聚丙烯腈纤维预氧化生产的在线动态研究

采用DSC、FT-IR、AE、TG-MS、XRD和SEM等分析手段,对连续生产的PAN预氧化纤维的各阶段取样研究。DSC、FT-IR和AE分析表明,在预氧化过程中,主要发生线型分子链的氧化、环化反应,最终形成耐热、不溶不熔的稳定结构;TG-MS分析结果表明,纤维在氧化环化的同时,不断地放出小分子物质,且随着预氧化程度的加深,释放小分子的量逐渐减少,释放温度向高温方向移动;XRD分析显示,晶区的特征衍射峰强度的锐减和非晶区衍射峰强度缓慢增强是纤维内部结构重组的信息,更是表明预氧化反应以晶区为主的重要标志;SEM分析结果表明,预氧化反应不足的纤维,有不同程度的皮芯结构形成,易被有机溶剂腐蚀形成孔洞和溶胀现象。

Dynamic Study Pre-oxidation Process of PAN Fibers

Polyacrylonitrile fibers in continuous pre-oxidation process was studied systemically by DSC、FT-IR, AE, TG-MS, XRD and SEM. The results of DSC、FT-IR and AE showed that oxidization and cyclization reaction of linear molecule chain were taken during pre-oxidation process. Heat-resistance and insoluble/infusible structure would be formed finally. TG-MS showed that evolution of small molecule weight gas decreased gradually with oxidization and cyclization extent, at the same time, the peek value of evolution temperature shifted to high. XRD indicated that the sharp decrease of crystal area and the slow increase of amorphous area was the information of structure recombination and pre-oxidation reaction mainly in the crystal area. SEM indicated that the core/sheath morphological structure of short of oxidative fibers could be observed, those fibers would be easily eroded by organic solvent and then hole and swelling occur.