz rule is a empirical observation that h() = h^*(w) when = w.

The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. Sharp observers will question how a sinusoidal deformation can be useful in a production setting which has unidirectional flow (or something close to it). The Cox-Merz rule is able to jump that gap - as long as the magnitude of the oscillatory frequency matches the magnitude of the steady-state shear rate, then the viscosities will be the same. This was first observed empirically and holds for many many materials, thus greatly simplifying the equipment and time spent in the lab.

But once one learns of the rule, the questions then arise as to when it won't work. Again, empirical observations have shown to be cautious with "networky" type materials such as filled polymers or systems with complex hydrogen bonding for example.

David Mead has a fine magnum opus published in Rheologica Acta (free access until the end of the year!) in which he is able to derive the Cox-Merz rule for polydisperse materials. This has been previous done for the idealistic case of monodisperse polymers, so this is a real advancement. The kicker however, is the last line in the article (actually, the last line in the Appendix):

"The Cox-Merz rule is effectively a 'suspicious' coincidence' based on identical dimensionless frequency transitions and correct asymptotic scaling behavior rather than anything predicated on fundamental polymer physics."

All this work and our basics thoughts aren't changed.

Mead, D. (2011). Analytic derivation of the Cox–Merz rule using the MLD “toy” model for polydisperse linear polymers Rheologica Acta, 50 (9-10), 837-866 DOI: 10.1007/s00397-011-0550-5

The Future is Clear

2011-12-12T10:29:00.004-06:00

Two new research articles were recently published, both of which have a common theme: taking objects that are normally opaque and (through the magic of chemistry) making them translucent. Both materials are made up a (more or less) continuous matrix which enclose open spaces. However, the approaches to translucency differ and make this an interesting comparison.

The first object to become clear is a crab shell (original article ($), review (free)), which involves immersing a (dead) crab into a serious of baths - HCl, NaOH and ethanol to remove the minerals, proteins, fats and pigments and leaving just the chitin behind. The chitin is then "clarified" after acrylic monomers are injected and reacted. Here's a picture from the abstract of the starting material, after the three baths, and then the final product.

The "clarification" that occurs in the last step occurs is the removal of scattering sites because the refractive index of the acrylic and the chitin are similar. Absent the acrylic, the air that filled the opening left by after the other materials were washed out in the baths was different enough in refractive index to cause scattering.

The second object that is clarified is an open-celled glassy, foam (original article ($), review article (free)). The preparation technique is completely different - a polyurethane sponge is used as a template, into which nanoparticles of silica are added, the pH is adjusted, and then the urethane is burned out leaving the clear glass foam behind. Nanoparticles are generally too small to scatter light, so even with the difference in refractive index between the silica and the air, clarity is maintained.

I'm not sure if this is the start of a trend that we will see more of, but it might very well be since transparency is generally considered "good" and increase visibility (and not just in science as transparency in government and financial institutions are both highly desired). A rheologist that I knew from an earlier portion of my career had replaced the covers on the twin towers of his Rheometrics RDA rheometer with acrylic so that all the electronics inside could be visible. It was quite a bit more interesting to look at than the normal beige - I'm just not sure that any real purpose was served.

Still Moving

2011-12-07T09:33:00.001-06:00

Posting has been slow, especially compared to the number of boxes I've been filling this week.

For those who missed the post last week, Aspen Research is on the move to a new, bigger-and-better location. But is all comes at a price. Mr. Client, we won't be running your sample this week.

In the process, we've all learned a few things.

Nothing gets chemists to stop bench work and start packing like shutting down their hoods.
A hydraulic lift table
is fabulous for sliding heavy lab equipment off the bench and then onto a pallet. Don't move without one.
I need to go through all the papers I've collected over the years and toss some of them. At the same time, some of them definitely need to be reread (and blogged about).
Everybody is all wrong about zombies. When they are wandering about, they are NOT looking for "Brains!", but internet connectivity. When we lose ours on Friday PM, you're going to see 42 lost people wandering around with their computers looking for "Internets!" If we were to become zombies, why would you expect us to behave any different?

After a week of this effort, we are making headway. Stuff is disappearing from the staging areas and into trucks faster than it is being replaced. People are starting to straddle between the two buildings. Off we go.

The Teacher Can Make All the Difference

2011-12-02T07:00:00.000-06:00

Quite a few years ago, I worked for a large corporation that had a high school "internship" program (for lack of a better word). The program was limited to students from the larger core city, not the suburbs (so it was a community outreach program as well). The program consisted of a weekly set of 2-hour "lectures" from January until June, followed by employment during the summer in various labs around the company. The lectures were taught by company employees about a wide range of technical subjects. I gave two talks about polymers and enjoyed it tremendously as it was a great bunch of kids to be working with.

I realized before starting this effort however, that I had to make it interesting, which meant only enough math and theory to clarify concepts, and lots and lots of time in the lab playing with all the craziest non-Newtonian materials I could devise. I had examples of rheopexy (cornstarch/water), the Wissenberg effect (rod climbing), Slime (PVOH/borax/water), Pluronic gels that thickened up heating and liquified upon cooling...Their homework assignment between the two lectures was to find non-Newtonian materials in their homes which they did reasonably well at [*]. And knowing that if I'm not excited about the subject, they wouldn't be, I put as much energy into the talks as possible, portraying how exciting polymer science can be.

The reviews came back at the end of the semester and my jaw hit the floor. The students thought I had done a great job, in fact they consistently ranked me as the second best teacher. It's just that "the cement guy" was better! CEMENT?!?! I never got a chance to talk to that guy, but if he could make cement even more exciting than polymers, I tip my hat to him, and say "the teach can make all the difference".

[*] My favorite discussion item for a non-Newtonian material at home is toothpaste - a Bingham fluid, but it has to be discussed "properly". To do so, I would set the scene by getting them to think about being in the bathroom. I would then slowly lower myself into an armless chair, pull out some reading material and talk about a material that you need to apply a certain minimal stress to get it moving. Not enough stress and it would pop back in, but with enough stress, things would move along smoothly. It wouldn't take too long before you would see some smiles and smirks and they finally realized what I was talking about - toothpaste! (What were you thinking?)

Moving - A Lab's Ultimate Nightmare?

2011-12-01T06:30:00.000-06:00

The calendar now says December, a month we have long dreaded here at Aspen Research. Normally we get the year end rush of people trying to get things done before the end of the year while they still have the money in the budget, but this year is entirely different. We are moving across town to a new location.

I've never moved a lab before. When I worked for a megacorporation, my wife's division had to move their lab to another building, but that was move from one lab building to another lab building. Things like hoods and benches were left behind and were already in place at the new location. This is entirely different. We are taking it ALL with us: extruders (and all of their auxillary equipment), benches, hoods, sinks... pretty much everything except for the lingering aromas of the many thiols I work with.

Why the move? Expansion. The new building is twice the size of this one and we will need it all very quickly.

In some ways, the sale of Aspen Research from Andersen Corporation back in February was a practice run, even if very little physically moved. As part of the sale, we needed to divorce ourselves from all the shared IT resources (not just internet and computers, but accounting, HR...), so we've been there and done that fairly recently, and in this day and age, quickly and efficiently moving and reestablishing IT resources is everything. Fortunately email addresses don't change, cell phone numbers don't change and the desk number (which are changing) will be rolled over automatically for a year.

Hopefully Santa Clause will still find us in the new location. There is this capillary rheometer [*] that I really want and I've been a good boy all year...

[*] "...with a compass in the stock and a thing that tells time..." and no, I'm not going to shoot my eye out.

Nylon Offgassing Ethylene

2011-11-30T07:08:00.000-06:00

Polish researchers have published a letter in Biotechniques discussing ethylene emissions from nylon. Doesn't that strike you as odd?

This emission is important to the researchers and other people performing plant research as ethylene is well known as a plant hormone (and it is effective at the parts-per-billion level or less), so if you are sprouting seeds on a nylon membrane (as is commonly done) and the membrane is outgassing ethylene, then you potentially have a problem.

I'm stuck on trying to identify the source of the ethylene in the nylon however. Nylon, whether through ring-opening polymerization (as in nylon 6) or as copolymerized (as in nylon 6,6) is not made from ethylene, and the extrusion/pelletization of the nylon should heat the material enough to degas any ethylene that is there for whatever reason. The exact nature of the nylon is unknown - it is only identified as "Whatman, Nytran N, 0,45 µm". The Whatman webpage mentions a couple of items that deepen the mystery: the nylon has a positive charge, and that the membrane is cast. Given all this, I see three possible sources of the mysterious ethylene:

Does the process of charging the nylon introduce the ethylene?
Do the solvents used in the casting process contain any ethylene?
Lastly, I wonder if the source of the ethylene is something as simple as the membranes being slipped into a polyethylene bag as a primary package when they are shipped. The membrane could absorb ethylene outgassing from the bag.

Any other ideas?

A Polymer with Reversible CHEMICAL Crosslinks

2011-11-29T07:09:00.001-06:00

One bit of research (Science Magazine, subscription required) that had a lot of discussion (here and here) this past week or so has been the development of a "thermoset" plastic that can be heated and allowed to flow as a thermoplastic does.

I do think the research is interesting and should prove to be quite useful in the future, but what I really dislike is all the hype that these reflow characteristics are so unique and novel - they are not. Styrenic block copolymers and other thermoplastic elastomers show this behavior all the time - they are nondeformable materials at room temperature, but when you heat them up, they become liquids that can be shaped to any form you desire. The materials are made up of blocks of two different polymers along the same chain. At room temperature, the blocks phase separate and form physical crosslinks that prevent deformation. Upon heating, the physical crosslinks soften and allow the material to flow.

What is novel in the latest research is that the crosslinks are chemical, not physical. Heat reversibly breaks up the crosslinks, while cooling restores them. That's a neat trick that I've not seen before and is certainly worth the discussion. It's just that the thermomechanical behavior isn't novel.

Strawman Arguments

2011-11-28T07:46:00.000-06:00

Everyone knows that you shouldn't compare apples to oranges, but then why can some people compare two items that are even more dissimilar and publish it as innovative research? That's what happened over the weekend, when researchers from the University of Sheffield compared silkworm silk to high density polyethylene (HDPE) (subscription required)(here is a open access review), and Surprise! Surprise! found that the silkworm is more efficient at polymer processing.

What a dreadful comparison. Chemically the two materials are entirely different - silk is a multiphase polyamide while the HDPE is a polyolefin. Moreover, the two materials aren't processed at the same temperatures, and yet this allows the researchers to win a strawman argument by showing that the silkworm is more energy efficient since it doesn't need heat and/or high shear to produce orientation in the silk.

Why didn't they compare a natural polyamide to a synthetic polyamide? Synthetic polyamides can be made at room temperature:

and you don't even have to look closely at the the synthetic strand to see that volumetric production rate for the synthetic polymer is more greater than for a silkworm.

A further fault in the comparison that the researchers made was that the silk is solvent spun (from water) while the HDPE used in this example was not (even though HDPE can be gel spun at room temperature).

While the mechanical properties of silkworm silk are different (tougher) than those of synthetic nylon, not necessarily better. Depending on what your design requirements are, tougher may not be desired at all.

And lastly, while silk does have a unique set of properties that scientists cannot yet match in one material, keep in mind that the silkworm was been developing their materials for millions of years while synthetic polymers have only been in existence for less than a century.

Why the researchers chose to overlook all these facts is beyond me. Surely they can't be that desperate for a publication that that they need to stoop this low for it.

Vacation

2011-11-23T07:29:00.000-06:00

I'm out of the office for the rest of the week (thanks to the miracles of modern technology, this post was typed up last week and is only appearing today) enjoying time with family and a turkey (the kind you eat, not the type of person you avoid). Posting will resume again on Monday, November 28th.

The Big Picture on Transportation Fuels

2011-11-22T07:20:00.000-06:00

Materials Today has a nice short article (open access) about the world energy system. and transportation in particular. I would make it required reading for engineers, environmentalists, politicians, and voters [*]. The point of the article is that the world uses a tremendous amount of energy, and no matter how much you want to replace petroleum from that amount, viable options to replace that large amount of energy do not exist, at least at present.

How large is large? Well, from the get-go, the article asks you to think about energy in units of PJ (Petajoules, 10¹⁵ joules), and EJ (Exajoules, 10¹⁸ joules). The fact that these prefixes need to be explained because they are used so seldom indirectly indicates the magnitude of the problem. Also eye opening one of the equivalences they provide: a million tonnes of oil equivalent (Mtoe) is 41.9 PJ. The total primary energy supply last year was 514 EJ, so you can do the math. Simply put, we use tremendous amounts of oil, and while it will eventually run out, we'll be seeing plenty more of it the rest of our lives.

If you don't agree with that last statement, then read the rest of the article. The authors spend most of the article looking at the alternatives being used and proposed. None of them will come close to replacing what is needed. We can't grow our way out of this, or use bugs or algae on a large enough scale. The summary of the article is pretty clear cut and impossible to argue with:

"Transport fuels of the future will require numerous sources; there is no silver bullet."

[*] I'd also add political commentators and talk-show hosts, but does anybody here think it would do any good? People like that already know the answer; what's the question?

Throwing Away Books

2011-11-21T07:03:00.001-06:00

I admit that I have always had a very hard time throwing away books. I've always loved books as long as I can remember and working in the local public library in high school furthered that love. Undergraduate education and then graduate school led to the acquisition of more books that I still refer to on a regular basis. Considering how much Gutenberg press changed the world, and how governments have burned books in order to keep power, a book has always been too valuable to just trash, and so I've always found someone else to take the ones I have no longer wanted, with libraries being a favorite option. Strangely the librarians that I've known have either felt exactly as I have or been of the extreme opposite, being able to toss one without a second thought. I didn't have a problem with the library throwing it out, as the blood was on their hands and not mine.

I discovered this weekend however, that those feelings are beginning to change in me. I had no problem with tossing out a couple of old dictionaries and a thesaurus. I hadn't used them in years, relying instead on online dictionaries, and I can't imagine a library taking them for pretty much the same reason. (I'm keeping the Scrabble dictionary however, as that is an integral part of the game as much as the board and tiles are.) I still can't imagine tossing other books just yet, but suspect that that too will change in the future for me.

