Dynamic mechanical analysis of compatibilized polymer blends

Immiscible blends of thermoplastics containing copolymer to enhance compatibilization between the phases have been analyzed using dynamic mechanical analysis. Results are compared to blends in which no compatibilization was attempted. Systems studied included polyphenylene sulfide/poly ether imide, impact modified polyphenylene sulfide/polyphenylene ether, polycarbonate/polyphenylene ether, and polycarbonate/polystyrene, where copolymer was present for compatibilization. For each system, the maximum in G″ corresponding to the glass transition temperature of the high Tg phase decreases with compatibilization. Also, G′ was found to decrease more rapidly between the Tg. This occurs whether or not the high Tg phase is dispersed or continuous. This behavior is explained in terms of the effect of copolymer on molecular mobility.