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 M_w = 3350 daltons to ultra-high molecular weight (M_v = 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...

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

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?

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?

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:

(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

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

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 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.

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

"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�t, (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:

�Plastic is a design failure, it never dies.�

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)?

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

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

Haber-Bosch and General Chemistry

C & E News is reporting a new iron-sulfur based gel that catalyzes the formation of ammonia from nitrogen. In contrast to the existing Haber-Bosch process which heats the nitrogen to ~ 400 ^oC under ~ 200 atm of pressure, this new process is performed at room temperature and in water. Depending on whose estimate you look at, the Haber-Bosch process uses between 1 and 2 % of the world's energy.

The social significance of this reaction is far greater, in that the product, ammonia, is then used to either directly as a fertilizer or it can be converted into ammonium nitrate - also a fertilizer, but one that is less hazardous to handle. The process was invented just over 100 years ago and has revolutionized agriculture. Prior to the invention, nitrogen fertilizers were limited to guano. With this new process for fertilizer preparation, agricultural production began to increase exponentially (as did population), so much so that it has been estimated that 80% of the nitrogen in your body has been inside a Haber-Bosch reactor. [*]

While I can see the potential for this new discovery, my more immediate thoughts (and ones that I would not have had just a year ago before I started teaching) are regarding chemical education. General chemistry is rife with multiple discussions on the Haber-Bosch process. The text that I use discusses it repeatedly in the sections on equilibrium, Le Chatelier's principle, the ideal gas law, partial pressures...No more Haber-Bosch process and the book needs a major rewrite.

Actually, I seriously doubt that a major rewrite would occur. Once a textbook is established, it becomes a Katamari Damcy ball that increases in size with each new edition as more and more material is added and nothing is taken away. The text I use still has a overview of qualitative analysis of metallic elements:

Seriously? Haven't the authors heard of an ICP? Look at the buckets of hazardous waste that this scheme generates. Also note shown in the scheme is that a flame test is proposed as the final step for identifying sodium in the alkali metals. Why don't we just send a telegraph of the analysis back to headquarters, using a gravity cell to power the process while we're at it since we seem to be stuck in the early 20th century?

No, the more likely outcome is that new textbooks would just not include the Haber-Bosch process and that would be a loss due to its usefulness in tying together so many concepts. It also gives us a chance to talk of the full work of Fritz Haber and to get students to start thinking early on about the ethical concerns that they and other scientists may have to face. Time will tell. Most new discoveries never make it far from the bench, and that is the likely outcome for this one as well.




[*] I've seen that 80% figure before, but never looked at the original source. Check it out for yourself (the article linked above is open access) and you'll see that there is no reference provided for it. So is this another one of those mythical numbers without any basis, such as the "8-glasses of water a day" legend?

Previous Years

May 24, 2012 - Slimy Alien Invaders in Minnesota?

May 24, 2011 - Smallest 3D Printer

May 24, 2007 - Why I love polyurethanes

Are plastics to blame for a diplomatic spat?

Plastics are often unfairly blamed for many problems in the world, but being blamed for a diplomatic spat is novel. But that is what the Daily Mail is doing. The Queen was heard to say that the Chinese in a recent visit were "rude". She thought that she was speaking privately and in a low enough tone to not be widely heard but that was not the case.

"Her majesty was clutching a clear plastic brolly in the drizzle, but it appears it amplified her comments and sent them towards a microphone belonging to her own personal cameraman. If her majesty was using a typical umbrella or the sun had been shining her comments would not have surfaced."

The Chinese were bothered by the remarks, but I don't expect much to come of it in the long run.

But are plastics really to blame? I think the shape of the umbrella is this case with its deep bowl and the not the flatter design of say, a golf umbrella would play a huge role. But more importantly, the article notes that the cameraman was using a "sensitive directional microphone". So did the umbrella play a role at all? Since even more sophisticated electronic eavesdropping equipment exists, the Queen really should be careful with any remarks she makes in any public area.

There is the old American expression from World War II "Loose lips sink ships". Perhaps her Majesty would do well to consider it.

