空气中γ辐照聚碳硅烷先驱丝的增重特性

Weight Gain Characteristic of Polycarbosilane Precursor Fibers Irradiated by γ-ray in Air

摘要: 利用γ射线在空气中辐照处理聚碳硅烷（PCS）先驱丝，采用凝胶含量、红外光谱、核磁共振、凝胶渗透色谱及理论计算等手段研究了PCS先驱丝在空气中的辐照增重特性。结果表明：吸收剂量为4 MGy时，PCS先驱丝的辐照增重为25.4%，Si—H键的反应程度为86.9%；Si—H键的反应程度与辐照增重呈很好的线性关系，R²=0.9972；在γ辐照作用下，空气中的氧通过与PCS反应形成了Si—OH、Si—O—Si、Si—O—C和C＝O结构而造成PCS先驱丝显著增重。理论计算表明，Si—CH₃上的C—H键与空气中的氧发生反应生成C＝O是增重的主要来源。

Abstract: Polycarbosilane (PCS) precursor fibers were irradiated by γ-ray in air atmosphere. The weight gain characteristic of the PCS precursor fiber was studied by gel content,IR, NMR, GPC and theoretical calculation. The results show that the weight gain is about 25.4% and the bond of Si—H reaction degree is 86.9% at the absorbed dose of 4 MGy. The Si—H reaction degree and weight gain show a good linear relationship, R²=0.9972. The structures of Si—OH, Si—O—Si, Si—O—C and C＝O are formed by means of reaction between oxygen and PCS, and this cause the PCS precursor fibers to gain weigh. The theoretical calculation shows that the C＝O formed from the reaction of C—H bond in the Si—CH₃ with oxygen is the main source of weight gain.