A hard, transparent, glasslike thermoplastic resin (see structure). Polystyrene is characterized by excellent electrical insulation properties, relatively high resistance to water, high refractive index, clarity, and low softening temperature.
High-molecular-weight homopolymers, copolymers, and polyblends are used as extrusion and molding compounds for packaging, appliance and furniture components, toys, and insulating panels. Styrene-butadiene copolymers are still used for automobile tires and in various rubber articles. The effects of blending small amounts of a rubbery polymer, such as butadiene-styrene rubber, with a hard, brittle polymer are most dramatic when the latter is polystyrene. The polyblend may have impact strength greater than ten times that of polystyrene. Various combinations of complex polyblends and interpolymers of acrylonitrile, styrene, and butadiene (ABS) resins are important as molding resins. ABS resins are also used as toughening agents for polymers such as polyvinyl chloride. Polystyrene is also used in combination with paints. The homopolymer and polyblends are used for panels or liners for refrigerator doors. Polystyrene may also be fabricated in the form of a rigid foam, which is used in packaging, food-service articles, and insulating panels. See also Acrylonitrile;
