Wednesday, August 26, 2015

Circular Plagiarism

So blog posts have been few and far between as I prepare for teaching. Classes begin in a week and the expected panic is beginning to set in.

Last night there was the orientation for new faculty. Over dinner, a couple of adjuncts spoke about the Adjunct Council, a newly formed group that advocates on the behalf of and provides support for adjuncts. During the informal Q and A session, the topic of plagiarism came up and that there should be some statement in our syllabus addressing the matter. Someone asked if the college had a formal statement that we could use. One of the moderators replied something to the effect of "No, I just used a statement that I copied from somewhere else".

Thank goodness I didn't have any food or drink in my mouth as I just lost it, bursting out in laughter and saying in a tone just loud enough for the people at my table to hear: "That's plagiarism!". They all started laughing, breaking the rather somber mood and drawing the attention of the entire room. I then felt obligated to repeat my remark out loud so that everyone could hear it. The speaker blushed as red as an apple. I tried adding "...as long as you don't provide attribution" but I think that was lost in the noise.

Sheesh, classes haven't even started and I'm already causing trouble.



Previous Years

August 26, 2014 - The Ebola outbreak would be so much worse without plastics

August 26, 2011 - Diary of a Summer Intern

August 26, 2010 - Scanning Plastic Films for Defects

August 26, 2010 - Grammar

Friday, August 14, 2015

Plastics to Aid in Fighting the California Drought

The State of California is suffering through a 5-year drought with no end in sight. Ironically, as much as Californians love to rage against plastics (instituting endless bag bans and regulating countless other chemicals that are added to plastics or used in their production), there are more and more examples of plastics being used to help the state in this time of need.

In just the past few days, the city of Los Angeles placed 96 million black, hollow polyethylene balls in a water reservoir. The balls float on top of the water reducing evaporation, keep away birds and provide other benefits.
The Worlds Largest Ball Pit - Black HDPE Balls in the LA Water Reservoir
That would have been fun to help install. And if the reservoir ever runs dry, then LA will have the worlds largest ball pit.

At the same time two, plastic pipe manufacturers are using the drought to help sell their products. Nationwide, about 16% of all purified water is lost due to leaks and broken pipes with most of the pipes being ductile iron. Large volume plastic pipes were not available when most of these water systems were originally installed but they are available now. PVC pipe is ridiculously easy to join. As many homeowners know, you brush on the primer and adhesive and then push the two pieces together. Voila - a solvent weld that is most likely stronger than the original pipe. Doing this with a 12" OD pipe or larger is a little more difficult due to the weight of the pieces, but the heavy equipment needed to lift them is readily available. HDPE pipes are also available. HDPE cannot be solvent welded however, so more specialized equipment is needed to heat up the end sections to allow them to adhere, but again, this is being done more and more in new installations.

The unfortunate part of this is that California is 5 years into the drought and only now are these steps being taken. Neither step will eliminate the drought, but they will allow existing water supplies to last longer. Had these steps been taken 4 years ago, the Hollywood movies stars might still be able to water their lawns. It's just another reminder of our inability to focus on long-term problems until they reach a crisis state.



Previous Years

August 14, 2014 - Oh Brave New World!

August 14, 2013 - The Pitch Drop Experiment for the Impatient

August 14, 2012 - Polymerizing Antioxidants

Thursday, August 13, 2015

I'm Going Back to School

Summer is winding down here in the Northern Hemisphere and that means that it's back to school time. For the first time in 26 years I will be part of that. There will be the usual excitement of meeting new students/professors /staff, finding my way around a campus that I am unfamiliar with, new books and supplies and making sure I am in the right classroom at the right time.

That last item is easily the most important, as if I'm not in the right room at the right time, there will be no class. This year, I'm returning to the classroom not to sit in one of the seats, but to stand at the front and speak - I'm taking at position as a adjunct professor at Augsburg College.

You may not have heard of this school, but you should have. Peter Agre, winner of the 2003 Nobel Prize in Chemistry received his B.A. in Chemistry there. Knowing that, I'm going to be constantly wondering if I am looking at a future Nobelist as well.

As you can imagine, the next few weeks will be pretty busy getting ready to this new adventure, so posts may not be as numerous or as lengthy, but they will continue. And once the school year starts, I'm sure that I will have plenty more material to blog about. I can't imagine that the students won't be an endless font of new ideas and items to discuss.



Previous Years

August 13, 2014 - A No-Brainer Approach to Turning Biowaste in Thermoplastics

August 13, 2013 - Limits to Innovation in F1 Racing

August 13, 2012 - A New Perspective on the Great Garbage Patch

August 13, 2010 - More Aspen Research Video Available

August 13, 2009 - More fun from the New England Journal of Medicine

August 13, 2008 - My only political comment and it's not political at all

Thursday, August 06, 2015

PVC-induced Acroosteolysis?

I look forward to my inbox on Thursdays because in it will be the links to The New England Journal of Medicine's "Images in Clinical Medicine". These are open access images that doctors from around the world have submitted that show something that is visually unusual in a patient that they examined and possibly treated. The images can be photographs, MRI's, x-rays, etc. and have a brief discussion about the condition, treatment and outcome.

This week, PVC was considered (but ruled out) as inducing the fingertip bones in this man's hands to be absorbed by his body:
Acroosteolysis
Source

The condition is called acroosteolysis [1]. PVC gets blamed for lots of things, but I thought it was odd that it, the polymer itself, would get the blame. A more likely cause would be the monomer (vinyl chloride, VCM), the catalyst or any of the various additives that are added to PVC (and there are A LOT of additives added to PVC). I dug a little further and that is where it gets interesting. I found a link to an Italian-language report on acroosteolysis in people that used to manually clean the tanks used to polymerize PVC.

