Thermally stimulated shape‐memory behavior of ethylene oxide‐ethylene terephthalate segmented copolymer

Abstract

A series of ethylene oxide—ethylene terephthalate segmented copolymers (EOET) with different long soft segments and different hard-segment contents were synthesized. The thermally stimulated shape-memory behavior of EOET segmented copolymer is characterized by the maximum recovery (Rf), the recovery temperature (Tr), and the recovery speed (Vr) or the temperature (TM) of the maximum deformation recovery rate against temperature and the maximum recovery speed (VM). These parameters show that the features of thermally stimulated shape-memory effects of EOET segmented copolymers are following: The crystallinity of soft segments determines the temperature Tr and TM, and the parameters Rf, Vr, and VM depend on the stability of the physical crosslinks formed by the hard segments, which at the same time are influenced by the length of soft segment. Rf, Vr, and VM decrease with prolongation of the keeping time (tk) and increasing stretching ratio. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2433–2440, 1997