Second-generation polymeric precursors for BN and SiNCB ceramic materials

Our recent work directed at the design, synthesis, characterization and applications of new types of polyborazylene and polyborosilazane polymers is reviewed with a focus on the use of these polymers as processable precursors to BN and SiNCB composites. A design strategy based on the controlled functionalization of preformed polymers with pendant groups of suitable compositions and crosslinking properties has been employed to yield second-generation dipentylamine–polyborazylene (DPA) and pinacolborane–hydridopolysilazane (PIN–HPZ) polymers, which, unlike the parent polyborazylene (PB) and the borazine–hydridopolysilazane (B–HPZ) polymers, are stable as melts and can be easily melt-spun into polymer fibers. Subsequent pyrolyses of these polymer fibers then provide excellent routes to BN and SiNCB ceramic fibers.