Previous Years

May 23, 2011 - Serendipity

May 23, 2011 - This is underwhelming, really underwhelming

3M is NOT science

Sports, particularly in the US never seems to reach a limit in its attempts to increasingly commercialize itself. Stadiums used to have names with a history behind them, but now they are all named after corporate sponsors. And then there are all the "official" products, especially with NFL football, which range from the mundane (Courtyard by Marriott is the official hotel) to the strange (Bridgestone is the official tire - this is football, not auto racing) to the truly bizarre (Covergirl is the official beauty product line. Seriously? How many NFL players use Covergirl?)

But yesterday saw a new level of commercialization that first had me laughing but then got me quite made: 3M is now the "Official Science Partner" of the Minnesota Vikings. What does that even mean? Details are few, but it does appear that 3M's line of bandages will be available at the first aid stations around the stadium, and of course they get a banner in the stadium but beyond that, not much else is explained.

But think about this further. 3M ≠ science. Official Science Partner? How can someone or some company suddenly claim "science" for themselves and then use it for commercial gain? With the other "official" products and services that the league and teams have, the "official" product or service is something that the company actually sells. 3M, however, does not sell science. They sell Post-It notes and sticky tapes and cleaning supplies and respirators and tens of thousands of other products, but they do not sell science. Call their toll-free number (1-800-3MHELPS) and tell that you want to buy some science and could they forward you to the proper salesperson.

Science is not for sale [1] and no one is in charge of selling it. So for 3M to suddenly equate itself with science and then leverage it for profit is maddening. How long until this cashing in with the name of science spreads to other sports, not just with a single team, but at a league level? What if Monsanto wanted to the be official science partner to the Premier League? Or if Amgen wanted to be the official science partner to cycling? (Oh wait, they already are [2].) To cloak a company within the good cloth of science is just too much for me.

Unfortunately, science as a term has no legitimate defenders. I can't see any legal recourse available. Even showing standing would be a nightmare, let alone damages. Short of an organized social media campaign putting pressure on the Vikings and/or 3M, I think this is the future and we are stuck with it.


[1] Publishers of non-open-access journals make me think otherwise at times

[2] I'm looking at you, Lance Armstrong.

Previous Years

May 19, 2014 - A Portfolio of Biobased PE and PP

May 19, 2010 - Back in the Office

May 19, 2009 - Accelerated aging gets even faster

Even the Megacorporations can be defrauded

While it is very common to read reports of individuals falling victim to fraudulent internet and email schemes, it is much less common to hear of businesses being scammed, especially very large businesses. But apparently that has happened with LG Chem and Saudi Aramco (the latter arguably be the largest company in the world). Plastemart reported last week that LG Chem was supposed to wire $21 million to Aramco as payment for some petroleum distillates that they had ordered. But things fell apart when LG Chem received an email detailing a "new" account number to wire the money too. The "new" account, as you might now guess, was not an account that belonged to Aramco.

This reeks of an inside job - someone not only had access to Aramco's email system but also knew that LG Chem was supposed to be making the payment, so the list of suspects is probably pretty short.

We've not actually seen the email that LG Chem claimed they received, so we just have to trust that the letter did indeed supply a new account number. OR maybe, just maybe, it might have started like this:

"Dear LG Chem,

You may not believe your luck, but I am His Royal Highness, Sheikh Abdul al Abdul and I have $773 millions dollars in a Nigerian bank account and I urgently need your help..."

Previous Years

May 16, 2014 - The New Wonder Polymer

May 16, 2013 - Buy & Selling Division in the Polymer Industry

May 16, 2012 - Time to Test My Beliefs

May 16, 2011 - Updating the Blogroll

May 16, 2011 - Definitely Updating the Blog Roll

Music influencing chemical reactions

The polymer chemistry world was "rocked" a few months back when an Australian research group announced that they had developed a new method for preparing potential cancer fighting medications that were overcoated with a Teflon-like coating generated from a plasma. What was so rocking about this? Well, in order to achieve a uniform coating over the entire particle, they needed a way to keep the particles in a constant tumbling motion. And being Australian, the music of AC/DC came to mind, and "Thunderstruck" in particular. They turned the volume up to 11 and voila, success and a paper that caught the attention of many more scientists (and the popular media) than it otherwise would.

