Degree of microphase separation in segmented copolymers based on poly(ethylene oxide) and poly(ethylene terephthalate)

Microphase separation effects in segmented copolymers based on poly(ethylen e oxide) and poly(ethylene terephthalate) (EOET) were studied with differen tial scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and opti cal microscopy. The PEO segments in a, segmented EOET copolymer showed a hi gher glass transition temperature (T-g), and lower melting temperature (T-m ) and crystallinity (X-c) than the corresponding PEO homopolymer. Experimen tal results revealed that both long PEO segments and high PET content in th e copolymers lead to a high degree of microphase separation. Both T-g and T -m of the PEO segments call be used to evaluate the degree of microphase se paration in the EOET copolymer. (C) 1999 Elsevier Science Ltd. All rights r eserved.