Almost every single piece of plastic ever made still exists. As an alternative to the traditional plastics, we are hearing a new term more and more often – bioplastics. Are bioplastics better? Dr. Maia McGuire answered this question in the last Water Wednesdays.

What are bioplastics?

Traditional plastic is made from petroleum-based raw materials. Bioplastic is made from plants or other biological materials. The terms “bioplastic,” “biopolymer,” and “bio-based plastic” are all used to describe a plastic substance made from plant material.

How biodegradable are bioplastics?

To answer this question, we need to clarify some terms.

Degradable: All plastic is degradable, even traditional plastic. It can be broken down into small pieces or fragments, however, does not mean the materials will return to nature.

Photodegradable: Since plastic is made of polymer of carbon, it breaks down more readily in sunlight.

Biodegradable: All carbon-based, or organic matter will eventually biodegrade. The process can also be called “composting,” but composting requires more specific settings. Biodegradable plastic can be broken down into water, carbon dioxide and compost by microorganisms under the right conditions. The right conditions mean in the presence of oxygen and water and at warmer temperatures.

Compostable: Compostable plastic will biodegrade in a compost site. Some bioplastics, such as PLA plastics, are called compostable. PLA is polyactic acid. It is typically made from the sugars in corn starch, cassava or sugarcane. They will not biodegrade in the environment or in a backyard compost pile. They need to be sent to an industrial composting facility, where composting takes place at a much higher temperature and oxygen than home composting piles. If the products are not composted under these conditions, they will likely persist in the environment for decades or longer.

Are bioplastics more more environmentally friendly than petroleum-based plastics?

Plastics that have similar chemical compositions have similar properties. Both may contain chemicals called plasticizers or additives. They make the materials more flexible or stiffer. These additives can still contain harmful chemicals, such as phthalates, which may affect hormone metabolism. In addition, harmful chemicals tend to attract more persistent organic pollutants in the ocean.

To learn more about bioplastics, please read Bioplastics—a better option for the environment?

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