| 引用本文: | 谢征芳,程祥珍,宋永才,等.高压合成聚碳硅烷的沉淀与复配.[J].国防科技大学学报,2006,28(5):26-29,41.[点击复制] |
| XIE Zhengfang,CHENG Xiangzhen,SONG Yongcai,et al.Precipitation and Blending of the Polycarbosilane Synthesized at High Temperature under High Pressure[J].Journal of National University of Defense Technology,2006,28(5):26-29,41[点击复制] |
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| 高压合成聚碳硅烷的沉淀与复配 |
| 谢征芳, 程祥珍, 宋永才, 肖加余 |
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(国防科技大学 航天与材料工程学院，湖南 长沙 410073)
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| 摘要: |
| 研究了沉淀与复配两种调控高压合成聚碳硅烷（PCS）分子量及其分布的方法。研究表明，在PCS的良溶剂（如二甲苯）溶液中加入沉淀剂（如丙酮）比例超过临界点后，PCS中分子量越高的部分越先沉淀出来，从而降低了PCS的软化点、分子量和分散系数，PCS的高、中、低分子量的比例得到调节。复配是将不同分子量分布的PCS均匀地混合在一起，其分子量、软化点和高、中、低各部分的含量基本符合混合率的关系。因此，可以按照混合率来设计所需PCS的软化点、分子量及高、中、低分子含量。 |
| 关键词: 聚碳硅烷 沉淀 复配 分子量及其分布 |
| DOI： |
| 投稿日期：2005-09-06 |
| 基金项目:湖南省自然科学基金资助项目(03JJY3070)；国防科技重点实验室基金资助项目 |
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| Precipitation and Blending of the Polycarbosilane Synthesized at High Temperature under High Pressure |
| XIE Zhengfang, CHENG Xiangzhen, SONG Yongcai, XIAO Jiayu |
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(College of Aerospace and Materials Engineering, National Univ. of Defense Technology, Changsha 410073，China)
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| Abstract: |
| The methods of precipitation and blending to adjust the molecular weight and distribution of polycarbosilane (PCS) synthesized at high temperature under high pressure were investigated in the paper. The results show that, the high molecular weight PCS can be precipitated by adding certain amount of precipitator (such as acetone) into the PCS solution of favorable solvent (such as xylene). The higher the molecular weight of PCS, the earlier it precipitates when acetone is added to a degree above the critical value. The softening point, molecular weight and polydispersity index of PCS are therefore decreased. The molecular weight distribution of PCS is thus controlled. Blending of PCSs with different molecular weights and distributions is another method to adjust the molecular weight and distribution. The results show that, the softening point, weight average molecular weight and content of high, middle and low molecular weight of the obtained PCS are accorded with the rule of mixture (ROM) when two different molecular weight PCSs are blended together. Therefore, PCS with required softening point, molecular weight and distribution can be designed in advance according to ROM. |
| Keywords: polycarbosilane precipitation blending molecular weight and distribution |
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