高强玻璃纤维复合材料热解动力学研究

Study on pyrolysis kinetics of high-strength glass fiber/epoxy resin composites

利用热重—差热同步分析仪研究典型高强玻璃纤维/环氧树脂复合材料在不同升温速率、不同载气气氛影响下的热解特性规律。升温速率取5、10、20、30、40℃/min;气氛取空气及氮气气氛(50 mL/min);实验温度范围为25~800℃。研究表明,随着升温速率的增大,热解反应各阶段起始温度、终止温度、最大失重速率温度均向高温方向移动。空气气氛下,玻纤复合材料热解分为两个阶段,分别是环氧树脂基材热解的两个阶段,玻璃纤维自身不分解;氮气气氛下,玻纤复合材料热解反应一步完成。相同升温速率下,玻纤复合材料与环氧树脂基材的热解初始分解温度、热解温度范围基本一致,玻纤复合材料的热解终止温度及热解各阶段失重速率明显小于环氧树脂基材。运用Kissinger法和Flynn-Wall-Ozawa法进行热解动力学分析,得到玻纤复合材料热解各阶段的表观活化能,两种计算方法所得结果基本一致。热解第二阶段表观活化能明显高于第一阶段,其热稳定性在热解过程中逐渐增强。

The regularity of the glass fiber/epoxy resin composite pyrolysis characteristics was researched at different heating rates and in the different atmosphere used TO/DTA simultane- ous thermal analyzer. The temperature rise rates were 5, 10, 20, 30 and 40 ℃/rain, the atmosphere was air or N2 by 50 mL/ min. The temperature varied from 25 to 800 ℃. Studies indica- ted that the initial decomposition temperature, the final decom- position temperature and the temperature of maximum weight loss rates shifted towards high temperature with the increase of the heating rate in every stage of pyrolysis reaction. The pyrol- ysis process of the glass fiber composite can be divided into two stages that are the two decomposition stages of the epoxy resin,and the glass fiber do not decompose, in air. Under nitrogen atmos- phere, the pyrolysis reaction of glass fiber composite completed in one step. The initial decomposition temperature and the pyrolysis tempera- ture scope o$ the glass fiber composite and the epoxy resin matrix are basically consistent under same heating rate. The final decomposition temperature and the weight loss rate of every pyrolysis of the glass fiber composite are significantly lower than the epoxy resin matrix~ s. The pyrolysis kinetics of the glass fiber composite was analyzed with Kissin- ger method and Flynn-Wali-Ozawa methods. The apparent activation energy was obtained in every pyrolysis reaction, and the results of two methods are basically similar. The apparent activation energy of pyroly- sis in the second stage is significantly higher than the apparent activation energy in the first stage. The thermostability is gradully enhanced in pyrolysis process.