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    Plastics Chemists: Don't Be Ashamed
    By Enrico Uva | November 8th 2012 12:00 AM | 13 comments | Print | E-mail | Track Comments
    About Enrico

    I majored in chemistry, worked briefly in the food industry and at Fisheries and Oceans. I then obtained a degree in education. Since then I have...

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    There’s irony in having small bits of floatable plastic debris in the Pacific, even if the trash, although worrisome,  doesn’t look like anything most of the public imagines.   Millions of years ago, many of the hydrogen and carbon atoms within these man-made polymers were part of marine life. Death, deposition and pressure simplified the organic molecules of the dead. Then a species that indirectly evolved from these oceanic ancestors accidentally stumbled upon a crude liquid. Eventually they learned to use not only its energy content but its building blocks. Some of these were linked into molecular chains that could be molded into any shape. But these chains proved to be resistant to the usual degradative action of bacteria and fungi.

    I curse plastic only when it breaks. Its other problems are amplified by human behaviour. We can't hold grudges against diligent chemists, and they should not feel guilty. They discovered the catalysts that made plastics more affordable and kept devising recipes in order to suit practical needs like placing side chains with hydroxyl groups on a contact lens polymer that could attract enough water to lubricate the eyes.  

    Yet perhaps because of the negative connotations of plastic, even chemistry professors writing organic chemistry textbooks for freshmen avoid the topic. The classic and otherwise excellent Organic Chemistry by Morrison and Boyd published between the late 1950’s and 70’s devoted only 8 of its 1183 pages to plastic. One could argue that the basics have to be covered adequately before one can understand how high temperatures can induce petroleum’s larger molecules to become free radicals, which with rapid cooling, convert into small, unsaturated hydrocarbons. One of those products, ethylene, is then polymerized into polyethylene which is used in wraps, squeeze bottles, disposable gloves, garbage bags and to weld cracks in kayaks.

    But Morrison and Boyd wrote a thesis relative to three recent popular organic chemistry textbooks, which only devote between one paragraph and a single page to plastics. And yet while sitting on a chair cushioned by polyurethane, I look around me and notice the acrylo-nitrile-butadiene-styrene(ABS)on my keyboard and mouse, two polyester backpacks on the floor and a polypropylene pot under my avocado tree. Students should learn how such ubiquitous substances are synthesized and that they have different tensile strengths and varying resistance to substances like alcohols.

    On the internet there are still people worrying about bisphenol A (BPA) leaching out of plastic pots and getting into their herbs and marijuana. For starters, polypropylene  production does not use BPAs. In addition, this year (2012) Health Canada, which banned BPA from plastic baby bottles in 2008, reassessed dietary exposure to the chemical and found that it was lower than what was previously estimated. They concluded that exposure to BPA through food packaging is not expected to pose a health risk to the general population, including newborns and young children. Other regulatory agencies in the United States, the European Union and Japan agreed with their analysis. The average exposure was 0.055 micrograms per kilogram of body weight per day. That’s a concentration equivalent to a little less than three drops in an Olympic sized swimming pool (2.5 million liters). 

    While China’s economy has mushroomed in the last two decades, its short-lived plastic exports have found their way into the world’s still largest economy, the United States. At the same time, we’ve had computer, electronic game and phone revolutions, all of which have fed an exponential growth in the amount of plastic found in municipal waste. The only plastics that can be recycled economically so far, and in part only because China buys most of the refuse, are high density polyethylene(HDPE), polyethylene terephthalate (PET) and polystyrene. Milk jugs are made of HDPE and PET is found in ziploc food storage bags, disposable water bottles, soft drink bottles and recently, vegetable packaging. The latter used to be code 6(polystyrene), which shrinks in the microwave when heated and is not as easily recycled.  in 2011, only 31% to 44% of Canadian homes had access to centers that could handle polystyrene, depending on the variety of that specific plastic.

    Although more recycling can be done---the recycling rates for those two materials in the U.S. are only in the 30% zone---people have not warmed up to the 3 R's“reduce” option. At least in theory, we could buy less plastic stuff when possible and drink tap water. To avoid plastic cups and cutlery at parties, spike the punch and get the guests to do the dishes. *
    Such an approach does not have to negatively impact the economy. 
    Money can be spent on non-plastic products and services and on paying down debt, which  in the long run increases purchasing power.  

    The idea of biodegradable plastics is appealing. If they are produced on a global scale, however, there could be undesirable effects, especially if the raw materials are grown on land and not extracted from algae. The land needed for additional biomass could lead to deforestation, and then subsequent growth of crops won’t compensate for CO2 released by decomposing trees and biodegradable plastic. One thing about conventional plastic: when not incinerated but kept in the home or in landfills, it does, at least for a century, keep petroleum’s carbon away from the atmosphere. And no one will throw away Canadian plastic $20s.


