典型碳纤维/环氧树脂复合材料热解动力学研究

Study on pyrolysis kinetics of typical carbon fiber/epoxy composites

以飞机结构中典型的碳纤维/环氧树脂复合材料为研究对象,通过热重分析实验研究了载气(氮气、空气)气氛和不同升温速率对其热解特性的影响,分析了热解过程,选用Kissinger和Flynn-Wall-Ozawa两种方法计算了相关热解动力学参数,并进行了对比分析。结果表明:碳纤维/环氧树脂复合材料在氮气气氛下热解只有一个阶段,即环氧树脂在无氧条件下的热解;空气气氛下热解有3个阶段,第一、二阶段为环氧树脂的热解,第三阶段为碳纤维的热解。两种气氛下,随着升温速率的增大,样品的初始分解温度、终止分解温度以及最大失重速率逐渐提高,热解温度范围也逐渐变宽。Kissinger和Flynn-Wall-Ozawa两种方法计算得到了样品在空气气氛下的各阶段表观活化能,经对比分析,所得结果较为一致。研究结果可为复合材料适航审定提供基础数据和理论参考。

In this paper,the typical carbon fiber/epoxy composite material in aircraft structure was taken as the research object.The effects of carrier gas(nitrogen,air)atmosphere and different heating rates on its pyrolysis characteristics were studied by thermogravimetric analysis,and the pyrolysis process was analyzed.Two methods,Kissinger and Flynn-Wall-Ozawa,were used to calculate the relevant pyrolysis kinetic parameters,and a comparative analysis was carried out.The results showed that the pyrolysis of carbon fiber/epoxy resin composites in nitrogen atmosphere had only one stage,that is,the pyrolysis of epoxy resin under oxygen-free conditions.There were three stages of pyrolysis in air atmosphere.The first and second stages were the pyrolysis of epoxy resin,and the third stage was the pyrolysis of carbon fiber.Under the two atmospheres,with the increase of the heating rate,the initial decomposition temperature,the termination decomposition temperature and the maximum weight loss rate of the samples gradually increased,and the pyrolysis temperature range gradually became wider.The Kissinger and Flynn-Wall-Ozawa methods were employed to calculate the apparent activation energies of the samples in air atmosphere at each stage,and the results were consistent after comparative analysis.The research results could provide basic data and theoretical reference for the airworthiness certification of composite materials.