Plastic Recycling Information

Plastic recycling is the recovery of scrap and waste plastics and the subsequent reprocessing of these into useable materials. Plastics take a lot more to recycle than other materials like glass and metal due to a low entropy of mixing. Entropy is a measure of randomness of molecules in a system which deals with physical processes and whether they occur spontaneously. When plastics are melted together they seperate like oil and water do, they then set in these layers. Along the boundaries of these layers there are structural weaknesses making polymer blends limited in their use. Bearing this in mind it is essential to ensure plastics are of nearly identical composition to ensure they mix completely.

At plastics recycling facilities the majority of work involves the sorting of plastics into resin/polymer type often this is coupled with separation into colour type as well to ensure resultant plastics are as homogenous as possible. Some pre processing companies will crush bales and flake the seperated material to sell on to recycling companies. The recycling companies themselves will first check the batches to ensure the cleanliness and then a melting process will take place taking the polymers to a molten form where they can then be put into plastic pellet form for further processing into a product. Further processing would take the form of injection moulding, extrusion or pulltrusion.

Recent developments in the plastics processing industry allow mixed polymers to be recycled using sophisticated techniques such as thermal depolymerisation which effectively converts mixed polymers into petroleum which can be used as a fuel source.

The most common forms of current plastics recycling are in consumer beverage containers and carrier bags where less dyes and additives are used making them easier to recycle and subsequently able to be recycled more frequently.

See our recycling symbols page to identify 6 of the main types of plastic that each are represented by their own symbol. Interestingly, there are over 50 types of plastic currently used!