Study on the improvement of interfacial strength between glass fiber and matrix resin by grafting cellulose nanofibers

The performance of fiber-reinforced polymer composites (FRPs) markedly depends on the fiber/matrix interface bonding. In this study, a new approach is proposed to improve the interfacial shear strength (IFSS) with cellulose nanofibers (CNFs) added on the surface of the reinforcing fiber. Different concentrations of CNFs were prepared and then used for the surface treatment of glass fibers. The effect of CNFs grafted onto fibers on the IFSS and the flexural strength of glass fiber/epoxy resin composites was investigated. A scanning electron microscope was used to characterize the surface morphologies. Micro-droplet and three-point bending tests were conducted to evaluate the properties mentioned above. The results indicated that these mechanical properties improved as the CNF concentrations increased. A maximum increase of 78% in the IFSS was achieved, while an enhancement of 20% was obtained for the flexural strength. This suggests that grafting CNFs onto GF can significantly improve the strength of glass fiber/epoxy composites.