“Breaking Down” the Types of Environmentally-Friendly Plastics
Biobased plastics ≠ biodegradable, recyclable, or compostable?
Are biobased plastics biodegradable? Not necessarily… Compostable plastics may not be recyclable either.
For example, a polyethylene (PE) packaging made from sugarcane-derived ethanol can be recyclable and biobased. It is important to note this PE is chemically identical to other PE made from conventional fossil fuel sources and is not compostable.
Another interesting case can be PLA or polylactic acid. PLA is a commonly used polymer that can be recyclable, biodegradable, biobased, and compostable. However, if a piece of PLA is thrown out into the ocean, it will not degrade even after 12 months, according to a study conducted by researchers from the University of Bayreuth in Germany. PLA is most effectively biodegradable in an industrial composting environment under elevated temperatures and specific conditions.
So what do these terms mean? Depending on whom you ask, different people define these environmentally friendly sounding terms differently. Generally speaking, these are some technical interpretations that can help you during product development.
Biobased plastics are plastics made at least partly from biological sources, e.g., sugarcane or corn. Please note that biobased does not necessarily imply biodegradable. Polyethylene may be biobased but, once produced, has the same limitations and advantages as polyethylene manufactured using petrochemical-based raw materials.
Biodegradable plastics are plastics that can be broken down by biological means, e.g., with bacteria or fungi.
Recyclable plastics may be plastics that can be recovered from the waste stream and turned into new plastic products. Because of how widely used this term is, there is an initiative to add new requirements for a product before it can be labeled “recyclable.” The new requirements might include the availability of recycling programs for typical consumers and the economics of the recycling process.
Compostable plastics are plastics that can be degraded under specific environments by biological means within a relatively short amount of time into materials that will not harm the utility of the remaining compost at a composting site.
Many entities supervise the use of these terms. For example, the Federal Trade Commission publishes guidelines for proper product marketing. The American Society for Testing and Materials (ASTM), European Committee for Standardization, International Organization for Standardization, and similar organizations set out standards for testing products. The Society of the Plastics Industry set out a coding system for plastic container labeling to facilitate recycling. When a product is advertised as compostable, it is often certified by institutions like Biodegradable Products Institute, DIN Certco, and Vincotte, according to ASTM D6400. When a product is advertised as biobased, it can be certified by the US Department of Agriculture, UL Environment, or others according to ASTM 6866.
Please note “oxo-degradable plastics” and “bioplastics” are other commonly used terms. “Oxo-degradable plastics” refer to plastics that contain an additive causing the polymer to fragment into smaller pieces under environmental exposure. Recently, the European Commission is calling on the restrictive use of this term.
“Bioplastics,” unfortunately, is still a poorly defined term and can mean biobased and or biodegradable plastics. It is best to ask for clarification when seeing the label “bioplastics” on a product.
Designing plastic products and wanting to help the environment? Contact our sales team or call 800-989-5594 to learn more about our custom additive package that suits your application needs.
Hoi Chun Ho, Ph.D.
Technical Service Representative