Shape memory thermoplastic polyurethane/polycaprolactone blend and composite with hydroxyapatite for biomedical application

Depending on its composition, thermoplastic polyurethane (TPU)/polycaprolactone (PCL) blend may present interesting properties for biomedical applications. Here, we have extensively developed and characterized blends of TPU/PCL and composites with 5, 10, and 20 wt% of hydroxyapatite (HA). The thermal, rheological, and mechanical characterizations showed that the blends present an intermediate behavior between pure TPU and PCL. The 75TPU/25PCL blend exhibited the best shape memory performance at temperatures below 50 °C. Filaments of this blend presented a fixation rate of 86.6% and a recovery rate of 73.3% at 50 ℃. The addition of HA had little influence on the shape memory properties; on the other hand, it strengthened the material, reaching elastic modulus values close to 100 MPa. In vitro tests revealed a biocompatible behavior for all blends, and the composite with 10 wt% HA from the 75TPU/25PCL blend demonstrated greater cell proliferation compared to the other composites. Graphical abstract