Music, and more broadly speaking, sound is mechanical waves that vary longitudinally (rather than transversely as with most other waves), so the use of it is not without merit. But this is not the first time that music in particular has been used to influence a chemical reaction. A little over 2 years ago, researchers in Kobe Japan used classical music to influence a chemical reaction. I don't know of any other reports of music influencing chemical reactions, but the leap from classical to rock was first suggested in a tweet from Vittorio Saggiomo.

I personally prefer Guns n Roses ("Take me down to Polymer city - where PLA is green and pigments are pretty - oh won't you please take me home...) so next time I'm in the lab and have an appetite for destruction, I may just see if a little GnR can be used for accelerated aging of polymers. I have this hunch that it just might work.

Previous Years

May 11, 2016 - How Cheap are Recycled Plastics Nowadays?

May 11, 2012 - What a Crappy Project

May 11, 2011 - Bouncing Jello at 6,200 Frames/Second

May 11, 2010 - Flow-Induced Phase Separation

May 11, 2010 - "9 Shocking Things Made from Oil" - Not!

May 11, 2010 - 10 Things I Like about Polymer Chemistry

May 11, 2010 - Follow Up on "9 Shocking Things Made From Oil"

May 11, 2007 - A much better QC test

BPA gets rehashed again

As might be expected when taking a 2-month "sabbatical" from blogging, there is plenty to comment on regarding BPA.

Campbell Soup is still feeling more heat than a simmering can of Chicken-and-Stars soup (sorry, couldn't resist) to get BPA out of the can liners. Still. As Plastics Today noted, this is not the first go-around for them. They had already said they were removing the BPA-containing liners back in 2012. The article pussy-foots around the obvious: they were only committing to do so in the future once an alternative could be identified even as it sounded like they were all ready to make the change. That certainly helped buy them some time as the concerned groups and individuals put the issue on the "back-burner" (sorry again).

4 years later and the alternative is still not in place and so they are feeling the heat again. This time, 2017 is the promised deadline to be BPA free. But of course, the unanswered question is what is the alternative and is it safer than the current liners.

Not content to just pressure companies, the European Food Safety Authority (EFSA, the European equivalent for the US's FDA [*]), has been asked to re-examine the safety of BPA despite having as recently as last January decided that the material does not pose a risk to ordinary consumers. And the FDA has consistently agreed with EFSA. As have other government bodies around the world.

All of this fuss over a can of soup when a clear alternative easily exists: make your own soup. It's pretty darn difficult to screw up making a soup and it will certainly taste better than anything from a can. The kitchen will smell wonderful and if you are concerned, you can control how much salt you add. Better yet, you can use fresh organic vegetables and free-range chicken (all locally sourced of course!) and knock yourself out with how the righteousness of your soup will protect the planet, improve your health and save the children.

[*] Update 5/19/2016: As is noted in one of the comments below, the EFSA is the equivalent of the FDA, but only the F (Food) part and not the D (Drug) part.

Previous Years

May 10, 2012 - The Technical Data Sheet for a Polymer? You Can Pretty Much Ignore Them

May 10, 2011 - The Reason for Resin

May 10, 2011 - Another Unique Bike

May 10, 2010 - Time-temperature Superposition and going nuts

May 10, 2007 - Chemical Comics

School's Out for Summer

The finals have been scored, the grades have been entered, the begging and pleading for higher grades has ended, the course evaluations ("student's revenge") have been compiled and with that, it's officially summer for me.

Teaching was a lot more difficult than I imagined. Being prepared for speak 3 days a week for 70 minutes at a time takes a good amount of time. Whenever I've given a technical presentation, I could spend days getting ready and perfecting a 30 minutes talk. I had no such luxury here. And then throw in the added time for writing and grading quizzes and exams and much of the week is shot because of just one class. And then the office hours too.

Having gone through this once, next year will be much better. The lecture notes will only need tweaking, and not be created from scratch. And I now know much better what to expect from the students and what to really emphasize, (although I also wonder if it will be the case of a general preparing to fight the previous war).

