中间相沥青纤维氧化增重过程

Mass Increase During Oxidative Stabilization of Mesophase Pitch Fiber

采用热重分析跟踪模拟中间相沥青纤维的氧化稳定化过程,研究升温速率、氧化终温及恒温时间对纤维氧化进程的影响,并在此基础上建立了氧化增重与反应时间和温度的关系。实验发现:在230～290℃空气中反应数小时稳定化能够完成,而且纤维的氧化增重量Δw与反应时间t0.3成很好的线性关系。通过Arrhenius方程拟合计算出不同温度下的动力学参数及活化能,确立了简单而精确的氧化增重与时间及温度的动力学模型,从而可准确把握和预测中间相沥青纤维在恒温空气下氧化增重的进程,实现稳定化。

The effects of heating rate, ultimate oxidation temperature and residence time on the oxidative stabilization of mesophase pitch fiber were investigated by thermogravimetry and scanning electron microscopy. The relationships among oxidation time, temperature and mass gain were examined. It was found that the oxidative mass gain at a constant reaction temperature （230-290℃） was proportional to a simple fractional exponent of oxidation time （t^0.3）. A simple and accurate mathematical model was proposed to de- scribe the overall kinetics of oxidative stabilization for mesophase pitch fiber with respect to temperature effect by the Arrhenius equation. The time required to achieve desired oxidation mass gain at a given reaction temperature can be predicted by the model for isothermal oxidative stabilizations.