THE ARCHITECTURE OF COMPATIBILIZING COPOLYMERS IN BLENDS

The efficiency of structurally different copolymers as compatibilizers for the homopolymer blend PVC/PS (polyvinylchloride/polystyrene) was tested. As expected, a diblock copolymer SbMMA of styrene and methylme thacrylate, with a MMA block twice as long as the styrene block, did w ell, refining the phase morphology of PVC/PS drastically. But a random copolymer ScoMMA with the same monomer composition was efficient as w ell. Particularly interesting are block-graft copolymers made by graft ing MMA or a random copolymer CHMAcoMA (CHMA: cyclohexylmethacrylate, MA: methylacrylate) onto a diblock copolymer SbB of styrene and butadi ene. With these block-graft copolymers, a mechanism of compatibilizati on in two stages was observed that leads to finer phase structures tha n theoretically expected.