液态聚碳硅烷的一步超声缩合制备及其表征  

One-Step Ultrasonic Condensation Preparation and Characterization of Liquid Polycarbosilane

作　　者：郭洪亮 王小宙[1] GUO Hongliang;WANG Xiaozhou(Science and Technology on Advanced Ceramic Fibers and Composites Laboratory,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学,新型陶瓷纤维及其复合材料重点实验室,长沙410073

出　　处：《硅酸盐学报》2024年第9期2800-2805,共6页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(51872329)。

摘　　要：液态聚碳硅烷(LPCS)是先驱体浸渍-裂解法(PIP)制备SiC陶瓷基复合材料的理想先驱体。以甲基氢二氯硅烷、甲基乙烯基二氯硅烷、二溴甲烷、金属钠为原料,经Wurtz缩合反应一步制备了含活性基团的LPCS。在超声波和醚助剂条件下,反应在40℃保温4 h即可完成,合成收率超过90%。采用Fourier变换红外光谱、核磁共振、紫外-可见光光谱、热重分析等对LPCS进行表征。结果表明:LPCS具有Si—C键的主链结构,同时形成了部分Si—Si键。所合成的LPCS含有丰富的Si—H、CH=CH_(2)等活性基团,1200℃以上热解后可转化为SiC,陶瓷产率最高为48.8%(质量分数)。Introduction SiC ceramic matrix composites have excellent mechanical properties and high-temperature resistance,and hence attracts increasing research attentions in aerospace and other fields.Precursor infiltration and pyrolysis(PIP)is one of the most common methods for the preparation of SiC ceramic matrix composites.The synthesis of organic precursors is the basis of the PIP process.Liquid polycarbosilane(LPCS)is an ideal precursor for the preparation of SiC ceramic matrix composites by PIP process.LPCS can be prepared using the Grignard coupling reaction,while this method suffers from the problem of long synthesis route and high cost.The Wurtz reaction,as another method for synthesizing LPCS,has a shorter route and less cost.However,it is difficult to directly synthesize LPCS containing active groups because of the severe reaction conditions.Ultrasound can significantly promote the effective contact between sodium and chlorosilanes and reduce the reaction conditions in the Wurtz reaction,and some ether additives can improve the activity of the reaction groups.Therefore,the introduction of ultrasound and ether additives is expected to realize the efficient synthesis of LPCS containing active groups.In this work,an active LPCS was prepared directly from chlorosilane monomer containing active groups by using ultrasonic and ether additives in Wurtz reaction.The basic structure of the product,ceramic yield and pyrolytic properties of the transformed ceramics were characterized.Methods CH_(2)Br_(2),MeHSiCl_(2)and ViMeSiCl_(2)were used as raw materials,and mixed with the molar ratio of 2:1:1.Under the conditions of no ultrasonic or ether auxiliary agent,ether auxiliary agent only and ultrasonic together with ether auxiliary agent,the reaction was carried out at 40℃for 4 h,and the excess Si—Cl was reacted by Me_(3)SiCl.The corresponding products were obtained by filtration and distillation.Diethylene glycol dimethyl ether(DGDME)or tetrahydrofuran(THF)was selected as ether auxiliary agent,and THF is easier to remov

关 键 词：液态聚碳硅烷 Wurtz反应 超声波 合成与表征 

分 类 号：TQ174.4[化学工程—陶瓷工业] TB324[化学工程—硅酸盐工业]