Tuesday, September 06, 2016

Curses! Environmental Stress Cracking

We've had a lot of aphids attacking plants in our garden this year. My usual approach is to use an insecticidal soap that I make by diluting down from a concentrate. "Normal" soap is the sodium salt of a fatty acid, while an insecticidal soap is just the potassium salt, which means the soap is relatively safe. It also works pretty well against the critters, and clean-up is easy. But they have gotten so out of hand that instead of making it up as needed, I made up a larger amount in a spray bottle and kept it in a cabinet.

Over the weekend, I knocked the bottle to the garage floor. No biggie; I picked it up and put it back in its place. But yesterday, I noticed that the soap had leaked out of the container. I picked up the bottle and saw this:
Environmental Stress Cracking of Polyethylene due to Soap
What an idiot I was. It was a polyethylene bottle with dilute soap in it and it had been stressed by the fall to the cement - a situation just begging for environmental stress cracking and that was what I got.

Environmental stress cracking (ESC) is where polyethylene and other plastics, when exposed to non-solvents and stress, break down unexpectedly. Soap and polyethylene. How can there by any interactions, especially at room temperature, especially when PE can withstand strong acids and bases, concentrated soaps and surfactants, bleach, hydrogen peroxide and more? And if you think you have an idea, then be prepared to explain why polypropylene doesn't experience ESC.

As you can imagine, I'll be on the lookout for a PP-based spray bottle for next year.


Previous Years

September 6, 2013 - A response to the ChemBark post (partially) about me

September 6, 2012 - Somewhere in a movie balcony...

September 6, 2011 - Polymorph Determination through Nanoindentation

September 6, 2007 - A resurgence of French?

Friday, September 02, 2016

A cool new fabric

The tale of The Emperor's New Clothes is as much about marketing hype as it is about keeping up pretenses in a social setting. The hype over "smart clothing" is just that, but a new report (open access!) from Stanford researchers about a radiative-transparent fabric appears to offer some real potential in comfortable clothing.

As humans, we feel either warm, cold or just-right depending on the heat balance that our bodies keep with the environment. Conduction, convection and radiation all play a part, with radiation dominating at over 50% according to the researchers [*]. The radiation is in the mid-IR with a peak at 9.5 μm. Unfortunately, most of the fabrics that we wear absorb rather strongly in that region, preventing that heat loss. As a result, we feel hot and need to kick down the A/C a few degrees to compensate. Polyethylene (PE) does not absorb in that region however, and so the researchers used it as the basis for a fabric that is transparent in the mid-IR.

The researchers found that a nano-porous polyethylene (normally used in the construction of lithium ion batteries) was opaque in the visible range due to the pores scattering visible light, but still transparent in the mid-IR. The PE fabric by itself was rather weak, so they ended up creating a laminate with a coarse cotton mesh to provide a stronger fabric. Tensile testing showed the laminate to be rather brittle (only about 15% elongation before break, vs. 70% for cotton), but that can be easily addressed in the future with other constructions.

Two comments: First, the use of polyethylene as an IR-transparent clothing choice is not a new idea. It was proposed (and modeled as effective) over a year ago (and earlier research may well exist too). Second, the biggest challenge I foresee is coloring the fabric. Pigments are an option for monotonic colors (no, black is not an option since it will absorb the mid-IR), but for people that want flashy prints, it could be a real challenge.

Nonetheless, it will be interesting to see what happens to this concept. PE is plenty cheap, and so a fabric based on this could be quite affordable and all that much more valuable to people in hot areas where cooling cost can be budget busters. And the use of it in athletic wear, especially for endurance events, could prove significant as well.


[*] The researchers cite articles from 1937 and 1939 (!) for this datum. (References 18 and 19). Maybe someone should look into updating it, as I wonder how valid it truly is.


Previous Years

September 2, 2010 - How To Have A Brainstorming Session

Thursday, September 01, 2016

You can't get there from here

Being on a new campus this fall means getting lost. Finding the right building is the easy part. Finding a staircase in the building is also fairly simple. But the real challenge is deciding if it is the correct staircase.

The building that I my office is in and that I teach in is over 100 years old and was concocted in bits and pieces over time. And the result that the floor plans are pretty complicated. There are floors between floors. There are floors made of unconnected sections where you need to go to a different floor to get to the other section. Worse yet, not all staircases access all floors. It's so bad they long ago gave up on numbering the floors and named them by colors instead. And of course, the colors are NOT arranged according to the rainbow. (I think the order from bottom to top is green, yellow, black, silver, blue, red, yellow and brown, but I may be mistaken.)

But all that pales compared to this:
Two sets of stairs in a double helix arrangement! We're probably all use to that with escalators, but stairs? Worse, the two sets of stairs don't stop at all the floors, so you will often see students hop the handrails when they realize that the stairs they are in won't got to the floor they want, but that the other one will.

As for me, I know how to get from my office to my classrooms and back. I'll explore more in the future when I have a lunch packed, a huge bag of bread crumbs and plenty of energy.


Previous Years

September 1, 2011 - My Version of the Triple Witching Hour

September 1, 2010 - A New Basis for Measuring the Significance of Research

Tuesday, August 30, 2016

Slide Rule Giggles

I've always loved slide rules. As soon as I learned in 8th grade about logarithms and how they formed the basis for a slide rule, I was hooked. Just like 2 rulers can be used to do addition and subtraction, so can 2 rulers, logarithmically scaled, be used for multiplication and division. That you have to keep your wits about you for locating the decimal is what separates the experts from the wannabes. 13 x 5.4 looks the same as 135,000 * 54. The significant figures were somewhat limited to 2-and-a-half or so, particularly as the value of the leading digit increased from 1 to 9. (The span between 1 and 2 takes up about 30% of the slide rule, while the distance between 8 and 9 is just 5%.)
Even with this, they were (and still can be) powerful calculation devices. Keep in mind that the atomic bomb was developed using just slide rules and that Apollo astronauts had slide rules in their capsule during their flights to the moon. No worries about power outages or dead batteries, they were consistent and reliable.

My wife and I both have slide rules that were passed on to us (mine from my grandfather, hers from her father) and they will never be tossed in the trash until you pry them from our cold, dead hands. They are not super fancy or collector's grade, but they are a way to still be in touch with these people, knowing that their fingers handled (and their brains engaged) the same instruments in the same way.

A recent alumni newsletter from Minnesota had a article on slide rules and it included anecdotes from various engineers who used them to get through engineering classes and even the early years of their jobs until electronic calculators came along. My favorite was this from a Hungarian emigrant:
"During his time in graduate school, [Erwin] Kelen served as a teaching assistant and decided he would have a little slide rule fun with his class.

'I was at the blackboard in front of my class, solving a problem, and I was reading the results off my slide rule. Four decimals first, then squinting, two more' he said. 'Imagine, six digit accuracy from a pocket slide rule!'

After class, all the students crowded around him, wanting to know how he could read this from a tool that basically had two decimal capability. At first, he was coy in telling them that it was a special secret that enabled him to calculate with such accuracy. Surprised, they insisted he tell them his secret.

'I 'fessed up that the last four decimals of the six were purely invention on my part and we all had a good laugh' Kelen said"
The fun of this is that the students themselves would have been limited to calculating just 2 or maybe 3 significant digits, and would have no way to prove that the last 3 (or 4) digits were wrong. I imagine having a Hungarian accent helped to give a further illusion of authority.

