| Waterborne epoxy-acrylate composite latex have excellent adhesion,corrosion resistance of epoxy resin,meanwhile it also combine superior gloss,color retention,weather resistance of acrylate resin.Simultaneously,using water as dispersed medium,it's such safety,environment friendly,non-toxic and tasteless that have a good application prospect.Generally,the waterborne composite resin are synthesized by water dispersion method and emulsion polymerization.In this paper,the composites are prepared by the two process,Aiming at the deficiency existed in each process,the improved solution are put forword for the purpose of enhancing the performance of composite latex coatings and finally meet the practical application.In the process of using water dispersed method to prepare composite emulsion,the high molecular low-epoxy value epoxy resin(E-12)was employed as graft body and appropriate decreased the reaction activity,so that to solve the poor storage stability of water dispersion method.In order to further improve the stability of the emulsion,the functional monomer acrylic polyethers(APEG)was used in graft copolymerization.The effect of reaction conditions on the polymerization process was discussed.The results shown that when the reaction time was 4h,reaction temperature was 110?,the radio of soft monomers and hard monomers was 4:1,the dosage of initiator was 7%of the monomers,weight,the polymerization course was stable and the graft ratio of composite resin could increase to 58%.When the acrylic acid was 9%of the monomers,weight,the APEG was 5%,the obtained emulsion had superior storage stability and the storage life reached to 75d.Coating properties test shown that comparing with low molecular epoxy resin,the composite emulsion had excellent hardness,solvent resistance with high molecular epoxy resin.In the process of using emulsion polymerization to prepare composite latex,in order to solve the problem of whiting etc due to traditional emulsifier molecules migrated in the coatings,using polymerizable emulsifier replaced the traditional emulsifier so that improved the performance of coatings.The results indicated that the polymerizable emulsifier SE-10 was employed to carry out polymerization,when the total amount of emulsifier was 2.5%of the monomers' weight,the water absorption of coating decreased to 2.7%and it had no whitening and rustiness.For purpose of improving the comprehensive performance of coatings,the epoxy-acrylate composites were modified by vinyl triethoxy silane(VTES).The addition way of VTES was studied and optimal dosage was 0.6%.The modified and unmodified composite resin was characterized by FT-IR,TG.The results shown that VTES was verified participating graft copolymerization and the modified composites had better thermal resistance.The morphology and particle size of composite latex particle were analyzed using TEM and laser particle size analyzer.Results shown that the distribution of particle size was around 120-150 nm with a stability core-shell spherical structure.The dynamic mechanical thermal analysis(DMA)was employed to characterize the damping property and the test results shown that when the content of AA was 1.4%,the tan? value of composites increased to 1.8 and the corresponding damping temperature range could reach to 50 ?.Accordingly,it indicated that the composite latex had better damping property and possessed potential application in the field of damping material. |
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