空气中两种辐照场下聚碳硅烷先驱丝的辐照不熔化效应

Effect of γ Ray or Electron Beam Radiation in Air on Radiation Curing of Polycarbosilane Fibers

摘要: 采用⁶⁰Co产生的γ射线与10 MeV电子加速器产生的电子束在空气中辐照聚碳硅烷先驱丝。利用凝胶含量测定、红外光谱分析、凝胶渗透色谱分析、热重分析等手段研究了经两种辐照场辐照后聚碳硅烷先驱丝的凝胶含量、化学结构、分子量分布及其热分解特性的变化。结果表明：两种辐照场下能满足聚碳硅烷先驱丝不熔化处理的剂量分别为3、6.5 MGy，两种辐照场下聚碳硅烷先驱丝的辐照不熔化机理一致，均通过形成Si—C—Si、Si—O—Si桥联结构而实现不熔化处理；在相同吸收剂量下，γ射线辐照不熔化效果较电子束辐照的好；γ射线辐照的聚碳硅烷先驱丝陶瓷产率也较电子束辐照的高。

Abstract: Polycarbosilane fibers were irradiated by γ ray or 10 MeV electron beam in air. Gel content, chemical structure, molecular weight distribution and pyrolysis properties were studied. The curing dose of polycarbosilane fibers irradiated by γ ray or electron beam is 3 MGy and 6.5 MGy, respectively. Bridge structures of Si—O—Si and Si—C—Si are formed in the irradiated products. Radiation curing mechanism of polycarbosilane fibers are uniform under two kinds of irradiation fields. The effect of radiation curing irradiated by γ ray is better than that of electron beam irradiation at the same absorbed dose, and the ceramic yields irradiated by γ ray are also higher.