So this all means (for better or worse) more regular posting here. I'll get back into the polymers again tomorrow.

Previous Years

May 9, 2014 - A Self-Healing Polymer for Really Big Holes

May 9, 2013 - The Oil Economy - It Will Be Around Longer Than Anyone Thinks

May 9, 2012 - Peak Plastic? Not a Chance

May 9, 2011 - Some thoughts on Choosing a Major: Chemistry or Chemical Engineering?

What was Justice Scalia worth? At least $835 million

The recent passing of Supreme Court Justice Antonin Scalia has been commented on heavily elsewhere, and I doubt I have any original thoughts to add. But is quite readily apparent that his replacement will not be appointed quickly, as in it might well drag on into 2017. The court has 9 members and voting on cases is strictly a majority-rules affair, so to have only 8-members means that not a lot of cases will be overturned in the near future. Getting a 5-4 vote for overturning a case is easier than get a 5-3 vote. For someone who's case is unfortunate enough to be on the calendar in the near future, that could seriously change the outcome.

One such case involves Dow Chemical, who almost three years ago was found guilty of price fixing and fined $1.2 billion. After many filings, motions and appeals, their case finally made it to the Supreme Court - and then Justice Scalia dies. To say that Dow thought they stood a chance with Scalia alive-and-well is quite clear, as they have now quickly negotiated a a final settlement for $835 million, still a mighty big chunk of change.

Dow stated in a press release:

"Growing political uncertainties due to recent events within the Supreme Court and increased likelihood for unfavorable outcomes for business involved in class action suits have changed Dow�s risk assessment of the situation."

Looks like Dow should have taken out a life insurance policy on Scalia. Even having a $2- or $3-hundred million would have helped offset this bitter pill.

Or as I suggested long ago, they could have settled early on for peanuts. Bayer (now Covestro), BASF and Huntsman paid a combined fine of only $140 million, but Dow bet on it's legal team and their analysis.

I imagine that the impending merger of Dow with Dupont also played a role. While large corporations will always have some legal actions against them at any point in time, the risk these actions pose is generally small. This case was quite different, and so having it settled - for better or worse - is always preferable to having an unknown quantity hanging over their heads as they enter into a merger.

Previous Years

March 1, 2013 - Giving the Skin Off My Back

March 1, 2011 - A Crack Smoking Poodle

March 1, 2010 - Unusual Recyling Mix

March 1, 2007 - Detox via Intox

Natural Exposure Testing and Pride

Long time readers of this blog know that one mistake way too many researchers and product developers make is to run poorly-designed simulations of weathering conditions in order to (hopefully) obtained faster results. But in the same way that a computer can give you a wrong answer faster, so too can accelerated aging tests give erroneous results when poorly designed and carried out.

That's why this report about the tarps used by international aid workers is so refreshing. The developer of the tarp, kept trying and failing in his design until he came up with a winner. He didn't do any of his testing in a lab however, he did it all in the real world. He needed to know how well the tarps would stand up to wind so he tied some prototypes to poles and stuck them in the beach along the coast. UV exposure? He let the tarps sit out in the sun.

Why is this so difficult for so many researchers to understand? The exposure conditions aren't as consistent as what we can create in a lab, but they are the real world and the real world is where the ultimate truth about product durability lies. I suspect in this case that since the developer was not an engineer with prior experience on weathering that he did what was logical. And the non-budget busting aspects of his testing were no doubt appealing too!

While some may think that we get so wrapped up in our instrumentation and mathematical analysis that we forget what we are ultimately concerned about, I think the real reason for missing the simple approach is ego. Since you don't need to a four-year college degree to run these simple outdoor-exposure tests, people may not look so kindly at an engineer that suggests such an approach.

For instance, when I was back at Aspen Research, we had a client that was concerned about the internal temperatures of an electronics enclosure. We offered to them 2-D equations for heat transfer that were simple to use and could predict the temperature after countless changes, but no, they wanted a bunch of 3-D FEA color images that had been run on a large computer (said images were generated in part by the same equations we had offered up). The images were useless for predicting what would occur after additional changes were made, but the client (and in particular, the management team at that client) loved the pretty pictures.

