High strength and toughness epoxy nanocomposites reinforced with graphene oxide-nanocellulose micro/nanoscale structures

Abstract The prepared micro/nanoscale structure had a strong and flexible 2D graphene oxide (GO) component (elastic modulus 250 GPa) with a high aspect ratio of 1D nanocellulose (NCC), which possessed excellent mechanical properties (elastic modulus 150 GPa) and was a versatile material for enhancing epoxy (EP) nanocomposites. In this work, we had proposed a strategy for chemically assembling a micro/nanoscale structure comprising GO grafted with NCC (GO-NCC). The GO-NCC, combined with the dense, covalently and hydrogen bonded EP molecule, led to highly effective load transfer between the micro/nanoscale structure and the EP. The inclusion of NCC effectively increased the contact area between the GO and EP and enhanced the interfacial strength and contact surface area of the GO-NCC/EP composite, contributing to its excellent mechanical properties (high toughness and strength). The GO-NCC provided dual advantages over conventional GO in its prominent reinforcement and toughening of the EP composite. Only 0.3 wt% of the GO-NCC was needed to significantly increase the tensile strength and Young's modulus by 69% and 13%, respectively, compared to those of the pristine EP. Moreover, the nanocomposite showed a 244% increase in critical stress intensity factor (KIC) and an 801% increase in critical strain energy release rate (GIC).