Silicone Rubbers via Clean Thermally Induced Cross-Linking

Cross-linked silicone rubbers are widely used in modern industry, while the improvement of material performance is hindered by current cross-linking methods. In this work, thermally induced [4 + 4] cyclization of benzocyclobutene (BCB) and [2π + 2π] cyclization of trifluorovinyl aryl ether (TFVE) groups are used to cross-link polysiloxane to prepare silicone rubbers. Polysiloxanes functionalized with BCB and TFVE groups were prepared by anionic ring-opening copolymerization, followed by thermally induced cyclization of BCB or TFVE groups to cross-link the polysiloxane chains. Such cross-linking does not need a catalyst or additional small-molecule cross-linker; thereby, the resulting silicone rubbers show superior performance to commercially available silicone rubber products in several aspects, including thermal stability, mechanical performance, and low-temperature performance. This work establishes a clean platform for developing high-performance silicone rubbers specifically engineered for aerospace sealing systems and under-the-hood automotive components.