On the cyclic material stability of shape memory polymer

This paper presents the experimental study of a Thermoplastic Polyurethane (TPU) based Shape Memory Polymer (SMP) produced from granulates of commercially available EstaneTM ETE75DT3 NAT022 (Oevel Westerlo, Belgium). This polymer is characterized by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Thermal Analysis (DMTA). The experimental procedure was designed to study the functional properties (shape fixity and shape recovery) of this shape memory polymer in multiple programming/shape-recovery cycles at three different programming temperatures. The results are displayed in the temperature-stress-strain space with focus on parameters which characterize the functional fatigue and material stability of the tested polymer during consecutive cycles. These results give a better understanding of this material class that has a potential for actuator applications in engineering.