Carboxylic-plasma-treated nanofiller hybrids in carbon fiber reinforced epoxy composites: Dispersion and synergetic effects

A nanostructuring approach was applied to epoxy/carbon fiber (CF) composite laminates to establish a short transport path between the CF of the adjacent laminates. This involved the utilization of carboxylic-plasma-functionalized multiwalled carbon nanotube (COOH-MWCNT) and carboxylic-plasma-functionalized graphene nanoplatelet (COOH-GNP) hybrids filled epoxy resin at various nanofiller hybrid ratios and concentrations. Novel Raman spectroscopy imaging and surface potential atomic force microscopy (AFM) mapping were employed to analyze the state of nanofiller dispersion on the laminate surfaces. The mixture of COOH-GNPs and COOH-MWCNTs in a ratio of 50:50 wt% at 4 phr was identified to synergetically improve their dispersion and the laminate electrical and mechanical properties. It offered optimal segregation of nanofiller hybrids. At this composition, the maximum electrical conductivity and the highest flexural strength were achieved in the composite laminate, which were approximately 75 S/cm and 675 MPa, respectively.