One-step surface modification of graphene oxide and influence of its particle size on the properties of graphene oxide/epoxy resin nanocomposites.

Graphene oxide (GO) was synthesized from expanded graphite with particle size of 130 μm (GO130) and 1200 μm (GO1200) and characterized. GO130 was oxidized to a higher degree and contained larger concentration of C O bonds. After the synthesis, the GO was kept in a form of viscous slurry in methanol to prevent formation of graphite oxide. The slurry was mixed with a hardener and methanol was evaporated. The nanocomposites with GO content from 0.25 to 1.0 wt% were prepared by mixing the epoxy resin, hardener and hardener/GO mixture and cured. The particles were homogeneously distributed within the polymer matrix as observed by SEM on the plasma etched samples. The glass transition temperature increased from 81 °C to up to 90 °C. The Young’s modulus increased by 35% and 30% with the addition of GO130 and GO1200, respectively, while the tensile strength increased for 10% only when GO1200 had been added. The optimum concentration of GO in the nanocomposite is from 0.25 to 0.50 wt%. [ABSTRACT FROM AUTHOR]