(國(guó)防科技大學(xué) 新型陶瓷纖維及其復(fù)合材料國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410073)
摘 要: 通過(guò)IR，TG及XRD等手段對(duì)聚二甲基硅烷（PDMS）與聚氯乙烯（PVC）共裂解合成制備的纖維先驅(qū)體(PC-P5, PC-P50)裂解進(jìn)行了研究。結(jié)果表明，在初始裂解階段，主要為小分子硅烷逸出，PC-P5發(fā)生 Si-H和 Si-CH3的脫甲烷、脫氫反應(yīng)而導(dǎo)致交聯(lián)程度的增加；而在PC-P50中，除了發(fā)生上述反應(yīng)外，還存在分子內(nèi)和分子間稠環(huán)芳烴結(jié)構(gòu)的脫氫縮聚。隨裂解溫度進(jìn)一步的提高, PC-P5表現(xiàn)為脫氫、脫甲烷的無(wú)機(jī)化過(guò)程，裂解產(chǎn)物從有機(jī)物轉(zhuǎn)變?yōu)榇嬖诓糠治⒕У臒o(wú)機(jī)結(jié)構(gòu)，裂解溫度繼續(xù)提高后，Si-C-O玻璃相和富余碳反應(yīng)使SiC晶粒尺寸增加，并伴有CO氣體的放出。
關(guān)鍵字: 碳化硅纖維； 聚合物； 裂解； 電阻率
--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