That client is no longer in business. Surprised?

Previous Years

February 25, 2013 - 3-D Printing Medical Implants

February 25, 2011 - Highly Accelerated Aging

February 25, 2010 - Cel Conservation

Oil Prices to Remain Low - For 10 Years?

While low oil prices are viewed by the majority of the public as good, the low prices are not without consequences (as is always the case with ANY economic news). Capital investments in the oil industry are down, so drillers, pipe manufacturers, steel suppliers of said pipe and so forth are seeing a similar downturn. At the other end of the...pipeline...(groan), plastic prices are down. This is generally great for manufacturers, but it is not so great for the recycling industry. With the difference in price between virgin and recycled resin disappearing, the incentives to use recycled resins are disappearing and so is the demand for recycled resins.

So a recent report that oil prices could stay low for another decade is something to take seriously. The source of the prognostication, Ian Taylor if the Vitol Group, is a respected opinionator:

"Vitol trade[s] in excess of five million barrels of crude and refined products a day, sufficient for the needs of France, Germany and Spain combined, and its views on the market [are] closely monitored."

The slowing of the Chinese economy and the shale fracking boom are to blame according to Taylor.

Surprisingly, nothing was said about Saudi output, which Saudi production, which as the linked chart shows, still remains steady. Opinions are numerous and varied as to why this remains so steady (The new Paris accord shouts one site! Fracking and Iran shouts another!) I don't have the time to assembly a list, but proposed reasons could outnumber the reasons offered for the Fall of the Roman Empire. Regardless, a quick decrease in their production could rapidly elevate prices.

As with any good (?) prediction, there are plenty of weasel words to allow for saving face. "Could", "should", "might" and "possibly" are all right up there, with dozens more waiting in the wings. So will oil prices stay low for another decade? I don't know. As Yogi Berra said (or was it Neils Bohr?), "It's difficult to make predictions, especially about the future."

Feel free to add yours in the comments section below.

Previous Years

February 23, 2012 - An Edible Drink Bottle - No Thanks, I've Lost My Appetite)

February 23, 2010 - Spec Sheets

Gooey Sweet Rheology

Foods always make for fun and interesting rheology experiments. Witness the ongoing (and incorrect) characterization of ketchup as thixotropic [1]. Talking about viscoelastic and other complex rheological behaviors of polymeric materials really won't grab the attention of too many people, even those with a technical background. But mention the unusual flow properties of food and suddenly everyone perks up.

And so it is with a new research paper (open access with registration until 3/29/16) on the rheology of caramels and how it changes with the recipe.

It's a nice little piece of work, the most surprising result being that even though there are 6 ingredients [2] in the recipe, the rheology can be simplified using standard techniques that greatly reduce the number of variable that we need to be concerned with.

What I really didn't like about the work however, was the comparison of caramel to rubber, or specifically to what they call "Ferry 'type VII'" materials. Can I see a show of hands of how many people know what that means? Anyone? Anyone? Yep, only the SOR (Society of Rheology) members got it.

John Ferry wrote a book, Viscoelastic Properties of Polymers which is canonic. I can't imagine anyone being serious about rheology and not having read the book - it is that good. In it, Ferry shows some "ideal" rheological curves for 8 different types of non-Newtonian systems, ranging from dilute solutions of polymers all the way to highly crystalline systems. One such plot is this:

which shows the curves, designated by Roman numerals, which is where the 'type VII' came from.

But no one ever calls something a Ferry "type x" [3] material. It's not wrong, it's not incorrect, it's just improper and shows a newness to the field. And so to call a caramel as a rubber is also improper. It may have some elastic behavior that mimics rubber, but it is not a rubber. A rubber has an entirely different chemical structure that I won't go into today.

But worse yet is think of this characterization of caramel as a "rubber" falling into the wrong hands, such as those of The Food Babe. She already made name for herself by associating an ingredient in Subway's bread with also being used in yoga mats, so imagine what could happen in a case like this where the researchers already have made the connection to rubber.

