Plastics

From Green Plastics

Plastics are a class of material that has one or more polymers as its primary ingredient, that is shaped by flow when it is processed (usually using heat), and that is solid in its final form. Plastics can be made up of many different kinds of polymer, and can be processed in many different ways, but as long as they satisfy these three conditions, they are bona fide plastics.

The general "recipe" for any kind of plastic is a combination of three ingredients: a polymer, one or more plasticizers, and one or more additives. These ingredients can then be processed into different shapes, resulting in a wide variety of different materials with different properties.

Polymers

Main article: Polymers

Traditional plastics are made up of synthetic polymers. In fact, over 90% of all plastics produced today are made from only five polymers: polyethylene, poly(vinyl chloride), polypropylene, polystyrene, and poly(ethylene aveterephthalate). All of these are synthetic polymers. However, environmental concerns have increased interest in green plastics that are made from biopolymers.

Plasticizers

Main article: Plasticizers

Additives

Main article: Additives

The pure polymer resin by itself may not always have the physical properties needed in the final product: it may be strong but too brittle, flexible but too elastic, or flexible and elastic but just plain ugly. Just like the polymer material itself, additives come in different varieties: some can be found in the environment, while others are manufactured. The amounts and types of additives used in manufacturing plastics are another factor that influence how environmentally-friendly they are.