| Based on environmental protection and sustainable development, the research processof anti-corrosion coatings can be summarized as two trends: the "greening" developmentand "high performance" development. Waterborne coatings has accounted for a considerableproportion of anti-corrosion coatings and develop rapidly, especially in the architecturalcoatings field. Practice has proved that two-component waterborne epoxy coatings can meetthe requirements of the heavy anti-corrosion coatings.The particle size of epoxy resinemulsion modified through chemical method can be nm-class. The focus of research is usingdifferent modified agent to meet the different needs.Unsaturated acids resin has the prominent advantages of high gloss and good weatherresistance while organic silicone resin has the excellent advantages of good heat resistance,chemical resistance, water resistance and flexibility. These two resins can be complementarywith epoxy resin so as to prepare the modified waterborne epoxy emulsion which showsexcellent performances. It has great value both in theory and practical application.In this paper, epoxy emulsion was successfully synthesized by grafting MAA, BA andSt, and modified by siliane coupling agent.The course of reaction and the rates of reactors were studied. The optimum reactionconditions was that epoxy resin E-06react as main body, n-butyl alcohol and ethyleneglycol butyl ether react as cosolvent, benzoyl peroxid react as initiator, the optimum amountof initiator was6%~8%, the best grafted temperature was110~115℃, the best grafted timewas5~6h, the best ratio of grafted monomer with epoxy resin was4:5, the amount ofmethacrylic acid was25%, the neutralization degree was90~100%, the salt temperature was55℃, the optimum content of silane coupling agent was7%and the best ratio of KH570with KH550was2:1.The results were characterized by using nanometer particle size analyzer, infraredspectrometer, UV-vis spectrophotometer, electrochemical workstation, contact angleanalizer and thermogravimetric analyzer. The laser particle size analysis showed that theaverage particle size belongs to nanometer level. The structure of epoxy emulsion modifiedby unsaturated acids and silane coupling agent was characterized by FT-IR and the resultsshowed that organosilicon compound had been grafted sucessfully by solutionpolymerization. UV-vis spectrum showed the ultra-violet resistance of modified emulsion increased dramatically. The results of EIS showed the modified epoxy emulsion hadexcellent anti-corrosion properties. The results of contact angle showed the film scantywater rate significantly increased. The results of TG showed after20%weight loss, thethermal stability of modified emulsion was better than pure epoxy resin, emulsion thermalstability obviously improved. The performance test showed that the film owned excellentperformance and flexibility had been improved. |
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