Polystyrene

Polystyrene is a form of chemical compound that is mainly used for a wide variety of packaging. It is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry. Polystyrene is one of the most widely used plastics, the scale being several billion kilograms per year.
Polystyrene can be in either a thermoset or a thermoplastic form.