I've haven't yet picked up a Kindle/Nook/electronic book reader, but I know that at some point in the future, I will own electronic books. At the same time however, I don't think the attachment will be there. I anticipate being able to easy delete those kind of books, maybe because of the whole easy-come/easy-go syndrome, and as those books become more ubiquitous, I think it will lessen my attachment to paper books, much like internet dictionaries have done so with paper dictionaries. I find it strange that easy access to information in one format cheapens the information in other formats.

Marine Pollution

2011-11-18T08:03:00.000-06:00

As I've mentioned before, plastic garbage has no business being in the ocean (or forests, fields, etc. for that matter). With rare exceptions [1], humans are to blame for releasing plastic into the environment. The plastic did not get up and run into the ocean all on it's own. As much as I hate posing dichotomies [2], in this case there are basically just two approaches to "solving" or preventing the problem. One approach is to ban plastics or at least some plastics, such as the bag bans occurring around the world. The other approach is to change human behavior so that humans prevent the release of the plastic into the "environment". What is somewhat strange about this dichotomy is that the two sides are not equal in effort. Bag bans are in the news constantly, but little is being done to change human behavior.

You see this uneven dichotomy in a wide range of other "problems". Guns for example, have one side attempting to ban them while little is done by the other side to prevent their use in crime. Drinking and driving is also being ever increasingly criminalized without an equal increase in preventing it.

The only example that I can think of where the forces are reversed is with matches. Here in the US, we have had a decades-long, public-ad campaign featuring a cartoon bear (Smokey the Bear) who's tagline is "only you can prevent forest fires".

No one is actively trying to ban matches - the focus is entirely on changing human behavior to prevent fires.

The effectiveness of Smokey's campaign (he and his message have extremely high recognition in the general public), efforts to change human behavior can be successful. So why aren't we doing this with plastic bags and other forms of plastic pollution?

I bring this up as both the Plastic New blog and the SPI blog, In the Hopper have recently discussed the marine pollution conference that occurred in Dubai. While I commend their efforts and desire for success, unless the programs are on the scale of a Smokey the Bear campaign, they will likely be too little to change anything.

[1] A variety of natural disasters can unintentionally introduce plastics into the environment, but these events are small and infrequent.

[2] Just 2 options for solving a problem? Only if you are uncreative.

An All Plastic Road Bridge

2011-11-18T07:27:00.000-06:00

I've been wanting to write about Axion International for some time, ever since I saw a military tank driving across a plastic bridge that they made. And not just any plastic, but recycled plastic. That was back this summer if I recall correctly. But now Axion has announced that one of their bridges will be used on a public road here in the US. This may seem like a risky proposition, but as I already mentioned, the military has used these bridges as well as railroads, so automotive traffic should be a non-issue. The low maintenance issues will be a definite benefit in a northern state such as Maine (I'm assuming that they use salt on their roads in the wintertime as we do here in Minnesota).

The Axion International website http://www.axionintl.com./has multiple videos showing their bridges in action. Assuming that the product performs (no reason to be otherwise), the use of these bridges will only continue to grow.

A boat that is completely solar powered

2011-11-17T07:05:00.001-06:00

Monday's post was about yachting (albeit with LNG tankers), so keeping with the nautical theme isthe cover story of the November 2011 issue of High Performance Composites. The picture itself if captivating:

That's right, it's a solar powered boat, with solar power being it's exclusive means of propulsion. At 31 meters long, 15 meters wide (and over 500 m² of solar panels), it's not for your average owner, but still clearly illustrates the role that composites can play in lightweight, innovative design. The ship, christened Tûranor, "is circumnavigating the world with the message of sustainable ship power."

The irony of course, is that while the "power" (don't they really mean energy?) is "sustainable", none of the materials of construction are.

That's Teamwork

2011-11-16T06:40:00.001-06:00

I received my latest issue of the Journal of Rheology yesterday as was taken aback by the last article in it - here's a scan of the first page:

I don't know if I've ever seen 7 authors from 5 different institutions before for a run-of-the-mill paper before. Sure there are the blockbuster papers such as those of the human genome, and the eventual papers on the Higgs boson, but this is just a 22-page long rheology paper.

A Great New Sensor to Detect Food Spoilage - It'll Never Make It

2011-11-15T07:59:00.000-06:00

I spent a number of years at a past employment situation working on a product that most people think is a pretty good idea - a time-temperature indicator for perishable food. Simply put, it was a small label that would change color to indicate that the food had reached the end of its shelf life and should be disposed of. It was sensitive to both time and temperature, as both of these (and the interplay between the two) affect the quality of food - even properly refrigerated milk will eventually spoil [*]. Such a product is far better than the printed date codes that never change when a product is thermally abused.

While I do think that the product was a good idea, it's one of those products that will never see the light of day unless it is mandated by the government. Why? Well, follow the money.

Here in the US, groceries are a very low margin business, typically just a few percent. So even if a label costs just a few pennies, that will wipe out the profit margin of the grocer unless they raises their prices, and there is no way that one grocery store will do that if their rivals won't, especially on low end foods like milk and ground beef. Beyond that, food distribution in this country consists of the producer, a distributor, the grocer and the consumer. For a label such as this to be useful, everyone in the chain has to agree to participate in the game, otherwise no one can. While the largest grocer in the US (Walmart, yes, Walmart) may want the label, rest assured they will not pay for it and will be loathe to be stuck with the "shrinkage" that occurs if the label goes off in their stores. They will make sure to blame the expired label on the distributor or the producer or whoever else, and fights will quickly ensue.

The product that I helped develop underwent a gradual color change, which we thought was a good attribute. (Contrast the gradual color change with one that occurred suddenly: for any one in the food chain buying the product, it would just like playing Russian roulette). However, with the gradual color change, we knew that consumers would look through the products for better less-changed labels, much like they currently pick through product for better shelf-life dates.

Despite have very simple, robust technology that was inexpensive, (far better than any competitive products out there at the time or developed in the last 10 years since then), management could see that they product would never make it and so they killed the project.

I was reminded of all this when I saw this report late last week about an novel oxygen sensor that will tell when food, in this case, whole cuts of meat, should be tossed. While the physics and chemistry are different, the economics in the food industry are the same. Nobody will decide who will pay for the label and nobody will decide who will pay for the spoiled product. Sadly, I can state that this product is DOA.

[*] You are actually integrating k t_i exp(E_a/ R T_i), where k is Arrhenius equation prefactor, t_i is the ith temperature interval with corresponding temperature T_i, E_a is the activation energy and R is the gas constant. By the way, we did this integration using adhesive tape and sandpaper (Eat your heart out, MacGyver!)

An Extreme Connection between Fracking and America's Cup

2011-11-14T08:38:00.001-06:00

The connection between America's Cup (that race held at irregular intervals to determine whether the US's millionaire sailors are better than those from around the world) and fracking, the technique of injecting fluids under pressing into gas-containing formations of rock to release the gas trapped within, may be difficult to see at first, but stick with me, this is a story inlike anything you have seen that will have you laughing by the end. Unless you already know the connection, there is not way you can imagine what I will tell you here.

The use of fracking to produce petroleum gases is growing in the US and around the world. Polymer producers - those making polyethylene(s) in particular - are quite excited about this as a good amount of ethane is mixed in with the methane. Being too high in fuel content to burn, the ethane is separated from the methane and sold to be polymerized (after conversion to ethylene of course). One of the larger formations in the US being fracked right now is the Marcellus shale formation which underlies large swaths of Pennsylvania, New York and West Virginia.

While plants are being built in the area to polymerize the ethylene made from the ethane, Sunoco wants to pipe the ethane through Philadelphia to the port, put in on Liquid Natural Gas tankers and float them to the Gulf coast for processing. But in order for this to occur, an Act of Congress was required. Not because of the risks associated with this option, but because of...well, I'll let the article directly explain the hoops that need to be thread and the cockamamie option that the US Congress took to solve the problem:

"... the LNG vessels that hold the supercooled liquid fuel in large spherical tanks now sail under foreign flags. A law known as the Jones Act requires that all ships carrying cargo between U.S. ports must be built, owned, crewed, and maintained by Americans. The ships Sunoco would charter are American owned and were built in the late 1970s in Massachusetts. But they were reflagged in the Marshall Islands in the 1990s. It requires an act of Congress to reflag the vessels as American, which would require them to use U.S. crews. [Senator] Toomey and Rep. Pat Meehan (R., Pa.) devised a novel way to reflag the tankers by including them in the America's Cup Act of 2011, special legislation that would permit 60 foreign vessels to participate in the America's Cup yacht race. The law is expected to receive final Senate approval and the president's signature this week, before the America's Cup race is scheduled to start Saturday in San Diego."

LNG tankers attempting to qualify for America's Cup? Can we really look forward to a ship such as this:

lining up against a ship such as this:

That would make for some lively TV coverage, wouldn't it? ("Oh no Jim, it looks like the catamaran got to close to the props of the tanker and that yacht is now flotsam for the fishes...")

Quite a connection, huh?

Flashing Labels

2011-11-11T07:35:00.001-06:00

A long time ago in a state far, far away, I worked on making polypropylene (PP) films, some of which went into making labelstock. One of the films we made was white, the white coming from white minerals that were mixed in with the PP. It actually was a three layer composite with a calcium carbonate in the middle layer and TiO₂ in the outer layers. (TiO₂ is a more effective whitener than the CaCO₃, but it costs more. The three layer approach let us economically make a very white label.) One problem that we would occasionally have in the product were "shiners", small little patches that were shiny, almost iridescent. If I still recall correctly, they were the result of moisture in the base resin. By themselves, I actually thought they were not bad looking - my wife suggested that we offer the material up as a winter or Christmas product since they could pass as snowflakes of a sort. I would have proposed that to the company if only we could control their production but unfortunately, we could not.

Any chance of going back to recreate that product is now dead, as PragmatIC Printing (yes, the company spells "pragmatic" just that way) has announced that they have incorporated printed ICs with light displays into BOPP (biaxially oriented PP) labels. (Sorry, there doesn't seem to be any video yet showing the prototypes.)

Flashing labels vs. labels with "shiners" on their surface? Given the Powerpoint presentations that ~~I've~~ we've all seen marketers put together incorporating every bit of animation and zing that Microsoft can imagine, I've got to believe the marketers will pick the former.

Birefringence in Polycarbonate

2011-11-11T06:50:00.001-06:00

Highline Polycarbonate has the second of series about the internal optical properties of polycarbonate - birefringence, the stress-optic law, etc. The articles are very well written and I would recommend them to anyone working with glassy polymers, PC or otherwise.

The first article (you probably should read them in order) is is here while the second one is here. A third article is promised in the near future as well.

Give me a photon! No, you better make it 2!

2011-11-10T09:01:00.001-06:00

It's pretty well known that polymers (and all organic materials for that matter) can fall apart when they are exposed to UV light. The energy of the photons (E = hc/λ) is in the same order of magnitude of the energy needed to break the chemical bonds [1] and so the end result is not too surprising. In some rarer cases, visible light can do the job too on certain bonds, although this happens only with small organic molecules, not full-length polymers. Since visible light has less energy than UV, the bonds being broken are inherently weaker. Trying to build a polymer with such bonds in the backbone would be especially problematic, since with the high number of bonds in a polymer, the odds of one of them breaking (and thereby degrading the molecular weight of the polymer and corresponding mechanical properties) would be pretty high.

So the report of a polymer completely degrading upon exposure to near-IR light (with their even lower energy photons) can be an eye opener [2], unless you know what it really occurring behind the scenes. The trick is not for the bond to absorb one photon, but to simultaneously [3] absorb two of the photons. The total absorbed energy is now 2hc/λ, so if λ = 470 nm (barely in the near-IR), then the energy absorbed in the bond is the equivalent of a single 470/2 = 235 nm photon, and that's plenty energetic to degrade most organic bonds.

The challenge preventing widespread adoption of this technique is that the near-IR light of each individual beam is not strongly absorbed on its path thought the material, so the odds of having the two photons absorbed in the needed time interval is also unfortunately small. But with the challenge also arrives a tremendous processing advantage: with two-photon absorption, the degradation reactions can be localized to very small spaces if the two photon beams arrive at right angles to each other. Furthermore, this local reaction site can be deep within the material. The degradation occurs only at the intersection of the beams and not along their individual paths.

The advantages of using this approach(subscription required) in therapeutic situations should be pretty obvious, even if the specifics are quite worked out just yet.

[1] For instance, an aliphatic C-C bond has a bond energy of 347 kJ/mol, which corresponds to light of 344 nm, and a C-H bond has a bond energy of 414 kJ/mol, corresponding to light of 288 nm.
[2] A scientific blog that forgets to mention that this is two-photon absorption?
[3] "Simultaneously" is too restrictive of a term - the absorptions need to occur within a very small time interval that depends on a number of variables in the experiment.

Nigeria, a Net Exporter of Plastics

2011-11-09T09:05:00.000-06:00

Plastemart is reporting that Nigeria has now become a net exporter of plastics. [*] This is no small feat as the country has the 31st largest economy in the world, and this is all just a result of the oil production. Petroleum contributes only 14% of the production in the country. More than anything, it represents the internal development of facilities to manufacture the plastic pellets and capture the added value in the product, rather than just selling the petroleum as a raw material.

All facts on the Nigerian economy were taken from Wikipedia

[*] It is not explicit in the article, but the focus appears to be about the resin pellets, as opposed to products made of plastic. If final products, packaging materials, adhesives and whatever else is made of plastic were considered in the trade balance, I have to believe that the net balance would be in the opposite direction.

Double Duty Additive for PVC

2011-11-08T07:26:00.001-06:00

Most polymers are compounded with a small amount of functional additives to help their performance in certain, critical manners, such as antioxidants, UV absorbers, slip agents, antimicrobials, antifungals, etc, These are added in small amounts (generally less than 2 wt%) for two reasons. First, they are much more expensive than the base compounds, and secondly, they generally work so effectively that that only small amounts are needed. This two characteristics still don't prevent some people from pushing this too far and not adding enough of the additives (usually as a cost reduction effort [*] but that is another issue for another day.

