Random and block copolymers as compatibilizers, directly compared

Most blends are two-phase systems that exhibit coarse morphologies with wea k interfaces between the phases. It is well known that these blends can be compatibilized by suitably adapted block copolymers is known. Less known is that random copolymers can compatibilize blends as well, forming interphas es. In this study, block and random copolymers of styrene and methylmethacr ylate were tested in direct comparison, in a blend of polystyrene and polyv inylchloride. The random copolymers are inferior, as regards the phase morp hologies, but competitive, as far as the tensile strength is concerned.