Polystyrene (PS)

Polystyrene is either used as a thermoplastic workable material or as foam (expanded polystyrene). Polystyrene is resistant to aqueous lyes and mineral acids, it is not resistant to non-polar solvents such as benzine and longer-chain ketones and aldehydes.
It is also UV-sensitive.
The density of solid polystyrene lies between 1040 and 1090 kg/m³, expanded polystyrene (EPS or PS-E) has a density between 20 (building insulation) and 90 kg/m³ (ski helmets).
Polystyrene burns with a bright yellow, highly sooting flame and a flowery, sweet odour of styrene.
The fumes should not be inhaled, they are possibly harmful to health because apart from styrene they can also contain other decomposition products.
Compared to solid polystyrene, expanded polystyrene has a low mechanical strength and elasticity. It is white and opaque and has a very low thermal conductivity.