Polyvinyl chloride (PVC) is nothing without additives, albeit the most common additives for PVC are plasticizers which added in much higher levels than noted above. But the other additives noted above are also commonly incorporated in PVC as needed. There is a new report out yesterday (subscription require) that some newly developed additives, amide derivatives of ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid, that were originally designed as antimicrobials, but were also found to have UV absoprtion properties as well. That is big. You now have one additive that can do the job of two. While UV absorbers are typically added at higher levels than antimicrobials, the use of this additive will decrease the amount of proper UV absorber that is needed, an approach that every processor can get behind.

[*] ...and even more usually combined with obtaining these additives from a low cost producer whose quality is also low

Termites Chewing On Plastic

2011-11-07T09:30:00.002-06:00

I was quite surprised to learn this morning that termites can actually eat plastic, or maybe more properly, they can chew through it. Not just plastic film, but even polyethylene pipe. Why the termites decided going through the pipe rather than around the pipe is something that only a termite would understand (although those with a more comedic sense could start a whole string of "why did the termite go through the pipe" [*] jokes).

I live in a climate too far north to be ever have been concerned about termites (for my southern brother, well that is a different story as termite protection of his house is a way of life), so I only know the basics - that they can be destructive to wood. I can only imagine the surprise when people first started finding termites chewing through plastic pipes.

So in quick attempt to turn this lemon into lemonade, I ask the following questions:

Could this "biotechnology" be used breakdown waste plastics? i.e., a low energy grinder.
Extending on this, could entomologists get varietals to only chew on certain plastics, thereby allowing for effective separation of mixed plastics. Start with a big pile of plastic over a screen, let the PET chewers in first and they breakdown all the PET which then falls through the mesh, then unleash the LDPE chewers...(Isn't it fun to tell other professionals what we think they should easily be able to accomplish?)
Can termites be used as a hardness tester for plastics? Or maybe an abrasion resistance test depending exactly on how the teeth of the critters interacts with the plastic?

[*] He just want to go with the flow. (Thank you very folks, you've been a wonderful audience I'll be in town all week be sure to try the brisket and tip your servers...)

First,you make up the data, then...

2011-11-02T08:24:00.000-05:00

Isis the Scientist had a post yesterday (with lots of discussion) about in what order the various sections of a lab report should be written. Whatever. People, do what you want, just make sure that the final product is good. To me, the most important part of writing a report occurs before you start experimenting: it's the the time when you make up the data.

Yes, make up the data. Believe it or not, this was something I learned to do as an undergraduate engineering student, and the professors actually encouraged it.

Hear me out. The junior level chemical engineering lab was a royal pain in the posterior. It was long, it involved larger pieces of equipment than any of us had ever worked with and we were given little guidance as to how to run it. Each week, the team would receive a memo written out as if it were something that your supervisor (in industry) might send your way - the overall objective was clear, but there was little guidance as to how to proceed. Days before the lab started, we had to look at the equipment, imagine how it would work and also figure out which equations we would use to analyze the data. We would then have to make a proposal to the prof as to what our plan was and what data we would collect.

Now while we all (thought we) understood the equations being used, the biggest challenge we faced was making sure that we collected all the data that we needed when we did finally got into the lab and used the equipment. If we didn't get the data at that time, we were up the proverbial tributary without a proper means of forward locomotion. We would not be given a chance to back into the lab and rerun anything (much like industrial situations, by the way). So the best way to avoid the problem was to make up some data before we got into the lab, and run some calculations with it to make sure that we had all that we needed.

This actually provided us with positive two outcomes: first, we could verify that we were going to be collecting all the data that we needed, and second, by making what we thought were realistic guesses for the variables (as opposed to random numbers), we were training ourselves to anticipate appropriate values. If the actual values were significantly different, then we were able to learn why out hunches were so far off.

It's still an approach that I use (mentally) to this day - think first about the all the data that you will need and how you will get it. You may not get the results you want, but you will be sure that you can stand by what you do have.

Just make sure that you don't confuse your made up numbers with the real data.

Fringed Micelles and Photoconductivity

2011-11-01T09:44:00.001-05:00

I generally do believe that a picture is worth a thousand words (or more), but sometimes, they can be misleading. Here's a perfect example of an image in a recent research paper (open access).

What you see is an iconic model of semicrystalline polymers – the famous "fringed micelles" - so upon seeing it, I immediately thought that I knew what the research was about: the crystallization and possibly the mechanical properties of semicrystalline polymers. I was wrong. But first some background: The image is made up of two principal components, the crystalline fringed micelles (the portions with multiple straight parallel lines) and the amorphous regions (the portions with the squiggly lines). Whole books have been written about how the volume proportions of each region can be influenced by molecular weight, thermal conditions, additives (particularly nucleating agents), externals stresses or strains, solvents, etc. Yet other books have been written about how the details of the structure (tie molecules in particular, stands that run out of one micelle and into another) influence mechanical strength, and I won't go into those details today. These subjects are quite broad and still actively researched, so it wasn't out of place for me to prejudge what the research was about.

But in fact the research was actually looking at the mechanisms of photo-conductivity in poly(3-hexylthiophene), (P3HT) which beside being conductive, is also a semicrystalline polymer.

(Notice the alternating pattern of single/double bonds? That conjugation is why the material conducts.)

The researcher found that the existence of the crystalline and amorphous regions in the solid is critical to conductivity. The absorbed photons created a charge separation, with the electron being trapped near the crystalline/amorphous interface and the hole being in the crystalline phase. Lower molecular weight materials, being mostly crystalline, do not have both of these regions and therefore lower electrical activity. The results were able to explain a wide range of conductivity results that had been previously reported without explanation.

So now the fringed micelle model is not only able to explain crystallization in polymers and mechanical properties, but also photoconductive behavior. Triple duty for a model – that's some heavy lifting. But this also suggests that the photoconductive properties of a given grade of P3HT can be adjusted by altering the crystallinity, albeit at the same time that the mechanical properties are being adjusted. I can see some contradictory optimizations in the future for some engineers. After all, what are the odds that the ideal crystallization scheme for the mechanical properties is identical to that for the photoconductivity?

Hat tip to Matteo Cavalleri (twitter @ physicsteo) for the lead.

Obadiah G. Reid, Jennifer A. Nekuda Malik, Gianluca Latini, Smita Dayal1, Nikos Kopidakis, Carlos Silva, Natalie Stingelin, & Garry Rumbles (2011). The influence of solid-state microstructure on the origin and yield of long-lived photogenerated charge in neat semiconducting polymers Journal of Polymer Science Part B: Polymer Physics : DOI: 10.1002/polb.22379

10 Halloween Scares for Polymer People

2011-10-31T07:34:00.001-05:00

Let's hope that nobody sees these frightful creatures around their business today:

ISO Auditors
FDA Auditors!
EPA Auditors!!
Tax Auditors!!!
Your resin supplier with their latest price monthly increase
Environmentalists telling you that they are gathering a petition to put you out of business
The manufacturing director telling you about the mishap over the weekend that bent the screw shafts and that replacement parts have a 4 week lead
The research director telling you about the mishap in the lab over the weekend, which led to the sprinklers going off which led to...
The sales director telling you that your largest client is going to 90 days net, and not because they want to, but because the bankruptcy court ordered it
The government with a $500 million loan because they believe your company is something the country needs to invest in

Stephan King has nothing over this list.

John's Tricks for Free Access of the Literature

2011-10-24T05:55:00.002-05:00

People in academic settings usually have enviable access to the scientific literature, but upon leaving the island, access to it can quickly diminish [*]. Large corporations will have good access, but for those of us in medium or small corporations, access is often limited. Subscriptions can be very high, and paying ~ $35 a pop for an article that may or may not be what you are looking for can also be an expensive proposition.

With that in mind, this post is an unorganized list of tricks that I have to try and find free copies of articles that you would otherwise have to pay for. This situation is dynamic and if I were to make the list again in another year, it would be different. Just keep in mind that there are no guarantees that any of these will work, but since you're not pay anything for this advice, that comes with the territory.

Many journal will provide open access within certain time windows. The most common approach is that access is free after 6 months. Examples of this include:
- Science magazine, but only the research articles, not reviews, new stories, brevia, etc.
- Proceedings of the National Academy of Sciences
In the other direction, the Institute of Physics makes all their articles available for free for the first 30 days after online publication. This usually means you if you see something in anyway related to your work, grab it right away as it will cost you later.

Many publishers will make the January issue of the current publishing year open access. This is true for the American Chemical Society and Elsevier.

Sign up with the journals of interest to receive their emails, such as their Tables of Contents. Every once in a while, they will alert you to free articles as well.

In a similar vein, other journals have blogs supporting them. A good example of this is the Royal Society of Chemistry, which has individual blogs for each of their journals. If a research article is discussed in their blogs, they will usually make it available for about a month or so.

A Google Scholar search for an article (I find using a good portion of the title works best) may show alternate mirror sites that have the article available. Look for hits that have a [pdf] annotation.

More and more professors are providing free copies to their published research via their own websites

Along these same lines, you can always contact the professors directly and see if they can supply you a copy of the article. This is the least desirable route as you may not get a quick response (or any response).

So that's what I do right now. It's not a perfect situation, but I have impressed many people here at work with my ability to scrounge up a free article at times. Sometimes however, you just have to breakdown and pay for the article. While I am all in favor of "open access", I have come to recognize that publishers do provide a valuable service that needs to be compensated, so if we ever do get to universal open access, the costs of it will be born some else than directly by the readers (as it currently is). If anyone wants to add to this list, feel free to post their tricks in the comments box (or you can email me personally at john dot spevacek at aspenresearch dot com). I will likely also set this up a permanent reference page too so that this doesn't disappear deep in the archives. [*] I recently was involved in an online discussion about this subject. The prof on the other side was arguing that students don't need to learn as many facts as they used to since they can access the information online. I hope nobody takes this advice - just wait until his students get into industry and try playing that game. If you are a student right now, consider yourself forewarned - his advice is unacceptable.

Those Chemicals Really Aren't That Expensive

2011-10-21T07:16:00.000-05:00

I mentioned the other day the high price of a polymer that I was trying to order lab quantities of. We've all experienced this some degree, and my point was not to pick on any one supplier, or even question why their prices are so high. I blindly accept that there are good reasons for it, or someone else would set up shop, undercut their prices and win big (Why yes, I do believe in efficient market theory! Why do you ask?)

My supervisors on the other hand, assume that the prices that I am initially charged indicate that the chemicals that I am working with are too expensive to work with in the long run and that I should be working with something else that is cheaper. The best argument I have found to set them right is this: look at the same catalog for a commodity chemical such as isopropyl alcohol (IPA) or polyethylene, and see how much that is marked up. Depending on the exact catalog and purity, a liter of IPA goes for $30 or more, even though I can go drive 2 minutes down the street to the K-Mart and buy the equivalent for a couple of bucks. So if the chemical I am ordering is going for $60 bucks a liter, that says to me that in bulk it will be about $4 a liter. When I put these numbers in front of my supervisor, suddenly all the talk of expensive chemicals goes away and I can proceed in peace.

The Inventors of Kraton...

2011-10-20T08:57:00.000-05:00

are Geoffrey Holden and Ralph Milkovich. The answer was supplied by Frank Van Haste on Twitter. A quick Google search confirms this, but raises more questions. If seems like the original patent (US 3, 265,765) was filed on January 29, 1962, and yet the Belpre plant was built in 1961. [*] So was the plant originally built for other products that weren't as successful as Kraton? Or maybe there is another scenario: At that time, the US had a 1-year grace period between when a product was made public and when you filed for the patent. Did Shell wait until the last possible minute to file? (I find this implausible). Fortunately, these questions certainly don't bother me near as much as who the inventors were.

[*] That explains why I couldn't find the inventors myself, as I only looked at patents that were filed in the 50's.

Who Invented Kraton?

2011-10-20T06:55:00.000-05:00

I saw in a trade journal that Kraton is celebrating it's 50th anniversary. Actually, it was the 50th anniversary of the Belpre Ohio plant where the stryeneic block copolymer is made. There are many variations of Kraton, but they all fall under the general umbrella of being tri-block copolymers with styreneic endblocks and a rubbery midblock. (If I remember correctly, half the styrene blocks are made first (anionic polymerization), then half the midblock is attached, and then midblcok portion is capped by a coupling agent. The coupling agent then brings to two halves of the polymer together to create the triblock product.) When heated to 100 ^oC or more, the endblocks soften and flow, but upon cooling they phase separate to form styreneic blobs in a rubbery matrix. Since the rubber is physically crosslinked, not chemically, the material can be processed with standard equipment and will reflow repeated, unlike vulcanized rubbers or other crosslinked rubbers. The rubber is used as the base for an immense number of materials - box sealing tapes, diaper tapes, footwear, as an additive to asphalt...

So the question occurred to me: who invented Kraton? There are lots of polymers where I can name the inventors: Carouthers invented nylon, Ziegler-Natta "invented" HDPE (or at least the catalyst that made it possible), Stephanie Kwolek invented Kevlar, Roy Plunkett invented Teflon,... So how come Shell has kept the inventors names under warps? I tried looking for relevant patents from the 1950's and 60's but didn't find anything that said to me: "Kraton!"

Any old Shell Chemical guys that can answer this? Considering that billions have been made from this material, someone should have had a pretty big reputation around the company.

It costs HOW MUCH?!?

2011-10-19T08:09:00.001-05:00

We've been looking lately at polymers that have acidic products after hydrolysis. Polyesters are the natural choice, with aliphatic polyesters (such as polylactic acid (PLA)) being the preferred choice (as opposed to semi-aromatic polyesters like polyethylene terephthalate (PET), polyethylene naphthalate (PEN)…).

Polylactic acid (PLA) is often called polylactide, which is perhaps a more technically correct name. In the polymerization of lactic acid, water is produced as a byproduct and it is difficult to reach high molecular weights with the water hanging around the reactor. Instead, the lactic acid is first dimerized to form a lactide – six member ring (and water).

The water is now easily separated from the lactide, and the lactide can then undergo a ring opening polymerization to form polylactic acid or again, the more technically correct name of polylactide [1], without creating any water.

If you study the illustrations above, you can see that this two-step polymerization can be performed with all α-hydroxy acids. Glycolic acid is a shorter α-hydroxy acid that forms glycolides that then are polymerized to polyglycolic acid (PGA). I thought PGA would be another good candidate for our screening tests but was floored by the price. One source has 10 g for $450! [2] [3].

