| Water-borne anticorrosion coating have attracted considerable attention in recent years attributed to low voc.Above all,waterborne polyurethane has be en widely used in coatings,adhesives and other fields attributed to their excellent flexibility,heat-and-cold resistance,solvent resistance and weather resistance.Water-based polyurethane recover insufficient for the coating in the water resistance,ha rdness and adhesion to metal deficiencies.At the same time,polyaniline that is used as the conductive polymer attributed to their high electrical conductivity,unique doping mechanism and simple preparation method has been widely used in anticorrosion coating.This article aims to explore effect of composite hydrophobic chain extender on antisepsis performance of waterborne polyurethane and antiseptic property of polyaniline doped with different protonic acids/modified waterborne polyurethane coating.The modifiedwaterborne Polyurethane emulsion?E-WPU?was synthesized based acetone on self-emulsified process by using of Polybutylene adipate?PBA?,isophorone diisocyanate?IPDI?and dimethylol propionic acid?DMPA?as the main raw material,hydrophobic chain extension agent epoxy resin?E44?,1,4-cyclohexane dimethyl?CHDM?and isophorone ketone diamine?IPDA?as modifier.At the same time,doped polyaniline was synthesized by the using of ammonium persulfateas oxidant,hydrochloric acid,citric acid,twelve benzene sulfonic acid and perfluorooctanoicacid as doping acid.Synthesized polyurethane and polyaniline were characterizedby means of FTIR,XRD,TG,hardness,adhesion and conductivity test.The polyaniline / modified waterborne p olyurethane anticorrosion coating was prepared by modified waterborne polyurethane which was film forming materials and polyaniline which was anticorrosion pigments.The coating was characterized by tafel polarization curves,electrochemical impedance and adhension test.The electronchemical behavior of coating was investigated in 3.5% Na Cl solution.The corrosion resistance of polyaniline doping by different acids in waterborne polyurethane system was compared.The results showed that using of E44/IPDA /CHDM had significantly improved the water resistance,hardness and adhesion on the metal of the E-WPU coating.When the R value was 1.2,the mass fraction of E44,CHDM and IPDA were respectively 7%,2% and 3% in the prepolymer,the comprehensive performance was obtained.The result of conductivity test showed the corrosion potential of polyaniline-containing coating increased,the corrosion current decreased about 1 2 orders magnitude.The results show that the corrosion resistance of the Eigenstate Polyaniline is best by comparing the tafel polarization curves and electrochemical impedance of different acid doped polyaniline/modified aqueous polyurethane anticorrosive coatings.The corrosion potential of Eigenstate Polyaniline-coating was-0.405 V,the corrosion current density was 7.237×10-9 A/cm2 and the impedance value is 8×105 ?·cm2 When the low frequency is 0.01 Hz. |
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