Self-reinforced thermoplastic polyurethane composite with excellent mechanical properties, heat resistance and sustainable recycling

Abstract

The traditional reinforcement and toughening approaches of thermoplastic polyurethane (TPU) fail to adequately address the mechanical properties, compatibility and recyclability of TPU composites. In this study, the self-reinforced TPU composite was successfully prepared by introducing self-reinforced fiber structure. The reinforced fibers and matrix phase had the same chemical composition, and the reinforced fibers could be uniformly distributed in the TPU matrix. The fibril network structure formed by reinforced fibers enhanced the rheological properties of self-reinforced TPU composites. The hydrogen bond interactions between reinforced fibers and TPU matrix improved the micro-phase separation structure. The fibril network and excellent interfacial interactions significantly enhanced the strength and toughness of TPU matrix. When the reinforced fiber content was 7 wt%, the tensile strength, elongation at break and tensile toughness of TPU7 were increased by 58.2 %, 107.1 % and 210.3 %, respectively. The introduction of reinforced fibers increased the heat resistance of TPU composites by 20–30 °C. After ten-times closed-loop recycling process, the elongation at break of TPU7 only decreased by 11.0 %. This work provides a solution strategy for preparing TPU composites with ultra-high mechanical properties, thermal stability and sustainable recycling-reprocessing.