Now I am well aware that PGA, and various PLA-PGA copolymers are commonly used for medical fasteners (sutures, staples…) and that those materials will be horribly expensive, but this particular application is worlds away from any medical usage. I'm just looking for some cheap industrial grade and am not finding it.

[1] If we are going to insist that all (additive) polymers are going to be named on their starting materials, than we better get rid of polyvinyl alcohol – it will now be called hydrolyzed polyvinyl acetate – polyvinyl butyrate – it will now be called butyrated polyvinyl acetate – and

[2] You know you looking at an expensive material when the material prices start with 1 gram quantities.

[3] The same source has HDPE for $37 a kilo, about a 16x markup over bulk commodity pricing. That "initial" markup is not what I am complaining about. I expect to be paying that for small lab quantities.

Slightly Toasty Polymers

2011-10-18T08:15:00.000-05:00

Thermal degradation of polymers, if carried out far enough. is pretty straight forward – all the carbon is oxidized to CO2, the hydrogens are oxidized to H2O. As for the heteroatoms, oxygen is already mentioned, and nitrogen will go to NOx.

The more interesting results occur when the material is only partially degraded. I ran across a research highlight discussing the burnout of ethylene vinyl acetate (EVA) copolymer in powder metal molding. In powder metal molding, the metal powder is mixed with a polymer emulsion, molded and baked so that the polymer burns and the metal particle melt and flow together. Keeping the shape is critical during the baking step and the research found that certain polymers are better than others in this regards. The research looked at what specifically was occurring to the polymer during the burnout and found that the acetyl groups hanging off the polymer backbone broke off and (probably by abstracting an adjacent hydrogen atom) became acetic acid. [1] The result is a double bond forming along the backbone – what the authors call an ethylene acetylene copolymer. [2]

I was not aware of this chemistry prior to reading the writeup, but it actually isn't that new. Research has already been published on using the partial thermal degradation of as a means of preparing polyacetylene.

Given that the unsaturated polymer would be inherently stiffer than a saturated polymer (the geometric options around a double bond are far less than a single bond), it is not surprising that the partially finished metal objects are benefitting from this degradation product.
Lastly, lest you think that all substituted vinyl polymers degrade in this fashion, polyacrylonitrile follows a totally different route, one that is used to create carbon fiber (albeit, this is done in an inert atmosphere).

[1] Isn't this strange? Most polymer chemists are familiar with acetic acid forming during a polymerization step (of silicones most commonly), and not as a degradation product.
[2] A similar polymer forms when PVC partially degrades – HCl comes off leaving double bonds along the backbone. If there are enough double bonds that form alternating with single bonds, the resulting conjugation absorbs visible and UV light (depending on the conjugation length). Under the right conditions, the longer visible wavelengths are removed leaving only the shorter, redder ones. If the PVC is already white (such as is used in windows), you can end up with pink windows! (And unhappy customers!)

How to (NOT!) Determine PVC Rheology

2011-10-17T08:51:00.001-05:00

We all know that the internet is filled with lots of bad information. A good example is this page entitled "How to Determine PVC Rheology". The strangest part of this is that this was published on "ehow.com", a site that is normally gives advice for general consumers (gardening tips, financial advice,...). Why anyone on the site would be interested in PVC rheology is beyond me.

Overlooking all this, the advice given is still awful. You can tell that there is a trainwreck coming anytime an article starts out with false compositional breakdowns of a material such as this:

"Polyvinyl chloride (PVC) is a synthetic thermoplastic resin made of 57 percent chlorine from industrial salt and 43 percent carbon in the form of ethylene from oil and gas sources.

First off, PVC is made from vinyl chloride monomer (VCM), which is what in fact is made from chlorine and ethylene. You don't just dump NaCl and oil/gas (or even ethylene) in a reactor, start it up and voila! - out comes PVC.

Unfortunately, the article has not yet bottomed out.

"Once formed, PVC can be resoftened by heating, with melting occurring at approximately 180 degrees Fahrenheit.

180 ^oF??? Only if it is greatly plasticized. The melting temperature of PVC is all over the map, probably more than any other plastic, and depends greatly on the formulation. 200 ^oC is not out of the question in some cases. But wait, there's still more:

" To properly manufacture PVC products, manufacturers study its flow properties when melted to learn how to successfully pour it into injection-molding machines."

Pouring molten PVC into an injection molding machine? Certainly the rheology of the pellets that are normally used to feed an injection molding machine could be what the author is referring to, but once you read the next sentence, you find out that that is not what was meant.

" Rheology is the study of how matter flows. So when you determine the rheology of PVC, you determine how it flows when melted."

This is only half true as the rheology of non-molten materials are also studied too.

At long last, the article then finally gets to the information on how to use make a measurement using a torque rheometer. The details are so insufficient that no one can possibly run it correctly even if they have access to the instrument. The final kicker is written in the "Tips and Warning" section:

"There are three typoes [sic] of rheometers: capillary, parallel plate and torque rheometers. Torque rheometers are the rheometer of choice when determining the flow proerties [sic] of polymers."

All of this is wrong - the types of rheometers are endless, and a torque rheometer would be the rheometer of choice in only a few situations, (such as when a test specifically calls it out, or if the operators are not trained or skilled in other techniques or...).

If this isn't enough of a laugh to start your morning, then check out the article that is listed in the "Related Articles and Videos" heading: "How to Use a UV Light to Evaluate PVC Rigidity" I kid you not! Throw away your tensile testing machine - all you need is a UV light!

Reshoring

2011-10-11T09:01:00.000-05:00

Reshoring is a term that isn't used too much here in the US, but it's popularity continues to grow. The terms means bringing back a manufacturing process that had been previously moved to another country in order to reduce manufacturing costs.

One of the most exciting projects I was ever involved with here at Aspen Research involved reshoring of an electronic device (sorry, I can't say who it was). The manufacturer had gone to China looking for lower costs, but the quality was just not acceptable and so we helped them return here. As part of our effort, we help redesign some of the equipment so that it was simpler to manufacture. This was a nice project as it provided good jobs here in the US.

The company was fairly small and owned by an individual, so making the decision was done without any pressure and external financial guidance. I don't think that major corporations have that freedom. It is simply too trendy right now to outsource plants and jobs and Wall Street won't take too kindly to the reverse efforts. I've also worked extensively with another client who initially went to China, but has since gone elsewhere (Viet Nam, Sri Lanka,...) looking for lower costs. All these changes mean more work for us in approving the new parts, so it isn't all bad, but still...

This all came back to me because a local company announced that the are reshoring some of their toothpick manufacturing.

Update: Dilbert's take on this issue.

The Philosophy of Space-Age Plastics

2011-10-04T10:17:00.001-05:00

I ran across the following poem at linebreak.org. I kinda like it, although I don't agree with all of it. There are some powerful images in it, nonetheless.

The Philosophy of Space-Age Plastics
By Andrew Kozma

My skin crinkles like cellophane. It disintegrates
in the sun. There is nowhere to run to, but I still run.
Every sunrise is a birth or a trick of the Earth’s rotation.
Every sunset is an opening into darkness or without alternative.
If I dreamt I set a field on fire, was it a field of plastic?
This green smoke settles on the skin and burns like ice, like stone.
In space no days pass, and so we never age. We mellow. We steep.
We grow stronger and stronger in our small cup of steel.
Then we die without warning, without goodbye, as nature intended.
As nature intended, we fall to the earth in flames, heaven-pushed
by jealous gods and wreathed in the glory of satellites. They expected
us to die, but we became our own saints. They gave us fire,
and from fire everything depended. O immortal plastic!
Here is a drought-starved town. Here is a dry field. Here is a match.

Rheology Analogies for Computer Networks

2011-10-03T09:09:00.003-05:00

I ran across this company who's name is based on a rheological concept: < ahref="http://thixotropy.net/index.html">"Thixotropic Networks".

From their homepage, there is a tab that describes thixotropy - the rheological concept - using the standard ketchup model. As for a computer network, they then make this analogy:

"At Thixotropic Networks, this describes our philosophy of computing services: stable, secure, and reliable, but still able to react to changing needs, and reconfigure themselves to solve the problem of today."

I can kinda see the connection. Personally, I think we all need a shear-thinning network, one where the more you use it, the faster it goes. This is the opposite approach taken by the ISP server for my home internet, which has a "speed boost" (or some such nonsense) where the initial downloads are fast but then start slowing down. Continuing the rheological analogies, this would be a shear-thickening network. The worst of course, would be a rheopectic network, one that becomes more and more rigid despite the need to "react to changing needs, and reconfigure themselves to solve the problem of today".

A thixotropic network? Not a bad idea.

The Chemical Reaction Carnival

2011-10-03T08:41:00.000-05:00

C & E News has published the complete listing of submitted reactions for the Chemical Reaction Carnival. Of the 22 submitted, only 3 were for creation of "large molecules" - specifically 2 were for polymers (the a lab-based synthesis using epoxidized limonene and CO₂, while the third was for preparation of dendrimers through a Michael addition.

Of the other reactions that were submitted, my favorite were the always popular and visually appealing Belousov-Zhabotinsky reaction (if you've never seen video of this reaction, you have to go there right now and do so), as well as the description of hydrocarbon combustion (the reaction isn't that exciting, but the authors description is worth the read).

The Research behind "The Perfect Polymer"

2011-09-30T09:04:00.001-05:00

Following up on the previous post, I did get a chance to read the paper and all I can say is "wow!". I'm going to review the paper first, and then will give some more grief to the PR blurb.

In a nutshell, the paper shows that the researchers looked at low density polyethylene (LDPE) and were able to predict flow behavior - linear, nonlinear and transient (!) - based on reaction conditions. That's plenty impressive. From the reaction conditions, they were able to predict the output material (molecular weight, molecular weight distribution, branching...) and then from that prediction, they were further able to predict the rheology. Again, that is plenty impressive. If you work with LDPE, this should be able to greatly aid in the development of new materials.

There are limitations to this work of course. First, it is limited to LDPE, although LDPE is nothing to laugh at. Given its extensive branching, modeling it is far more challenging than modelling it's linear cousin, high density polyethylene (HDPE), so I would expect similar results for HDPE sometime soon. Second, it is only predictions of the melt properties, not the properties of the final product after the polymer has cooled. Melt flow properties are plenty important, as the LDPE will have to be melted and forced to flow at some point in order to make useful products from it, but ultimately, people buy products based on the properties of the solid LDPE, not the molten LDPE.

Neither of these limitations that I just mentioned are criticisms of the work. It's great work. Papers that find universal truths for all of polymer science are very rare indeed, and nobody expects that.

But let me return to the original PR blurb. I am now even more flabbergasted by it. How they could prepare such a pile of trash is entirely beyond me. The authors never use the phase "the perfect polymer" (they do use the work "perfect" twice, but only in connection with polymer models: "Figure S1 shows an example of a time-dependent correlation map of relaxation time and priority (for LDPE 1). It also indicates the two extreme structures of perfect combs and perfect Cayley trees that constitute bounds for such maps." Emphasis added). Even within the realm of LDPE, they don't claim to have found the perfect LDPE, only that they now feel confident in making the noted predictions about it and short cutting the amount of experimentation. The reason we have so many grades of LDPE (Matweb lists 1176 grades) is that LDPE is used in so many different ways. A perfect LDPE? It doesn't exist. And the fact that the work doesn't make any predictions about the solid state properties means that experimentation is still needed.

I guess that means that, just like in the case of "The Ultimate Adhesive", we haven't reached the end of the road yet in polymer research. Our jobs are secure for a least another week (until next week's issue comes out). "Back to the lab people!"

Read, D., Auhl, D., Das, C., den Doelder, J., Kapnistos, M., Vittorias, I., & McLeish, T. (2011). Linking Models of Polymerization and Dynamics to Predict Branched Polymer Structure and Flow Science, 333 (6051), 1871-1874 DOI: 10.1126/science.1207060

Now that we have "Perfect Plastic", you don't need me

2011-09-30T06:58:00.000-05:00

I have read way too many PR blurbs that have categorically overhyped research discoveries, but this one is the ultimate. Truly, the ultimate as you can not ever hope to succeed it:

"Scientists and engineers create the ‘perfect plastic’ "

I am not joking about this. That is the actual title of the press release. And the idea is repeated in the second paragraph:"The breakthrough will allow experts to create the 'perfect plastic' with specific uses and properties by using a high-tech 'recipe book'. "

I really can't believe that a good university like Leeds let this out. We don't have "perfect metals", "perfect ceramics" or "perfect anything". All plastics have their strengths and weaknesses and there is not perfect plastic that can act as an adhesive and a high temperature aerospace material and a low temperature sealant and a structural material and be biodegradable in a landfill (but only once it knows that it is in the landfill) and costs next to nothing to buy and can be processed using an E-Z bake oven and...After all, that would be the perfect plastic in my mind and the mind of many others.

Sadly, I've run into this type of mindless naming before. A person came up with a good adhesive with some new properties and he proceeded to name it "the Ultimate Adhesive". Everyone's response was, "well let's close up shop boys, we've got the ultimate adhesive now. There's no need to work any further in this area." Sure enough, they quickly found a new name for the adhesive that wasn't quite so egotistical.

The Perfect Plastic. Hah!

Updates:

I discuss the actual research (it's actually pretty good) in this post.
While many sites ran with the "Perfect Plastic" headline, the Royal Society of Chemistry blog, Chemistry World didn't, and instead entitled it "Solving a tangled polymer problem", which is quite appropriate.

Cool video of the day

2011-09-29T07:55:00.000-05:00

If you have 2 minutes to spare in watching a video, check out the moving sculpture video over at the Plastics News blog. I'm pretty much speechless to see how creative someone can be with PVC tubing.

Presenting Rheology Data

2011-09-29T07:23:00.000-05:00

I posted a new page today that provides a very brief overview of dynamic mechanical analysis and time-temperature superposition. You can read it here if you are unfamiliar with rheology testing or want a review.

One of the most difficult aspects of rheology is that the data, particularly that generated by dynamic mechanical analysis, can be plotted in so manner different, but more or less equivalent manners.

As you saw from Monday's post, I prefer working the storage and loss moduli (G' and G" respectively) vs. frequency, although I most often supply clients with viscosity vs. frequency since that is a simpler concept to explain. Other rheologists have a built in bias towards working with compliances, J' and J", while others are hung up on tan δ. The strangest set of plots I ever saw was from a guy who always plotted G* vs. tan delta. The information is always the same, it's just that sometimes you have to work a little bit more to figure it out.

