The effect of temperature on the fracture of rubber modified polystyrene

Brittle fractures were obtained in rubber modified polystyrene over the temperature range −120 to 20° C using the surface notch method. When compared with single edge notch data, a thickness effect was apparent and this was described in terms of plane stress and plane strain fracture toughness values. The plane strain value agreed closely with that of the polystyrene matrix indicating that the constrained region showed no toughening effect. The relaxation process of the rubber was apparent in the plane stress toughness.