Compatibilizer‐aided toughening in polymer blends consisting of brittle polymer particles dispersed in a ductile polymer matrix

Blending brittle polymer particles in a ductile polymer matrix is a new way to obtain toughened plastics. Although the nylon‐6/poly(acrylonitrile‐co‐styrene) (SAN) system is a ductile/brittle combination, the blend does not result in a toughened plastic. We have investigated the effect of adding a small amount of a third component, poly(styrene‐co‐maleic anhydride) (SMA), to the nylon/SAN system. SMA significantly improves the tensile and impact strength of the blend. Morphological observations indicate a finer dispersion of the SAN particles when SMA is present in the blend. The improved dispersion is attributed to the formation of nylon‐SMA graft copolymer, and infrared analysis supports this supposition. That is, a “compatibilizer” seems to be produced during melt mixing of the ternary system. The role that the compatibilizer plays in improving the stress transfer in the two‐phase system and its potential to induce a brittle‐ductile transition of the glassy SAN particles are considered to explain the toughening mechanism.