Part of the reason I like G' and G" is that the generic shape of these curves is well established. If something is varying from it, I can immediately pick up on it probe for further details. If you are working with tan δ, you only have the ratio of G"/G', and the only universally significant measure then is whether it is greater than, less than or equal to 1. You have a similar issue with G*, where it can hide many details that are otherwise noticeable.

In some ways, all these different plots are fun - you need to be on your toes in order to run the mental manipulations in your head to translate the data back to your preferred reference frame. I imagine that it really would be best to work within the other frameworks much like it is best to be thinking in a foreign language that you are speaking, rather than translating it all into your native tongue, preparing your response and then translating it back into the foreign language. I'm just not sure that this would happen anywhere in the rheology world as a given lab will have a given preferred format. It's only when you start working with others labs or researchers that you might start running into this issue, but those conversations don't happen all that often - you're much more likely to talk with fellow labmates than with people in other labs.

Hidden Problems in Heat Transfer

2011-09-28T08:38:00.001-05:00

I get a pretty large number of trade magazine, but one that I am always excited to see is "Electronics Cooling". As you would expect, the magazine is largely oriented towards heat transfer in electronics applications, a problem that I am rarely concerned with, but there is at least one article per issue that addresses heat transfer in general, and often in very enlightening ways. This month is a terrific example with the article "Does Your Correlation Have an Imposed Slope?".

This article (combined with the editorial at the front of the issue really take engineers to task for relying excessively on those darling dimensionless numbers. For those not familiar with dimensionless numbers, these are grouping of variables that are dimensionless. The most commonly used one is the Reynold number which is ρVL/μ, where ρ is the density of the fluid, V is the velocity of the fluid, L is an appropriate length from the test setup and μ is the viscosity of the fluid. When running fluid mechanics test, you don't need to explore the impact of all these variables over their full ranges, you only need to explore the Reynolds number of its full range and your covered for all situations. Quite a time saver, eh? You can see why engineers love them so much.

The dimensionless numbers in heat transfer are numerous and I won't get into any of them today. Their large number would be expected since there are 4 modes of heat transfer (conduction, forced convection, natural convection and radiation). As the article points out, the numbers by themselves are not a problem. The issue arises when multiple dimensionless numbers are used in heat transfer correlations, and when the same parameters are used in multiple numbers. One example given is when the Nusselt number, Nu, is correlated to the Rayleigh number, Ra, as

Nu = C Raⁿ

Looking at the parameters that make up these numbers, you find:

q L/(ΔT k) = C [g Βρc_pΔT L³ / k ν ]ⁿ

where ΔT (temperature difference), L (length) and k (thermal conductivity) are on both sides of the equation. This then leads to situations were random numbers can show correlations and the article gives a specific example of this.

Correlating dimensionless numbers with each other leads in other situations to an increase in the errors associated with the correlations, something that I remember well from my undergraduate days. I dug out my old heat transfer book and sure enough, I see correlations with 2, 3 or even 4 dimensionless numbers in the same equation. I am quite sure that my professor never warned us of these issues, despite their existence first being described back in 1963!

"Electronics Cooling" is free - you can get a subscription at the bottom of the first page I linked to above. If you work with heat transfer (and unless you work exclusively all day long with room temperature equipment and chemicals, you do work with heat transfer), do yourself a favor and get a subscription.

Plastic Rims for Cars

2011-09-27T06:43:00.000-05:00

A plastic wheel rim, made from BASF's Ultramid (nylon) with long glass fiber reinforcement:
While the engineers in the video make some backhanded references to the mass of the rims, the point that is missed is that the moment of inertia for these wheels versus metal is much lower, so that the car will accelerate faster. Let me explain with an example.

Back when I used to race bicycles, I and the people I trained with would have two sets of wheels for our bikes: a standard set that used clincher tires and another set that used sewups. You are most likely familiar with the former - the tire had a wire edge that you had to pry off with tire levels (let's be honest.. we all used screwdrivers didn't we?) in order to access the tube. Sewups tires are a completely different beast. The tire encloses the tube entirely and is sewn shut, hence the name. The really freaky part is that the tire is then glued into a small u-shaped depression on the rim.

The sewup tire and rim is much lighter than the clincher tire and rim combination, I can't recall the exact weight difference, but back in the late 80's, it probably was about 100 g difference in weight between the two. The absolute difference of 100 g is not much, given that my bike was about 8 kg, and I was about 77 kg, but all that mass loss was at the rims so that the moment of inertia difference was big. Come race day, we would switch out the clunky clinchers for the lightweight sewups. Oh what a difference! It was so much easier to accelerate, a key factor in a bicycle race. With clinchers, it always felt like we were "wearing a showercap". We used them for training as fixing a flat was much easier than cutting open the sewup, fixing the flat, sewing the tire back together and then finally gluing it back on the rim.

Back to the car rims, the new Ultramid rims are only a 12 kg weight reduction, but for the rotational weight in a car, it is huge. 100 g in a 85 kg bike + rider combination is 0.11%, and that was a very real difference in performance. 12 kg is 0.11% of 10,200 kg, far more than any car weighs, so the ratio of mass lost is even greater far a car than it was for the bike scenario I mentioned above.i.,e if the car weighs 1000 kg, then the mass reduction is 1.2%, a much greater improvement than in the bicycle example. Even though the mass difference isn't entirely located in the outer portion of the wheel, the difference in rotational inertia should still be quite noticeable. It would expect these rims to accelerate quite a bit faster, and that's big for improving the mileage of any car in stop-and-go traffic, gas electric or hybrid. Drag racing anyone?

PET Rheology

2011-09-26T07:02:00.000-05:00

Some serious rheology discussions today on dynamic mechanical analysis (DMA) in oscillatory shear, and to some degree, this will followup on some of the issues about the multiple requirements placed on a water bottle that I discussed a few weeks ago. Be forewarned. I ran these 'quick and dirty". PET picks up water, so measuring PET rheology is best performed on samples that are either dried or exposed to a known amount of moisture depending on what your needs are. I did neither - the PET came from recently used Fiji water bottles and a Gatorade bottle. Given this, I would assume that the bottles were at a constant and equal loading of water (although certainly not uniform throughout the walls of the bottle [1]), but I have no data to support this assumption. Both bottles had the "1" recycling code, so I took that as truth that the bottles were PET and without significant additives such as plasticizers. (Don't worry, if a customer was paying for this work, I wouldn't be working with these assumptions.)

In a nutshell, I ran temperature and frequency sweeps on the samples, then used time-temperature superposition (TTS) to generate the master curve for 280 ^oC (only a very small portion of it as you will see). The samples were from 2 different sizes of Fiji water (500 ml and 1 l) and also a 593 ml Gatorade bottle (G2, orange flavor if you want all the bloody details). The storage and loss moduli are shown below for the Gatorade bottle - the results for the Fiji water bottle were qualitatively similar.

Clearly this is the terminal zone. The loss modulus, G" ("liquid" component) dominates the storage modulus, G' ("solid" component). The other region of the modulus curve where there is a similar slope is the transition to glass, but there G' > G". The slope of G" is 1 which is also a good match to theory. You can also see that at the very low frequencies, the data is a little noisy.

The next plot is a little more interesting as it shows comparisons between the viscosity of the three bottles.

I went with viscosity curves for the comparison since there would only be three of them, rather than the 6 curves needed if I kept going with the G' and G" curves. The Fiji water bottles are pretty much the same, but the Gatorade bottle is much more viscous. The flatness of the curves also is what would be expected for terminal zone behavior and gives us the zero shear viscosity, although the Gatorade bottle is just beginning to show small signs of shear thinning.

I'm not surprised with these differences, as if you've touched both a Fiji water bottle and a Gatorade bottle, you know that the former has a softer feel and look to it than the Gatorade bottle does. PET is a funky polymer as it is semicrystalline, but the crystallization usually occurs as a result of orientation in the processing, and not just from temperature alone. That gives you two levers to play with in forming the bottle and creating a certain "look" with it. These characteristics are also something that the manufacturer is looking for and are additional requirements beyond the basic functionality of the bottle itself.

[1] Uniform amounts of water throughout the bottle's walls would mean that there is no concentration gradient in the bottle, meaning that there is no diffusion through the bottle and that is certainly not the case with PET.

[2] If you are not familiar with DMA, and TTS, you can get some the needed background at this site. Don't look at < a href="http://en.wikipedia.org/wiki/Time-temperature_superposition">the Wikipedia article - it's like most of their mathematics articles - great for a review but horrible for learning from. I've still yet to find a great site on the web for this stuff. Why can't someone explain what G' and G" are on the same page as TTS? The concepts flow (pun intended) togehter quite nicely.

Completely Off Topic Post for a Friday

2011-09-23T07:47:00.000-05:00

I've never cared for basketball much. To me it is simply: "go up the court and shoot a basket, go down the court and shoot a basket, go up the court and shoot a basket...". Any game where each team scores 40, 50 or 60 times a game is too much [*]. And the fact that it is intelligent play to intentionally foul the other player at the end of the game puts me over the top. If it is "smart" to break the rules, then something is seriously wrong and needs to be changed. But now I have an extra argument against basketball - it's all statistical. Researchers have found that scoring in a game can be modeled as a random walk. Two thoughts on that: Yea! it's a random walk, so I can reach and say that this is in some weak way ties into polymer and rheology (since polymer configurations are modeled with random walks) and two, this is exactly what I would expect when you score 40, 50 or 60 times a game (wait, I already said that). From the conclusions:

"Thus seen through the lens of the theoretical physicist, basketball is merely a random walk (albeit in continuous time and with some additional subtleties) so that all of the observable consequences of the game that are of interest to the quantitative scientist follow from this random-walk description."

The botom line: If I'm going to look at a random walk, then I'm going to look at some polymer modeling research instead.

[*] Soccer (football to non-US based readers) [**] is quite the opposite - not enough scoring. What I really like is lacrosse - about 10 scores a game for a team, fast paced and a wide open field. Basically it's a mix of hockey and soccer, but the result has an unexpected synergy.

[**] Since Brits seem to get so upset with Americans calling the game "soccer", could one of them explain to my why the British journal publisher Taylor & Francis publishes a journal entitled "Soccer and Society"? Please?

Another Source of Ocean Plastics - Your Clothing

2011-09-22T09:02:00.002-05:00

Today's post, like yesterday's is also about ocean plastics, but it's about research (open access!) that identifies a disturbing new source of ocean plastic - your laundry. The researchers took samples from 18 beaches around the world and also looked at effluent from washing machines and waste-water treatment plants and found small bits of polyester and acrylic fibers everywhere.

I said this was disturbing, as this is a tough one to avoid. We can all do a better job of making sure that large pieces of waste are properly disposed of and not let loose in the environment, and personally living near the North American Pole of Inaccessibility some 1300 miles from the nearest ocean means that even if I threw all my trash out the window, exceedingly little of it would ever reach the ocean, but how can we prevent microfibers from being washed away from our clothing?

I'm not sure that clothing can be suitably modified to solve the problem. It is well known that washing machines abuse and abrade clothing, a large part of the reason that clothes age over time. I also don't think that washing machines can be suitably changed to eliminate this issue either, although I would love to be proven wrong. Changing the wastewater treatment processes might be the best shot, and certainly from a technological view, it can be done with fine enough filters. The economics of that option however are unknown to me, and the same goes for the use of new flocculants or other clarifying aids.

The open question that needs to be answered as well is does this matter negatively impact the oceans to a significant degree?

I also see that the Plastic News blog is discussing this today, with a tongue-in-cheek question about addressing the situation. Check it out.

A Method for Green Washing

2011-09-21T09:26:00.000-05:00

Method Products launched a press release on the 15th headlined by "Method Unveils Breakthrough Bottle Made of Ocean Plastic"(emphasis added), and by "Ocean Plastic", they state "a bottle made out of plastic collected from the North Pacific Gyre".

The only problem is that the North Pacific Gyre, the worst of the Gyres, has a plastic density of 5.1 kg/km² according to research cited in Wikipedia. Assuming that an empty bottle weighs 100 g (about 4 oz.), then a boat would have to trawl an entire square kilometer and collect every single piece of plastic in it in order to make 51 bottles [*]. Further, keep in mind that collecting these plastics pieces requires a very fine net and a slow moving boat.

So did Method Products and their partner Envision Plastics actually use a boat, all the while generating CO₂ to collect all this plastic? No, of course not. Instead, they

"... tapped into a network of beach cleanup organizations, particularly in Hawaii. Hawaii is of the most remote land masses on the planet, and happens to sit at the southern edge of the Gyre. Because of the ocean winds and currents in the region, much of the plastic from the Gyre ends up washing up on the beaches of Hawaii."

In other words, they collected plastic on the beach, called it "Ocean Plastic from the Great Pacific Gyre" and used that instead. How is this a "breakthrough"? How is it that no one seems to be calling them out on it? Sure, it is great that the plastic is being collected and recycled, (plastic that has no business being in the ocean in the first place), but to hype it as Ocean Plastic? That's where I have to draw the line. There are plenty of people working quite hard to actually provide true "green" products (yours truly included) and to see this junk get a free pass is quite maddening.

That Method Products makes a very large line of cleaning products adds further irony to calling this PR "greenwashing".

[*] Another estimate of the plastic in the Gyre is 8 m² per km². Any way you look at it, it s a very small volume, but people seem to imagine it looking like this:

If it actually did look like that, the economics would be entirely different, although I certainly would prefer that the economics stink rather than having a problem truly that awful.

Controlling Molecular Weight and Branching

2011-09-20T09:16:00.000-05:00

Plastics News had a recent "Ask the Extrusion Expert" webinar with Allan Griff as the expert. Most of his answers were quite fine, especially given the constraints of trying to answer in a small space questions that have many conditions and caveats. But one of his answers really needs to be commented on. The question was:"How are polymer lengths and branching controlled?" and the answer Allan gave was:

"The answers seem simple - time, temperature, pressure, co-monomers and catalysts/other active chemicals - but their application can be quite complicated. Regarding length, the longer the mass is at reaction conditions, the more of it will react, but there is a diminishing-returns principle acting when the mass is, say, 95% polymerized, and the remaining 5% of monomer is looking for a loose end to hook up with. Some polymerization, notably PVC, can be done in water suspension, which enables more free movement of monomer and short chains looking for others, but requires a draining and drying step at the end of the line.

