材料期刊网

以甲基乙烯基二氯硅烷为原料，经硼氢化、氨解以及热聚合反应合成了一系列聚硼硅氮烷(PBSZ)，重均分子量(MW)为9．0×104~2．6×105.利用改进的姜黄素直接光度法测得其实际硼含量为2．59％~9．92％(质量分数).用FT-IR和1 H NMR对 PBSZ 结构进行了表征，发现硼含量高的 PBSZ 具有线型结构，硼含量低的PBSZ具有星型结构.线型结构的PBSZ可溶解于四氢呋喃、甲苯、乙酸乙酯、三氯甲烷和无水乙醇等常用有机溶剂中，星型结构的PBSZ不溶解.通过TGA对该系列PBSZ与自制的聚硅氮烷(PSZ)的热性能进行了对比测试，结果表明，在1350~1500℃区间PBSZ的失重率为0~0．09％，而PSZ的失重率为0．73％，说明该系列PBSZ转化成的Si-B-C-N四元体系陶瓷比Si-C-N三元体系陶瓷具有更好的高温稳定性.

A series of polyborosilazanes(PBSZ)were prepared from dichloromethylvinylsilane by hydroboration, ammonolysis polycondensation and thermopolymerization.The polyborosilazanes have weight-average molecular weights (MW)of 9.0×104-2.6×105 .The real boron contents of the polyborosilazanes are 2.59%-9.92%(ω)de-terminated by modified curcumin spectrophotometric method.The structures of the polyborosilazanes were characterized by FT-IR and 1 H NMR.The high boron contents polyborosilazanes have linear structures and low boron contents polyborosilazanes have star structures.PBSZ with linear structures are soluble in common organ-ic solvents such as THF,toluene,ethyl acetate,trichloromethane,absolute alcohol and so on whereas star PB-SZ are insoluble.The thermal properties of the polyborosilazanes and self-made polysilazanes were contrastive tested by TGA.The results showed that the mass loss of the polyborosilazanes at 1 350-1 500 ℃ were 0%-0.09% whereas the mass loss of the polysilazanes were 0.73%.It revealed that quaternary system Si-B-C-N ce-ramics derived from the polyborosilazanes had better high-temperature stability than ternary system Si-C-N ce-ramics.