Functional Modification Of Graphene Oxide/carbon Nanotubes And Its Application In Anti-corrosion Coatings

The durability of metallic materials is often reduced due to their corrosion process.Since ancient times,animal fat and beeswax have been applied to metal surfaces to inhibit corrosion of metal tools.Today,organic coatings are formulated to provide more effective protection for metals.The widespread use of organic solvent-based coatings contains large amounts of volatile organic compounds(VOC),which can cause serious environmental pollution problems.As environmentally friendly alternatives,water-based polyurethane(WPU)and ethanol-based polyvinyl butyral have excellent abrasion and chemical resistance,as well as strong adhesion to substrates.More and more attention has been paid.In order to improve the corrosion resistance of coatings,nano-fillers such as carbon nanotubes,graphene and its derivatives were added to prepare polymer-based composite coatings.In this paper,graphene oxide(GO)was prepared by modified Hummer's method,and GO was functionalized modified with isophorone diisocyanate and nitrogen nitrogen dimethylethanolamine.Finally,graphene derivatives(IP-GO)were prepared.The IR-,X-ray photoelectron spectroscopy,and Raman spectroscopy characterize the successful preparation of IP-GO.0.3 wt%of GO,IP-GO and reduced graphene oxide were added as anticorrosive fillers to the WPU coating to prepare a composite anticorrosive coating.Different coatings have been tested by salt spray test,electrochemical impedance,water absorption and other tests.The addition of GO and IP-GO can improve the overall corrosion resistance of water-based polyurethane,but IP-GO-enhanced water-based polyurethane at 3.5 wt%after 50 d immersion in sodium chloride solution,the impedance modulus remained above 10~8?.In order to further improve the anti-corrosion performance of the composite coating,a zinc-rich anti-corrosion coating was prepared by using IP-GO in combination with zinc powder and polyaniline functionally modified carbon nanotubes.The addition of polyaniline effectively improved the electrical conductivity of multi-walled carbon nanotubes(MWCNTs),and then explored the effect of different mass ratios of polyaniline and MWCNT on electrical conductivity,and finally concluded that the mass ratio of polyaniline to MWCNT was 5:1.The conductivity is the best at 5:1.Finally,the anti-corrosion mechanism of(PMWCNT)and its synergistic effect with functionalized graphene and zinc powder were discussed to enhance the anti-corrosion mechanism of WPU.A green non-toxic and rapid reduction method is used to prepare reduced graphene oxide(RGO)films,and RGO high hydrophobicity and molecular impermeability are used to prepare anticorrosive coatings with different layer structures.The coating structure is an alternating coating of RGO layer and polyvinyl butyral(PVB)polymer.After anti-corrosion test,the anti-corrosion efficiency of PVB coating reinforced by GO and RGO film will be significantly improved,but the anti-corrosion efficiency of PVB coating is the highest after the introduction of RGO film.