CNTs强化碳纤维/环氧复合材料界面过渡层及其对界面性能的影响

采用上浆的方法将碳纳米管(CNTs)引入到碳纤维表面,制备CF/CNTs/环氧多尺度复合材料。相比上浆处理前,复合材料的层间剪切强度及弯曲强度分别提高了13.54%和12.88%。采用力调制原子力显微镜及扫描电镜的线扫描功能对复合材料界面相精细结构进行分析。结果表明:CNTs的引入在纤维和基体间构建了一种CNTs增强环氧树脂的界面过渡层。该界面过渡层具有一定厚度,且其模量和碳元素含量呈梯度分布。在固化成型前对含有CNTs的复合材料进行超声处理,促使碳纤维表面的CNTs向周围树脂中分散,发现复合材料的界面过渡层被弱化,其层间剪切强度及弯曲强度较超声处理前分别下降了7.33%和5.34%,验证了CNTs强化的界面过渡层对于提高复合材料界面性能的重要作用。

Strengthening Interface T ransition Layer of Carbon Fiber/Epoxy Composites with CNTs and Its Effect on Interfacial Performance

The sizing treatments were used to introduce carbon nanotubes (CNTs) to carbon fiber (CF) surfaces for fabrication of CF/CNTs/epoxy multi‐scale composites .Comparing with the base composites without CNTs ,interlaminar shear strength (ILSS) and flexural strength of the modified composites were increased by 13 .54% and 12 .88% ,respectively .Force modulation atomic force mi‐croscope and linear scanning system of scanning electron microscope were carried out to analyze the microstructure of composite interface .The results indicate that a transition layer reinforced by CNTs is constructed between fiber and epoxy (EP) matrix ,which has certain thickness and exhibits gradient distribution of modulus and carbon element content .The composites containing CNTs are sonicated before curing to disperse CNTs in the surrounding resin .As a result ,the interface transition layer is weakened and the ILSS and flexural strength of prepared composites decrease by 7 .33% and 5.34% , respectively .Therefore ,the significant role of the interface transition layer in improving the interfa‐cial performance of composites is evidenced again at another perspective .