The role of co-monomers is shown with linear-low-density PE. To get short branches, a small amount of another monomer with a double bond such as butene (4 carbons instead of the two of ethylene) is included. The butene goes into the chain with its 2-carbon double bond just like ethylene, but that leaves 2 carbons in a short chain (the branch) dangling from the main chain. Similarly, hexene (6 carbons) makes 4-carbon branches and octene (8 carbons) makes 6-carbon branches.

There are many more complications but this addresses the basics of your question."

While the question is only marginally answered (the answer doesn't really describe how to control molecular weight, and controlling branching is given in only in the context of olefin copolymerization), even within the answer itself, there are sections that I take issue with, and these were highlighted in bold.

First, to more properly answer the question: Molecular weight can be controlled by the adjusting the amount of initiator (more initiator leads to more chains with smaller molecular weight), addition of chain-transfer reagents (more of it will stop the chains short), and adjustment of reaction conditions such as time, temperature. Branching can controlled by the addition of polyfunctional monomers, appropriate catalysts, reactor design or as Allan suggested, by use of select comonomers. And also as Allan noted, "There are many more complications..."

But turning now to the answer Allan provided and the sections I bolded, the idea that the remaining monomer needs to find the growing end of the chain is correct, but this model is oriented pretty much exclusively towards free-radical (addition) reactions, and not condensation reactions. In the latter reaction such as between a diacid and a diamine to form a polyamide, the monomers disappears very quickly - one of the comonomer merely needs to find one of the other comonomer to react with and boom, they're gone. The situation of having 95% polymerized material and 5% monomer speaks to a free-radical reaction where only a certain number of monomers were initiated and the chains grow only from them. Certainly a larger volume of commercial polymers are prepared by a free-radical reaction (all the olefins and PVC for starters), but without condensation reactions, there would be no nylons, polyesters, polyurethanes and others - a group of polymers too large to ignore, even in this small space for answering.

Regarding water suspension polymerization, the water does not "enable more free movement of monomer", at least to the extent of aiding the kinetics of polymerization. The reaction kinetics of suspension polymerization are well documented as being equivalent to bulk polymerization and thus limited in the manner previously noted. The water does allow for freer movement within the reactor, but once the monomer has moved within the suspension particle, the water is absent and the diffusion of the monomer to the reactive end is again the limiting issue.

I'm not sure that clarifying any of this will help an engineer with extruding a plastic, but it certainly doesn't hurt to know (and and to know it correctly).

There is Lots of Money to be had in the Plastics Industry

2011-09-20T07:53:00.002-05:00

I am very surprised that that one scene from the beginning of the movie "The Graduate" is still being kept alive, the one where Mr. McGuire tells Benjamin "Plastics", advice to help him make lots of money, but while the movie is now irrelevant [*], the advice might have more longevity than we think. Plastics News came out with their annual list of top-paid executives in the plastics industry, and while some of these people aren't quite as wealthy as yesterday's executive, Zhang Yin, the income of a few of the executives was eyepopping. How about the $58 million in compensation for Frank Stronach, the Chairman of Magna International, the Canadian auto parts manufacturer? Or the $20 million for Belinda Stronach (Frank's daughter), also of Magna International? Or the $16 million to Donald Walker, CEO of Magna International. Or the $15 million to Siegfried Wolf, of ... you guessed it...Magna International? That's a total of $109 million! Yes, there is lots of money to be had in the plastics industry, at least if you are in or near the corner office. Polymer scientists and engineers such as myself only make far less than 1 percent of that.

The next person on the list is the first person to break the Magna International logjam, and that is Mark Ketchum of New Rubbermaid ($9.3 million), but than we go right back to Magna International management again with Vincent Galifi ($8.9 million). One last Magna International executive is on the list at the #10 spot, Jeffrey Palmer ($6.9 million). While their certainly is plenty of doom-and-gloom to go around in the plastics industry, some small corners are doing quite fine by nearly anyone's outlook.

[*] Afterall, the movie came out 44 years ago in 1967, and it's not like everyone has seen it. It may have been an important movie back then, but it's time has come and gone. Think I'm wrong? Ask some Gen-X or Gen-Y person any question about the movie's storyline, such as "Who was Mrs. Robinson?" or "How does the movie end?", yet they all will know the line "Plastics".

Recycling Paper Around the World - Literally!

2011-09-19T07:32:00.001-05:00

On Friday, one of our colleagues gave a "Brown Bag Seminar" (i.e., he talked at noon while the rest of us at lunch - a very informal setting as you can imagine) on recycling markets, something he was pretty familiar with from prior experience. I'm not going to go into a lot of the details, but one slide really caught our eye. It was a picture of Ms. Zhang Yin and as the question "Who is this women and what does she have in common with Oprah and J.K. Rowlings?"

The snide response was that she was filthy rich, and it turned out to be totally correct. In fact, she is richer than Oprah and Ms. Rowlings, and is regarded as the richest-self made woman in the world. She is the largest shareholder of Nine Dragons Paper Holding Company, a company that - in part - imports paper waste from the US and then makes cardboard with it for shipping products back to the US. We were all taken aback by the expense of shipping paper waste across the ocean, but then realized that it probably makes sense. The boats are empty from what the US imports and doesn't export, so putting pretty much anything in the empty containers is economical, and it adds a second layer to the meaning of "recycling" as the paper cycles the globe.

Follow Up on Yesterday's Post

2011-09-15T06:52:00.000-05:00

Curiously, there were a couple of post yesterday on other blogs that relate closely to what I mentioned yesterday.

First, Don Loepp at the Plastics News blog discusses (and thereby amplifies my point) that passing resin increases on is not easily done.

Second, the "In the Hopper", SPI blog has a video about how PET bottles are reused in the rural areas of the Philippines and Brazil as an affordable skylight.

Lastly, here is my personal opinion about single-use plastics, be it shopping bags, water bottles,... Use your head. When you are done with the plastic bag/bottle/container, THROW IT IN THE TRASH, where it belongs, or in a recycling bin or keep it and resuse it... but dispose of it properly. Plastic in the environment is there because people put it there (directly or indirectly). Oil in the Gulf of Mexico? Sorry, but some of that is naturally there. Plastic in the Gulf of Mexico? There is nothing natural about it at all. If all the plastic were disposed of properly, I'd be blogging about something else and all these silly bans on plastic bags wouldn't be occurring.

Here's What Single-Use Plastic Really Does

2011-09-14T09:32:00.000-05:00

While there certainly are people who seem to think that ALL plastic is bad, others are coming to the realization that it is really "single use" plastic that is the problem - plastic that is used to hold drinking water, for instance, or juices, yogurt,...The overwhelming perception is that the container's only purpose is to hold the food/drink item until the item is consumed, and then the plastic is thrown away.

As a product developer, I can tell you that life is not that simple. No manager or client company has ever approached me or any other product developer and said " I need something to put the food and drink in. That's it, nothing else matters." Such a situation is so far removed from reality that you can't even call it a pipe-dream.

While it is true that as far as the consumer is concerned, once the product is consumed, the container is waste, that is only looking at the last step in a long chain of events. The truth is that even a single-use disposable plastic item has to perform a wide range of tasks long before the consumer even sees it.

Let's consider just consider the object of scorn de jour, the PET water bottle. Here's what I think the requirements are and why the requirements exist:

It needs to seal the water in and all other contaminants out. That's pretty obvious, that's on the top of everyone's list, but for some people, they think the list stops there. It doesn't.
It needs to be made from materials that will not leach unsafe levels of chemicals into the water, or react with the water. The FDA monitors this, but some people are still not happy with the results.
It needs to not have any structural failure:
- during shipment from the bottles' manufacturer (who is often someone different than the company filling the bottle) to the filling plant
- while it is in the filling equipment
- while the bottle is put into
  - the secondary packaging (often shrinkwrap)
  - into the tertiary packaging (a cardboard box)
  - additional packaging (such as to secure it to a pallet)
- or during shipment via (multiple) trucks or boats
- while on the shelf or rack, particularly when multiple layers of filled bottles are stacked on top of it
- during the "normal" lifespan that the consumer has it
Keep in mind that during shipment and in the hands of the consumer, the bottle can see temperature extremes from below freezing temperatures to 140 ^oF or more, as well as UV light which can degrade polymers. If there is structural failure, the water will leak from the bottle, requiring that at the very least, that bottle be thrown away or recycled. Keep in mind that that bottle's contents are then also wasted. Depending on the extent and location of the leaker, the cardboard packaging may be weakened so that handling the other bottles or even the pallet with a forklift may be a problem, and therefore many more bottles may end up being trashed.
The bottle needs to cost as little as possible. While you may think that this is so that the company can pocket the difference, that is not the case. With companies like Wal-Mart and others constantly asking for price concessions so that they can have a steady stream of markdowns, consumers are the only ones who can really pocket the difference. Similarly, when the price of petroleum increases, the price of the plastic increases as well, but passing such increases along is very difficult, leaving the manufacturer to pay the higher price.
The water can only diffuse very slowly through the bottle's walls. Once too much water has evaporated, the bottle no longer holds the volume stated on the label, say 500 ml. Now it's mislabeled, and cannot be sold, so into the wastestream it goes.

Those are the strictly technical requirements that are off the top of my head. There are still more semi-technical requirements that are related to the labeling, branding and selling - the label needs to adhere to the bottle, the bottle needs to be clear and free of visual defects, it may need to have a certain shape (for branding),.... While many consumers will shout "I don't care about that", research on consumer behavior proves otherwise, and so there are additional requirements that the bottle needs to meet.

If some of these requirements didn't exist, the bottles could be made of less durable materials or construction and the job of a product developer would be much easier, but that is not the reality of the situation. Beyond the PET bottle, a long of list of requirements exists for any product made of plastic [*], with most of these requirements completely overlooked by consumers who often only see the end result of the effort of making the bottle, filling it, and delivering it to the store. To look only at the act of buying/consuming/seeing waste and complain is to fail to see the larger issues involved.

[*] or metal, wood, fabric...

My Favorite Reaction

2011-09-13T07:02:00.000-05:00

Chemical and Engineering News is hosting a Blog Carnival - a gathering of blog postings around a common theme, which in this case is "My Favorite Reaction". In my mind, you can't have a Carnival without a lion (or a lion tamer),

and so using my best barker's voice I invite you "to step right up and prepare to see the Greatest Show on Earth..."

In most cases, free-radical polymerization can be compared to a hungry lion on the Serengeti, randomly grabbing wildebeests and zebra as they scurry by. First a wildebeest, then a zebra, then maybe two or four wildebeests, then back to a zebra again, all in no particular order until the last of the herd is gone. This is what occurs in free-radical polymerization when more than one monomer is present - the result is a statistical distribution of the different comonomers. Enter the lion tamer, who is able to control the lion's appetite so it carefully alternates back and forth between the wildebeests and the zebras. The lion tamer goes by the name "thiol-ene polymerization". In this reaction, the growing chain clearly and forcibly alternates back and forth between the two monomers present, the thiol and the ene of whatever sort they may be, resulting in a perfectly formed alternating copolymer --ABABABABA--. The two main reaction steps are:

Were the formation of an alternating copolymer the only advantage of thiol-ene polymers, the lion would have been tamed, but left as a small amusement in the Carnival's sideshow and this post would never have been written. In fact the advantages of thiol-ene chemistry extend far beyond the regularity of the polymerization. Besides being a solvent-free/water-free reaction, thiol-ene systems can react fast, shockingly fast. I've developed floor coatings that under UV light have converted monomers into a hard coating, suitable for walking on, in one-tenth of a second using just a lamp plugged into a 120 VAC outlet, not a souped-up unit drawing enough electricity to power half of Tokyo.

But even better yet is that these systems do not suffer from the oxygen inhibition that commonly occurs in UV cured-acrylates. The hydrogen of the thiol group is labile enough that when oxygen adds to the chain to form peroxy radicals, the radicals are still able to abstract that hydrogen, thereby creating a new thiyl radical allowing the polymerization to continue. Acrylate polymerization comes to a standstill. In summary, you have:

Control of stereoregularity
Solvent-free reactions
Water-free reactions
Extremely fast reactions, and
No O₂ inhibition

It is quite a set of benefits to have in a single reaction.

A Review's Dilemma

2011-09-12T08:11:00.002-05:00

In an editorial published in Nature a few weeks back, Nai-Xing Wang of the Chinese Academy of Sciences argues against the Chinese obsession with publishing their research in journals with high impact factors. In a nutshell, the impact factor of the journal is used by the Chinese government to rate the quality of the research. Wang discusses this at length and makes many good arguments which I will not discuss here (read the editorial, it's worth the time).

I've been aware of this situation for some time, but it has always made me feel uncomfortable for an additional reason - I'm a reviewer for a number of journals published by the Royal Society of Chemistry and am increasingly reviewing more and more papers by Chinese authors. Certainly if the research is of poor quality and should not be published without rework/more data/..., I have no problem in stating so and recommending rejection. But more and more I papers that are more or less acceptable, but maybe should be published elsewhere, in a journal with a lower impact factor. How do I decide that, or even more importantly, should I be deciding that? A large part of me thinks that my job as a reviewer is to pore over the research and decide if it should be published, but that the publisher and their editors should be the ones deciding if it is appropriate for their journal. The editors all have technical backgrounds so the decision should not be that hard to make.

It could be argued that the reviewers are likely the readers of that same journal and could provide valuable input as to what they want to read in it. I find argument weak. There are very few journals that I have subscriptions to - I spend most of my time scanning tables of contents from a large number of journals and seldom concern myself with the specific journal that a research article is published in. I will value an article from "Polymer" as much as one from "Soft Chemistry" or "Journal of Applied Polymer Science" or "Macromolecules" - the idea that there is a particularly brand or brand quality is lost to me [1], so I don't feel that I should be in the position of making this judgment for a journal, and now knowing that this decision could have a big impact on the career of the researchers does not help at all.

I'm sure China will eventually change it's ways (seriously, deciding a research article is more valuable because it is published in a journal where the mean impact of previously published articles was high is akin to valuing a single company's stock based on how well the Dow Jones did over the last 2 years!), but that doesn't make my job any easier in the present.