"The disease was observed for the first time in mid-1963 in Belgium (Jemeppe) in a chemical plant operated by Solvay, and affected two workers whose job was the manual cleaning of vessels used for the polymerization of vinyl chloride; similar cases occurred in almost all PVC production plants all over the world, but not in the plants where the main activity was the production of vinyl chloride monomer (VCM). Little more than one hundred cases are described in the scientific literature, and this number increases by a few dozen if we consider known but unpublished cases. These figures confirm the rarity of the disease, which peaked at the end of the 1960's and disappeared during the 1970's, probably due to the complete elimination of manual reactor cleaning. Observation of the disease lasted no more than fifteen years and the disease was not replicated in experimental conditions on animals.

The disease was clinically characterized, had a short latency (from several months to several years), was rare and unequivocally linked to the manual cleaning of PVC polymerization tanks. However many questions still remain open: the period when the disease first appeared (many years after the start of PVC production in the world), the etiology of the disease (the most accredited hypothesis considers three concomitant factors: a chemical factor--one of the many substances used during polymerization, and particularly vinyl chloride monomer, a physical factor--microtraumas of the fingers during manual cleaning, individual susceptibility), the pathogenetic mechanism (in particular: the role of skin, respiratory, or digestive system, as entrance door), a method (or test) to screen subjects potentially predisposed to the disease. In our view acroosteolysis of manual tank cleaners in PVC production is an occupational disease which is distinct from "vinyl chloride disease" as identified by Viola (1974)."
[2]

That's a puzzler alright. PVC was first produced commercially back in the 1920's and yet this condition didn't appear until the 60's. So what changed? And what is there that the workers would have been exposed to that would have led to acroosteolysis, such a very rare and unusual condition? Despite what the doctors stated, I doubt that it is the PVC itself as workers that process PVC in all it forms don't seem to suffer this way. Most of the additives to the PVC would be added in a post-polymerization operation (having all those compounds around during the polymerization would be a nightmare). So what was the cause?

Given that the condition amongst workers has extinguished itself, I doubt that we will ever know what the cause was.


[1] If I am parsing this word correctly, acro- refers to the extremity, osteo- refers to bone and -lysis refers to the breaking down. Acroosteolysis - a good name.

[2] That second to last sentence needs some help, but it's beyond me as to how to rewrite it correctly, so I left it as it was originally written.


Previous Years

August 6, 2014 - So you want to develop sustainable polymers, do you?

August 6, 2013 - Where There's Smoke, There's Bad Smells

August 6, 2012 - The Secrets of Oobleck Revealed - Partially

August 6, 2010 - Backlash on BPA - Infertility Report

Friday, July 31, 2015

Maybe this is why the Philae Probe didn't "Stick the Landing"

The Philae lander that made (multiple) contacts with the 67/P comet last November has finally reported back some data on the chemistry at the surface. And it appears that there is a polymer, polyoxlmethylene (POM) amongst the mix. The official report is behind a firewall (which means I haven't read it), but there is also extensive reporting by Carmen Drahl (formerly of C & E News) and C & E News itself.

Whenever I think of POM, two thing immediately come to mind. The first is that this polymer probably has more names associated with it than any other polymer. POM is also commonly referred to as acetal, polyacetal, and Delrin (the latter being a tradename that is well on its way to becoming generic). Most other polymers have only a couple of names associated with them.

But the other immediate thought is POM is well known for it's low coefficient of friction (COF) - it's excellent for making plastic gears and other parts that slide past each other. So is the low COF part of the reason that the probe had such a difficulty in landing and staying landed?

Don't laugh. There may be lots of polymer on the surface

"If the polymer covers much of the comet, it could explain the object’s dark colour..." For such a strong visual effect, the polymer is would have to be more than just a monolayer. Additionally, "The polymer may also be masking signals from other interesting compounds formed earlier in the comet's history...", again, indicative of a thicker layer. (And did you notice how junky polymers are already taking the blame polluting up the comet.)

Landing a probe on any comet will always be challenging since the gravitational attraction is so low. But having a slippery surface is only going to make matters worse. This is still mostly speculative, but if it turns out in the future that there actually is a slippery, thick layer of POM on the surface, well, you read it hear first.



Previous Years

July 31, 2014 - Polyprefixicide

July 31, 2012 - Accelerated Aging, Flash Photography and Museums

July 31, 2009 - "It's all about the Entanglements"

Thursday, July 30, 2015

Polydopamine

One of the more fascinating puzzles in contemporary polymer science is polydopamine. As you might guess, this is made from polymerizing dopamine, a fairly simple molecule:
Dopamine
Even though this monomer has been polymerized and extensively studied for 8 years, there still is disagreement on what the structure of the polymer is. And this has nothing to due with whether the polymerization proceeds through the 3- or 4- hydroxy group. The hydroxy groups are not part of the polymer's backbone (as far as anyone can tell!).

Look at this rogues gallery of structures that have been proposed:
Possible structures of polydopamine
Source ($) and Source (OA)

All from such a simple monomer. Heaven forbid someone would want to copolymerize something in along with it.

While polymer science is fairly advanced and the number of good mysteries is being reduced, I'm glad something like this can come along once in a while to keep us on our toes.


Previous Years

July 30, 2009 - Class Action Junk

July 30, 2008 - Getting Violent over Glass