Here's the rest of the comments.

Previous Years

August 30, 2013 - The Week that Snowballed Away from Me

August 30, 2012 - Viscoelasticity: It's Not Just for Polymers Anymore

Wednesday, August 24, 2016

Theology, Rheology and some freaky strange search results

Dan Lowry (@DrFriction) tweeted last night "Whenever life seems devoid of meaning or humor, just do a web search on 'theological properties'" (referring to the fact that spellcheckers typically attempt to change "rheological" into "theological"). So I did just that.

Wow. Wow. Wow. Look at this screenshot:
The spellcheckers are winning far more often than I would have ever imagined.

But a little bit of digging suggests that there may be a far more sinister plot, one of revisionist history. I clicked on the first link and found this:
while at the bottom of the page there was this:
So what gives? Was the title later fixed? (That doesn't seem possible as it looks like an image capture, but I'm no expert in these areas.)

But weirder yet is what I found at the fourth hit:
Clearly an image of an original document, with a correct title. But that is not the weird part. It's when I searched the rest of the document for "theol" with the crtl-F key. Every single return (31 total) pointed to a word correctly spelled as rheol...For instance:

What is going on? I know and expect that Google would return a search for most people "rheology" (no quotes) as "theology", but for a word finder in a .pdf document to do that?

Again, I am swimming in the deep end. Any insight that someone could offer would be most helpful as there things here that are disturbing. I know my google search results are not neutral and haven't been for years, but for the text search in a pdf to be like that is not good.


Previous Years

August 24, 2011 - Review: "Social Marketing to the Business Customer"

August 24, 2010 - The Deborah and Weissenberg Numbers

August 24, 2009 - BASF as a hostile takeover target?



Tuesday, August 23, 2016

Polyiodide

The number of elements that are capable of forming a polymer just by themselves and without the assistance of other elements is very small. A large part of this is due to most of the periodic table being made of metals, elements that not capable of forming polymers (at least as far as we currently understand). Throw out the noble gases and you only have a very tiny wedge of the table for consideration, consisting of the metalloids, the nonmetals and the halogens - a total of 16 out of the 92 naturally occurring elements.

Boron, carbon, silicon and germanium are all known to form covalent network solids, which I would consider to be polymers (although others certainly would be entitled to disagree). Sulfur can polymerize under high pressure, but that is it. 5 elements.

Now a new report (Open Access) has found that iodine can polymerize. Not as polyiodine, but as polyiodide (the anion). Oligomeric forms of iodide are already known. I mentioned I3- (triiodide) many times in my general chemistry class last year (it's a good one for drawing a Lewis structure) and higher iodides such as I5- and I7- are known to exist, but now comes proof of In-.

The unusual aspect of the polymer is that it doesn't exist by itself, but instead is supported by a pyrroloperylene crystal structure, with the entire iodide-pyrroloperylene complex being crystalline as well. That crystallinity is what made it possible to clearly identify the polymeric nature of the iodide. (Ferreting out the structure of an amorphous polymer is a whole new level of hurt.)

While the iodide-pyrroloperylene complex is of interest to the researchers because of its electrical conductivity, they also realize that polyiodide may finally crack a chemical mystery that is nearly 200 years old: the nature of iodine in the blue solution that form when iodine is added to starch (an elementary school favorite). Polyiodide has been suggested as a possible form, but without any proof (the iodine-starch complex is amorphous...), it was just a suggestion. This new research doesn't prove that the of iodine in a starch complex is polyiodide, but it does provide support for what could only be previously considered as just a hypothesis.

And it gives us a 6th polymeric element.


Previous Years

August 23, 2013 - Analysis of Silly Putty Swallowing a Magnet

August 23, 2011 - Plastics are Forever Jewelry

August 23, 2011 - How the Indian Supreme Court Indirectly Impacted PET Film Makers



Friday, August 19, 2016

The plastics revolution: we already had it

A news feature article in this week's Nature entitled "The plastics revolution: how chemists are pushing polymers to new limits" is more of the same old, same old. And it doesn't help that it's from the same old researchers contributing to this nonsense.

The same old researchers being Lodge and Hillmeyer of Minnesota and the Center for Sustainable Polymers in particular, (They seem to be everywhere these days, even on the local news a few weeks back). And the same old hype is that we are about to enter a fantastic new future where bio-sourced polymers will magically appear and be so much better than the polymers we have now.

As I've discussed many times in the past, the future of polymers is already here. Polyethylene? It's currently derived from petroleum, but it is already established that it can be made from bio-based feedstocks such as corn, beets and sugar cane. Ferment the sugars to ethanol and then dehydrate it (remove H2O) and you have ethylene. That ethylene can then be a true, drop-in replacement for the petroleum-sourced ethylene to make polyethylene (PE).

This process will overwhelmingly crush any other options for making a bio-based polymer that is functionally equivalent to PE because it takes advantage of the existing capital equipment. To make the (mythical) alternative polymer, new capital investments will have to be made and there will be plenty of risks with that path.

And so it goes with the other Big 6 polymers (polypropylene, polystyrene, vinyl and polyester). Processes are being developed to create biobased versions of the petroleum-based monomers so that existing equipment can be used to polymerize them. Yet somehow researchers keep thinking that they can create some miraculous new polymer to displace them. Sure, right, good luck with that.

The plastics revolution is not in the future, it was in the past when plastics began to become an essential part of modern life. Changing to alternative feedstocks will undoubtedly create new polymers, but those polymers will only be successful when they fulfill the requirements of a new product, not the requirements of an existing product. And that is not a revolutionary thought. Not at all.


Previous Years

August 19, 2014 - The Death Ray returns to my backyard

August 19, 2013 - Defects in Crystalline Polymers - Part 1

August 19, 2010 - Updating Your Resume

August 19, 2009 - What I did for my summer vacation


Thursday, August 18, 2016

Trash Talking Translational Research

A new editorial (open access and less than a page long) in ACS Chemical Neuroscience takes a few swings at all the emphasis being placed on translational research and proposes that more of it should go back into basic research, particularly in synthetic chemistry. And of course, there are testimonials from famous synthetic chemists to support this view (surprising, huh?) The editorial is being praised around the internet (Ash Jogalekar, Chemjobber and Tehshik Yoon, and I'm sure there are more to follow.)

I don't agree, or perhaps more accurately, I think that the value of translational and applied research are greatly overlooked. Not because of their focus on a defined endpoint, but because of the unpredictable results that can arise from it. In some cases, the results are basic science. Consider these examples:
  • Louis Pasteur was trying to determine what caused wine to turn to vinegar, and ended up creating the field of microbiology.
  • While attempting to reduce noise in a communication signal, Arno Penzias and Robert Wilson discovered the cosmic microwave background radiation, the residual heat of the Big Bang.
  • Roy Plunkett was working was trying to improve the coolant gases used in refrigerators and discovered Teflon
  • Viagra was originally developed to help with angina pectoris (chest pains). It didn't do so well at that, but the researchers discovered an unexpected side effect.
Research is research is research, basic, applied or translational. It can (and should) lead to unexpected results. The old clichés are "If we knew what we were doing, it wouldn't be called research" and "Chance favors the prepared mind". True clichés, but completely spot on in this case. Put them two together and good things will happen, including the discovery of fundamental science, intentional or not.


