宇航级T800碳纤维复合材料界面调控

Interface adjustment of aerospace-grade T800 carbon fiber composite material

上浆剂对高性能碳纤维(CF)表面的修饰作用及对其复合材料界面性能的调制作用至关重要。以湿法制备的宇航级T800碳纤维为研究对象,分析上浆前后纤维表面微结构、化学组成和化学反应特性的变化规律,并对其复合材料的宏微观界面性能进行表征评价。采用X射线光电子能谱(XPS)、差式扫描量热法(DSC)、傅里叶变换红外光谱(FTIR)等表征方法,分析上浆剂的反应性及其与环氧树脂(EP)、双马来酰亚胺树脂(BMI)的化学反应行为。结果表明:在树脂固化温度条件下上浆剂与纤维表面基团发生化学反应,使得纤维上浆剂提取量及纤维表面活性碳元素含量降低,并且上浆剂与EP、BMI工艺具有良好的化学反应性。经过高温处理后CF表面的上浆剂失活,CF/EP的界面剪切强度发生一定变化,CF/BMI的界面剪切强度下降13%。综上可见:具有化学活性的环氧类上浆剂可明显改善CF表面特性,进而对复合材料的界面性能产生影响,其中上浆剂与树脂体系的反应性对界面亦有影响。

The effect of the sizing agent on the surface modification of high-performance carbon fiber(CF)and the modulation effect on the interface performance of its composite is very important.In this paper,the aerospace-grade T800 carbon fibers prepared by the wet method are used,and the changes in the surface microstructure,chemical composition,and chemical reaction characteristics of the fiber before and after sizing are analyzed,and the macro and micro interface properties of the composites are characterized.In addition,the reactivity of the sizing agent and its chemical reaction behavior with epoxy resin(EP)and bismaleimide resin(BMI)were examined using X-ray photoelectron spectroscopy(XPS),differential scanning calorimetry(DSC),Fourier transform infrared spectroscopy(FTIR),and other characterization techniques.The results show that the sizing agent reacts chemically with the groups on the fiber surface under the curing temperature of the resin so that the extraction amount of the sizing agent and the content of active carbon atoms on the fiber surface is reduced.The sizing agent has good chemical reaction characteristics with EP and BMI.The surface of CF sizing agent is rendered inactive after the high-temperature treatment,which also results in a little change in the interface shear strength between CF and EP but a 13%reduction between CF and BMI.In conclusion,the epoxy sizing agent with chemical activity can significantly improve the surface properties of carbon fiber,and then affect the interface properties of composites,in which the reactivity between the sizing agent and resin also affects the interface performance.