Preparation of boron-containg hybridized silicon rubber by in-situ polymerization of vinylphenyl-functionalized polyborosiloxane and liquid silicone rubber

In this study, a kind of boron-containg hybridized silicon rubber (VP–PBSi/SR), which possess great thermal and mechanical properties, was successfully prepared. First, the vinylphenyl-functionalized polyborosiloxane (VP–PBSi) possessing good storage stability were synthesized by reacting triethoxyvinylsilane (VTEOS), phenyltriethoxysilane (PTEOS) and boric acid (BA) by sol-gel method. From the results of GPC, FT-IR, ¹³C-, ²⁹Si, ¹¹B-NMR characterization, the structures of VP-PBSi were confirmed to be the cage structure. Then, the VP-PBSi/SR were prepared by in situ polymerization of vinylphenyl-functionalized polyborosiloxane (VP–PBSi) and addition liquid silicone rubber (SR). The effect of VP-PBSi on thermal stability and mechanical properties of SR were mainly discussed by scanning electron microscope (SEM), thermal gravimetric analysis (TG), universal testing machine, and dynamic mechanical analysis (DMA), respectively, and the results showed that the thermal stability and mechanical properties of the SR were significantly enhanced. The maximum thermal decomposition temperature (T_max), char yield and tensile strength can reach 675 °C, 72.3% and 4.65 MPa, respectively, and 21.8%, 26.1% and 20.2% higher than that of neat SR. We believe this work can provide reference for the preparation of high-performance heat resistance rubber materials.