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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.

Dynamic mechanical thermal analysis (DMTA), often simply referred to as dynamic mechanical analysis (DMA), is one of the most versatile techniques available for the characterization of time-, frequency-, and temperaturedependent mechanical properties of polymers. No other characterization method provides more information in single test. [1,2] The technique may be used to characterize various polymers including thermoplastics, thermosets, elastomers, and polymer blends. Furthermore, DMA allows to assess the molecular mobility of polymeric chains and to draw conclusions regarding the morphology of the investigated polymer (e.g., crystallinity, molecular weight, crosslinking, etc.). [1][2][3][4] In standard DMA tests, the stiffness (modulus) of polymer and its damping capacity (energy dissipation) are measured under periodic (harmonic) loading conditions. Tests can be carried out in both stress-and strain-controlled deformation modes. [1,5,6] The results from such tests performed over a wide temperature and frequency range provide detailed informa- COMMUNICATION[*] Dr.