[1] Now if the article is published in the "Major Asia Minor Journal of Polymers, [2] I might not be quite as interested, or at least I would be initially more skeptical of the data, results and conclusions.

[2] I've have nothing against researchers from Asia Minor or it's present day descendants - the name Asia Minor has always hit me as funny ever since I was a child.

Deuterated Gels

2011-09-08T09:24:00.000-05:00

There's a new report (I only have access to the abstract, and you will too unless you have a subscription or pay to view the article) that really has a curious result. Let me cite the abstract:

"The isotopic effect of exchanging deuterium with hydrogen on the mechanical and surface properties of agar gel is examined. The elastic modulus of the D₂O gels obtained by AFM nanoindentation is significantly higher (factor of ≈1.5–2) than the modulus found in H₂O agar gels. Furthermore, the modulus is independent of loading rate. Surface imaging reveals that the surface roughness gets progressively smaller with increasing agar concentration. All these data suggest that the isotopic replacement of deuterium enhances the mechanical properties of the agar gel, with significant advantages in its use as a biphasic scaffold"

I think it's a poorly written abstract, as on the one hand they refer to the deuterium from the heavy water exchanging for the hydrogens in the agar [1], but then they refer again to D₂O gels as well. They don't seem to be isolating the results of the exchange reaction from the heavy water itself.

Maybe this dichotomy is addressed in the paper itself (it likely is), but I still am full of wonder as to why a deuteration of the water and/or the gel would alter the mechanical properties by a factor of 1.5 or 2. Deuteration and other isotopic changes are known to alter reaction kinetics [2], but to alter equilibrium interactions is a new one, at least for me, and I am having a hard time justifying the results in my mind. Anyone?

[1] A deuterium-hydrogen exchange is probably the only way to efficiently produced deuterated agar, although the thought of growing the red algae in a pool of heavy water is an intriguing one.

[2] It is known that heavy water is toxic to animals for just this reason.

Coffee Ring Formation and Rheology

2011-09-07T09:00:00.002-05:00

I wasn't able to comment much last week about the recent discovery that had quite--a bit--of buzz (pun intended) on coffee ring formation (subscription required), but I think my perspective might make it worth the wait, as just like yesterday's discussion of a topic far removed from polymers (aspirin), it will definitely be related to polymers and rheology. As any of the links above will tell you, coffee ring formation has been a puzzle for a time - the question being why does the stain form as a ring at the outer perimeter and not as a uniform stain under the entire cup? The answer involves quite a bit of transport phenomena of the three most common types - mass, momentum and heat transfer, with evaporation being greatest at the staining location, encouraging the particles in the coffee to deposit their. While this has been known for some time, the researchers here found a new key variable - that particle shape has tremendous impact on ring formation, and that elongated particles do not form a ring pattern, but rather form a uniform staining pattern. The picture below from the article shows the particle shape above the corresponding stain pattern.

The capillary forces between the different particle shape is different and that difference is enough to totally change the outcome of the drying pattern. The authors suggest in the article that surface roughness may induce strong capillary effects and these results could be relevant to ink jet printing, which I can certainly see as being an issue (a more uniformly drying drop would result in a better image), but getting back to the idea of surface roughness had me thinking another thought: painting, as in painting the walls of your house.

If you ever undertake repainting the walls of your house, you'll find that flat (matte) paints are much easier to work with. As you move from section to section, you don't need to be overly concerned about keeping the edge of the paint wet - my wife and I have stopped for long periods of time in the middle of a wall and started right up again without any issues and trust me, she is plenty picky about these issues. In the same vein, touching up the paint, even months or years later is easy. But as you go to increasingly glossier finishes (eggshell to satin to gloss), these issues become much larger - we've tried glossy paint once and will never do it again, despite the fantastic scrubability. You could easily see how each section of the wall was divided up as we move along, and I suspect that it is probably for a reason related to this research - the particles in the glossy paint favor a ring formation type mechanism is seen in coffee.

So my question is this: Could the use of modified particle shapes in paint be useful in creating glossier paints that won't show how the wall was sectioned off? The challenge of course, will be changing particle shapes without monkeying with the other rheological aspects of the paint.

Yunker, P., Still, T., Lohr, M., & Yodh, A. (2011). Suppression of the coffee-ring effect by shape-dependent capillary interactions Nature, 476 (7360), 308-311 DOI: 10.1038/nature10344

Polymorph Determination through Nanoindentation

2011-09-06T09:23:00.001-05:00

Some chemicals are capable of crystallizing in more than one geometry. These forms are called polymorphs, and are usually designated with Greek letters to indicate the order of discovery. Not surprisingly, the alpha form is usually the most stable, followed by the beta,... Polymorphs do occur in some semicrystalline polymers, something that is not as widely known in the polymer community as it should be, although being able to select for a particular polymorph can be difficult. Polypropylene is probably the best example (at least it is the largest volume polymer exhibiting polymorphism) - the beta form can be prepared simply with select nucleating agents such as dibenzylidene sorbitol. Polyvinylidene fluoride and polylactic acid are two other polymorphic polymers that I can name off the top of my head.

As with all crystalline structures, determining the geometry of the unit cell requires x-ray diffraction, although the various polymorphs usually show differing physical properties as well - melting temperatures, and in the case of polymers, differing mechanical properties.

So given this background, you might be able to quickly see that a research paper (open access) examining polymorphs in a small, nonpolymeric molecule, aspirin, with a nanoindentor could be easily adaptable to polymers, but only if you knew that polymers can also be polymorphic. In the study, the nanoindentation was performed on single crystals of the aspirin and even more specifically, on previously identified faces. As expected, the different crystals showed different mechanical properties.

Applying this test directly to polymers would be more challenging for two reasons. First, unless extreme steps are taken, any polymer will be polymorphic even when processed so as to produce a dominance of any one crystalline form. Second, unless extreme steps are again taken, the orientation of the crystals in the polymer will be oriented in numerous directions so that accessing a single face repeatedly would be quite a challenge.

Nonetheless, this work raises in my mind the idea that this approach certainly could be used to study the surface of a polymorphic polymer. After looking at different samples of pure isomorphs at different angles, you could then map the entirety of the surface to see if and where one particular crystal dominates.

As I do not have access to a nanoindentor, this is beyond my capabilities, but is anyone else up for the challenge?

My Version of the Triple Witching Hour

2011-09-01T07:21:00.005-05:00

Despite there being plenty of fun things that I could be blogging about, I'm in the home stretch today of filing 2 patents and an SBIR grant proposal. Worse yet, they are all on the same subject, so it's not as if I get a break to think about anything else. And since the SBIR grant discusses information that is in the patents, the patents have to be filed first, and since the SBIR grant has today as a deadline, that means all three documents are being filed today.

Fun, huh?

Diary of a Summer Intern

2011-08-26T07:15:00.001-05:00

If ever this young chap darkens your doorway:

just think about this line from the song "Toes" by the Zach Brown Band

"Life is good today, life is good today"

A truly fantastic intern, about to set sail into his senior year of chemical engineering and then off to grad school. With no hesitation, I can firmly state that he will be quite successful in whatever he endeavors and then some. ~~Somehow I managed to luck out getting him for the summer~~ - Somehow Aspen Research managed to luck out getting him for the summer. He has made huge contributions not only to my projects, but also projects that were given to him by people that don't think interns should have choice projects but rather the most undesirable grunt work imaginable (how about some ISO 17025 documentation?) and everything in between.

Somebody in the near future will be blessed with him in their lab in the near future; may it be you.

Ancient Egyptian Rheologists

2011-08-25T06:54:00.003-05:00

The identity of the world's first rheologist is most likely lost to the annals of time. Whether it was Ugg, Grugg, or their wives that were dragged by their hair into their caves after being clubbed over the head, we will never know who they were nor what they developed. A commonly cited candidate for the first rheologist is Heraclitus the Obscure, who stated "Everything flows" (Panta Rei), thus giving the Society of Rheology its motto.

But Heraclitus lived about 500 B.C., some thousand years after Amenemhet, who made a 7 degree change in the drain line of a water clock in order to compensate for the density differences in the water between day and night, and this was all done about 1600 B.C., although I'd argue that studying Newtonian fluid mechanics does not a rheologist make.

But there now appears a new claimant to the throne, an unidentified individual who back in 3500 BC developed a hair gel used by Egyptians. (Links for the research article, and a Nature News report (open access)). Being gels, they easily qualify as rheological materials, and hence there was a rheologist behind them, although who he/she was, we'll likely never know. (This also proves that human vanity has existed for ~ 5500 years).

All this raises the question of whether we'll ever seen an older example of rheology. Mummies don't get much older than this. Archaeological remains, however, do go back much further, but then trying to determine if a given artifact has rheological implications gets to be far more challenging. It is fun to think about though, isn't it?

Review: "Social Marketing to the Business Customer"

2011-08-24T08:42:00.000-05:00

The last time I did a book review was probably in the 7th grade, so don't expect much from this effort.

"Social Marketing to the Business Customer" [1] is a timely book focused on how to use all the available social media - blogs, Facebook, Twitter, LinkedIn...to help with marketing you business. I say timely, because there certainly is a need for this. We've all seen way to many efforts by businesses [2] that fell flat. I also say timely as a pun, because given the rapid pace of change in social media, many parts of the book are already obsolete. Google+ for instance, has arrived on the scene. While in a sense this changes some of the technical details, in other ways, the overall message of the book doesn't. If you understand that message, incorporating Google+ and whatever else is yet to come will not be a problem.

As for what that overall message is, here are several themes that I found repeated over and over:

The website is king. Everything you are doing should be aimed at getting people to your website, regardless of how popular Twitter, Facebook, etc. are. The website is where you can completely control your message and where you can convert prospects to customers
Getting results will take lots of
- time
- energy, and
- courage, yes courage
Nobody has this whole Web 2.0 figured out yet. It is one of the greatest open-ended experiments of all time, so you have to learn as you go, and at the same time, copy the success of others
You will fail if you are too "corporate"

The first point doesn't need much further comment, and it is one of those things that is rather obvious when you think about it. But with this frame of mind, you can then see that just setting up a Twitter feed with canned messages once a day isn't going to cut it. Why would anyone follow that? How does that drive anyone to your website or do business with you?

As for the second point, I know from experience with this blog that it takes a long time to build a following, and seeing the sitecounter show extremely small numbers forever-and-a-day is quite discouraging. Granted, polymers isn't as controversial a topic as politics, but still, there are hundreds of thousands of people around the world working with polymers, so the fact that I am only getting a 500 visitors a week shows that I still have a long way to go. The mention of "courage" is important, because you will see plenty of failures along the way, and you need to face up to it. You and your corporation also need courage because the legal department will be very leery of your efforts - the messages going out are not controlled, whitewashed and cleared by every committee available.

I can also expand on the last point, as that is a variation of what I just mentioned: if you let the legal/marketing communications/sales/... departments preapprove everything, you will come across as very "corporate" and fail. As is said in the book, people want to interact with a company, not a brand. One of my favorite examples is what that megacorporation, IBM, does with its employees and blogging - aggregates links to them on a corporate page. This clearly lets you see that the blogs are not the corporate message, but it also humanizes the corporation by letting you see the thoughts of individuals working there.

While the focus is on B2B, the same ideas can be applied to anyone wanting to drive visitors to their website, or in my case, this blog, which is basically my website.

[1] The book was provided to me courtesy of the Don Loepp of the PlasticsNews blog. Thanks, Don.

[2] Want proof? Look at what my employer attempted on Twitter.

How the Indian Supreme Court Indirectly Impacted PET Film Makers

2011-08-23T13:00:00.006-05:00

Way back in earlier December I blogged about the Indian Supreme Court deciding that plastic is more dangerous than tobacco - it outlawed plastic bags that held gutka, a tobacco product. Now the secondary effects of that ban are being felt: Plastic News reported in their August 1 edition that Indian film suppliers have 220 million pound of PET inventory that they can get rid of. Suddenly last year's shortage of PET film has been become a glut on the market as the Indian inventory is being sold at low prices. A legal decision half-a-world away has now impacted the wallets of PET film makers in the US and elsewhere. The glut will eventually disappear, but it would be painful to have to live through it and compete against it.

Plastics are Forever Jewelry

2011-08-23T08:07:00.005-05:00

"Plastic is Forever", that battle cry which in the past has been the exclusive domain of environmentalists and artists, now has apparently added a jeweler to the effort.(O.k., fine, they changed the tagline to "Plastics are Forever")

I say apparently, as the remainder of the ad is so tongue-in-cheek that you begin to suspect that this is a gag gift.

You want to get a special gift, something that will last the test of time, something that demonstrates you care, and that you will care forever. Precious, rare, and synthetic, give the gift of plastic garbage to your special someone. Haha. 5 Gyres has partnered with designer Katelin Gibbs a New York jewelry designer who has designed these beautiful pieces to help support our work at 5 Gyres. The pieces are made from pre-production plastic pellets (nurdles) and actual micro-fragments of plastic collecting in the South Pacific Gyre. 25% of sales go directly to support our work fighting plastic pollution in the world's oceans. Thank you so much Katelin! (emphasis added)

Additionally, there is no information on pricing or ordering.

As I've mentioned before, this jewelry will not last forever or anywhere close to it. The oxygen in the atmosphere will degrade the polymers, aided by the sunlight and ozone, leaving the owner with having to explain that plastics really are not forever.

Glad I'm not buying propylene in China

2011-08-22T08:45:00.003-05:00

Just look at the first sentence of this news report (courtesy of Plastemart):

"Spot homo-PP prices in China have been trading close to par with spot propylene prices on an FOB Korea basis since the beginning of August, resulting in significantly squeezed margins for non-integrated producers..."(emphasis added)

In other words, some plants have to buy the monomer and sell the processed polymer for nearly the same price. Keeping in mind that the processing includes not only the use of the equipment and the energy associated with it, but also the catalysts, the QC testing, the final packaging, administrative costs, sales costs...Somebody is taking a hit in the wallet and I'm glad it is not me.

Names for Biobased Polymers

2011-08-18T08:09:00.000-05:00

Since bio-based polymers are the rage, we need new terms to properly describe them, right? So here are my suggestions. If you feel like commenting, let me warn you that I already have donned my flameproof suit with self-contained breathing apparatus so I can hold out for quite some time.

