A new strategy for improvement of interface and mechanical properties of carbon fiber/epoxy composites by grafting graphene oxide onto carbon fiber with hyperbranched polymers via thiol-ene click chemistry

For the purpose of improving the interface and mechanical properties of carbon fiber reinforced polymer (CFRP) composites, a new strategy was proposed to graft the graphene oxide (GO) onto carbon fiber (CF) surface fast and effectively via thiol-ene click chemistry reaction using vinyl-terminated hyperbranched polyester (VHBP) as bridging agent. The successful synthesis of the CF-VHBP-GO hybrid reinforcement was verified through Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscope, thermogravimetric analysis, and scanning electron microscopy. The simultaneous introduction of GO and hyperbranched polymers changed the fiber surface morphology and improved the wettability and surface energy of CF. Judging from the results of the micro-droplet test, the interfacial shear strength for epoxy (EP) based composite reinforced with CF-VHBP-GO was significantly increased by 137.8% compared to untreated CF/EP composite owing to the synergistic effect of VHBP and GO. In addition, the tensile and flexural strength for CF-VHBP-GO/EP composite were improved by 47.6% and 65.8%, respectively, compared to untreated CF/EP composite, respectively. This work offers a promising technique for developing high-performance CF composites with excellent interface properties.