LAUSR

Abstract Polyborosilazane synthesized from trichlorosilane (SiHCl3), boron trichloride (BCl3) and methylamine (MeNH2) is highly sensitive to moisture for hydrolysis of -NHMe unites and is easy to cross-link for dehydrogenation of Si-H, N-H, which affected the industrial scale production of SiBNC ceramic fibers. In this paper,a new nitrogen source(n-propylamine, C3H7NH2) was used instead of MeNH2 to synthesis polyborosilazane precursor. The influences of nitrogen sources on the structures and properties of SiBNC ceramic fiber precursors were investigated. As compared to SiHCl3/BCl3/CH3NH2 system, polyborosilazane precursor synthesized from the SiHCl3/BCl3/C3H7NH2 system exhibited lower crosslink density, lower sensitivity to moisture and good melt spinnability, and the obtained ceramic fibers showed higher tensile strength (1.03 GPa, an increase of about 37.3%). This synthesis route (SiHCl3/BCl3/C3H7NH2) may serve as a suitable synthetic route for a large-scale production of SiBNC ceramic fibers.