Study On Synthesis Of Waterborne Epoxy Emulsifier And Properties Of Emulsion

Waterborne epoxy resin coating is a kind of the promising environmental friendly anti-corrosion coatings, one of the key technology of waterborne epoxy coatings is the waterborne epoxy resin, of the three methods, the mechanical method gets poor stability and now has basically abandoned, phase-inversion method and chemical modification method are used at most, the key of phase-inversion method is to choose the emulsifier which has a similar structure to epoxy resin, in order to obtain the particular emulsifier, chemical modification method has to use. Preparing high performance waterborne epoxy emulsion by using the combination of the phase-inversion method and the chemical modification method is an inevitable choice.This paper firstly used Polyethylene glycol diglycidyl ether and ethanolamine to modify epoxy resin CYD-128, synthesized a kind of waterborne epoxy emulsifiers which has a similar structure with epoxy resin. A real-time tracking of epoxy value change was used in the reaction process, so as to determine the best synthesis conditions. When the temperature of reaction is 70 ?, the time of reaction is 5 hours, the dosage of 1-methoxy-2-propanol is 5%, optimum synthesis conditions was got. The chemical structure of emulsifier was analyzed by using Four ier Transform Infrared Spectroscopy(FTIR). Waterborne epoxy emulsifier's cloud point, critical micelle concentration(CMC), hydrophilic lypophilic balance value(HLB) and other performance were measured. The HLB is 12.35 which is between 8 to 18, it can be used as emulsifier in the emulsion of oil in water type, the Cloud point is 85 ? shows that the phase-inversion temperature can not be more than 85 ?.Secondly, the phase-inversion method was used to emulsify epoxy resin CYD-011 with self-made waterborne epoxy emulsifier and a small amount of solvent, the optimal process conditions for preparing waterborne epoxy emulsion was determined by orthogonal experiment: the molar ratio epoxy and amine is 1.10, the molar ratio of polyethylene glycol diglycidyl ether and epoxy resin CYD-128 is 8, the dosage of emulsifier is 9%, the phase-inversion temperature is 60 ?. The average particle size of the prepared emulsion is 50.4 nm and has a uniform distribution, the solid content is 49%, the pH is 8, the epoxy equivalent weight is 827, the viscosity is 174 mPa·s, peforming good stability.Finally, self-made waterborne epoxy resin emulsion, proper waterborne epoxy curing agent and other component were used to prepare waterborne epoxy coating, and SiO2 nano particles were used to modify waterborne epoxy coating. Electrochemical impedance spectroscopy(EIS), thermogravimetric analysis(TG), contact angle, scanning electronmicroscopy(SEM) and other methods was used to evaluate performances of coating. The research results show that when the molar ratio of epoxy and amine is 1:0.5, the content of SiO2 nano particles is 2%, the size of SiO2 nano particle is 7 nm, the best corrosion resistance which is 16413 ? was got. The comparison of film performances of self-made product and market product shows that comprehensive performances of self-made coating have reached the level of similar products of famous brands on the market.