| Acrylic resin(PA) coatings has good waterproof, weather resistance and good mechanical properties, but it will stick at higher temperature and become brittle at lower one, and wear-resistance is poor.Polyurethane coatings has good flexibility, good low temperature resistance and abrasion resistance, but it also has shortcomings such as poor water resistance, low intensity and so on. According to the advantages and disadvantages of both PU and PA can be complementary in performance, PUA emulsion polymerization can overcome their shortcomings. According to the research status of acrylate modified polyurethane, because of acrylate conversion rate is low, also in order to make better water resistance and mechanical properties of coating film,allyloxy hydroxyl propanesulfonic salt(AHPS) and Glycidyl methacrylate(GMA) is used in polymerization system. This article is divided into two parts, one is the preparation of polyurethane/polyacrylate composite emulsion, the other is to prepare waterborne coating by using the synthesized emulsion and test it.Waterborne polyurethane/polyacylate emulsion(WPUA) was synthesized mainly with poly-caprolaclone glycol(PCL1000),isophorone diisocyanate(IPDI), 2,2-dimethylol butyric acid(DMBA),methyl methacrylate(MMA) and butyl acrylate(BA). GMA and AHPS were introduced, a stable epoxy-modified waterborne polyurethane /polyacylate emulsion under polmerizable emulsifier(EPUAS)compositeemulsion with 43% solid content had obtained. The structure and morphology were characterized by IR, TEM, XRD, TGA and AFM. The amount of GMA and the amount of AHPS on properties of the emulsion and films were discussed. The waterborne coating was prepared by using the synthesized emulsion and test it.The results show that:(1) IR test results showed that epoxy group and hydroxyl group of GMA both reacted with WPUA, AHPS had been successfully bonded onto the particle surface. A core-shell structure is observed by TEM.and XRD examination showed that GMA was crosslinked with WPUA,TGA test of the membranes showed that the thermal stability and the decomposition temperature were increased with the increment of the PA,GMA, AHPS content. The property test of emulsion and films of EPUAS showed that the solid content, water resistance, hardness and mechanical property. were improved when w(PA) is 30%, w(GMA) is4% and w(AHPS) is 2% of the mass of PA. WEPUAS can be used in wall coating.(2) With the PA content increased from 0 to 40%, the average diameters was increased gradually, the decomposition temperature increased, the tensile strength increased and elongation at break decreased gradually, water resistance increased, the hardness increases gradually, But when the PA content was 40%, the emulsion was unstable,when PA content was 30%, WPUA and the performance of its film achieved the best.(3) When ω(PA) = 30%, ω(AHPS) = 0, mechanical properties of the film, the gel content, the thermal stability increased gradually with the GMA content increased from 0 to 5%, the emulsion average diameters increases gradually, Zeta potential values of the emulsion varied range from-40.5mv to 37.5mv, solvent resistance decreases after increasing first. But the emulsion storage stability was poor with ω(GMA)= 5%,therefore, polymers achieve the best performance when GMA content was 4%.(4) When ω(PA) = 30%, ω(GMA) = 4%, as the AHPS contentincreased from 0 to 5%, the addition of AHPS can improved the conversion rate of the emulsion and the solid content, but if AHPS content was too high, water aborsorbtion is too high, The test result showed that when ω(AHPS) = 2%, the emulsion was stability and had a high solid content, the other performance also were excellent.(5)The waterborne coating was prepared by using the synthesized emulsion, and the test showed that the pencil hardness, gloss, abrasion resistance, the impact resistance, light loss resistance were good, and it can be used in wall coatings. |
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