THE TECHNOLOGICAL COMPATIBILIZATION OF NATURAL RUBBER POLYSTYRENE BLENDS BY THE ADDITION OF NATURAL RUBBER-GRAFT-POLYSTYRENE/

Compatibility of natural rubber (NR)/polystyrene (PS) blend is poor an d can be enhanced by the addition of a graft copolymer of natural rubb er and polystyrene (NR-graft-PS). The effects of homopolymer molecular weight, copolymer molecular weight, copolymer concentration, processi ng conditions and mode of addition on the morphology of the dispersed phase have been investigated by means of optical microscopy. The addit ion of a small percentage of the compatibilizer decreases the domain s ize of the dispersed phase. The effect levels off at higher concentrat ions. The leveling off could be an indication of interfacial saturatio n. The experimental results were compared with the theoretical predict ions of Noolandi and Hong. The addition of the graft copolymer improve s the mechanical properties of the blend and attempts were made to cor relate the mechanical properties with the morphology of the system. At tempts were also made to understand the conformation of the graft copo lymer at the interface.