Friday, September 21, 2007

Green Plastics

Author: E. S. Stevens
Published: 2002

There is a lot of science in this book. Skimming those sections is okay. The point still comes across that plastic materials can be made not only biodegradeable but also compostable. What is required is markets and the will.

Interesting to learn that the problem with plastics is not their feedstock necessarily, although the petroleum, natural gas, and coal are limited resources. The toxicity of the stew is due to the additives included to make the plastic stable and durable. The danger of leaching later is compounded by the difficulty to recycle some plastics due to the additives fouling the plastic stew during reprocessing.

Stevens makes the point that current plastics are simply over-engineered for their purpose. A sandwich bag doesn't need to last 50-100 years. Some applications for plastics could be re-engineered right now to starch based products which have very short shelf lives.

And corn starch is, as of the writing, the cheapest and therefore most economically viable option. I thought I had read about problems composting corn starch, but searching around proved my memory faulty. This seems to be the way to go in the short term. Some kind of new 'chasing arrows' labeling system is needed though so that mass produced products will have a clear indication of their compostability.

No comments: