Monday, March 02, 2009

Corn plastic: good or bad?

I'm sure that most of us have been introduced to plastic-like products that are actually made of corn. We use them every Wednesday night at church, so I thought I would look up some information on them.

Corn plastic is made of polylactic acid (PLA) resin. This product is considered environmentally friendly because it's made from renewable materials and it is compostable (i.e. it biodegrades under certain conditions). PLA is produced by the fermentation of dextrose, which is extracted from the starch in milled corn. The lactic acid is then converted to lactide, and these molecules are converted to the polymers that make up the "plastic".

At first, this product seems like it would be a perfect solution to overconsumption of plastics, which make up 25% of the volume in dumps. However, it does have some negative characterstics. The author of this Smithsonian article writes that the PLA requires a specific environment to break down. A compost facility that holds compost at 140 degrees Fahrenheit for 10 days can break down the products, but a corn-based cup thrown in a dump or backyard compost heap could last just as long as a plastic one.

Still, PLA requires 65 percent less energy to produce than plastics and produces 68 percent fewer greenhouse gases. Not to mention that they contain no toxins. In the meantime, I expect that I'll continue to recycle any plastic I use, but I won't complain if I get handed a corn product or two.


Source: http://www.smithsonianmag.com/science-nature/plastic.html?c=y&page=1

1 comment:

Anonymous said...

I was at a conference/workshop and chili was served in those types of bowls. The chili was hot and the bowls began to melt as chili was poured. Great concept, but not perfect.