DURABILITY OF RUBBER-MODIFIED POLYSTYRENES

摘要

Five commercially available rubber-modified polystyrenes were subjected to 160°F storage and to outdoor exposure for periods of up to three years. The Izod impact strength, flexural strength, flexural deflection, and flexural modulus of each material were determined at frequent intervals over this period. All the materials tested suffered some ad?verse effects during prolonged storage either at 160°F or outdoors. The ratings given to the five materials varied, de?pending on which of several properties was under consideration. Since the prin?cipal purpose of modifying polystyrene with rubber-type polymers is to increase its toughness and its resistance to shock loads, the Izod Impact Test was used as the primary criterion of durability.