Abstract
Block copolymers of bisphenol A isophtalate and sebacate were prepared by a two-step interfacial polycondensation. The copolymers had sebacate contents of 1:5 and 1:3 molar with block lengths (DP̄) of 4, 9, and 19. Thermal analysis of the copolymers by DSC showed the T m of PBI. The crystallizability of PBI chain segments in the block copolymers was confirmed by X-ray diffraction. The T m of the copolymers was primarily influenced by the DP of the chain segments rather than the sebacate content. The sebacate, being compatible with the isophthalate, had a plasticizing effect upon the polyarylate, which resulted in an improvement in toughness of the copolymers.