γ射线辐照改性聚碳硅烷提高热解陶瓷产率

摘要

Polycarbosilane (PCS) was irradiated by γ-rays in N2 atmosphere. The chemical structure, molecular weight, thermal decomposition characteristics of the irradiated PCS were investigated by Fourier transform infrared spectroscopic analysis, gel permeation chromatographic analysis and thermogravimetric analysis, respectively. The results showed that a slight weight loss of PCS was found after γ-rays irradiation, both the molecular weight and softening point of PCS increased with the absorbed dose. These results indicated that crosslinking reactions occurred between PCS molecules induced by γ-rays irradiation. According to the results by Fourier transform infrared spectroscopic analysis, the crosslinking site of PCS was Si?C?Si structure which was formed by combining of Si?H with C?Hstructure. The ceramic yield of irradiated PCS increased significantly with its absorbed dose. When the absorbed dose reached 1.5 MGy, the ceramic yield increased from 61.9% of non-irradiated sample to a saturated value of 80.0%.%在N2气中用γ射线对聚碳硅烷(Polycarbosilane,PCS)进行辐照,利用傅里叶红外光谱分析、凝胶渗透色谱分析和热重分析等手段研究了不同吸收剂量下PCS的化学结构、分子量和热分解特性.结果显示,经γ射线辐照处理后的PCS轻微失重,分子量和软化点随着吸收剂量的增加而增加,说明PCS经辐照后发生了分子间的交联反应.红外分析表明,PCS的交联主要是通过Si–H键和C–H键的断裂产生新的Si–C–Si结构实现的.热重分析表明,PCS热解为碳化硅的陶瓷产率随吸收剂量的增加显著升高,剂量达到1.5 MGy后PCS样品的陶瓷产率基本提高到稳定值,此时,陶瓷产率从改性前的61.9%提高到80.0%.