Co-modification of nano-silica and lysine on graphene oxide nanosheets to enhance the corrosion resistance of waterborne epoxy coatings in 3.5% NaCl solution

Abstract

This work successfully synthesized γ-(2,3-glycidoxy) propyltrimethoxysilane (GPTS) functionalized silica nanoparticles (GSiO2). The obtained GSiO2 was grafted onto lysine-modified graphene oxide (LGO) by covalent bonding to prepare GLGO nano-hybrid material, and then the prepared GLGO nano-hybrid material was used as a nano-filler for the waterborne epoxy resin (WEP) matrix. The fracture surface of the composite film was investigated by SEM, it was observed that GLGO was uniformly distributed in the WEP matrix. In addition, the contribution of GO, LGO and GLGO on the corrosion anticorrosive performance of WEP coatings in 3.5% NaCl(aq) was estimated via potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). Experimental data exhibited that the impedance modulus of the GLGO/WEP coating system with only 0.1 wt% GLGO added at |Z|f=0.01Hz was about two orders of magnitude higher than that of the pure WEP coating after 40 days immersion. Therefore, GLGO nano-hybrid material was an effective green anti-corrosion nano-filler for WEP matrix.