Polystyrene is an aromatic polymer made from the aromatic monomer styrene,
a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. Polystyrene is a thermoplastic substance, normally existing in solid state at room temperature,but melting if heated (for molding or extrusion),
and becoming solid again when cooling off.Pure solid polystyrene isa colorless, hard plastic with limited flexibility.It can be cast into molds with fine detail. Polystyrene can be transparent or can be made to take on various colors.