凝胶点前聚碳硅烷先驱丝的不熔化机理研究  

Studies on curing mechanism of polycarbosilane precursor fibers irradiated by γ-rays below gelling dose

作　　者：黎阳[1] 许云书[1] 

机构地区：[1]中国工程物理研究院核物理与化学研究所

出　　处：《辐射研究与辐射工艺学报》2008年第3期146-150,共5页Journal of Radiation Research and Radiation Processing

基　　金：中国工程物理研究院科学技术基金重大项目(2004Z0502)资助

摘　　要：采用γ射线在开放空气气氛中辐照聚碳硅烷(Polycarbosilane,PCS)先驱丝,研究了吸收剂量低于凝胶点剂量的PCS先驱丝的化学结构以及后续的热解反应过程。结果表明,在射线作用下,空气中的氧通过与PCS中的Si-H、Si-CH3反应而被引入到辐照产物中,形成Si-OH、Si-O-Si和C=O等结构;随着热处理温度的提高,在产物中进一步检测到Si-O-Si以及Si-C-Si等桥联结构,并存在凝胶化产物;辐照以后的PCS先驱丝其起始热解温度从320℃提高到约600℃,陶瓷产率也从57.5%提高到约83%。在本实验范围内,凝胶点剂量前的PCS先驱丝试样均能烧成得到微观形貌完整的碳化硅(Silicon carbide,SiC)陶瓷纤维。Polycarbosilane （PCS） precursor fibers were irradiated by y-rays in air. The structure and the subsequent pyrolysis reaction of PCS fibers irradiated below gelling dose were investigated. Results show that a little of oxygen is imported to form the structures of Si-O-Si 、 Si-OH and C=O from Si-H and Si-CH3 of PCS in irradiation process. And gelatinized products formed from the Si-O-Si and Si-C-Si bridge structures obviously increase with the heat treatment temperature. It has been also found that the initial pyrolysis temperature of irradiated PCS fibers increases from 320℃ to 600℃, and the ceramic yields increase from 57.5% to about 83%. All the samples of PCS precursor fibers irradiated below gelling dos and under the condition with a little of oxygen can be pyrolyzed into SiC ceramic fibers with intact microstructure.

关 键 词：聚碳硅烷先驱丝 γ 射线辐照 桥联结构 不熔化处理 热交联 

分 类 号：O631.34[理学—高分子化学] TQ343.6[理学—化学]