Enhanced mechanical property and flame resistance of graphene oxide nanocomposite paper modified with functionalized silica nanoparticles

Graphene oxide (GO) paper with outstanding integrated multiple functionalities (good mechanical performance, thermal stability and flame resistance, etc.) is strongly needed for numerous potential applications in cutting-edge fields. In this work, we report a facile and green process to fabricate GO-based nanocomposite papers via introducing functionalized silica (f-SiO 2 ) nanoparticles. The results reveal that addition of f-SiO 2 produces simultaneous improvements in mechanical strength , stiffness and flame resistance for GO paper. With incorporation of 10 wt% f-SiO 2 , the tensile strength , elastic modulus and toughness of the GO/f-SiO 2 nanocomposite papers can be increased by about 51%, 317%, and 69%, respectively. Various characterizations disclose that hydrogen bonds and covalent interactions between GO sheets and f-SiO 2 mainly contribute to the effective load transfer and energy dissipation between them, and thus leading to the improvements of mechanical properties . Based on the structural observation and analysis, the improved flame resistance of the GO/f-SiO 2 papers should be attributed to the formation of rGO/SiO 2 protective char, which are derived from the decomposition and redeposition of the grafted silane molecules and inorganic SiO 2 and thermal reduction of GO into rGO. Our results suggest that the mechanical and thermal properties of GO papers can be tuned by introducing inorganic/organic f-SiO 2 , providing a new route for the rational designing and development of mechanically flexible and flame-retardant GO-based nanocomposite paper materials.