Abstract:

Polyborosilazane (PBSZ), a novel precursor to SiBNC ceramic, was synthesized via cocondensadition approach by using dichloromethylsilane (MeHSiCl2), boron trichloride (BCl3) and hexamethydisilazane ((CH3)3SiNHSi(CH3)3) as the starting materials. Precursors with different softening point can be obtained by altering the dosage of MeHSiCl2. Rheological property study show that PBSZ melt is a typical shear stress diluting fluid and the shear rate, the flow index, the viscous flow activation energy, the apparent viscosity is 10~110 s-1, 0.83~0.90, 142 kJ/mol, 400~2400 Pa·S, respectively. The as-synthesized polyborosilazane shows good processability in wide temperature range and endless polymer fibers can be obtained in 87℃ in N2 atmosphere.

Key words: Polyborosilazane, Synthesis, Rheological Property, Melt-spinning