Silicone-Based Thermoplastic Elastomer with Stable Interface Interaction Based on Polymerization-Induced Phase Separation

The rubber-plastic blend thermoplastic elastomers (TPEs) have become a significant research topic due to their excellent performance, combining the strength of plastics and the elasticity of rubbers. However, for highly incompatible systems such as silicone-based TPEs (Si-TPEs), achieving a finely tuned and controllable phase morphology remains a significant challenge. In this study, a thermoplastic polyurethane/silicone rubber thermoplastic elastomer (TPU/SiR TPE) was prepared via polymerization-induced phase separation (PIPS), with silicone rubber (SiR) as the dispersed phase and thermoplastic polyurethane (TPU) as the continuous phase, which possessed a fine phase morphology, flexible formulation, and performance tunability. Moreover, the precursor of the SiR phase polydimethylsiloxane was modified by grafting with polar esters, and the phase morphology, interface interaction, recycling performance, and elasticity were all improved. The average dispersed phase size of the obtained TPU/SiR TPE decreased to as low as 1.93 μm, and the interface thickness simultaneously increased from ∼420 to ∼ 570 nm. Moreover, under the influence of polarity and interfacial hydrogen bonding, the tensile strength after repetitive processing was maintained above 90% of the initial value, indicating a better recycling performance. The successful preparation of TPU/SiR TPE by PIPS provides a convenient and efficient way to prepare rubber-plastic blend TPE with fine phase morphology, and the excellent mechanical and surface properties of the obtained TPU/SiR TPE, especially the enhanced performance of comfortable texture, make it potentially used as a flexible electronic material, skin-friendly material, such as watch straps, intelligent e-skin material, etc.