Plastic Recycling

Plastic Recycling | Biodegradable Plastics | Plastic Recycling Companies

Recycling plastics as opposed to glass or metallic materials, poses some exceptional challenges from a recycling perspective. Plastics or plastic bottles are much harder to break down, which is due to the high molecular weight of large polymer chains. Another way of stating this problem is that, since a macromolecule interacts with its environment along its entire length, its enthalpy of mixing is large compared to that of a small organic molecule with a similar structure; thermal excitations are often not enough to drive such a huge molecule into solution on their own. Due to this uncommon influence of mixing enthalpy, polymers must often be of nearly identical composition in order to mix with one another. To take representative samples from beverage containers, the many aluminum-based alloys all melt into the same liquid phase, but the various copolymer blends of PET from different manufacturers do not dissolve into one another when heated. Instead, they tend to phase-separate, like oil and water. Phase boundaries weaken an item made from such a mixture considerably, meaning that most polymer blends are only useful in a few, very limited contexts.

Another barrier to plastic recycling is the widespread use of dyes, fillers, and other additives in plastics. The polymer is generally too viscous to economically remove fillers, and would be damaged by many of the processes that could cheaply remove the added dyes. Additives are less widely used in beverage containers, plastic bottles and plastic bags, allowing them to be recycled more frequently.

The use of biodegradable plastics is slowly on the increase. Plastic recycling companies are starting to develop, however most plastic recycling to date is very little and in most places none. There is issues with recycled friendly plastics for recycling, the recycled plastic is less valuable and cannot be mixed with plastic that is not good for recycling.

Many such problems can be solved by using a more elaborate monomer recycling process, in which a condensation polymer essentially undergoes the inverse of the polymerization reaction used to manufacture it. This yields the same mix of chemicals that formed the original polymer, which can be purified and used to synthesize new polymer chains of the same type.