Highly dispersed graphene oxide–zinc oxide nanohybrids in epoxy coating with improved water barrier properties and corrosion resistance

Abstract

Epoxy resin (EP) coating that prevents corrosion is subject to premature failure as its crosslinking network appears to be porous due to the presence of hollow spaces across the network, which leads to poor water barrier. This study introduces a novel approach of utilizing the stable surface property of zinc oxide (ZnO) to facilitate the dispersion of graphene oxide (GO) sheets in epoxy coating to improve water barrier and corrosion resistance properties. The ZnO nanoparticles (ZnO NPs) were decorated on GO sheets by using (3-aminopropyl)triethoxysilane as coupling agent. The GO-ZnO nanohybrids were successfully formed, as demonstrated in Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses. The GO-ZnO sheets were well dispersed in epoxy matrix with no significant agglomeration, as verified via field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy. The decoration of GO with ZnO NPs expanded the spacing between GO sheets, as observed from the outcomes of X-ray diffraction analysis, which improved exfoliation and compatibility in epoxy matrix. Based on the investigations and characterization outputs, the well-dispersed GO-ZnO nanohybrids in the epoxy coatings had effectively improved water barrier properties, as well as adhesion and corrosion protection, in comparison with neat epoxy (EP) and GO–epoxy coatings.