Yesterday, you saw my suggestion for the block copolymer made from mad cow parts - "block cowpolymers"
If a similar approach is taken to chicken feathers, they could be "flock copolymers"
Continuing with the barnyard animals, a polymer made from female horses could be a polymare
Polymers made from epoxidized mushrooms could be "polyethylene mycol" (mycology is the study of fungi)
Polymers made from reacting diols, diisocyanates and urine could be "polyurineates"
Polymers made from diamines, diisocyanates could be "polydiarrheas"
Polymers made from ethylene glycol, terephthalic acid and birds nests could be "polynesters"

Thank you very much ladies and gentlemen, I'm in town all week. Be sure to tip your servers...

And if anyone is tempted to tell me not to quit the day job...this is my day job - making polymers from a wide range of biomaterials.

Mad about Mad Cows

2011-08-17T06:59:00.001-05:00

I've mentioned before that polymer chemists are clever enough to make polymers out of pretty much anything [*], with the emphasis clearly being on any sort of bio-based feedstock. Yesterday's announcement pretty much ices the cake. Tell me you don't chuckle a little bit when you read the headline

"University Turning Mad Cow Parts into Plastic"

Before anyone gets too excited about the commercial possibilities, take this whole project as a sign of academic naivete, considering that "about 5,000 tons of cow parts a week are dumped into landfills, estimated [research David] Bressler. That garbage could yield 3,500 tons of raw material for the new plastic." Who is going to develop and commercialize a process that is capped at 3500 tons of plastic a year? What application is that small? Even if you make a large margin of 10 cents a pound (and I am being very generous in citing a margin like that for a low performing plastic), that is a profit of only $70,000/year.

"We don't have a name," he laughed. "We don't really have a catchphrase nickname for it." I can at least help with that. Since it is made with blocks of protein and blocks of synthetic materials, how about a "cowpolymer"?

[*] Isn't that sneaky that I can complement both my fellow polymer chemists and myself in a subtle manner?

The Ultimate Time Drain

2011-08-16T09:46:00.002-05:00

The past few weeks and the next few weeks are already booked out at work. If you look at my calendar however, you will see very few appointments. Instead, I am glued to my computer spending more time writing than you would think possible for someone who normally spends lots of time in the lab.

I am simultaneously engaged in the two most time-sucking activities known to man. If you've never undertaken either of these activities before, you will have that cure naive innocence that says "Oh, that looks easy and shouldn't take too long!" What am I talking about?

Writing a grant proposal

which is plenty time-consuming, but in terms of "where did the time go and why is this taking so long and how many more revisions do I have to go through", it's a child's play. No, I am talking about the ultimate time-kill, the one where a whole week can be spent, where endless searching of exotic databases is needed, where you leave the building each day in a mind-dead zombie-like state (where you can't even count to 4!) without having even looked out the windows once to even see if it was a nice day. I'm talking about

Writing a patent application

Lest someone complain about grants, grants are an internal driven process. When you are happy with it, you might have a few colleagues look at it for some comments, but with patents, it's back and forth with the lawyers, who have an entirely different (and appropriate) view on everything. Plus there is the almost absolute guaranty that there will be more back and forth in the coming years as the patent office and the patent examiners starts to get into the game.

An Issue on Nomenclature

2011-08-15T08:57:00.001-05:00

Yep, one of those again, although in this case, I'm not sure that I know enough to have all the background, so please feel free to enlighten me if you know more.

So today's battle is: "Interpenetrating Polymer Network" vs. "Double Network", or IPN vs. DN. IPN has the presumption of history on its side (I believe), a term used to describe two independent polymer networks (generally crosslinked [1]) that are intermeshed at a molecular level. To assembly such a beast, two different reactions are run, either sequentially or simultaneously, but most importantly, there are no chemical bonds connecting the networks. The end result in either case is two truly entangled networks. Interpenetrating polymer network is a great term to describe them as if is accurate, and in my mind, abstruse enough that you need to know what the term means - you can't fake it nor does it mislead. At 11 syllables however, "interpenetrating polymer network" is a mouthful, although IPN flows nicely as an 3 syllable abbreviation [2].

So now along comes the term "double network" that I first ran into in a paper on hydrogels. The authors of the paper do use IPN to describe their polymers, but seem to prefer using "double network" instead. At first I thought it was just an upstart term, but a search shows that it appears to be limited to just IPN's that interact strongly with water (hydrogels).

So is that the only time DN is used, and if so, what is wrong with IPN?

Part of my problem with this discussion is that I also think "double network" is a pretty good term to use as well. Just like "interpenetrating polymer network", it's accurate and abstruse. It's also only 4 syllables, although DN doesn't quite roll off the tongue as well as IPN does.

This is not like some of the monstrosities that IUPAC has foisted on us, such as replacing "intrinsic viscosity" with "limiting viscosity number", a change that was not asked for or accepted by rheologists and polymer practitioners, but then again, isn't also the case for "double network"?

[1] When only one network is crosslinked, then you have a semi-interpenetrating polymer network.

[2] The worst abbreviation in the world? www, as in world wide web. The acronym has 9 syllables, three times that of what is being abbreviated.

Polymer Drone

2011-08-12T07:58:00.005-05:00

The Polymer Drone is a musical act, not a chemist so I'm probably being a little harsh in picking on his chemical structure, specifically,

it's not a polymer
~~it has two Texas carbons (carbons with more than 4 bonds - name comes from the saying "Everything's bigger in Texas")~~
the unpaired electrons are shown as being inside the heterocylic ring, not outside as they normally are.

Tetramethylfuran?

Update: Sure, I can count to 4. Heavens, what an embarrassment. Blame it on the patent application

Swirling Wine Clockwise and Counterclockwise

2011-08-12T06:43:00.000-05:00

Here's a good laugh for a Friday. It's too early to start drinking, but we can certainly plan ahead for a few experiments with this evenings imbibitions. As far a bogus science goes, this might be the limit. Fortunately, no one is getting hurt from the claims (just maybe a little tipsy), so it's "no harm, no foul".

"Like all living things wine cells have a magnetic polarity, just like humans and the Earth. The positive pole is more highly charged, just like the North Pole of the Earth, which is why there are Northern Lights in the Arctic Circle, but not Southern Lights in the Antarctic."(Sorry, this is completely false.) "This polarity tends to keep wine cells generally upright, (Why? The magnetic field is vertical only at the magnetic poles) spinning on their axis when they are being swirled. This magnetic action within a liquid is commonly demonstrated in laboratories. Because plant molecules are mostly liquid, when they form they are also subject to the electromagnetic forces that are a component of the rotation of the Earth. As a result, the pores on the surface of the molecules (Pores on the surface of molecule?) develop based on that rotation, like the shingles on a roof.

When you swirl the wine counter-clockwise you are pushing against the molecules nap (So somehow the molecules inherently pick up a clockwise spin. How? Why? Do Australian wines spin the opposite direction?) , just like stroking the fur of a cat the wrong way, this dislodges anything on the surface. Since the flavor from the barrel is introduced fairly late in the wine's development it tends to concentrate in the outer layers. When you swirl the wine counter-clockwise it dislodges that flavor, while at the same, pushing liquid into the pores, inhibiting the fruit flavors that are inside the cell from coming out.

In comparison, when you swirl the wine clockwise the pressure of the surrounding fluid forces the fruit flavors out through the pores. It also pushes any flavors concentrated on the surface down onto the skin of the molecule. (Well if a molecule can have pores, it can have a skin too.) The fact that the wine is alive, electrically charged, and still changing is why this happens."

Oh, and there's a followup article too!

"Someone quite rudely took exception with my use of the word cell, which is in fact incorrect. The proper term would be molecule or even atom. Everything has a polarity right down to the atomic level, and when put into suspension in a liquid it rotates in relation to that pole. Because we are on a planet that has both a polar system and a consistent rotation, everything forms with a pole and a circular patterning. Wind it one way and it tightens and wind it the other and it unwinds.

Honestly this is just basic physics related to molecular science and plant chemistry, something which herbalists and herbal researchers deal with all the time. A pretty sober group of people."(emphasis added)

It's also basic physics that the thermal energy in a wine of drinking temperature is more than enough to rapidly randomize any orientation that could possibly exist as a result of the weak magnetic field felt here on Earth.

Cheers!

Hat tip to Stuart Cantrill for the lead (Twitter @stuartcantrill)

Why We Need to Sort Plastics for Recycling

2011-08-11T07:59:00.000-05:00

Here's a question from another site:

"Dear EarthTalk: Why can’t plastics of all types, instead of being initially sorted, simply be melted together to be separated later?"

Overlooking the simple issue that each individual polymer has separate melting/softening temperatures and just shooting for the highest temperature needed would degrade the lower melting materials, there are thermodynamic issues as well involved that challenge all polymer scientists and engineers that are looking to make a compatible blend between two polymers (never mind attempting to blend all 6 different versions of purified streams available after sorting by hand).

Compatible blends of polymers are very much an exception and not the rule. Small differences in polymers can have a tremendous impact on solubility. The most extreme example that I'm aware of is deuterated polymers phase separating from their non-deuterated equivalents. The only possibility more extreme would be a homopolymer separating from itself - and even that isn't that remote of a possibility at times (such as in field-flow fractionation).

Polymer compatibility is challenging and it is all because of the high molecular weight of the materials involved. Little help is provided from entropy (the number of molecules per unit volume is so much smaller than for a low molecular weight material) and so much is therefore requested from the enthalpic interactions which occur at every repeat unit. If the interactions aren't right, you will not have a soluble mixture since there are so many of them.

It would be great if these constraints didn't exist and all plastics could be thrown into a big gemisch, but that won't happy anytime soon and probably not ever.

A Sceptical Chemist

2011-08-10T06:43:00.003-05:00

Not sure what I was sceptical [sic] about, but a recent email interview with me was published in the Sceptical Chymist blog from Nature Chemistry.

Monomers and Residues

2011-08-09T08:29:00.005-05:00

One of the few (make that exceedingly few!) ways in which I think biochemists have better vernacular than chemists is when dealing with macromolecules and the materials that are used in their biosynthesis. Specifically, the use of the word "residue".

Proteins are synthesized from amino acids, but the process is a condensation reaction which removes a molecule of water from each amino acid. As a result, the amino acid that enters the chain is similar, but not in fact exactly the same as what is after it is part of the chain. The amino acid monomer is now referred to as a "residue", since it is the residue of the polymerization. This picture of cysteine and the cysteine residue should make it clearer.Strangely, I don't think I've seen that language used when speaking of synthetic monomers and polymers. Ever heard of "ethylene residue" to refer to a repeat unit of polyethylene ?[*] Sure, that is an addition reaction, but is it any better for condensation reactions? Every heard of "terephthalic acid residue"?

I'm not going to start a one-man effort to change the world, but it this is something that we should all be aware of, and consider the use of "residue" if appropriate in discussion of polymers and their monomers.

[*]...which completely overlooks that the repeat unit in the final product is actually methylene - CH₂

What's in a Name? What's in a Number?

2011-08-08T07:41:00.001-05:00

If you've ever worked with certain polymer additives such as antioxidants, UV absorbers, photoinitiators, etc., you probably have noticed a pattern. Take for instance, Irganox 1010, a product of Ciba.
As an temporary aside which will later not be an aside, it's a pretty complicated molecule until you look at the structure a little bit. First, you can see that there are four identical arms. As such, this imagesimplifies the matter. Looking at the left end, you may recognize the butylated hydroxytoluene segment, aka BHT: a well known antioxidant. So know we can see that Irganox 1010 is simply 4 molecules of BHT bonded to a central molecular segment (I suspect that it is pentraerythritol.) BHT by itself is too volatile and mobile to be very useful in durable plastic applications, but when modified like this, it will be much more effective in the long run.

But getting back to my original intent, I don't know for sure that Ciba first starting marketing this product, but you will see numerous products from other companies that have their own name for the product, but kept the 1010 number with it, such as Plaox 1010, BNX 1010, Songnox 1010 and Westco 1010. I've no experience with trademark laws, but it seems as if Ciba, or whoever first developed these products, could protect their name - Irganox - but not the number 1010 (nor the combination of name and number). This pattern exists with more than just the 1010 molecule. It clearly is more than a coincidence.

In some ways, this is a good things as it simplifies the sourcing of alternate materials, but it also oversimplifies the situation by implying equivalence. Since we do a lot of work here at Aspen Research on degradation of polymers, we've had the opportunity to examine in details many of these "equivalent" products and found them to be not so "equivalent". The biggest culprit is that the reaction binding the BHT to the central framework is not as well completed as it should be - i.e., there may only be 3 BHT moieties instead of 4. That 4^th BHT molecule is actually in there, but it is footloose and fancy free to disappear rather than stick around where it is needed. The bottom line is beware of implied equivalence - analyze and test the materials to prove to yourself the equivalence.

Sometimes You Can Sew A Silk Purse From a Sow's Ear

2011-08-04T08:32:00.008-05:00

Graphene is now the wonderchild of the material science world, although obtaining it has been very expensive. This is not only because of the slow throughput and expensive capital equipment, but also because the carbon sources used in its production have been of very high purity.

A new paper (open access) shows that high quality carbon sources are in fact not needed. Look at the labels of the Raman spectra and try not to laugh too hard - this is serious science.Need a few specifics on the materials (I do - "Plastic"?! Seriously, they labeled it just "Plastic"?)

"Six different carbon sources were used: Girl Scout Cookie (the Girl Scouts of America Troop 25080 from Houston, Texas, provided the cookies, shortbread flavor), chocolate (Chocolate Kennedy Half Dollar Gold Coins), grass (Ophiopogon picked at Rice University), plastic (Fisherbrand polystyrene Petri dishes, catalog # 08-757-12), dog feces (Miniature Dachsund) and a cockroach leg (American cockroach caught in a house). The grass and the dog feces were dehydrated in a vacuum oven (102 Torr) at 65 °C for 10 h before being used in the growth process."

Where they got the nerve to try some of those options, I can't imagine. Technology Review has estimates that a single box of the cookies can product $15 billion dollars worth of graphene, so maybe order a few extra boxes next year when the Girls Scouts are at your door.

Hat tip to Neil Withers (twitter - @neilwithers) for the lead