基于氧化石墨烯修饰活化碳纤维的聚醚醚酮基复合材料

Polyetheretherketone Matrix Composites Based on Graphene Oxide Modified Activated Carbon Fibers

碳纤维增强聚醚醚酮(CF/PEEK)复合材料是重要的航空热塑性复合材料,其弱点是碳纤维(CF)与基体界面结合性差,导致层间剪切强度(ILSS)较低。文中将氧化石墨烯/聚醚酮酮(GO/PEKK)混合上浆剂涂覆于活化CF表面,制备了纤维-基体界面修饰的具有高ILSS的CF/PEEK复合材料。采用扫描电子显微镜(SEM)、傅里叶红外光谱和热重分析分别对表面修饰剂及其改性CF的微观形貌与结构进行表征,采用静力学测试、动态力学分析和SEM等对复合材料断裂行为进行评价与分析。结果表明,当GO质量分数不超过0.5%时,在PEKK中分散良好;由于界面修饰剂的氢键作用,CF/PEEK复合材料的弯曲强度、模量和ILSS均大幅提高,断裂形式从纤维-基体脱粘转变为基体变形及断裂,表明基体与增强体的相互作用增强。

Carbon fiber reinforced polyetheretherketone(CF/PEEK) composite is an important thermoplastic composite for aviation. The weak point is the poor wettability and interfacial interactions between carbon fiber(CF) and matrix, resulting in low interlaminar shear strength(ILSS). In this study, CF/PEEK composites with fiber-matrix interfacial modifications and high ILSS were prepared via coating sizing agents of graphene oxide/polyetherketoneketone(GO/PEKK) mixtures onto activated CF. SEM, Fourier transform infrared spectroscopy and thermogravimetric analysis were used to characterize micro-morphologies and structures for sizing agents and modified CF. Mechanical test, dynamic mechanical analysis and SEM were used to evaluate and analyze the fracture behavior of modified composites. The results show that GO is well dispersed in PEKK oligomer if the concentration is not more than 0.5%;because of hydrogen bonds between PEKK and GO/CF, the flexural strength, modulus and ILSS of CF/PEEK composites are markedly improved. Dominant failure types shift from fiber-matrix debonding to deformation of breakage in matrix, indicating that interactions between matrix and reinforcement are enhanced.