Previous Years

August 18, 2014 - 9 Activities that BOTH Academic Researchers and Industrial Researchers Perform

August 18, 2011 - Names for Biobased Polymers

August 18, 2010

August 18, 2010 - The Wall Street Journal and "Glass Transition"






Tuesday, August 16, 2016

Is there a retraction ahead for the microplastics and fish larvae research?

Retraction Watch is reporting that a recent article in Science regarding microplastic pollution is undergoing a thorough re-examination. The article claims (in part) that the particles reduce hatching rates and are preferably eaten by hatchlings over their normal food.

I was immediately critical of the whole publication as were others. It'd be nice to think that my comments played a role in this investigation, but if they did, they would be just a small part of the picture. There are other fish to fry here. Eyewitnesses of the testing have reported
"...there is a significant mismatch between what is described in the paper and how the experiments were actually performed. Examples include:
• The exposure times of eggs and larvae reported in the paper are longer than the actual duration of the experiment at the Ar research station in Gotland, Sweden.
• The actual number of replicate tanks and fish is lower than what is stated in the paper.
• Aquaria maintenance and monitoring were not conducted as described in the paper"
Yikes! If verified, it looks like this paper is head for Davey Jones' Locker.


Previous Years

August 18, 2013 - If the Ocean Could Hire an Ad Agency...

August 18, 2012 - The Omics of Polymers

August 18, 2011 - The Ultimate Time Drain

August 18, 2010 - On the Loss of the Usenet

August 18, 2010 - Just Wondering

Monday, August 15, 2016

Behold the lowly syllabus...

One of the unexpected surprises of starting a teaching career is the syllabus. I don't remember much detail about how they were when I was in school some 30+ years ago, although I know that they would have office hours, exam dates, how grades were determined (% from quizzes, % from homework...) and that is about it. Maybe there was more, but that would have been all that I cared about - and I can't imagine it being different for other students both then and now.

Unfortunately, administrators have a different outlook. The lowly syllabus has now become a document of great significance, almost a legal document, with more and more burdens placed on it. "Course objectives" are now a major concern for accreditation and attempting to change them requires approval from above. "Competencies" must be present as well. Policy statements about academic honesty, disabilities, attendance, harassment and more are required. What should be a simple 1 - 2 page handout becomes a 10-page (or more) monstrosity. The schoolwide policies are repeated verbatim on every syllabus for every class and so I am not surprised in the least that students don't put the effort into reading it. (Or they read it and forget it.)

And it's only going to get worse - we've already been given a heads-up for changes coming next semester.

I would love to split the syllabus into two parts, but that's too large a Gordonian knot for me to slice.



Previous Years

August 15, 2013 - Another Monomer I Won't Work With

August 15, 2012 - Helmet Gels to Reduce Head Injuries in Sports

August 15, 2011 - An Issue on Nomenclature

Friday, August 12, 2016

How to NOT Write a Patent Claim for Plastic Films

One of the stranger patent claims that I have ever encountered is this one:
” 1. A multi-layer, thermoplastic stretch wrap film containing seven polymeric layers, comprising:

(a) two outer layers, at least one of which having a cling performance of at least 100 grams/inch, said outer layer being selected from the group consisting of linear low density polyethylene, very low density polyethylene, and ultra low density polyethylene resins, said resins being homopolymers, copolymers, or terpolymers, of ethylene and alpha-olefins; and

(b) five inner layers, with each layer being selected from the group consisting of linear low density polyethylene, very low density polyethylene, ultra low density polyethylene, and metallocene-catalyzed linear low density polyethylene resins; said resins are homopolymers, copolymers, or terpolymers, of ethylene and C3 to C20 alpha-olefins.”
(US 6, 265, 055)
What is so strange about it? It’s not the overall claim. What the inventors are describing at a high-level is just a 7-layer plastic film. And both paragraphs (a) and (b) are pretty clear for the most part; the end of Paragraph (b) is what is known as a Markush claim, where some key elements of the composition are described (in this case, that the resins are homo-, co- or ter-polymers) and non-key elements are left vague (the ethylenically unsaturated C2 to C20 monomers).

What is so strange about this claim is it’s inconsistent use of the words “comprising (of)” and “consisting of”. To me and most people, we wouldn’t think twice about using either phrase and would be likely even less concerned that both phrases were used in the same sentence. But to an attorney, especially a patent attorney, the usage is mindboggling.

It is well established in US patent law that when identifying a group of something (polymers in this case), “consisting of” means that the group is exactly what is listed – and nothing more. “Comprising of” means that the group is representative, but that other entities can belong to the group as well.

So know you can see why this is such a weirdly written claim. First you have the use of “comprising of” (the initial paragraph), and then you have two uses of “consisting of” (paragraphs (a) and (b)) and then you finish up with a Markush claim. The use of “comprising” and a Markush claim is expansive, and attempts to broaden the claim, while the use of “consisting of” is restrictive and narrows the claim. So we have expansive → restrictive → restrictive → expansive. (Mindboggling indeed. Particle-wave duality, you’ve met your match!)

None of this is a concern for receiving the patent in the first place, but only for attempting to enforce the patent. Unfortunately for the patent owners, that is now a reality. Another firm began making 7-layer film that is very similar to what was claimed above, so close that they ended up being sued. But were they infringing or not? Does the expansiveness of the Markush claim trump the restrictiveness of the “consisting of” phrase? What exactly does this claim cover?

A recent Federal Appeals Court decision said that the “consisting” restriction wins out over the Markush and given the facts of the case, there is no infringement. Let that be a lesson for us all. Consistently use the phrase “comprising of” in your patents.

Why the attorneys who filed this patent decided to risk anything by going with the wording “consisting of” is beyond me. I hope they have good malpractice insurance – I think they are going to need it.



Previous Years

August 12, 2013 - Combating Molecular Weight Reduction from Shear Forces

August 12, 2011 - Swirling Wine Clockwise and Counterclockwise

August 12, 2011 - Polymer Drone

August 12, 2010 - Pity the Resin Purchasing Manger

August 12, 2010 - Quick Thoughts




Monday, August 08, 2016

The Fettuccine Approach to Vinyl Siding

It's an interesting question: "Stone, concrete, wood, metal and glass all have inherent qualities that can be celebrated. What inherent qualities come to mind for vinyl in any of its forms?"

This question was raised on a recent blog post by Catherine Kavanaugh last week at Plastics News. It highlights my longstanding feelings about plastic (or any other material) being used as a substitute for another material, namely that there are.
"...two diverging paths for the industry. One would be to build a system of components that are so good that they’re indiscernible from wood siding and trim at arm’s length. The other is to build a system of cladding that makes no attempt to fake wood, but rather celebrates the fact that it is vinyl."

I've always felt this way about other products, such as vegetarian food. Many omnivores (including me) look askance at something that is a vegetarian knockoff of a meat-containing dish. Yet dishes that don't contain meat and don't pretend to be meat are commonly consumed without question. Nobody complains that fettuccine Alfredo is vegetarian, and that is because it doesn't pretend to be a meat-substitute. But vegetarian hot dogs? Not a chance. The fettuccine celebrates the inherent qualities of being vegetarian while the mock hot dog only mocks it.

