IN-SITU COMPATIBILIZATION OF PBT/ABS BLENDS THROUGH REACTIVE COPOLYMERS

Abstract

Styrene-acrylonitrile-glycidyl methacrylate (SAG) copolymer with ethyltriphenyl phosphonium bromide (ETPB) catalyst has been used successfully as in situ compatibilizer to compatibilize the immiscible and incompatible blends of poly(butylene terephthalate) (PBT) and acrylonitrile-butadiene-styrene (ABS). This SAG copolymer contains reactive glycidyl groups that are able to react with PET end groups (-COOH or -OH) under melt conditions to form SAG-g-PET copolymer. However, the rate of the grafting reaction is slow without the presence of catalyst. The ETPB catalyst is highly efficient: even at a concentration as low as 50 ppm, it is able to promote the grafting reaction to obtain the maximum achievable properties. The compatibilized PBT/ABS blend has smaller phase domain, higher viscosity, and significantly improved mechanical properties compared to the corresponding non-compatibilized blend.