Polystyrene

Polystyrene, a versatile plastic, has been produced since its discovery in 1930 by the free-radical polymerisation of styrene. Originally known for its hardness, colourlessness and brittleness, pure polystyrene (PS) is also distinguished by a remarkable brilliant surface gloss. It shows remarkable resistance to acids, alkalis and alcohol, although it is susceptible to many non-polar solvents.

Despite its clarity and hardness, polystyrene has some weaknesses. It has low toughness, which makes it particularly prone to fracture under impact loads. Nevertheless, it offers impressive water-clear transparency, and its refractive index number to ISO 489 is 1.59 at a thickness of 1 mm. When polystyrene is coloured, it loses its transparency and becomes opaque.

Through copolymerisation, polystyrene can be developed into high-quality copolymers such as styrene-acrylonitrile (SAN) and acrylonitrile-styrene-acrylate (ASA). These copolymers expand the possible applications of polystyrene and improve its mechanical properties as well as its weather resistance.