(国防科技大学 新型陶瓷纤维及其复合材料国家重点实验室，长沙 410073)
摘 要: 通过IR，TG及XRD等手段对聚二甲基硅烷（PDMS）与聚氯乙烯（PVC）共裂解合成制备的纤维先驱体(PC-P5, PC-P50)裂解进行了研究。结果表明，在初始裂解阶段，主要为小分子硅烷逸出，PC-P5发生 Si-H和 Si-CH3的脱甲烷、脱氢反应而导致交联程度的增加；而在PC-P50中，除了发生上述反应外，还存在分子内和分子间稠环芳烃结构的脱氢缩聚。随裂解温度进一步的提高, PC-P5表现为脱氢、脱甲烷的无机化过程，裂解产物从有机物转变为存在部分微晶的无机结构，裂解温度继续提高后，Si-C-O玻璃相和富余碳反应使SiC晶粒尺寸增加，并伴有CO气体的放出。
关键字: 碳化硅纤维； 聚合物； 裂解； 电阻率
--Pyrolysis of polymer precursors
（CFC, National University of Defense Technology, Changsha 410073, P.R.China）
Abstract:The precursor polymer was prepared by means of thermal rearrangement reaction of polyvinylchloride (PVC) and polydimethysilane (PDMS). The pyrolysis process of the precursor polymer was studyied by IR, TG and XRD. The results show that the process is dehydrogenation and dehydrocarbonation condensation with the evaporation of low molecular mass for the first stage in PC-P5; besides those, the dehydrogenation of the aromatic structure occurs in PC-P50. PC-P5 is converted into the inorganic structure by decomposition of the side chains of polymer with the increasing temperature. When the temperature is further increased, the crystal size of SiC grows by the reaction between excess carbon and Si-O band.
Key words: SiC fiber; polymer; pyrolysis; resistivity
