| In this paper,mesoporous silica microspheres?SiO2/BTA?loaded with the corrosion inhibitor benzotriazole?BTA?were prepared,and the surface was hydrophobically modified.Then,waterborne anticorrosive coating was prepared by adding SiO2/BTA to the styrene-acrylic emulsion.The coating doped with SiO2/BTA could retard the corrosion process caused by paint defects through the slow release of corrosion inhibitor,and the corrosion resistance of coating was significantly improved.The content of the paper is mainly divided into the following three parts:1.Mesoporous silica microspheres loaded with benzotriazole?BTA?corrosion inhibitor were prepared by inverse emulsion polymerization using TEOS as silicon source,and the surface was hydrophobicly modified by hexamethyldisilazane?HMDS?.Taking the stability of reverse-phase emulsion and the load rate of BTA as reference factors,the factors including the ratio of oil and water,the content of emulsifier,the reaction temperature,the solution pH,the reaction time etc.were discussed.Taking the contact angle as reference factor,the factors including the amount of modifier,reaction temperature and reaction time were discussed.The surface structure,load and release of SiO2/BTA were analyzed by Scanning Electron Microscope?SEM?,Transmission Electron Microscopy?TEM?,Fourier Transform Infrared Spectroscopy?FTIR?,Thermal Gravity Analysis?TGA?and X-ray Diffraction?XRD?.The results showed that when the ratio of oil and water is 2:3,the content of emulsifier 8 g,the reaction temperature 35?,the solution pH 10,the reaction time 24 h,emulsion has the best comprehensive performance.When the mass ratio of SiO2/BTA and modifier HMDS 3:1,the reaction temperature 65?,and the reaction time 6 h,the hydrophobic modification effect of SiO2/BTA is the best.Nitrogen adsorption test showed that SiO2/BTA has a porous structure on the surface and is a mesoporous material with a pore diameter of 3-10 nm,a specific volume of 0.4 cm3/g and a specific surface area of 156 m2/g.The TG test showed that the load rate of BTA in the microsphere was 20%.The UV absorption spectra test showed that the SiO2/BTA could self-release the loaded BTA in response to changes of solution with different pH values,and the release rate was the highest under alkaline conditions,reaching 9.33 mg/L after 104 h.2.Waterborne anticorrosive coating was prepared by adding SiO2/BTA to the styrene-acrylic emulsion.In the experiment,pure coating was used as the control group.Then,BTA,SiO2 and SiO2/BTA were added to the coating formulation respectively.The physical mechanical properties and corrosion resistance of coatings were studied by traditional coating test methods.The factors including the amount of SiO2/BTA,the SiO2/BTA before and after modification and the solution pH on coating properties were discussed.The results show that compared with pure acrylic coating,the corrosion resistance of coating added with BTA was significantly improved,but its mechanical properties were decreased and the storage stability was bad.The mechanical properties of coating with SiO2 were increased,but the corrosion resistance was not significantly improved.However,the coating added with SiO2/BTA not only had a significant improvement in corrosion resistance,but also has a certain degree of improvement in mechanical properties.At the same time,it had a good storage stability and does not appear discoloration.When the amount of SiO2/BTA 1.5%,the solution pH 8,the comprehensive performance of the coating is the best.3.The electrochemical properties and the failure behavior of waterborne coating was studied by electrochemical impedance spectroscopy?EIS?.Coating resistance value and its change trend showed that:the resistance value of pure acrylic coating and doped with SiO2were the lowest,and their trend were slowing down quickly after the slow change.The resistance value of the coating doped with BTA is relatively high,its trend was slowing down quickly after the change until failure.The resistance value of coating doped with SiO2/BTA was the highest,and the trend was changing slowly from beginning to end. |
PDF Full Text Request