There is a new kind of plastic additive to induce biodegradation in conventional polymers. It is designed specifically to cause biodegradation of polymers in landfills and in natural bodies of water. I call this class of additives, microbiodegradable. This is completely different than oxodegradable additives. There is no UV light or heat treatment phase needed to initiate biodegradation. All degradation caused by using these additives is biodegradation, because no catalysts are used. See http://earthnurture.com to learn more.
This particular study is focused on plastics derived from petroleum and natural gas, not bio-based plastics. The additives they are to be treated with will accelerate anaerobic biodegradation, which implies that the process is for hydrobiodegradable plastics. Using at least one of the additives, either methane or humus and CO2 can result, so yes, those add to the greenhouse problem.
But oxo-biodegradable plastics aren't entirely "clean", either. Their biodegradation, which involves metal salts as catralysts, leaves behind tiny fragments of metals and plastics.
It seems that the current state of plastics biodegradation solutions either add CO2, or don't entirely biodegrade, or both.
@Symphony Environmental: The plastics described in this article appear to be different from either oxobiodegradables or bio-based (PLA) biodegradable plastics. They are designed to be broken down by anaerobic bacteria in a landfill; as you point out, this will produce methane, but the accompanying press release discusses capturing this methane and using it for energy production. You're right that this is probably not the best solution from a climate change perspective.
Oxobiodegradable plastics are not without their problems, either. They can't be composted or recycled, and if they make it into a landfill, they won't break down. As you say, they are designed to break down in the open environment. What his means is that, perversely, you may be better off throwing them out of the window of your car than trying to dispose of them by normal means.
As Tim pointed out, biodegradable plastics are the "fat free donut" of plastics. This is a good analogy. If you want to lose weight, you shouldn't eat too many donuts; if you want to live a sustainable lifestyle, you shouldn't use so much disposable packaging or so many disposable products. My opinion is that, rather than searching in vain for a fat free donut, you're better off simply eating your fruits and vegetables - where "eating your fruits and vegetables" means reduce/reuse/recycle, instead of trying to come up with a guilt-free way to maintain our disposable lifestyle.
I would like to clarify a few points. Oxo-biodegradable additives add a very small amount to the cost. Using bio-based plastics however, would add approximately 400% to the overall cost.
Secondly, unlike bio-based plastics, Oxo-biodegradable plastic has the same performance as conventional plastics during its useful life. Several of the comments I read mention anaerobic decomposition, but this is highly undesirable as it creates methane and adds to the green house gas problem.
Oxo-biodegradable plastics are designed to deal with the problem of plastic litter in our open land environment and oceans. They have been tested to international standards and are verified by published science.
Biodegradable polymers have been the fat free donut of the polymers. They have been something that always seem possible but never really worked well. The use of additives to help during anerobic decomposition is great. This opens the door to non-corn based polymers that can degrade naturally. It would be good to see the rough cost of the additive.
@William: you're right, "Because we've always done it that way" is one of the most maddeningly stupid justifications for anything, especially when the way we've always done it is obviously not working. However, inertia is something which needs to be taken into account in industries as well as mechanical systems.
@Rob Spiegel, Alexander Wolfe, and everybode else talking about regulatory compliance: Ann is exactly right that this story really has nothing to do with government regulations. This is about industry and academia coming up with voluntary standards in order to better define what biodegradability means for a specific class of plastics. Given that, in a mostly unregulated environment (with the exception of California), the term "biodegradable" has been somewhat abused by applying it to plastics which had poor properties, were environmentally unfriendly, or both, this seems like quite a sensible move.
Alex has a good point. Because the electronics industry (many industries acturally) is global, U.S. companies have to adhere to European Union regulations. While the EU provides for input from industry, European reulations tend to be more advanced than anything we could expect on the federal level in the United States.
Globally, the whole industry has to meet the strictest regulations among the markets where products might be sold.
Many companies in the electronics industry are fine with regulations that do indeed make sense from an environmental POV. Much opf the complaints about EU regs have to do with regs that were passed without scientific scrutiny.
That aspect has changed in the EU in recent months. The EU responded positively to calls for scientific inquery by IPC earlier this year.
Although plastics make up only about 11% of all US municipal solid waste, many are actually more energy-dense than coal. Converting these non-recycled plastics into energy with existing technologies could reduce US coal consumption, as well as boost domestic energy reserves, says a new study.
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