250℃下时间效应对PAN纤维热氧稳定化反应的影响及关联

Effect and Relation of Thermal Treating Time at 250℃ on the Stabilization of Polyacrylonitrile Fibers

借用傅里叶变换红外光谱(FT-IR)、元素分析(EA)、X射线衍射(XRD)和示差扫描量热分析(DSC)等手段,对比研究了热氧稳定化过程中250℃下时间效应与两种聚丙烯腈(PAN)共聚纤维及其炭纤维结构和性能之间的关联。研究结果表明,PAN纤维在250℃温区内停留超过9min时,最终热氧稳定化纤维的环化度(RCI)、体密度和芳构化指数(AI)的增加速率开始变小;炭纤维的孔含量(Vp)值与内部微晶的d002值开始增大,微晶排列的规整程度变差,缺陷增多,拉伸强度开始降低。

Polyacrylonitrile（PAN） stabilization fibers and carbon fibers were prepare from PAN precursors.Effect of thermal treating time at 250 ℃ of PAN fibers on their evolution to carbon fibers was investigated by Fourier transform infrared spectroscopy（FT-IR）,element analysis（EA）,wide-angle X-ray diffraction（WAXD） and differential scanning caborimetry（DSC）.Two kinds of PAN precursors with different chemical compositions were used for comparison.It is found that when thermal treating time at 250 ℃ is more than 9 min,the increasing rate of relative cyclization index（RCI）,density and aromatization index（AI） of stabilization fibers become slow,carbon fibers with bigger d002 of crystallite and Vp of carbon fibers can be got,worse crystallite layers pile up,more microvoid content and less tensile strength appear.