Second-generation polymeric precursors for BN and SiNCB ceramic materials

Abstract

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.

Synthesis and pyrolysis of novel polysilazane to SiBCN ceramic

“…The polymer to ceramic conversion leads to ceramic yields up to 72%. The yield of the obtained preceramic polymer in this study is similar to that of HPZ families [27]. The initial weight loss observed at 100-300°C could arise through a crosslinking reaction with NH groups in the polymer backbone and Si-N linkages [28].…”

Pyrolytic Organic-to-Inorganic Conversion of Precursors into AlN-A Review

“…To overcome this drawback, new polymeric precursors to BN ceramics were prepared through reactions of polyborazylene with diethylamine DEA, dipentylamine DPA, and hexamethyldisilazane HMD. [95][96][97] The DPA-polyborazylene polymers led to the successful preparation of continuous polymer fibers 30-40 mm in diameter with a melt-spun technique. Pyrolysis of the polymer fibers under ammonia gave high-quality BN ceramic fibers 30 mm in diameter.…”

Borylborazines as new precursors for boron nitride fibres

“…Polymer 4 was prepared by metathesis reaction of a dichloroborazine derivative (NMe 2 )Cl 2 B 3 N 3 H 3 with an aminoborane B(NHMe) 3 (Fig. 4).…”