Study On Preparation And Anticorrosive Mechanism Of New Waterborne Composite Anticorrosive Coatings

Metal is easy to multi-phase chemical reactions with surrounding media,resulting in corrosion.Anticorrosive coating is an effective method to prevent metal corrosion.In recent years,waterborne anticorrosive coatings have received more and more attention.Although waterborne anticorrosive coatings have the advantages of environmental protection,non-toxic,and consistent with the long-term development strategy,they also have the disadvantages such as long drying time,easy to rust,poor water resistance and so on,so the long-term anticorrosive effect is not ideal.To enhance the performance of waterborne coatings,polyvinylpyrrolidone(PVP)was used to modify graphene oxide(GO)and doped into the water-borne anticorrosion system as nanoparticles to improve the resistance of water-borne coatings to corrosive media penetration.Polytetrafluoroethylene(PTFE)and polydimethylsiloxane(PDMS)were used to prepare hydrophobic layer to improve the hydrophobic effect,thereby reducing the penetration and collapse of water molecules on the coating,and improving the anticorrosive performance of the water-based coating.The physical and chemical properties of the composites,such as internal structure,functional group types and microscopic surface morphology,were studied by various characterization methods.The protective performance and anti-corrosion mechanism of the coating on metal substrate were studied by electrochemical workstation.The results showed that: PVP/GO nanofiller was prepared by solution blending method and doped into the waterborne epoxy resin emulsion(EP)to prepare polyvinylpyrrolidone/graphene oxide/water-based epoxy resin(PVP/GO/EP)composite coating,the protection efficiency of composite coating to metal reached 94.69%,which was higher than 70.79% of the protection efficiency of single EP coating.This is mainly due to the uniform distribution of doped nanoparticles within the coating,which delays the corrosion process.The water contact angle of the PTFE/PDMS/EP coating prepared by the layer-by-layer assembly method could reached 141°,which greatly reduced the contact between water molecules and anticorrosive coating,and thus enhanced the anticorrosive performance of the coating.According to relevant test calculations,the protection efficiency of PTFE/PDMS/EP coating on metal could reached 98.83%.This is mainly because the problem of poor water resistance of the coating surface has been solved,so it has efficient and stable anticorrosion performance.In this study,two kinds of composite materials,PVP/GO and PTFE/PDMS,were used to modify the interior and surface of the waterborne epoxy coating,so that the stability,corrosion resistance and water resistance of the water-based epoxy resin coating were greatly improved.