So what are the inherent properties of vinyl that we can celebrate? (Unfortunately, Catherine's blog has not yet had a single comment). To me, one of the key characteristics of vinyl or (any other plastic) is that it is plastic in the traditional definition, meaning moldable. Plastic can be easily formed into three dimensional shapes that wood, stone and brick can't. Take advantage of that and do so in a way that allows it to excel in any of the demands placed on siding (weatherability, water/hail/snow-repellency, insulation, visual appeal).

I don't have any specific proposals, but that would be how I would tackle the problem. Call it the fettuccine approach. The vegie dog approach has already been tried and we know the results. Not good (or we wouldn't be having this conversation).



Previous Years

August 8, 2013 - Oh, We Tried That and It Didn't Work

August 8, 2012 - Swimming and Viscosity

August 8, 2011 - What's in a Name? What's in a Number?

August 8, 2008 - Accelerated Aging - Getting Bad Data Even Faster - 2nd in a Series



Friday, August 05, 2016

An Unexpectedly Quick Ending to my Summer

It’s been a pretty crazy summer for me, and it just got shortened tremendously: I landed a fulltime teaching job at a local college. Yep, no more adjunct hell.

My wife and I just would have liked to know that this was coming, as I was in the midst of a very large project at home, painting the kitchen cabinets. While I/we did know and plan for other project this summer, neither my wife nor I had any idea that we would be painting the cabinets too. It was a terrible accident. It had all started innocently enough when we decided to replace the cooktop in the kitchen island. It was original to the house and needed to go. We also realized that it would be a good time to update the surface on the island from vinyl to a “solid surface” (i.e, a quartz/polymer composite).

We picked out the new appliance and surface and had it installed. It was then that we realized that we had a major problem. The wood cabinets, which I previously liked, suddenly looked awful. My wife had wanted to paint them for the past year and I had always disagreed, but I couldn’t any longer. They had to be painted.

The painting has turned into a nightmare however. The water-based primer we applied wasn’t blocking the tannins(?) from bleeding through and so we had to switch to an oil-based primer. I’ve very limited experience with oil-based paints, and I now realize what a blessing a good water-based paint is.

In oil-based paints, the polymer is dissolved in solvent. The solvent evaporates and the unsaturated segments of the polymer eventually oxidize and crosslink (cure), leaving a good tough coating. While both solvent (in a solvent-based primer) and water (in a water-based primer) start evaporating the moment you start painting, it seems like the oil-based paint's viscosity increases much more rapidly. This makes it difficult for the paint to level (i.e., for the brush or roller marks to disappear). You need to work quickly, get an even coating and then leave it alone. Water-based paints are entirely different. They are far more forgiving, better at leveling and can be easily touched up.

Painting the cabinets themselves is no small job. First, all the the doors and drawer faces come off. One side is primed and allowed to dry, then the other side is primed and allowed to dry. Then comes the paint, first on side, followed by drying time, then the other side is painted and allowed to dry. If needed, an additional coat of paint on one of more sides is needed to coat spots that were missed or dewetted. All this is done on some 8-feet long 2-by-4’s that are supported by sawhorses, meaning we were limited to about 8 linear feet of doors per batch, which isn’t very much. It was a long, project, but I was home most of the time so I was able to make steady progress.

So you can imagine the panic when I was offered the new position and a quick start date. Our kitchen looked like this:
and still looks like that - halfway to nowhere. Instead of being able to paint during the week, I am now only to paint on weekends, and we already had other plans too for that time slot. The slow process has gotten even slower. Maybe I’ll be done by September, just maybe.

About the new job: it’s at Dunwoody College of Technology. The position was listed for a math/chemistry instructor (you mean a chemical engineer, such as moi?). The school is expanding and starting a bachelor's of mechanical engineering program. As part of that, they need to establish a chemistry program. And that is a big part of my new position – building a chemistry program from scratch, both course and lab.

I have prior experience in building a lab from thin air, so I’m not overly concerned, but teaching fulltime will be a new experience, guaranteed to keep me plenty busy. New classes which I’ve not taught before so I’m preparing multiple lecture notes and gathering new materials. Classes don't start until the 22nd, so thankfully I have time to get even further prepared. And thank goodness I taught last year. I have a much better feel for how much I can cover in each class period and how to keep students engaged.



Previous Years

August 5, 2013 - Another Week, Another Attack on BPA

Tuesday, July 05, 2016

When Packaging Peanuts are Outlawed, only Outlaws will have Packaging Peanuts

There a plethora of stories over the long weekend around a common theme of ocean plastic, so I'll just offer a few quick comments on them.
  • Oahu, Hawaii banned plastics bags a year ago, but surprisingly (?) the ban isn't working. The ban apparently covered thin plastic bags, and according to one advocate, "There's thick plastic bags because the stores replaced the thinner plastic with thicker ones. So we are seeing those on the ground. There are all of the food bags because those were never banned so there's really little to no change..." The ban specifically calls bags thicker than 2.25 mils (1 mil = 1/1000 of an inch = 25.4 μ) as reusable, so that appears to be the route that retailers are taking. With resin prices being so low, this option looks a lot more affordable than it did a few years ago.
  • California passed a referendum a last year to charge 10-cents for plastic bags, but that referendum will be revoted on this fall, kinda like a Brexit revote, I guess. But unlike a Brexit revote, there will also be a second related question: what is to be done with the 10-cent fee. Currently the retailers get to keep it (seriously?), but a group led by bag manufacturers wants the dime to support various environmental groups. I'm not sure how the exact question is worded, but I suspect that it might be done in such a manner as to confuse the issue.
  • San Francisco is stepping up their efforts to ban more styrofoam, only they don't include Styrofoam. That's probably a little confusing, but the confusion is from the fact that Styrofoam is a trademark owned by Dow for their brand of expanded polystyrene that is used to make rigid insulating foam - and only rigid insulating foam. (That's right, there is no such thing as a styrofoam coffee cup, or styrofoam food packaging or styrofoam egg containers or anything else.) Since Styrofoam is considered a durable object so everyone seems fine with it. However, the expanded ban does include peanuts, coolers, beach toys and more (see page 11+). I think the wording of the ban however, is going to be problematic. Look at Section 1605(c):
    "No person may sell, offer for sale, or otherwise Distribute within the City any Packing Materials made, in whole or in part, from Polystyrene Foam, as prohibited in subsection (a)..."emphasis added
    So does that mean that a shipping goods company that sells packing peanuts will now have to block access to their website to people from San Francisco? Will people be arrested for viewing such items? I think the definition of criminal solicitation just got a whole lot broader.
  • Lastly, greenwashing efforts to take advantage of ocean plastic are ongoing, with Adidas being the latest proponent. Using Parley Ocean Plastic (you know, the kind easily recovered from beaches rather than the much bigger and more challenging plastic thousands of miles offshore) and deep-sea gill nets, they have made 50 pairs of shoes, not as a kickoff effort, but as the entire product run. 50! Wow, that really reduces the amount of plastic in the ocean, and look at how much free publicity they get for it! Greenwashing, greenwashing, greenwashing.


Previous Years

July 5, 2011 - How to Torture a Chemist

July 5, 2011 - Bicycle Racing is a Team Sport...

Wednesday, June 29, 2016

A Plastic Object without any Temporal or Geographic Information

If you are not already familiar with the writings of Ethan Zuckerman, let me introduce you. He is a director in MIT's Media Lab and has a wonderful blog, My Heart's in Accra. He doesn't write often, but when he does, it can introduce quite an expansion into your thinking. My favorite post of his, Desperately Seeking Serendipity was how I was first introduced to his work.

