Why are some plastics recyclable and others are not?

Do you recycle your plastic packaging? Some plastics can take up to 1000 years to decompose...

16th June 2017
Why are some plastics recyclable and others are not? (Getty)

Asked by: Mark Warmsley, Southampton

Most of the plastics we use are either thermoplastic or thermosetting.

Thermoplastics include acrylics, nylon and polyethylene (polythene). As you heat them up they get soft, so they can be shaped into any form you like, which also makes them easy to recycle. Milk containers can be melted and reformed into furniture, plastic water bottles become fleece jackets, and hard bottle tops can get a new lease of life as storage boxes.

Thermosetting plastics, like Bakelite or polyurethane, are different because they harden as you heat them. Once they have set, you can’t melt them. This makes thermosetting plastics almost impossible to recycle. 

 


Get more fascinating Q&As from BBC Focus magazine by following @sciencefocusQA