ENHANCING THE INTERFACIAL ADHESION VIA CHEMICAL GRAFTING MULTILAYER POLYETHER AMINE/GO ON CARBON FIBER SURFACE

摘要

Inspired by the hard/soft phase combined structures of biological and natural materials, nano-structured polyether amine/GO (DG for short) multilayers were attached onto carbon fiber surface by chemical grafting approach. Scanning electron microscopy reveals the uniform coverage of DG multilayer on fiber surface, and the compactness and thickness of this coverage increase with increasing layers from 1 (CF-DG) to 4 (CF-DG4). The detected oxygen gradually increases with enhancing grafting layers, which leads to enhanced polar component of surface energy. Simultaneously, the wettability of fiber with resin improves corresponding with increased grafting layers. After modification, the interfacial shear strength of CF-DG, CF-DG2 and CF-DG4 are improved 7.7%, 18.8% and 60.0% as compared with untreated CF, and the improving efficiency is most outstanding for reinforcement with 4 layers (CF-DG4). This outcome can be ascribed to: i) brick-and-mortar structure is formed on fiber surface when the layer number reaches 4, where platelet structured GO acts as a role to increase strength, deflect cracks and redistribute stress, while polyether amine acts as a role to interlock with GO and provide a soft phase to allow movements of GO sheets; ii) the abundant active groups on CF-DG4 surface can improve the wettability and form strong chemical bonds with epoxy matrix; iii) the uniform coverage of multilayers could effectively avoid stress concentration.