I wish I had found his blog earlier since just a month before that post, he had written about white Monobloc chairs. And as expected, he had an unusual take on them:
"Fifteen years ago, one of my jobs at Tripod was managing our abuse and legal teams. With several million webpages hosted on our service, some of them violated our terms of service and hosted pornography. That wasn’t a bit problem – we deleted pages that violated our TOS. But when we encountered pages that might be hosting child pornography, we had a more complicated procedure. We copied files to floppy disk (remember, it was 1996!) and mailed them to our regional FBI office, along with information on the IP address the user in question had signed up from.

One of the best guys on my team went to Boston for a week to train to become a “confidential informant”, so he could testify if we’d found evidence in a child pornography case that went to court. Curious guy that he was, he asked whether the information we were providing – the IP address signed up from – was helpful in building cases. Sure, he was told, but not as useful as the information in the photos. Almost every detail in a photo held information about the time and location the photo was taken. The shape of electrical outlets, labels on any consumer products, fabrics, clothing all were clues as to whether a photo was taken in the 1970s or last week, in Sweden or Schenectady.

Virtually every object suggests a time and place. The Monobloc is one of the few objects I can think of that is free of any specific context. Seeing a white plastic chair in a photograph offers you no clues about where or when you are. I have a hard time thinking of other objects that are equally independent of context. Asking friends to propose a similar object, most people suggest a Coke can… but I can tell you that Coke is presented very differently in different countries, in glass bottles as well as cans, with labels in local languages. The Monobloc offers no linguistic cues, no obvious signs that it’s been localized. Wherever you are, it’s at home."

An object so common that its presence tells you nothing.

If another such object exists, it would have to have the following characteristics:
  • A simple, fundamental design
  • Easy and cheap to make
  • Sold and used around the world
  • Made by multiple companies

To the average person (including me), an AK-47 would be potentially such an object. It meets the first 3 requirements above, but it is only produced (so far as I know) by one company. That means that there likely have been small design changes over the years that can provide some clues to time. So I've struck out. Anyone else want to suggest something?




Previous Years

June 29, 2016 - Resonance in Plastics and Metals

June 29, 2011 - BPA Followup (2/2)

June 29, 2010 - Tapes in Space

June 29, 2010 - Pretzel Logic from the Supreme Court



Tuesday, June 28, 2016

The mechanical properties of polymers arise from more than just entanglements

I ran across a PR blurb from Stanford yesterday entitled How do you design a better polymer?" and am not sure whether to laugh or cry. Start with this highlight:
"The polymer research process has always followed a similar pattern. Researchers would synthesize a new polymer in the lab and send it off for testing to determine its physical properties – melt temperature, elasticity, tensile strength and so forth. Only then would its creators look for suitable commercial applications."
Sorry, but most polymers are designed with specific applications already in mind. What the researchers envision here occurs very infrequently.

But it get's worse:
" 'All polymers get their mechanical properties not from chemistry, but from the way that the individual molecules are entangled together,' says [Jian] Qin..."
Wow that is riddled with errors, and being a direct quote, we know that it wasn't some PR hack that is just trying to meet a deadline - it's from a professor that should know better.

  • "All polymers..."? How about just glassy ones, or maybe better yet, non-crystalline ones. Crystalline polymers derive much of their strength from being crystalline, which is why the Nobel Prizing winning research of Ziegler and Natta for polymer catalysis was so important. Prior to that, making crystalline polypropylene was extremely difficult. Amorphous polypropylene is a very weak, slightly tacky material. Crystalline polypropylene is a good strong plastic. The difference is from the crystallinity, not "...from the way that the individual molecules are entangled together..."
  • "...not from chemistry..." You can't just throw out inter- and intra-molecular interactions just because polymers get entangled. If that were true, we would be able to blend any polymer with any other polymer. But we can't. Compatible polymer blends are the exception and not the rule. Why? Because of chemistry. If the right van der Waals interactions, hydrogen bonds and other intermolecular forces aren't there, you don't get a blend, exactly the same as with non-polymeric materials. All of this then means that mechanical properties can and do arise from chemistry.
To be clear, entanglements are an important contributor to the mechanical properties of a polymer. But are the only contributor? Not by a long shot.

One more quote before I stop torturing you:
"The sort of knowledge that Qin is imparting to the field is also profoundly important to the multibillion-dollar plastics industry, among others. The manufacture of many well-known products that make up our lives, like a polyethylene water bottle, for instance, requires a complex balance of interrelated molecular stresses and fluid dynamics. This is no easy feat. The maker must create a precise blend of molecules to ensure a uniform and properly formed finished product."
Polyethylene is largely bought and sold on the basis of the melt flow, a single value that kinda resembles a viscosity measurement, but not really. The test is only performed at a single condition. Polymers are non-Newtonian and have viscosities that change in a non-linearly as the test conditions change, so for any melt flow value, there are dozens of different "blends" of molecules that can have the same melt flow index. "Precise blends"? Hahahahahaha.

The point of the blurb is to highlight the new professor's research in computer modeling of polymers.

May I kindly suggest getting some practical, hands-on experience first?




Previous Years

June 28, 2011 - BPA Followup (1/2)

June 28, 2010 - Anomalous Diffusion

June 28, 2010 - Another Blogroll Update


Monday, June 27, 2016

1 Trillion Dollars

No matter who you are, $1 trillion is a lot of money. And according to Ernest and Young that is how much money is pent up in private equity firms, waiting for the right investment opportunities in oil and gas.

Think that the oil and gas industry is going away? The Paris Agreement was just signed after all, wasn't it? And haven't low petroleum prices have turned the fracking boom to a bust?
Source

One trillion dollars says otherwise. (Maybe the Rheothing Oil and Gas Company should incorporate this week...)




Previous Years

June 27, 2012 - The Most Important Reaction for Polymer Chemists that is NOT a Polymerization Reaction

June 27, 2011 - Gas Chromotograph & The Supreme Court

June 27, 2007 - Design, Good Design and Plastic Chairs



Thursday, June 23, 2016

Olefin metathesis - as a degradation route for PE?

Normally when I hear of olefin metathesis in connection with polymers, it is regarding polymerization (such as ring-opening metathesis polymerization (ROMP)). So I was surprised the other day to read a paper where metathesis was used to depolymerize a polymer, and not just any polymer, but a polymer lacking in olefin groups - polyethylene.

The report appears in Science Advances (open access) and shows off some clever tricks. The polyethylene is dissolved in a light alkane (naptha or similar) and then a dehydrogenation is carried out on both the polyethylene and the solvent. After that, the metathesis can happen.

A metathesis reaction is one where there a cross-exchange between two different chemicals. An example would be A-X + B-Y → A-Y + B-X. For olefin metathesis, the A and Y are on either side of a double bond, as are the B and X. And the same is true for the A-Y and the B-X, so the reaction is A=X + B=Y → A=Y + B=X. where A=X is the partially dehydrogenated polyethylene and B=Y is the partially hydrogenated light alkane. If the double bond is near the center of the PE molecule, you are able to pretty much cut the molecular weight in half in just one reaction. Since the molecules are dehydrogenated in multiple locations, the PE can quickly be reduced to very short chains by allowing the reaction to repeatedly occur. And all the while, the degradation products are completely soluble in the solvent.

