A stable amphiphilic hybrid nanoparticle compatibilizer constructed from polyhedral oligomeric silsesquioxane (POSS) for immiscible thermoplastic polyurethane/methyl vinyl silicone elastomer (TPU/MVQ) blends

Abstract

TPU/MVQ blends are widely used in biomedical electronic equipment, intelligent wearable materials, and other fields. As they are immiscible systems, compatibilization of TPU/MVQ blends is required. Several types of compatibilizers have been developed to enhance the compatibility between TPU and MVQ, but some challenges still exist such as poor amphiphilicity and difficulties in controlling their structures. In this study, modified POSS nanoparticles (NPs) with an octahedral cage structure and reactive functional groups were used as the matrix. POSS nanoparticles with stable amphiphilicity and easily controllable structures were successfully synthesized through grafting of polydimethylsiloxane (PDMS) chains and chain segments similar to polyurethane (PU). The compatibility with silicone rubber is enhanced by the physical entanglement between PDMS chains and MVQ, while PU analogues enhance the interfacial interaction with TPU through the combined effect of physical entanglement and hydrogen bonding. After compatibilization, the average diameter (D_n) of the dispersed phase with 10 wt% compatibilizers is only ∼1/5 compared with that without a compatibilizer, and the interface thickness is 4.1 times compared with that without a compatibilizer. Moreover, due to the Pickering effect, the obtained system is stable even after annealing at 180 °C, with the D_n value of the dispersed phase only increased by 7.5%, while the D_n value of the dispersed phase increased by 45.1% when using a commercial compatibilizer (silane modified polyurethane, abbreviated as V-165). The amphiphilic POSS nanoparticles not only provide an effective compatibilization solution for the industrial development of TPU/MVQ thermoplastic vulcanizates (TPVs), but also open up new avenues for the preparation of other incompatible blend materials.