| Abstract: | Segmented thermoplastic polyurethanes (TPU)s with amorphous soft segments from the reaction of hexamethylene diisocyanate and 1,2‐butanediol and crystalline hard segments from 4,4′‐methylenediphenyl diisocyanate and 1,6‐hexanediol showed sharp glass‐transition temperatures that could be used as shape‐recovery temperatures. The thermal, mechanical, and shape‐memory effect of these TPUs of various block compositions and lengths were studied by differential scanning calorimetry, dynamic mechanical testing, and tensile testing. As the block lengths decreased, phase mixing increased and hysteresis in the shape‐memory behavior decreased. Too low a content of hard segments increased the hysteresis in the shape‐memory behavior. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2652–2657, 2000 |
