【摘要】 以氯甲基三氯硅烷（Cl₃SiCH₂Cl）和乙炔基溴化镁（HC≡CMgBr）为原料,经过Grignard偶合反应和还原反应制备得到乙炔基封端的氢化超支化聚碳硅烷（EHBP）。通过红外光谱、核磁共振（碳谱、氢谱、硅谱）、差示扫描量热、流变分析和热重分析等方法研究了EHBP聚合物的结构、固化行为以及热性能;采用X射线衍射、拉曼光谱、扫描电镜和高倍透射电镜分析了EHBP聚合物的陶瓷化过程。结果表明,在分子链末端引入Si—H和乙炔基,使EHBP聚合物具有优良的耐热性和耐热氧化性。氮气氛围下EHBP失重5%时的温度(T_d5)为578.8℃,1 000℃时的质量保留率为82.3%;空气氛围下T_d5为549.6℃,1 000℃时的质量保留率为69.2%。1 600℃下EHBP的裂解产物中存在α-SiC和β-SiC晶体,结晶完善,晶粒分布均匀,晶粒尺寸为15²0nm。更多还原

【Abstract】 Ethynyl-terminated hydrogenated hyperbranched polycarbosilane（EHBP）was prepared by Grignard coupling polymerization and reduction reaction, in which chloromethyltrichlorosilane（Cl₃ SiCH₂ Cl）and ethynylmagnesium bromide（HC≡CMgBr）were chosen as materials.The chemical structure,curing behavior and thermal properties of EHBP polymer were characterized by FT-IR,NMR(¹ H-NMR、¹³ C-NMR、²⁹ Si-NMR),as well as DSC,rheological analysis and TG.The process of ceramization was analyzed by XRD,Raman spectroscopy,SEM and HR-TEM.Results showed that the thermal and thermal-oxidation stability of EHBP polymer were greatly improved after the introduction of Si—H and unsaturated ethynyl groups at the end of the chain.The temperature of 5% mass loss(T_d5)and residual mass at 1 000 ℃ were 578.8 ℃ and 82.3%in nitrogen atmosphere,and 549.6 ℃ and 69.2%in air atmosphere,respectively.With the increase of heating temperature,the pyrolysis of EHBP polymer became more and more sufficient. When the temperature reached 1 600 ℃,the crystallinity of the pyrolysis product was perfect,and the product contained not onlyα-SiC crystals but alsoβ-SiC crystals which had high temperature stability.All SiC crystals with the size of 15²0 nm could be uniformly distributed in pyrolysis product.更多还原