The technique works for the whole spectrum of PE, from Mw = 3350 daltons to ultra-high molecular weight (Mv = 1.7 x 106 daltons), as well as LDPE and LLDPE (no surprise there, but glad they checked) as well as on PE that had antioxidants compounded into it. Would it work for polypropylene? Polystyrene? PVC? Inquiring minds want to know!

The statistics of this reaction are intriguing to think about. This degradation reaction is actually more akin to a condensation reaction (run in reverse, of course) than the addition reaction that created the PE, but there is so much more. Is there an optimal level of dehydrogenation (as a function of MW, MWD, branching...)? Is there is an optimal light alkane mix? Would having alkenes already in it help or hurt? Modeling this could be quite a bit of fun.

The use of the end product as a fuel is suggested by the authors, who strongly believe that it is an economically feasible route, much better than anaerobic pyrolysis. No numbers are provided however. I won't get into criticizing them at this point, since this is just a first discovery and with just 56% yield, there is a lot of work ahead for someone. But this process and its simplicity seems promising and I would encourage the researchers to push on.



Previous Years

June 23, 2011 - Older workers

June 23, 2010 - Skewing the results - heavily

June 23, 2009 - If anybody dares quote Paul Simon...








Monday, June 20, 2016

Some advice to companies looking for employees

  • Don't ask for my social security number as part of the application. Seriously? Why could you possibly need it at this point in time, since most likely 95% of the applications are going to be rejected out-of-hand. If you make me a tentative offer and I tentatively accept it, then you can have my SSN. But up front? Not a chance.
  • Don't ask for an electronic version of my resume and then ask me to complete an online application which includes me having to re-enter my employment history. Why? You just got my resume. For someone with my experiences, it can take the better part of an hour, even using cut-and-paste to complete the online application.
  • I really question that I should have to register on your website, but fine whatever. And maybe you even do need me to establish a password. But can you please let me know up front what rules you have for the password? Why waste everyone's time by telling them later when you could have told them upfront that the password needs to be at least 18 characters long, must include at least 1 uppercase astrological symbol, 1 Roman numeral and at least one cuneform?
And academic positions can have their own inner-circle of hell
  • Fingerprints? To teach chemistry? If I'm applying for a security clearance position with the government, fine, but I'm not and I'm not applying to your position either.
  • Letters of references, upfront? Again, 95% of the applications will be rejected out-of-hand. Don't you already have more than enough paperwork to look at having gotten my 8-page CV, my cover letter, my research proposal(s), my teaching philosophy, my ethics statement/statement of faith, my graduate transcript and my undergraduate transcript? Do you really have that much time to go through all of that for each applicant? I've gotten most of my industrial positions without having to even list references, let alone supply letters up front.

And to industry and academia alike, is it really that difficult to send out an email saying that someone else got the job?



Previous Years

June 20, 2104 - Will we finally see less packaging when ordering lab chemicals?

June 20, 2013 - Polylactic Acid - from Methane?

June 20, 2012 - A Vinyl Window with a Great R-Value

June 20, 2011 - Viscosity


Thursday, June 16, 2016

Polymers and Soccer Balls

One of the things that I don't understand about soccer/football/futbol [*] is never ending changes in the design of the ball. You can read a little bit about the construction at Compound Interest, which briefly discusses some of the polymers used (urethane for the skin, butyl rubber for the bladder...). Every time there is a World Cup, out comes a new ball design. The 2014 World Cup had the Bazuca, which was used because nobody liked the knuckle ball characteristics of the Jabulani which was used in the 2010 World Cup. Before that, there was the Teamgeist and the Fevernova.

It's not just the World Cup that switches things up. The Euro Cup for instance, used the Tango 12 back in 2012 and this year is using the Beau Jeu.

Just the fact that these ball have names has me shaking my head. Can you imagine a baseball having a name and its design being changed every few years? Or an (American) football with a name? Part of the beauty of those sports is that the designs are so constant. Unless partially deflated, a football is a football is a football. Why would such an well established game as this need to keep changing the ball? (Obviously Adidas is making some money off of all this, but it can't be that much.)

The differences in these balls are not just the color, but the actual construction. The number of pieces in the skin and their joints are always in play and that translates into different aerodynamics, such as how the player can bend the ball when it is kicked. That means that every few years or so, or maybe even just between different competitions, the players have to adjust to a different ball.

Since FIFA is fine with such adjustments, why not start adjusting other things. Let's make the goal a couple of meters taller in all international competitions (that way guys wide open with the ball in front of the net with a sterling chance to score will have a harder time sailing it clear over the top). Don't worry - the keepers will adjust.



[*] Other things I don't understand include:
  • Why can't the players do a better job of drawing a foul? You can see better acting at a 6th grade school play. Surely there must be some actors who are soccer fans that would be thrilled to help coach that skill
  • Why don't they have retractable/removable flags in the corners? There are no other obstructions anywhere on the field except in the corners. I think we could devise a simple solution.
  • Hooliganism



Previous Years

June 16, 2015 - When does the "chemistry" disappear in a polymerization?

June 16, 2011 - UV Abosrption and Sun Protection Factors

June 16, 2009 - A sign of economic turnaround?


Wednesday, June 15, 2016

Throwing the baby (fish) out with the (ocean) water

Concerns about oceans plastics first focused on just the existence of a trillion pieces of plastic floating around. Now concerns are switching to the impact of the plastic on the ocean environment and the entities living there. A recent report in Science which got a lot of free publicity (since it was in Science after all) found that ocean perch hatchlings prefer microparticles to their regular food, gain less weight and don't respond as well to danger signals, meaning they are more likely to be eaten by predators. And this is all on top of have a reduced hatching rate in the first place.

Rather than studying fish in the natural environment, this was all done in a lab. Ocean water was filtered and put into 1 L bottles that had an aeration system. Plastic particles were added at a low concentration (10,000 particle/m3) and high concentration (80,000 particle/m3). Water without any particles was the control.

I'm amazed that all the results can be attributed to a physical entity - a microplastic particle. After all, a plastic particle is too large to induce much in the way of a (bio)chemical reaction, and even plastic molecules themselves are too large to induce a reaction either. So how does this happen strictly via physics?

It doesn't. There is some chemistry involved, but it is not chemistry with plastic as a starting reagent. Something else such as unreacted monomer, residual catalyst, etc. is the real culprit and that rogue actor was never identified. Since we are now talking chemistry, the universality of the results is called into question.

Surprisingly, the researchers used polystyrene microspheres that they got off the shelf from Polysciences. Why?

Why polystyrene, with a specific gravity of 1.04? In the Supplemental Information (SI), the researchers noted that about 60 - 70% of the particles settled to the bottom. First off, how did they come up with that number? No information is provided. But secondly, is that value the same for both the high concentration tanks and the low concentration tanks? Really? Because as an engineer, I seriously question how a simply designed tank could achieve that same degree of flotation/separation across a multitude of concentrations.

In the main article, the authors infer that the low hatch rates with higher concentration of plastic is due to an unnamed chemical:"
"This suggests that polystyrene particles may be chemically affecting larvae in both average and high concentrations, as exposure potentially reduces hatching rates of fertilized P. fluviatilis eggs."
But then they remark in the SI:
"Thus, fertilized eggs may have been in direct contact with some of the polystyrene microparticles and that is why the authors are unable to say that the reduced hatching success of larvae exposed to microplastic particles are solely due to a chemical effect."
In other words, the reduced hatching results may be due to nothing more than the eggs being buried by the settling particles?

