CONTACTS: Smithsonian’s “Corn Plastic to the Rescue,” www.smithsonianmag.com/science-nature/plastic.html; NatureWorks, www.natureworksllc.com.

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11 Comments

1. 1. concernedchemist 12:21 AM 7/2/08

   PLA is touted as carbon neutral? Has anyone done an assessment of the energy inputs required to grow and harvest the corn and then convert it to PLA and compared them with those for producing conventional plastic? Since the carbon in a conventional plastic isn't released unless it is burned the energy inputs in manufacture are what determine the carbon footprint, not where the carbon in the plastic came from. From this standpoint I strongly suspect PLA products actually score worse than traditional plastics in terms of atmospheric carbon release.

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2. 2. rcdohare 05:27 AM 7/2/08

   This is a remarkable effort to reduce CO2 by changing mind set from normal plastic to bio-degrable plastic consumption.I thing if you burn, it is produce less pollution than normal plastic burning. Most important is that if society is not able to handle the plastic, than nature will take care of without any harmful effect . Whereas in normal plastic if not collected, left for natural degradation it may take 500years in somekind of plastic. Till than plasic location site can not produce anything. most of the drainage system clogged in INDIA and many other nation. Many animals (COWS) eat up this plastic & died by clogging of their instentine.
   rcdohare25@yahoo.co.in

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3. 3. dannyuchiha 07:52 AM 7/2/08

   Although its usefulness is still questioned, I think we can all agree that this is a first step towards a greener earth. There may be more questionable inventions or ideas, but the important thing is that we as a society are actually more and more concerned about our environment.

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4. 4. Paul.Cline 11:25 AM 7/2/08

   Please keep in mind that genetically modified crops have a known upside in addition to "unknown future costs." These crops are measurably increasing yields while reducing the demand for fertilizer, pesticides, and water. And while gene splicing is a new technique we have been modifying wild plants to make crops for thousands of years.
   All the best,
   Paul

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5. 5. dannyuchiha 01:15 PM 7/2/08

   I think you're right. It's important to focus on the benefits and try to support new, environment-friendly ideas. Every idea needs to be supported, because if it's not good in itself, it might be a predecessor to a better one.

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6. 6. joshhaglund 04:51 PM 7/2/08

   I'm not at all thrilled about PLA. Plastics are just as carbon neutral -- that whole

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7. 7. joshhaglund 04:57 PM 7/2/08

   My comment got chopped...
   
   I'm not at all thrilled about PLA. Plastics are just as carbon neutral -- that whole not degrading in landfills thing. It's got the same carbon effect as leaving the petroleum underground. And PLA requires a TON of energy in fertilizer, transport and processing putting its production closer (tho i don't have numbers) to the impact of plastic.
   
   Furthermore, while PLA can't be recycled, plastic can. A compostable plastic would be wonderful. But you just try composting PLA container in your compost -- it doesn't break down and (like the article said) proper infrastructure does not yet exist.
   
   So, how about we just stick with conventional plastic when plastic is necessary? We can use more fiber based materials where appropriate and reuse more.
   
   But PLA, it's green washing to me. Just because it comes from a plant doesn't mean it's natural or better for the environment.
   

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8. 8. jevans@computer.org 07:08 AM 7/3/08

   One big issue with plastic is that it finds its way into the marine environment. It may be that PLA products degrade faster than petroleum products in the oceans. This alone would be worth the effort of conversion, as petroleum plastics are not broken down in the ocean and are causing a large impact to marine life when ingested. Since we are at the top of the sea-food food chain, we will ultimately be ingesting these chemicals.

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9. 9. biogreen2 07:23 PM 1/22/09

   There are a lot of problems with PLA - If we made all of the plastic disposable items used in the world every year, it would take one hundred million tons of corn to make it. That would lead to mass starvation in the third world, as that represents at least 10% of the world's grain supply. Also, in landfills, PLA exudes methane when it decomposes-and methane is a potent greenhouse gas. It also takes a huge amount of diesel to grow, fertilize, ship, and process this corn. As a practical matter, it is also not recyclable. The alternative? Oxo-biodegradable plastics. See http://biogreenproducts.biz for full information. -Tim Dunn

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10. 10. scubasteve 08:44 AM 2/8/09

    We are all responsible to openess to a future that embraces many solutions; landfill managment to tap into the vast energy resource now dormant, PLA has identified a need for biopolymers in a world where recycling is less than 5% of total plastic processed. The huge balance of plastic waste is a source of energy, recycled efficiently waste plastic is a source of carbon saving in new products. The ability to make existing polymers biodegradeable is also a new technology that taps into the solution offered by the PLA technology but without affecting the water, land, fertilizer, etc. intensity needed to support a farmed base raw material source.

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11. 11. R.Pocius in reply to concernedchemist 04:59 PM 1/21/12

    This argument is settled quite quickly by referring to an article published in August, 2000 in Scientific American Magazine. in it, two American Scientists from two separate Universities, published their findings on this subject.
    It clearly states that although the main goal of PLA was to reduce our dependance on Petroleum Products by replacing conventional plastics with the PLA Corn Based alternative, it does just the opposite. PLA actually uses more Petroleum Energy than regular Plastics. So right off the start it has failed it's main purpose. Add to this the fact that Corn uses more Nitrogen than any other food and this runs off, down to the rivers and eventually the oceans, thereby creating Dead Zones devoid of Oxygen in which no life can survive. We now have a 10,000 square mile Dead Zone just off the Mississippi Delta which continually grows due to excess Nitrogen and other chemicals, pesticides, etc.
    Gasoline takes 1 gallon of water to drive a car 1 mile.
    Ethanol takes 90 gallons of water to drive a car 1 mile.
    45% of US Corn production goes to making Ethanol and PLA.
    Corn prices are rocketing up and so are the death rates of 3rd world children who cannot afford Cornmeal anymore.

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