Monday, October 31, 2011

10 Halloween Scares for Polymer People

Let's hope that nobody sees these frightful creatures around their business today:
  1. ISO Auditors
  2. FDA Auditors!
  3. EPA Auditors!!
  4. Tax Auditors!!!
  5. Your resin supplier with their latest price monthly increase
  6. Environmentalists telling you that they are gathering a petition to put you out of business
  7. 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
  8. The research director telling you about the mishap in the lab over the weekend, which led to the sprinklers going off which led to...
  9. 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
  10. 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.

Monday, October 24, 2011

John's Tricks for Free Access of the Literature

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.

Friday, October 21, 2011

Those Chemicals Really Aren't That Expensive

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.

Thursday, October 20, 2011

The Inventors of Kraton...

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?

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.

Wednesday, October 19, 2011

It costs HOW MUCH?!?

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.

Tuesday, October 18, 2011

Slightly Toasty Polymers

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!)

Monday, October 17, 2011

How to (NOT!) Determine PVC Rheology

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 "", 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!

Tuesday, October 11, 2011


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.

Tuesday, October 04, 2011

The Philosophy of Space-Age Plastics

I ran across the following poem at 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.

Monday, October 03, 2011

Rheology Analogies for Computer Networks

I ran across this company who's name is based on a rheological concept: "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

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).