|This is the article describing green plastics. To view the article about the book called Green Plastics, see Green Plastics (book).|
Green Plastics, sometimes also called Bioplastics, are plastics that are biodegradable and are usually made mostly or entirely from renewable resources. Frequently there is also a focus on environmentally friendly processing. Green plastics are the focus of an emerging industry focused on making convenient living consistent with environmental stability.
Like all plastics, bioplastics are composed of a polymer, combined with plasticizers and additives, and processed using extrusion or thermosetting. What makes green plastics "green" is one or more of the following properties:
- they are biodegradable
- they are made from renewable ingredients
- they have environmentally friendly processing
Because different compounds can satisfy some or all of these criteria to different degrees, there are different "degrees of green" in green plastics. To evaluate how "green" a plastic material is, you need to ask three questions:
- how quickly can the plastic be re-integrated into the environment after it is no longer being used?
- how quickly are the ingredients that go into making the plastic created in the environment?
- how much pollution or waste is created during the process of actually making the plastic?
Traditional plastics fail on all three of these points.
Biodegradability (What happens to them?)
For bioplastics to become practical, they must have properties that allow them to compete with the current plastics on the market: bioplastics must be able to be strong, resiliant, flexible, elastic, and above all, durable. It is the very durability of traditional plastics that has helped them in the marketplace, and has been a major goal of plastics research throughout the years. However, it is exactly this durability that now has people increasingly worried. Now that we wrap our sandwiches in bags that will still be around when the sandwich, and even the person who ate it, are long gone, many people are wondering: have we gone too far?
There is a lot of current research going on concerning methods of decomposition. There is also research on controlling the time-line of biodegradation. One goal of this research is to make a product that is programmed-degradable: in other words, a product that allows you to control when and how it degrades, while insuring that the product remains strong while it is still in use.
Renewability (What are they made of?)
Processing (How are they made?)
|This article contains material that has been adapted from the Green Plastics book, copyright © 2002 Princeton University Press, with permission from the author.|