When caramels are outlawed, only outlaws will have caramels. But at least we have a good understanding of how to prepare them.



[1] Well, maybe incorrect isn't the correct word, as ketchup is thixotropic, but that characteristic isn't what makes it so hard to get it out of the bottle. It's the yield stress that drives the us nuts.

[2] Or maybe you can call it 4 since 2 of them were held constant. Apparently the researchers are not familiar with Designed Experiments for formulations or similar types of analysis.

[3] Or should that be Ferry 'type X', since they are all Roman numerals?

Previous Years

February 18, 2013 - Viscoelasticity in the Bathroom

February 18, 2011 - How to (not) Become a Polymer Engineer

February 18, 2010 - A Concept Kitchen

"Those who can, publish; those who can't, blog"

Those words in the headlines were part of a published interview (open access) with Palentologist Jingmai O'Conner, and as you would expect, were met with quite a bit of negative reaction from bloggers (and twitter users). I'm not going to go into a full rebuttal - others have. Zen Faulkes gives a line-by-line set of counter arguments that are excellent.

I just going to make a quick couple of points that that I've not seen expressed elsewhere:

• I blog and don't published because I am employed in industry. I can't publish, not because my research isn't adequate, but because my employer won't let me.
• My publications are limited to patents.
• But my biggest beef is this: In the interview, Prof. O' Conner is very respectful of pre-publication reviews. Well, I am a very active reviewer for the Royal Society of Chemistry. So how come Prof. O'Conner respects my pre-publication reviews, but my post-publication reviews are without any merit? It's the same brain and fingers writing at the same keyboard in both cases. Why the respect in one case and the disrespect in the other?

Or did the idea that bloggers can also be reviewers never occur to her?

Previous Years

February 4, 2014 - Is the Word "Plastic" Destined for the Trash Heap?

You can't push back the tide

Despite all the flaws in the new World Economic Fund/Ellen MacArthur Foundation report about plastic packaging in the ocean, someone is buying it - literally. To the tune of �500,000:

Looks like they are going to beat me to the punch in developing that new super-polymer.

It's commonly said that lotteries are taxes on stupidity, but in this case, stupidity is a tax on the lottery. There are many, many more legitimate causes than this one that can do real good with this money. But having a good PR campaign and reinforcing peoples' perceptions rather than realities goes far. Trying to fight this nonsense about plastic is like trying to push back the ocean tide.

Previous Years

February 2, 2011 - Nitrogen Filling Tires

There's something Fishy about so much Plastic in the Oceans's future

A long time reader of the blog, Alan Blayney, first brought to my attention the "splashy polymeric headline of the day" (his words, not mine) about the report released by the World Economic Forum/Ellen MacArthur Foundation (WEF/EMF) regarding ocean plastic. It's been all over the news, usually under the headline of how by the year 2050, plastic in the ocean will outweigh the fish.

You can read a summary or the full report if you so desire, but I really would recommend against it. I found it very difficult to go any further than 2 sentences without grunting, slapping my head, rolling my eyes and otherwise expressing frustration. That this report took three years to put together is mindboggling. It really looks like a cut-and-paste job by a 7th grader. Seriously. While the vocabulary is well above a that of a 7th grader, the logic might even be below that level.

I cannot even begin to start with a detailed response, so let me give you a couple of high-level arguments which should be enough to support my previous comparison.

1) On page 14 of the full report, they have Figure 5:

Let's just focus on the oil barrels, showing that plastics consumption of oil growing from 6% to 20%.

My fist thought was Wow! Plastics are really going to explode like that? How come no one else is expecting such a boom? So then I looked into the details. The WEF/EMF relied on an IEA report for future oil production. The IEA report is actually fairly involved and looks at multiple scenarios for future oil production, including one called "New Policies Scenario", which is described as

"The New Policies Scenario � the central scenario in WEO-2015 � takes into account the policies and implementing measures affecting energy markets that had been adopted as of mid-2015 (as well as the energy-related components of climate pledges in the run-up to COP21, submitted by 1 October), together with relevant declared policy intentions, even though specific measures needed to put them into effect may not have been adopted."

