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?

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