Miscibility and shape memory effect of thermoplastic polyurethane blends with phenoxy resin

Segmented thermoplastic polyurethane (TPU) with poly(caprolactone) (PCL) ba sed soft segment and hexamethylene diisocyanate (HDI)/1,4-butane diol (BD)/ 4 ,4 ' -dihydroxy biphenyl (DHBP) based hard segment was blended with pheno xy resin to examine miscibility and shape memory effect. The PCL segment an d phenoxy resin made single miscible domain with single glass transition te mperature (T-g) which lied between those of PCL segment and phenoxy resin. In the shape memory effect, utilizing this miscible domain as a reversible phase and utilizing phase separated hard segment domain as a fixed structur e memorizing the original shape, hysteresis was reduced as the content of h ard segment was increased in the blend and the block length of TPU was decr eased. (C) 2001 Elsevier Science Ltd. All rights reserved.