There is also a "Current Policies Scenario" which is based on, you guessed it, current policies, rather than the wishful thinking of what politicians have promised. The New Policies Scenarios then assumes that less oil will be used for energy production, hence the relative increase in the percentage of oil used to make petroleum. No boom at all. It's all just slight of hand that may or may not happen.

But even if this does happen, the question remains: so what? Let's carry out the "New Policies Scenario" to an extreme and imagine that in 2050, all energy is petroleum-free (we're all driving Teslas and heating our homes with bio-methane, etc..), in which case plastics will consume about 50% of all the petroleum extracted (the other 50% going into non-polymeric chemicals as currently happens). Why is that a bad outcome? Or even if plastics consumes 100% of the oil produced, why is that bad?

The point of this figure is to create the illusion that plastics are growing like made and the reality is that they aren't.

A further argument against this illustration is that they are playing fast and loose with future policies and changes in consumer behavior. Because it helps their cause, the WEF/EMF assumed that changes will occur within oil production (the "New Policies Scenario"), but then rather than using a "New Policies Scenario" for the future of plastics, they use a "Current Policies Scenario" for plastics use. What wonderful logic. The mind reels.

2) The report is largely focused on plastic packaging, although there are plenty of examples where the distinction is not clear at all. But let's focus on the packaging aspect. On page 12 of the full report is Figure 3:

While you can argue with the 95% number, an even bigger counter argument can be made regarding this illustration. Consider again petroleum production. 100% of it ends up in a combustion reaction and would anyone consider this an economic loss? Or is this energy consumption a basis for having an thriving economy in the first place?

Like almost all generic complaints against plastic packaging, the arguments always focus on the "single-use" aspect of it. And why it is certainly true that most plastic packaging is not reused, by focusing on just the very last activity, the bigger picture is lost. Plastic packaging is required to meet a very large list of requirements for a number of customers, not just the final consumer. Consider the hated PET water bottle:

• It needs to seal the water in and all other contaminants out. That's pretty obvious, that's on the top of everyone's list, but for some people, they think the list stops there. It doesn't.
• It needs to be made from materials that will not leach unsafe levels of chemicals into the water, or react with the water. The FDA monitors this, but some people are still not happy with the results.
• It needs to not have any structural failure:
  • during shipment from the bottles' manufacturer (who is often someone different than the company filling the bottle) to the filling plant
  • while it is in the filling equipment
  • while the bottle is put into
    • the secondary packaging (often shrinkwrap)
    • into the tertiary packaging (a cardboard box)
    • additional packaging (such as to secure it to a pallet)
  • or during shipment via (multiple) trucks or boats
  • while on the shelf or rack, particularly when multiple layers of filled bottles are stacked on top of it
  • during the "normal" lifespan that the consumer has it
• It needs to withstand temperature extremes from below freezing temperatures to 140 ^oF or more, as well as UV light which can degrade polymers.
• The water needs to diffuse very slowly through the bottle's walls. Once too much water has evaporated, the bottle no longer holds the volume stated on the label, say 500 ml. Now it's mislabeled, and cannot be sold, so into the wastestream it goes.

Consider the consequences of just one bottle failing these requirements and leaking. At the very least, that water is lost. But depending on the location of the bottle within a shipment, additional bottles may be lost if the cardboard becomes wet and weakens, perhaps even and entire pallet full of water bottles. That is a true loss of economic value.

I could go on (and on. And on. And on.) but you get the point. If you want a good laugh, look at the "moon-shot" (yes, they used that word) technical innovations that they propose on Page 26. I can't wait to get started working on that new "super-polymer". Who's in with me? Maybe a Kickstarter project. We'd only need $50 million or so.

Lastly, I found the following comment in the report to be as filled with irony as any I've ever read:

"Society�s perception of plastics is deteriorating and perhaps threatening the plastics industry�s licence to operate. According to Plastics Europe, an industry organization, 'There is an increasingly negative perception of plastics in relation to health, environment and other issues'."

I wonder why?

