Shape Memory Properties of Poly(ε-Caprolactone) Based Thermoplastic Polyurethane Secondary Blends

Abstract

Thermoplastic polyurethanes with introduced poly(ε-caprolactone) (PCL/TPU) show shape-memory properties. Such materials are widely used for orthopaedic splints production but create large amount of waste. Generally, this waste disposed of to landfill; therefore, utilization problem arise. The goal of this investigation was to study possibilities of different PCL/TPU production waste recycling and secondary application. For investigation secondary blends of three types of PCL/TPU were prepared by mastication and mechanical properties and shape memory behaviour have been studied. The mechanical testing results suggest that after recycling PCL/TPU and their blends properties remain unaltered. All investigated thermoplastics are compatible and form simple blends without synergetic or anti-synergetic effects. Only some interaction between PCL/TPU-1 : PCL/TPU-2 blend components was observed. After recycling, individual PCL/TPU and their blends show significant shape memory behaviour under drawing at high temperature – their recovery rate was about 80 % – 90 % for a tensile deformation of 50 %. Thus, secondary PCL/TPU blends show mechanical properties and shape memory behaviour closely comparable to the virgin materials. Therefore, they can be repeatedly used for orthopaedic splints production.