| A new kind of waterborne epoxy resin dispersant is synthesized with mixed epoxy and poly(ethylene glycol diglycidyl ether)(PEGDGE)as raw materials and ethylene glycol propyl ether as co-solvent and a waterborne epoxy resin emulsion is prepared through phase inversion technique with a mixture of the dispersant as emulsifier,the medium molecular weight solid epoxy resin E-20 and a moderate amount of co-solvent ethylene glycol propyl ether.The emulsion has a solid content of 50%.The waterborne epoxy curing agent is prepared through Mannich reaction with cardanol,phenol,paraformaldehyde and diethylenetriamine(DETA)as raw materials.In addition,the modified epoxy acrylate resin is prepared under a certain temperature with nonionic surfactant,epoxy resin E-20 and acrylic acid.Afterwards,the UV-curable waterborne epoxy emulsion is obtained by phase inversion method.The choices of raw materials,reaction conditions and reaction processes are optimized.The comprehensive performance analysis of double component emulsions and curing agents,especially the particle size of emulsions as well as the mechanical property and salt-spray corrosion of paint films under different conditions(such as different reaction materials and reaction processes)are carried out.The final result is:the ratio of mixed epoxy and poly(ethylene glycol diglycidyl ether)is 1:3,while the dispersant with the best emulsifying effect is prepared by using ethylene glycol propyl ether as co-solvent;the emulsion is prepared as the content of dispersant at 8%through phase inversion technique,which has a good particle size as less than 400 nm.The curing agent is prepared through one step method with paraformaldehyde,diethylenetriamine and phenol with 15% mol fraction cardanol as raw materials,whose paint films has excellent corrosion resistance and mechanical properties after mixing with emulsions.The comprehensive performance analysis,especially the particle size of emulsions as well as the electrochemical performance and salt-spray corrosion of paint films under different conditions(such as the types of epoxy resin and photoinitiator)are carried out on one component emulsion.Results show that the stability of the emulsion with the particle size as about 250 nm and the film performance(including paint film mechanical properties,electrochemical properties and corrosion resistance)can be the best with the selection of epoxy resin E-20,lightinitiator IRGACURE 651,esterification reaction temperature 105?,reaction time 3hours,emulsifying temperature 25~30? and stirring speed 800 r/min. |
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