| Epoxy resin is widely applied in civil, military industry, civil construction,chemical corrosion protection, aerospace and other fields, for many excellentperformances such as corrosion resistance, chemical stability and high strength whichbecome the fundamental materials in various fields. The traditional epoxy resin is notsoluble in water, while it is soluble in organic solvents, the organic solvents must beused as a dispersion medium in using process, which is not only waste resources toincrease the cost, but also easy to cause pollution of the environment and damagehuman health. Development of environmentally friendly water-soluble epoxy systembecome the research focus in the present, this article use the hydrophilicity to modifythe epoxy resin, methacrylic acid monomer in the epoxy resin introduction ofhydrophilic segment in main chain to obtain the waterborne epoxy resin emulsion,which has an stabilizing system and nanoscale particle size. The main contentsinclude:(1) The waterborne epoxy resin system was obtained by solution polymerizationmethod. Using methyl acrylate, styrene, butyl acrylate as grafting monomer, n-butylalcohol, ethylene glycol butyl ether as a solvent and diluent, two benzoyl peroxide asthe initiator synthesis the waterborne epoxy resin emulsion. Methyl acrylic acidcontent and temperature on the emulsion stability are discussed, the optimalexperimental conditions was obtained. Examines various performances such as theemulsion solid content, pH, viscosity, etc in the best experimental conditions.(2) The waterborne epoxy resin system was obtained by emulsion polymerizationmethod. The experiment process is divided into opposite process and chemicalreaction process. Temperature, dosage of emulsifier drop rate were discussed in theemulsification process to obtain the relationship between those and the watershed rate, the optimum emulsification conditions: reaction temperature is80℃, compositeemulsifier addition amount was3.6g, dropping speed of0.5ml/min, the emulsionparticle size0.8-2.5μm in this situation. Observed by particle size analysis and TEMpictures: the structure of waterborne epoxy resin colloidal particle is core-shellstructure through chemical reaction process, along with the increase of the content ofmethyl acrylic acid emulsion particle increased thickness of the shell structure, withthe increase of temperature, latex particle size, particle size distribution is wide, theemulsion particle size is between50-150nm. By Fourier infrared spectrum and UVspectrum proved that the methyl acrylic acid monomer successfully grafted to theepoxy resin. The synthesis of emulsion were tested.(3) The preparation of emulsion film have good acid, alkaline, salt resistance andadhesion by both methods after the curing reaction. The coatings had high bibulousrate prone to swelling because of containing hydrophilic groups. Through infrared testdiscussed the change of methyl acrylic acid content after the changing structure of thepolymer; Using contact Angle, water absorption and electrochemical testingmetallographic photos and methyl acrylic acid content change is discussed on theproperties of emulsion coating curing membrane after layer effect, After the curingreaction, the contact angle, water absorption, adhesion, the porosity and defectspresent in the coating were lower with the increasing of the ratio of MAA to the epoxy,the lower contact angle and water absorption led to the higher corrosion resistance,but the lower porosity and defects were not conductive to corrosion protection. |
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