高压合成聚碳硅烷的分子量分布与可纺性  

THE MOLECULAR WEIGHT DISTRIBUTION AND SPINNABILITY OF POLYCARBOSILANE SYNTHESIZED UNDER HIGH PRESSURE

作　　者：程祥珍[1] 谢征芳[1] 宋永才[1] 肖加余[1] 

机构地区：[1]国防科技大学航天与材料工程学院,cfc重点实验室湖南长沙410073

出　　处：《高分子材料科学与工程》2005年第5期59-62,共4页Polymer Materials Science & Engineering

基　　金：湖南省自然科学基金03JJY3070

摘　　要：采用高压合成方法合成了聚碳硅烷(PCS),研究了高低分子含量、分散系数对PCS软化点、分子量分布及可纺性的影响.结果表明,可以用软化点加分子量分布来判断PCS的熔融可纺性.当PCS的软化点低于200 ℃,分散系数小于1.8,高、中分子含量比例小于0.1时,可纺性很好;随着分子量的增大,软化点的升高,高分子含量增加,分子量分布宽化,可纺性开始变差,当软化点大于260 ℃,分散系数大于2.2,高、中分子含量比例大于0.3时,可纺性很差,甚至失去可纺性.要得到软化点高、分散系数低、可纺性好的PCS,必须控制PCS的高、中分子含量比例约为0.1～0.3,低、中分子含量比例约0.8左右,分散系数约为1.8～2.2.The preceramic polymer polycarbosilane （PCS） was synthesized at high temperature and high pressure. The influence of different molecular weight PCS content and polydispersity index on softening point, molecular weight and distribution and spinnability of PCS were investigated. The results show that, the melting spinnability of PCS can be estimated by softening point and molecular weight distribution. The spinnability of PCS is very good when the softening point is lower than 200 ℃ with polydispersity index lower than 1.8 and WH/WM, the ratio between the content of high molecular weight PCS and middle molecular weight PCS, lower than 0.1. The spinnability worsenes when the molecular weight, high molecular weight PCS content and softening point increase with molecular weight distribution broadening. The spinnability of PCS becomes poor or very poor when the softening point is higher than 260℃, polydispersity index higher than 2.2 and WH/WM higher than 0.3. Therefore, to obtain PCS with high softening point, narrow molecular weight distribution and good spinnability, WH/WM shall be controlled in the range from 0.1 to 0. 3 with the WL/WM, the ratio of the content of low molecular weight PCS to that of middle molecular weight PCS, about 0.8 and the polydispersity index about 1.8-2.2.

关 键 词：聚碳硅烷 软化点 分子量分布 可纺性 

分 类 号：TQ343.6[化学工程—化纤工业]