Synthesis of a Two-Component Carbosilane System for the Advanced Manufacturing of Polymer-Derived Ceramics

A novel two-component system consisting of a hyperbranched polycarbosilane (HBPCS) and a dihydrosilane cross-linker is presented as a synthetic route for the generation of silicon oxycarbide (SiOC) and silicon carbide (SiC) ceramic materials. Upon addition of the reactive silane cross-linker (33 wt %), rapid gelation of the HBPCS occurs indicating network cross-linking and increased molecular weight. After thermal oxidative curing, the gel is converted to a rigid solid state material that has an 80 wt % ceramic yield of SiOC when pyrolyzed to 1000 °C. Continued heating of the ceramic to 1800 °C induces reorganization and crystallization, providing crystalline β-SiC. This new system affords the opportunity to modulate the hyperbranched polymer’s chemical and rheological properties, to boost ceramic yield, and is amenable to the aerosol jet printing of polymer-derived ceramics.