TY - JOUR A1 - Bothe, Martin A1 - Pretsch, Thorsten T1 - Two-way shape changes of a shape-memory poly(ester urethane) JF - Macromolecular chemistry and physics N2 - Phase-segregated PEU exhibits two-way shape changes under various constant stresses. Most distinct actuation (expansion on cooling and contraction on heating) can be detected between +60 and -20 °C when the maximum stress applied during a thermo-mechanical pretreatment approached the point where deformation-induced crystallization of the PBA soft segment sets in. The driving forces for the strain-related two-way shape changes consist of PBA crystallization and PBA melting-induced entropy elasticity. At low constant stresses (<1.5 MPa), entropy elasticity also contributes to specimen expansion on cooling. The results of multiple- cycling experiments imply that PEU is an appropriate candidate for the fabrication of thermoresponsive actuators working under constant stress conditions. KW - Actuation KW - Entropy elasticity KW - Mechanical properties KW - Phase change KW - Polymorphism KW - Poly(ester urethane) KW - Poly(1,4-butylene adipate) KW - Semi-crystallinity KW - Shape memory polymers KW - Stimuli-sensitive polymers KW - Stress KW - Two-way actuator KW - Two-way shape memory PY - 2012 DO - https://doi.org/10.1002/macp.201200096 SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2378 EP - 2385 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -