Bioplastics: Are They the Solution?

October 8, 2012

By Sarah (Steve) Mosko, PhD

Published in:

Throwaway living debuts after WWII
(Photo: Peter Stackpole, 1955)

Bioplastics are simply plastics derived from renewable biomass sources, like plants and microorganisms, whereas conventional plastics are synthesized from non-renewable fossil fuels, either petroleum or natural gas. It’s a common misconception, however, that a bioplastic necessarily breaks down better in the environment than conventional plastics.

Bioplastics are nevertheless marketed as being better for the environment, but how do they really compare?

The Problems with Petroleum-Based Plastics
The push to develop bioplastics emerges from alarming realities starting with the staggering quantity of plastics being produced, over 20 pounds a month for every U.S. resident, according to the latest numbers from the American Chemistry Council.

Conventional plastics do not biodegrade (defined below) within any meaningful human timescale – they just break apart into smaller plastic fragments. Also, the overall recycling rates for plastics remain fairly low, eight percent in the United States and 24 percent in the European Union in 2010 for example, in large part because plastic products contain unique proprietary blends of additives which prevent recycling of mixed batches of products back into the original products. So, unlike glass and aluminum which can be recycled in a closed loop, most plastics recycling is considered “down-cycling” into lower quality, hybrid-plastic end-products, like lumber or clothing, which aren’t recycled again. This means that, except for the fraction of plastic that is combusted for energy production, all plastics eventually end up as trash, either in landfills or as litter.

Petroleum and natural gas are actually organic substances, but why plastics synthesized from them do not biodegrade is straightforward. The exceptionally strong carbon-carbon bonds created to form the backbone of plastic polymers do not occur naturally in nature so are foreign to microorganisms which readily eat up other organic materials.

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Posted by Sarah (Steve) Mosko