Thermoplastic Polyurethane/Silicone Rubber (TPU/SiR) Thermoplastic Elastomers with Fine Phase Structure and Comfortable Texture based on Polymerization-induced Phase Separation

In this study, the polymerization-induced phase separation (PIPS) method was employed to prepare thermoplastic elastomer (TPE) without using any compatibilizers. The polydimethylsiloxane (PDMS) was dispersed in the Poly-tetramethylene-ether-glycol (PTMG), and underwent phase separation during the polymerization, the TPU/SiR TPEs which were composed of crosslinked silicone rubber (SiR) as the dispersed phase and TPU as the continuous phase. The chemical structure, phase morphology, and mechanical property of the obtained TPE are easily tunable, with an average size of dispersed phase ~0.37 μm and a tensile strength of 13.5 MPa when the pre-polymerization time of TPU is 20 min and the SiR dispersed phase content is 22 wt.%. After repetitive processing, the tensile strength of the recycled material can still reach approximate 80% of the initial value. Moreover, the material exhibits comfortable biological tactile performance, the static and dynamic friction coefficients of this TPE with 33 wt.% SiR are 0.512 and 0.246, respectively, which are much lower than the pure TPU (Us=1.046; Ud=0.544). This method provides a convenient and efficient way to prepare TPE composed of two immiscible phases, and the regulation of phase morphology is very flexible and simple compared with the traditional method.