热氧稳定化过程温度效应对PAN纤维径向氧元素扩散速率的作用

摘要

The gradient warming and isothermal oxidative stabilization of polyacrylonitrile（PAN） fibers were carried out,and the formation mechanism of skin-core structures and pervasion of oxygen elements of PAN fibers at different stabilization temperatures were investigated systematically by means of FTIR,13C-NMR,EA,DSC,energy dispersive analysis system of X-ray（EDS） and density.The study indicates that the lower the oxidation rate than the diffusion rate,the greater is the difference between outer and core of PAN fiber cross-section,and the morphologies of skin-core structure will appear on the cross-section simultaneously.The formation of skin-core structures of the preoxidized fibers is not only relevant to the temperature,but also highly relevant to the heating mode.By using EDS,the radial pervasion of oxygen elements of preoxidized fibers at different temperatures can be effectively quantified,the oxygen uptake on the different regions of the cross-section of stabilized fibers also can be visually displayed.%在梯度升温和恒温两种模式下,对聚丙烯腈（PAN）纤维进行了热氧稳定化处理,借助FTIR、核磁共振碳谱（13 C-NMR）、元素分析（EA）、DSC、X-射线能谱（EDS）、密度等多种表征手段系统研究了不同温度下热氧稳定化纤维皮-芯结构的形成机制和氧元素的扩散速率。研究结果表明：氧化反应速率小于氧的扩散速率时,PAN纤维横截面外层与芯部差别较大,将出现皮-芯形貌结构特征;热氧稳定化纤维皮-芯结构的产生不但与温度有关,而且与升温模式密切相关;EDS表征方法可以有效地量化不同温度下,热氧稳定化纤维径向氧元素的扩散速率,同时可直观显示出氧在纤维截面不同区域的结合速率。