Effects of adding graphene nanoplatelets and nanocarbon aerogels to epoxy resins and their carbon fiber composites

Highlights: • It is difficult to evenly mix nanocarbon materials with different dimensions, such as GNP (2D) and NCA (3D) in the polymer matrix because of the differences in their structure, and the reinforcing behavior from adding nanocarbon hybrids (2D+3D) in CFRP laminates is unknown. However, we success to evenly mix GNP and NCA hybrids to epoxy, and fabricate GNP/NCA/CFRP laminate. • In our earlier studies, it was demonstrated that adding NCAs and GNPs to epoxy and CFRP laminates to improve the mechanical properties of the composite laminates, respectively. However, we did not know the mechanical properties of the composite when GNP/NCA hybrids add to epoxy and their CFRP laminate. Therefore, it's imperative to investigate the effects of GNP/NCA hybrid reinforced epoxy and GNP/NCA-reinforced CFRP laminates. -- Abstract: In this study, graphene nanoplatelet (GNP)/nano-carbon aerogel (NCA) hybrids were used to reinforce epoxy resin and epoxy/carbon fiber composite (CFRP) laminates in order to investigate the synergistic effects on their mechanical properties. The GNP/NCA hybrids (1 wt%) with different mixing ratios (i.e., 10:0, 9:1, 7:3, 5:5, and 3:7) were dispersed in epoxy resin to prepare GNP/NCA/epoxy nanocomposites. The mechanical properties such as ultimate tensile strength, flexural strength, flexural modulus, and impact strength of these nanocomposites were investigated. Additionally, the fracture surfaces of the specimens examined using field-emission scanning electron microscopy and transmission electron microscopy to determine the dispersal mechanisms of the GNP/NCA hybrids in the epoxy resin. A 3k carbon fiber fabric impregnated with different amounts (i.e., 0, 0.25, 0.5, 0.75 and 1.0 wt%) of GNP/NCA epoxy resin, and epoxy/CFRP laminates was prepared using a fixed mixing ratio of 5:5. The synergistic effect of the GNP/NCA hybrid on the mechanical properties of the carbon-fiber-reinforced epoxy resin composite laminates was also investigated. The experimental results demonstrate that the mechanical properties of GNP/NCA/epoxy nanocomposites and GNP/NCA/CFRP laminates are optimized via reinforcement upon the addition of GNP/NCA hybrids.