Thermoplastic polyurethane/polytetrafluoroethylene composite foams with enhanced mechanical properties and anti-shrinkage capability fabricated with supercritical carbon dioxide

Effects of different morphologies and contents of polytetrafluorethylene (PTFE) on the foaming and rheological behavior of thermoplastic polyurethane (TPU) and mechanical properties of TPU/PTFE composite foams were investigated. High-pressure rheological test results showed that fibrillated PTFE had a more significant effect on the reinforcement of TPU than PTFE particles. In addition, the TPU/fibrillated PTFE composite foam exhibited good compression recovery properties, and its compressive strength was 109% that of TPU/PTFE composite foam with PTFE particles. Furthermore, with increasing PTFE content, TPU/PTFE foams exhibited higher compressive strength and good compression recovery properties. Retention of maximum stress was approximately 90%, and the strain recovery rate of the TPU/PTFE foam was approximately 80% of the initial value after 50 compression cycles. Moreover, the shrinkage ratio of the TPU foam decreased with increasing PTFE content, and fibrillated PTFE enhanced the hydrophobicity of TPU. (C) 2020 Elsevier B.V. All rights reserved.