聚丙烯腈纤维预氧化过程中氧化反应和环化反应的动力学研究

Kinetics of Oxidation and Cyclization Reactions during the Pre-Oxidative Stabilization Process of Polyacrylonitrile Fibers

采用差示扫描量热仪(DSC)研究了聚丙烯腈/衣糠酸共聚物纤维在氧化性气氛(空气)和非氧化性气氛(氩气)下环化反应和氧化反应受加热速率的影响,计算了不同气氛下的反应活化能.采用元素分析技术研究了不同温度下氧化反应速率的变化,分析了氧的扩散机制.研究结果表明:含氧气氛中的反应活化能高于惰性气氛中的反应活化能,预氧化初期整个反应速率由环化反应速率控制;预氧化温度越高,氧的结合速率越快,但随着预氧化时间的延长,氧的结合速率逐渐降低,整个反应速率受氧的扩散速率控制.

The effects of heating rates on the cyclization and oxidation reactions of polyacrylonitrile/itaconic acid copolymer fibers under oxidative（air） and non-oxidative（argon） atmospheres were investigated by using differential scanning calorimetry（DSC）.The activation energy was calculated.Elemental analyzer was used to study the changes of oxidation reaction rate under different atmospheres and the diffusion mechanism of oxygen.The results show that the activation energy is higher under oxidative atmosphere than that under inert atmosphere,and the whole reaction rate is controlled by cyclization reaction rate.With increasing temperature,the rate of oxygen uptake gets faster.But it gradually decreases with time,and the whole reaction rate is controlled by the diffusion rate of oxygen.