    * In the sixties throughout the 1980's, a party with any combination of my 14 aunts was guaranteed to be free of plastic utensils.  After cooking a mind-blowing meal for 30 people, they were happy to chat among themselves and wash dishes faster and better than the average machine while the men played Italian card games---another activity with a low environmental impact. :)
    People often forget that we pay for packaging. If it's good enough for stores to keep thing visible and organized, why not do likewise?

    Additional Sources:

    Comments

    Thanks for reminding me why people don't trust science any more.

    Pretty much like all the other assholes in academia, the only thing you've persuaded me is that you're a tiny dicked little man who never got over missing the prom and can't handle people disagreeing with you.

    You can whine all you want, but the truth still remains:
    Plastic monomers intercalate into the basepair stack of B and Z DNA. Plastic softeners are proven endocrine disruptors. Equilibrium thermodynamics dictates that an appreciable fraction of each one of those will be present where plastics are used.

    "Plastic monomers intercalate into the basepair stack of B and Z DNA."

    There are thousands of different plastics. Saying "plastic is bad" is like saying "chemicals are bad." Which ones? None of the best-studied DNA intercalating agents that I know of (e.g., ethidium bromide) are used as plastic monomers, so you're going to have to provide some more information here.

    "Plastic softeners are proven endocrine disruptors."

    So are certain foods, like soy and nuts. The question is one of dosage and physiological relevance.

    "Equilibrium thermodynamics dictates that an appreciable fraction of each one of those will be present where plastics are used."

    I think the term you're looking for is "chemical equilibrium." And once again, the question is a matter of dosage. Everything is poisonous in a high enough dose, but most things are not poisonous in low doses.

    UvaE
     can't handle people disagreeing with you
    Hmm... Who is the one resorting to juvenile insults simply because a different viewpoint is being presented ? 

    Very interesting facts about plastics. Thank you for sharing.

    vongehr
    There is much in words. "Plastic" just sounds cheap, thus ...
    Plastics generally, categorized according to the polymer bond that makes them plastics, should include our skin, though I have never seen this being done anywhere.
    UvaE
    It's a good point. Someone wrote that it was polymer with weak barrier properties.
    rholley
    "Plastic" just sounds cheap, thus ...
    Quite so, Sascha.  Take, for example
    I was born with a plastic spoon in my mouth
    from Substitute, by The Who.

    One problem I found is people simply transferring designs over from metal, without understanding the different material properties.  For example, tool boxes that break at the hinges, because they have not taken into account the need to make them bigger, especially since the tools themselves are still made of metal.


    Robert H. Olley / Quondam Physics Department / University of Reading / England
    UvaE
    I was born with a plastic spoon in my mouth
    From that same song:


    Substitute your lies for fact
    I can see right through your plastic mac
    Plastic has also long been a metaphor for what's not authentic and so "un-life like", and yet plastic IV tubing saves lives every day in hospitals. 


    Old nurses are not exactly nostalgic about the days when such tubing did not exist.
    Ahhhh yes the good old days....when nothing was disposable. IV containers were glass, tubing latex and needles metal, bedpans were metal, anything that went on a bed was cotton or linen, GI suction was "Wangenstien" with a glass collection bottle, and pleurovacs were glass bottles in a line. You would have to clean everything, check the needles for barbs or dullness, and send them to central processing, then wait for them to return. Everything cleaned, processed and reused. We have come a long way!
    Posted by: oldnurse | Oct 31, 2007 3:47:58 PM _http://medscapenursing.blogs.com/medscape_nursing/2007/10/what-if-we-neve.html


    MikeCrow
    As I read that it played out Daltrey singing those words.

    I grew up near Akron, and with all of the polymer companies in the area, I believe the University has had a plastic's institute for a long time.
    Never is a long time.
    rholley
    Quite so, Enrico.

    You might enjoy my Polymer Picture Gallery, which I’m slowly updating, and also the History of the Reading Polymer Group.
    Robert H. Olley / Quondam Physics Department / University of Reading / England
    UvaE
    Thanks for the links. Those are great electron micrograph images of polyethylene crystals and lamellae.
    Interesting idea: carbon sequestration = plastic in landfills

    I've just had my first colonoscopy.

    The hospital is full of plastics--supple, sterile, sturdy, efficient plastics.

    I love plastics.

    I live in the country where people throw plastic cups, plastic straws, plastic bags, plastic boxes out their windows and clog up our streams and endanger our cows (a cow will unknowingly eat plastic with grass).

    I hate plastics.

    "Plastics." "Chemicals." "Pesticides." I love them all. I hate them all. Like "people."

    Generalize at your own hazard.