Would the results be different with polyethylene and polypropylene, both of which are far more common in oceans (having been produced in much larger quantities and more often as single-use articles) and both of which have an specific gravity less than one. Flotation would eliminate the burying-the-eggs-alive problem and any leachates from the olefin plastics would be quite different chemically than that of the polystyrene.

And why not run a set of experiments with unfiltered ocean water - a real control (adding more plastic as needed). Then there would be some idea of how well these results mimic reality.

Sorry, but I'm just not impressed much with this report. The authors took a rather complicated system and threw out so much of it that there is likely little chance that the results will ever translate back into the real world. Reducing a complicated system is often a good idea, but you have to take care to not overly reduce it. Unfortunately, that is what happened here.






Previous Years

June 15 - 2015 - Is a Vegan Tesla even Possible?

June 15, 2011 - Sustainability

June 15, 2007 - PVA - Err, is that alcohol or acetate?



Friday, June 10, 2016

Some Friday Fun with the Leidenfrost effect (or maybe something that just looks like it )

Here's a fun video with some Orbeez added to a hot fry pan. I can't find an exact description of what Orbeez are, although they are a water-swellable polymer so they must be crosslinked. However, they are not the usual superabsorbant polymer (SAP) or polyacrylamide. More on that in a minute. First, the video:
As I said above, the chemistry of Orbeez is clearly not that of an SAP or a polyacrylamide. Similar "toys" made from those compounds, such as Waterbalz have been pulled from the market after they caused internal obstructions from children swallowing them. Orbeez have been allowed to continue being sold, largely because research has shown [*] that their swelling in water and gastric fluids is so much less. What I find most interesting is that Orbeez swell to the greatest extent in vodka. Vokda is less polar than water and so the base polymer must be less polar too, or at least have fewer options for hydrogen bonding. This also makes them inherently safer - at least from an ingestion viewpoint - as long as you aren't drinking straights shots of Stolichnaya.

The videomaker states that the activity is a result of the Leidenfrost effect, although strictly speaking, that is highly unlikely since the temperature of the pan's surface was so highly uncontrolled. Film boiling, such as was observed here, is actually a fairly complicated affair. Here's a plot showing all the different boiling regimes that can occur with water in an open pan:
Boiling regimes
(Source - Credit)

The x-axis is the temperature excess between the heated surface and the boiling point of the liquid, and the y-axis is the amount of heat transferred. For people seeing this plot for the first time, it is actually surprising. It is intuitively expected that heat transfer would monotonically increase with excess temperature. While this does occur initially, as the excess temperature is further increased beyond a certain critical value, the heat transferred actually drops. This drop continues to a minimum, which is known as the Leidenfrost point, after which increases in excess temperature lead to increases in heat transfer. This last region of increasing heat transfer is known as the film boiling regime as there is a continuous layer of gas/vapor that keeps the liquid from making direct contact with the heated surface, hence the relatively inefficient heat transfer. (You can see why engineers prefer to use columnar boiling for heat transfer - you can get a good amount of heat transfer without having to excessively heat the surface.)

The Leidenfrost effect and film boiling are visually similar, but as you can see from the curve, the amount of heat transfer can be drastically different (that is a logarithmic y-axis after all). And as I mentioned earlier, the fact that the excess temperature of the pan was so uncontrolled, the bounciness of the Orbeez was likely the result of film boiling and not the Leidenfrost effect.

Overly pedantic? Maybe so, but maybe not. Think about this: plenty of people claim the Leidenfrost effect saves them such as when they immerse their hands in liquid nitrogen or molten lead. The effect (or a low order film-boiling effect in the immediate vicinity) certainly does. There are plenty of videos to prove it. But by such logic, the same could be tried with liquid helium and molten titanium. However, both those situations would put you firmly into the extreme right-hand-side of the boiling curve - the part where the takes off to infinity, never to return.

So be careful with the Leidenfrost effect and what you ascribe to it. It may well be film boiling and you can't tell the difference just by visual inspection. Now that you know how the two phenomenon work and how they differ, you can see that you literally could be playing with fire.



[*] The poster could use a do-over, namely so that all the plots have the same scale on the y-axis, rather than relying on their software to autoscale to the data.


Previous Years

June 10, 2015 - What's in a Name? Marketing Gobbledygook #2

June 10, 2014 - Hillary woos the plastics industry

June 10, 2013 - The Future of Sustainable Polymers: Bio-based Monomers or Polymers?

June 10, 2011 - Have You Considered a Career in Plastics?

June 10, 2011 - The Supreme Court Decides On Freebase Cocaine

June 10, 2010 - Pull Up a Chair

June 10, 2009 - Another Journal Scandal


Wednesday, June 08, 2016

Senator Flake's List and the Importance of Justifying Research

US Senator Jeff Flake recently released a hardcopy of his list of 20 "highly questionable" research projects funded by the US government. Professor David L. Hu of Georgia Tech was associated with 3 of them and wrote a very polite response, "Confessions of a Wasteful Scientist", describing potential benefits of the research and also noting his failures to communicate with the public more clearly about the research and its value. I would highly recommend you read his response.

All of this lead to a number of divergent thoughts:

  1. It's this type of political haymaking by Sen. Flake that is in large part responsible for researchers (and their associated University PR offices) having to overhype any little research result. It's why each week we have a new cure for cancer/heart disease/Alzheimer's (all at the same time for some really revolutionary cases), a new green chemistry that will get us completely off our petroleum based economy and a pill that will help us lose weight/look young forever/give us the hair that we always wanted (but only in the places that we want it). Researchers are having to sell the results of all they do so that they don't appear on some senator's list and the national news.

    While taxpayers certainly have a right to accountability for all government spending, this opportunistic politicking is NOT a responsible inquiry.
  2. Professor Paul Baran of the Scripps Institute recently spoke about increasing the private (corporate) funding of academic research. I see this as "meet the new boss - same as the old boss". The private funding sources, even philanthropies, are going to want to know that their money is being well spent. They certainly aren't going to publicly humiliate you or attempt to leverage your "inane" project to gain a competitive advantage, but they are paying the piper and so they will want to call the tune (or least the band and the album - you can pick the tune). I experienced this first hand back in grad school when my adviser took a small amount of some corporate money."Never again!" he was heard to cry.

    The idea that corporate money will fund basic research is especially laughable, given that corporations such as DuPont have been downsizing their corporate labs and assigning the staff to frontline divisions. (Other corporations are as guilty of this as well - they just are doing it more subtly and not making headlines.)
  3. Something that always seems to be overlooked when criticizing academic research are the side benefits, specifically the training of new researchers. Doing research in graduate school (and as a post doc) is critical to becoming a researcher - a bachelors degree just won't cut it very much. It doesn't matter how "applied" the research is, as long as the research field is deep enough and challenging enough, the end result will be one or more newly trained researchers, who can then go into industry, academia, the public sector...and be comfortable in doing independent research.
  4. This doesn't mean that basic research is dead (despite the comments from Baran highlighted in the article I linked to above). Over $13 billion dollars was spent finding the Higgs boson and the US contributed over half a billion of that. What this really means is that physics (and astrology/cosmology...) have done a far better job of selling their research than chemists ever have (and maybe ever will). When quarks have charm and flavor, the Higgs boson is "the God particle" and the Hubble telescope provides breathtaking pictures of nebulae, the public is captivated. In contrast, we chemists have supramolecular objects, ylides and ToFSIMS - not the same thing at all. Buckyballs were a good start, but ultimately flamed out. Even the personalities associated with physics (Einstein and Hawking) are popularized while our champions (Woodward, Hoffann,...) are completely unknown to the public.

