Graphene oxide (GO) was functionalized using three different diamines, namely ethylenediamine (EDA),
4,40-diaminodiphenyl sulfone (DDS) and p-phenylenediamine (PPD) to reinforce an epoxy/glass fiber (EP/
GF) composite laminate, with the aim of improving the overall composite mechanical performance.
Different mechanical characterization techniques were used to determine the mechanical performance,
including: tensile stress strain, double cantilever beam (DCB) mode-I fracture toughness and dynamic
mechanical thermal analysis (DMTA). Scanning electron microscopy (SEM) was used to support the results
and conclusions. The results demonstrated remarkable enhancements in the mechanical performance
of EP/GF composite laminates by incorporation of functionalized graphene oxide (FGO) nanofiller,
whilst the mechanical performance of the GO reinforced composite only improved marginally. Finally,
the mechanical performance of the EP/GF/FGO multi-scale composites was found to be dependent on the
type of FGO functional groups; of which EDA exhibited the highest performance. These investigations
confirmed that the EDA-FGO-reinforced EP/GF composites possess excellent potential to be used as
multifunctional engineering materials in industrial applications.