The nature of impact improvement in glassy thermoplastics modified by a discrete rubber phase

Two-phase rubber-reinforced thermoplastics based largely on polystyrene (PS) and copolymers of styrene with acrylonitrile (SAN) or methyl methacrylate (SMMA) and toughened with polybutadiene (PBD) or poly(styrene-butadiene) (SBR) grafts were examined with reference to the Izod impact strength, dynamic mechanical properties by a vibrating reed technique and crazing behaviour under tensile or impact tests. The impact strength was dependent on the particle size, the minimum particle size for reinforcement increasing in the order PVC < SAN < PMMA < SMMA < PS. [Continues.]