    Much of this is the ability of physicists to work together on "big physics". The Manhattan Project started it all, and it is continuing with the various particle colliders, NASA/ESO, etc. "Big chemistry"? It doesn't exist and no one is proposing any such projects. And if if proposed, who would the field turn to to help sell the project to the public?
We can pine all we want for the good old days when money for basic chemistry research flowed easily and was unquestioned, but they're gone and not coming back. We need to justify our research now and into the future. Professor Hu, who I started this article with, gets it.

Previous Years
June 8, 2011 - It's a Bloody Good Mystery to Me

June 8, 2011 - A New Journal in Polymer Science

June 8, 2010 - Polymer Physics

June 8, 2009 - Memory Foam

Thursday, June 02, 2016

BPA is not a plasticizer

BPA is not a plasticizer. Plain and simple. BPA (bisphenol A) is not a plasticizer.

BPA is not an plastic additive. Plain and simple. BPA is not a plastic additive.

BPA is not added to plastic to make it harder. Plain and simple. BPA is not added to plastic to make it harder.

These thoughts that have become so widely spread across the internet that not only are the mainstream media falling for them (1, 2, 3 and 4), but scientists are publishing papers and books making these mistakes as well (1, 2 and 3).

Let me try and rectify the errors. Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change the properties of an existing plastic - it's one of the chemicals that reacts to form a new plastic.

In order to effectively plasticize a plastic, plasticizers need to be added in significant amounts, sometimes as much as 50 wt%. That's why an IV bag (extremely soft) and a white drain pipe (extremely hard) can both made from the same base material - PVC. With so much plasticizer in the plastic, it is readily apparent that some of it could leach out, hence the concern about potential hazards from the leachate. But there are also concerns about BPA leaching out of plastic as well. While BPA can and does leach out of plastics, it is unreacted BPA that is leaching out. (Polymerization reactions are seldom able to achieve 100% yields due to a combination of factors, including very high viscosities reducing reactant diffusion rates.) The amount of unreacted BPA is very small, far less than 1%, and far less than the concentration levels of any plasticizers. I think the fact that both phthalates and BPA can diffuse out of plastics is the source of much of the confusion.

Big, bad BPA
When used as a monomer, BPA (shown on the right) will react to form hard plastics. The 2 phenyl rings are not flexible, and since the reaction of BPA with another monomer puts them directly into the backbone of the polymer chain, the chain is also not very flexible either. And so, a plastic made from BPA will be harder than one not made with it, but that is not the same as saying "BPA is added to plastic to make it harder". The latter statement is about modifying an existing plastic to make it harder, while the former is about creating an inherently harder plastic.

The misstatements that I opened this post with have almost taken on urban legend status (and I didn't even cover the laughable "all plastics contain BPA" statement). I run across them far too often and from people that should know better. But expecting this post to change anything is like expecting a spitball to bring down an F-16.



Previous Years

June 2, 2015 - Moving

June 2, 2010 - Artificial Weathering

June 2, 2010 - The Futures Market

June 2, 2010 - Operator Error

June 2, 2009 - The Car Industry after GM's Bankruptcy

June 2, 2009 - More drugs from Botulism Toxin

June 2, 2009 - Cap-and-Trade and the Chemical Industry



Tuesday, May 31, 2016

"Plastic is a design failure, it never dies" (?)

While out yachting yesterday with some chums on the good ship Rheothing and glancing through the newest offerings from Billionaire.com (gauche, I know, but there simply isn't a Multibillionaire.com site) I was between bites of Coquilles Saint-Jacques and sips of vintage Mo√ęt, (You were expecting me to say "Dom"? Oh good heavens! Most certainly not with Coquilles Saint-Jacques), when I came upon the most repulsive idea I have ever read:
I insisted to the captain that we must immediately dock, even if it was just in Newport, and that the Rheothing jet was to be waiting at the nearest airport so that I could get back home quickly and scribe a reply.

Oh where to begin. How about with the assumption that plastic never dies? Of course it does. Plastics are organic chemicals, vulnerable to degradation from oxygen, UV light, heat, ozone, mechanical stresses and more. That's why we add additives to plastics - to combat these problems. The additives help for a time, but they don't last forever as in many cases, they are organic chemicals themselves. This degradation drives museum curators batty trying to preserve art made from plastic.

Or maybe we can begin with the assumption that this is a design failure? No, the usefulness of plastics is in large part due to their inertness. The author of that inane article on billionaire.com is alive and well and able to post their mindless drivel because of the inertness of plastics. The keyboard that they type on, the mouse that they click, the coatings on the wires inside the computer and on the power cord and on the electrical circuitry in the walls of the home/office that they worked in and much more are all made of plastics, plastics that last for quite a long time. By design. Is the author really suggesting that the coating on electrical wires should have a shorter product life? Are they will to apologize for all the lives and property that will be damaged and lost because of their proposal to short out electrical systems (by design)?

Ironic picture of nasty plastic trash on a beach with a plastic surfboard
The site is so clueless as to have this photograph on the right accompanying the article. Yes, there is a lot of trash on the beach, but the surfer's board is made of plastic and their suit is also a polymeric material, both of which - by design - are intended to last for a very long time.

Anything made of metal is also - by design - intended to last a long time. So how come metals don't get the same bad rap as plastics?



Previous Years

May 31, 2011 - Plastics: A Toxic Love Story


Wednesday, May 25, 2016

Shocking News! Biodegradable Plastics don't Biodegrade in the Ocean!

Just as Captain Renault was "...shocked! - shocked! - to find that gambling is going on in here!", the announcements surrounding the newest United Nations Environment Programme report that biodegradable plastics don't biodegrade in the ocean is as equally unshocking. But you would not know that from the much of the hullabaloo around the web.

"The enemy of the environment" screams one such headline. For me to call that an overstatement is equally as much of an understatement. Biodegradable plastics make up such a small proportion of all plastics (keep in mind that the Big 6 are high density polyethylene, low density polyethylene, polypropylene, polystyrene, polyester and polyvinyl chloride, they comprise 76% of all plastics produced and they all are non-biodegradable), that their lack of biodegradability in the oceans is an equally small concern.

Besides, I really have never seen much potential for biodegradable plastics, at least as an approach to pollution elimination. No matter what the material, biodegradability is a slow process and yet the creation of pollution is instantaneous. Newsprint is one of the most biodegradable materials available, but newspaper pages blowing around in the park is still considered an eyesore and an example of pollution for the weeks that the paper is still undegraded.

Biodegradation is a long-term solution to immediate pollution, and this new report simply confirms what has been known for decades. Plastics has no business being in the ocean - do your part to keep it out.



Previous Years

May 25, 2012 - My Favorite Toxic Chemical

May 25, 2011 - A New Variable in Polymer Degradation Chemistry

May 25, 2010 - Exhibits that I liked at ANTEC

May 25, 2007 - Why I hate polyurethanes