Polystyrene (PS) is a thermoplastic polymer which can be extruded, injection moulded, and vacuum formed. It can be rigid or foamed – expanded polystyrene (EPS), and is one of the most widely used plastics. It is naturally transparent but takes up colour easily. The material has low water permeability and is inexpensive to produce thus it is an ideal material for products being made in very large numbers. It has a tendency to be brittle but in its toughened form is known as HIPS or high impact polystyrene.
Styrene polymers were first developed in 1929 by I.G. Farben and by United States Dow Chemical Company circa 1935. It was not until after the Second World War that it became widely used commercially.
In its solid form polystyrene is used for many everyday items such as the Bic Biro case, disposable razors, CD and DVD cases, Airfix kits, and in its expanded form as disposable food containers such as clam shell boxes and coffee cups, packing material, building insulation etc.
Polystyrene in all its forms is readily recycled. EPS scrap can easily be added to products such as EPS insulation sheets and other EPS materials for construction applications.