Structure and morphology of the 60/40 poly(p‐oxybenzoate‐co‐ethylene terephthalate) copolymer

Abstract

The copolyester composed of 60 mol% p‐hydroxybenzoic acid and 40 mol% ethylene terephthalate has been studied extensively by earlier workers. However, some confusion exists particularly with respect to the nature of the thermal transitions and the possible presence of additional phases. In the present study we have examined this copolyester and found that it is possible to separate the material into soluble and insoluble fractions with significantly different ratios of p‐hydroxybenzoic acid to ethylene terephthalate. In fact, the soluble PET‐rich fraction is blocky in nature, while the PHBA‐rich fraction is more random. The multiple thermal transitions can now be readily interpreted in terms of a heterogeneous composition which tends to segregate and phase separate. Copyright © 1989 John Wiley & Sons, Inc.