Previous Years
January 28, 2014 - Dynamic Mechanical Analyzers - Male or Female?
January 28, 2011 - Miscellany
January 28, 2011 - Designing a Crematorium
January 28, 2010 - Holy Grail Projects
January 28, 2009 - Chemical Security
January 28, 2009 - So that's what it's called...

Another example of the lonliness of polymer chemistry

I recently discovered the Open Syllabus Project, a site that crawls the web looking for syllabuses and then looks at what texts are being used in the class. From this, they prepared ordered lists. While the Project openly admits that their methodology is not perfect [*], it can be considered somewhat representative of what texts are being used and to what degree. Can it accurately split the difference between #11 and #12 on the list? Probably not. But they should be able to clearly differentiate between #1 and #100.

You can filter the list by different fields. When the "Chemistry" filter is applied, the #1 text is "Chemistry: The Central Science" by Brown, et al. No surprise there - it's the text I use and I've always heard that it is extremely popular. There are 3 other General Chemistry texts in the top 10, as well as 4 Organic texts, 1 P-Chem text and 1 Analytical text, which is also not too far from what I would expect. Enrollment in upper level chemistry classes is always much smaller since all the premeds and other nonmajors have left, so P-Chem, Analytical and Inorganic would be expected to be lower.

Being a polymer chemist, I'm curious where the first polymer chemistry text is on the list. It's a disappointing #122 - Polymers: Chemistry and Physics of Modern Materials by J. M. G. Cowie. In fact, there are 9 biochem texts higher on the list than this. 9! Apparently polymer chemistry classes are quite rare, about as rare as the polymerization of a non-terminal olefin. Augsburg College, where I teach, doesn't have a polymer chemistry class (despite my efforts to create and teach one), and I suspect that that is true elsewhere given the data above.

This is all just another example of how lonely it is to be a polymer chemist. If you want to be rich and/or famous for writing a chemistry textbook, write one for General, Organic, Physical, Inorganic or Bio-chemistry. ANYTHING but polymer chemistry.


[*] Of that I'm sure. The syllabus for the class I teach is only available on the college's internal website - no webcrawlers allowed.

Previous Years

January 27, 2012 - Open Access, Curation and Seredipity

January 27, 2011 - Baroplastics

King Tut is now minding his own beeswax

Exactly a year ago, I blogged about King Tut's iconic mask being damaged, specifically that the beard had fallen off and was hastily repaired by the 3 Stooges and some 5-minute epoxy (all of which exposed him to TOXIC! levels of BPA). A German art conservator was brought in last fall to attempt a repair.

The National Geographic website reported back in December on his efforts. These included removing the epoxy by heating it and using wooden scrapers to avoid further damage to the mask. Prior to this, they performed a number of scans on the mask and discovered that a previous repair from 1946 had been done using a soft solder. But in this repair, they used an adhesive with ancient roots - beeswax.

As you might guess, beeswax adhesive is not straight beeswax since it is just a softish waxy material with little or no adhesive properties. It is typically mixed with rosin to increase the tackiness. That this is a "natural" adhesive is a selling point, but the repair is certain to not last an eternity (too bad, as Tut will need it that long). Another repair will be needed at some point down the road, but removing the beeswax adhesive should be relatively simple compared to an epoxy.

I wonder how they decided on beeswax, and more importantly, how much (and which) rosin to add to it. Like any tackifier, too much rosin will decrease tackiness, so getting the levels just right is important. Rosins also have varying degrees of unsaturation, all of which will be oxidized over time and potentially changing the adhesive. It would be nice to think that this was all studied and analyzed in great detail, but I suspect that might not be the case.

As for the fate of the artifact-altering-associates, they are facing trial for their "work". There is no word on what potential sentences they are facing, but I think gluing their fingertips together with an epoxy or a cyanoacrylate would be a good start.

Previous Years

January 25, 2015 - King Tut and BPA

January 26, 2012 - Viewing History through an Oil Refinery

January 26, 2011 - My Most Embarrassing Moment at Work

January 26, 2010 - Phosgene Death

January 26, 2009 - More on Dow and Rohm & Haas

January 26, 2009 - Biodegradation of Polymers