This post is part of our definitions series on “eco-lingo” and technical terms.
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photo credit: Tecknor Apex
The term “bioplastic” generally refers to plastic made in whole or in part from plant-derived renewable resources and/or compounds that are subject to degradation from microbial action.
The “and/or” is key and this is where the confusion comes in. ”Bioplastic” is a catch-all term that refers to several different classes of plastics. For example, some petroleum based plastics (non-renewable resource) can be made in such a way that they biodegrade over time, leaving behind a toxic residue. And some “bioplastics” made from renewable resources will not biodegrade.
While not a very new technology, bioplastics have only recently begun to take off in the U.S. There have been many new products hitting the shelves with claims that they are a cleaner and greener option. But not all of these products are interchangable with each other, or with the conventional plastics that they would replace.
To help you sort your plastics, here is the difference between “degradable”, biodegradable”, and “compostable”:
Degradable plastics are essentially meant to address the “lingering” characteristic of traditional plastics that can take decades or longer to break down, persisting as litter or consuming valuable landfill space. Degradable plastics are those that are engineered to break down into fragments, particles or residue more rapidly than conventional plastics, but “degradable” does not itself define what the constituent materials are.
Biodegradable plastics are typically a hybrid of sythetic polymers and biomass or starch-based plastics. Like degradable plastics, they break down to a point, but are not 100% biodegradable unless they are marked “compostable”…
Compostable plastics are able to fully biodegrade without leaving toxic elements behind (made completely without the use of synthetic polymers); however, compostable plastics are not instantly ‘back to nature’. Although composed of biomass, most compostable plastics break down very slowly and often need the assistance of a commercial composting facility. The unfortunate misconception here is that one can toss a soy-plastic fork in a meadow after a picninc or in the backyard pile, and it will dissolve quickly. “Compostable” plastics can thus lead to litter and perhaps irresponsible consumer behaviors.
In part 2 of this post, I will discuss the recycling and end-of-use considerations of bioplastics.
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What exactly does “sustainability” mean? How about “green”, “eco” or “environmentally friendly”? The truth is that these terms are just vague enough to mean many different things to many different people. With the staggering array of “green” products, ‘lifestyles’ and concepts being promoted by marketers and environmentalists alike (as well as the necessary coining of new terms to match new ideas) our definition series aims to make sense of the rising tide of “eco-lingo” and technical terms.