军用航空有机玻璃热分析动力学研究

对某型号军用飞机上航空有机玻璃用热重-差热(TG-DTA)分析仪进行了热分析动力学研究,实验在不同的氧气浓度(5%,10%,15%,21%)和升温速率(15℃/min,30℃/min)条件下进行,用改良的Coats-Redfern法计算出了动力学参数,用Doyle法计算理论失重值。研究发现表观活化能和频率因子都随氧浓度的下降而增加,在升温度速率分别为15℃/min和30℃/min条件下当氧浓度变化时表观活化能分别为100~108kJ/mol和87~92kJ/mol,而频率因子分别为(7~35)10⁶/s和(0.4~1)10⁶/s。计算结果很好的吻合了实验结果。

Kinetic Study on Aircraft-used Polymethyl Methacrylate under Different Oxygen Concentration

The decompositions of aircraft-used polymethyl methacrylate are studied by means of thermogravimetric analysis and differential thermal analysis. Four kinds of oxygen concentrations are used (5%,10%,15%,21%)and heating rates used vary from 15 ℃/min to 30 ℃/min. Improved Coats-Redfern method is used to determine the kinetic parameters and Doyle method was used to calculate the decomposition data. The active energy and pre-exponential factor both increase when the oxygen concentration decreases. The active energy is in the range 100-108kJ/mol and 87-92kJ/mol at the two heating rates when oxygen concentration decreases, while the pre-exponential factor is in the range (7-35)×10⁶/s and (0.4-1)×10⁶/s. The simulation of weight loss process accords with the real weight loss process well.