Abstract:A polysilazane PHSZ with high molecular weight was prepared via the polymerization of cyclic si鄄
lazane MHSZ in the presence of tetrabutylammonium fluoride as catalyst. MHSZ was synthesized by the ammonolysis
of methylhydrodichlorosilane. Combined with apparatus of IR, NMR, GPC and TGA, the effect of polymerization time
on the composition, structure, molecular weight and ceramic yield of PHSZ was studied. The structure and composi鄄
tion of the pyrolyzed products in the atmosphere of ammonia combined with nitrogen were investigated. It is suggested
that the molecular weight of the polymer PHSZ improved with the extension of the reaction time and TGA decreased;
PHSZ converts into Si3N4 ceramic matrix composites with a carbon content of 0. 5wt%, the product of pyrolysis at 1
600益is completely crystallized, the crystal phase is mainly 琢-Si3N4.
