| Metal corrosion causes damage for the metal structure,resulting in serious accidents and considerable economic losses.Coating the metal surface with anti-corrosion coatings is one of the most effective and convenient way to resist metal corrosion.Zinc-rich anti-corrosion coatings become the most widely used coatings because of its unique anticorrosion mechanisms.However,for the traditional solvent-based zinc-rich coatings,the zinc powder only works with a large amount.This kind of coatings contains high amounts of zinc powder and VOC,which is liable to cause pollution for the surrounding environment and pose a hazard to the health of people,so developing efficient environmentally-friendly anti-corrosion coatings is the development trend of anti-corrosion coatings.The silane coupling agent/acrylic emulsion modified by epoxy was used as the binders,which does not contain organic solvents.Part of the zinc powder were replaced by the polyaniline/graphene oxide conductive composites to improve the corrosion resistance and reduce the amount of zinc powder.A kind of water born zinc-rich anticorrosion coatings were developed.The adhesion,strength,salt water resistance,salt spray resistance,electrochemical properties and the anticorrosion mechanisms were also discussed.The crosslinking degree of the acrylic emulsionis was improved by the seed emulsion polymerization,using the silane coupling agent KH-570 and the epoxy as the modifier to improve the water resistance,salt water resistance and salt spray resistance,and then the silane coupling agent/acrylic emulsion modified by epoxy was prepared.The effects of the amount of emulsifier,catalyst concentration,raw materials proportioning,reaction conditions and condition of cure on the properties of water-borne emulsion were studied.The optimum conditions are as follows;the ratio of emulsifier OP-10/SLS is 3: 1,the amount of emulsifier is 4.76 %;the amount of epoxy is 30 %;the amount of initiator is 1.85 %;the amount of silane coupling agent is 4.32 %;the ratio of water-borne emulsion to the curing agent is 100: 1;the curing temperature is 120 ?;the curing time is 5 h.The properties of the prepared silane coupling agent/acrylic emulsion modified by epoxy are up the standard,according to HG/T 4842-2015 elastic emulsion for architectural coatings.Polyaniline(PANI)/graphene oxide(GO)anticorrosion components were prepared by in-situ polymerization.The structures and properties of the composites were studied by SEM,XRD and FTIR and at the same time we explored the effects of the amount of GO on the dispersibility and conductivity of the polyaniline-graphene oxide composites,as well as the effects on the hardness,water absorption,adhesion of the water-borne emulsion prepared earlier.SEM analysis shows that spherical PANI are between the surfaces and layers of GO.Successful compound was produced between PANI and GO.The composites has good conductivity,excellent dispersibility in water,and good compatibility with silane coupling agent/acrylic emulsion modified by epoxy.PAGO improved the hardness and adhesion of the coatings and reduces the water absorption,which laid a good foundation for the application of PAGO composites in water-borne zinc-rich coatings.In order to prepare efficient PANI/GO acrylic zinc-rich anticorrosion coating by modified epoxy,the silane coupling agent/acrylic emulsion modified by epoxy was used as the binders,and replaced part of the zinc powder with the PAGO conductive composites acting as the anticorrosion components to prepare the modified zinc rich coatings.The corrosion resistance of the zinc-rich anticorrosion coatings before or after being modified by PAGO was compared by open-circuit potential(OCP),Tafel plot,EIS and salt spray test and other methods.The results shows that the corrosion resistance of the zinc-rich coatings is greatly improved.This kind of coatings has the advantages of high corrosion resistance,without volatile organic solvent and small amount of zinc powder. |
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