Effect of Graphene Oxide on Interfacial Interactions and Fracture Toughness of Basalt Fiber-Reinforced Epoxy Composites.

Multiscale hierarchy is a promising chemical approach that provides superior performance in syner-gistically integrated microstructured fibers and nanostructured materials in composite applications. The main purpose of this work was to introduce graphene oxide (GO) between an epoxy matrix and basalt fibers to improve mechanical properties by enhancing interfacial adhesion. The composites were reinforced with various concentrations of GO. For all of the fabricated composites, the optimum GO content was found to be 0.5 wt%, which improved the interlaminar shear strength and fracture toughness by 66.2% and 86.1%, respectively, compared with those of neat composites. We observed a direct linear relationship between fracture toughness and certain surface free energy. In addition, the fracture toughness mechanisms were illustrated using a crack theory based on morphology analyses of fracture surfaces. Such an effort could accelerate the conversion of multi-scale composites into high-performance materials and provide rational guidance and fundamental understanding toward realizing the theoretical limits of mechanical properties.