Crystallization and melting behavior of the soft and hard segments in poly(ester-ether)s. II. Ethylene oxide-butylene terephthalate segmented copolymers

The crystallization behavior of a series of ethylene oxide-butylene terepht halate (EOBT) segmented copolymers with different soft segment molecular we ight and hard segment weight content were examined by differential scanning calorimeter (DSC) and polarized microscope. Combined with the comparison w ith the crystallization behavior of ethylene oxide-ethylene terephthalate ( EOET) segmented copolymers, it can be concluded that the crystallizability of both the soft segments and the hard segments in poly(ester-ether) segmen ted copolymers is much worse than these of the corresponding homopolymers d ue to the interactions between the soft and the hard segments. The crystall izability of the soft segments is mainly determined by the soft segment mol ecular weight, but is weakened by the hard segments. On the other hand, the soft segments have complicated influences on the crystallization of the ha rd segments. The melting temperatures of the hard segments change monotonic ally with the average hard segment length, but the corresponding melting en thalpies will reach a maximum at an intermediate soft segment molecular wei ght. (C) 1999 John Wiley & Sons, Inc.