群子统计理论研究PAN预氧化过程的成环机理  

A theoretical study of the cyclization of polyacrylonitrile during the pre-oxidation process using sub-cluster statistics theory

作　　者：孙国防[1] 许志献[1,2] 代永强[1] 薛立伟[1] 张力[1] 易凯[1] 李金波[1] 金日光[1] 

机构地区：[1]北京化工大学化工资源有效利用国家重点实验室,北京100029 [2]安阳师范学院化学化工学院,河南安阳455000

出　　处：《北京化工大学学报（自然科学版）》2009年第3期26-30,共5页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：国家自然科学基金重点项目(50333060)

摘　　要：将通过自由基聚合得到的聚丙烯腈(PAN)在不同温度下进行预氧化反应,借助X射线衍射(XRD)分析,根据群子统计理论,研究了PAN在预氧化过程中从线形结构到环形有序结构转变的机理,求出了预氧化反应过程中的活化能,探讨了PAN在预氧化过程中成环和成线的竞争关系。研究结果表明,在250～300℃范围内,预氧化温度越高,越容易进行成环反应,环化度越高;预氧化过程中环化活化能为63.57kJ/mol,成环反应不占优势,环状结构与线性结构共存,PAN只有进一步高温炭化,才有可能使更多的线性结构转化为环状结构。Polyacrylonitrile was obtained by radical polymerization after pre-oxidation at different temperatures. A micro-structural transformation during the pre-oxidation step, from the fibrous linear structure to a cyclic structure, was observed by XRD. The activation energy of that process was calculated, and the mechanism investigated using sub-cluster statistics theory. The competitive relationship between cyclization and linearization during the pre-oxidation step was studied. The results show that in the temperature range 250 to 300 ℃, the degree of ring formation increased with increasing pre-oxidation temperature. The activation energy of the cyclization reaction in the pre-oxidation process is 63.57 kJ/mol, showing that the cyclization reaction is not favorable. Cyclic structures and linear structures co-exist in this temperature range and further high-temperature carbonization is necessary in order to convert all of the linear form into cyclic structures.

关 键 词：聚丙烯腈 预氧化 环化反应 群子统计力学 

分 类 号：O212[理学—概率论与数理统计] TQ342.742[理学—数学]