Synthesis of Silane Functionalized Graphene Oxide and Its Application in Anti-Corrosion Waterborne Polyurethane Composite Coatings

In this study, novel silane functionalized graphene oxide (PVSQ-GO) composite material is synthesized through the hydrolysis condensation reaction of vinyl triethoxysilane monomers occurred at the surface of graphene oxide. Results obtained from FTIR, Raman, X-ray photoelectronic spectroscopy (XPS), XRD and TGA measurements reveal that polyvinyl sesquisiloxane microspheres adhere to graphene oxide lamellae in the form of chemical bonds. Meanwhile, it is intuitive that abundant polyvinyl sesquisiloxane microspheres stick to the surface of graphene oxide and increase the thickness of the flake. Modified graphene oxide changes from hydrophilicity to hydrophobicity were owing to the existence of polyvinyl sesquisiloxane microspheres on the surface of graphene oxide (GO). PVSQ-GO composite exhibited good dispersion in eco-friendly waterborne polyurethane coating. Electrochemical impedance spectroscopy manifested that the anti-corrosion performance of waterborne polyurethane (WPU) coating embedded at 0.5 wt.% PVSQ-GO composite improved effectively. Tafel curves reveal that 0.5 wt.% PVSQ-GO/WPU coating specimen shows the lowest corrosion rate of 8.95 × 10−5 mm/year when compared with the other coating specimens. The good anti-corrosion abilities of PVSQ-GO composite coating can be interpreted as the good compatibility between PVSQ-GO composite and waterborne polyurethane, however, the intrinsic hydrophobicity of PVSQ-GO composite is beneficial to inhibit the permeation of corrosive medium and thus slows down the corrosion rate.