Simultaneously tuning interfacial and interlaminar properties of glass fiber fabric/epoxy laminated composites via modifying fibers with graphene oxide

A series of graphene oxide (GO) with various oxidation degrees were synthesized in this work and then grafted onto the surface of glass fiber fabric (GFf), and subsequently a resin infusion process was engaged in the fabrication of GFf/epoxy laminated composites. Interlaminar and interfacial properties as well as interlaminar microstructure of laminated composites were investigated in detail. Results showed that various oxygen-containing functional groups on the GO surface due to oxidation degrees endowed GO with different dispersion states in composites and strengthening/toughening efficiency, thus greatly influenced composites’ interlaminar and interfacial adhesion. Also, the desorption and diffusion of GO from the fiber surface into matrix-enriched interlaminar region during the resin infusion process were evidenced. Making use of a moderate weight ratio of oxidation agent (KMnO4)/graphite (2:1), the optimal oxidation degree of GO was achieved for reinforcing fiber/matrix interface and matrix-enriched interlaminar regions. Under this case, the interlaminar shear strength and work of fracture of resultant composites were raised by 28.2% and 138.3%, respectively; storage moduli in glass regions and at the beginning of rubbery regions were enhanced by 22.3% and 104.5%, respectively; the significantly fiber/matrix interfacial adhesion and glass-transition temperature were obtained, compared with those of the control sample. This work provides a guiding strategy for optimizing strength and toughness of fiber-reinforced composites by regulating GO oxidation degrees.