The Latex Synthesis And Coating Preparation For Waterborne Mastic Damping Coatings

With the development of society, people’s living standards are increasing fast. It is a major problem to eliminate noise pollution now. Waterborne damping coating can form a film on the workpieces. It can convert mechanical energy to heat, so it could weaken vibration and noise. Compared with traditional asphalt board damping materials, waterborne damping coating in a complex space have a superior workability and it is environmentally friendly. The material has got more and more concerns from automobile industry, aircraft industry and other industries. This dissertation designed and synthesized a series of styrene-acrylic polymer latex with different compositions and structures based on emulsion polymerization. The latex performances and latex film damping properties were systematically investegated. Then the latex was selected with excellent polymerization stability and superior damping property. The pilot scale experiment was carried out based on the emulsion polymerization of the latex. Furthermore, mastic waterborne damping coatings were prepared using the synthesized polymer latex as the film-formation matrix which are of high solid content and can be thickly coated. The effects of various additives and fillers were also systematicly studied. The main work includes the following aspects.1、Synthesis of poly(styrene-acrylate) latex with high solids content and the damping properties of the latex filmS-01 and B-01 were used as the main monomers to synthesis polymer latex with high solid content and high stability in the requirements of waterborne damping coatings. The influnence of the synthesis parameters on the emulsion polymerization and product stability was investegated. The latex film was prepared using the synthesized latex. The damping properties as well as the influnences of different monomers and their ratios were characterized by using dynamic mechanical analysis (DMA)2、Modifications of polymer latex and the damping properties of the latex filmThe further attempts to improve the damping properties of the latex was also done by using chemical copolymerization with monomers with large side groups or physical blending polymer latex with different glass transition temperatures. The peak position and width of the latex film on the tan8-T curves could be thereafter adjusted. Furthermore, the thesis also used S-01 and B-01 as the main monomers to synthesis a series of core-shell polymer latex. The stability of the latex was found to be effected by using different polymerization processes and different emulsifiers. Latex films was also characterized by DMA. The results revealed that the crosslinking agent D-22 added in the core layer has a significant effect. At the D-22 content of 2%, an interpenetrating network (LIPN) could be built with the the latex particles which could effectively broaden the effective damping temperature range of the latex film.3、Waterborne damping coatings:preparation and propertiesSeries of waterborne damping coatings were prepared by using the poly(styrene-acrylate) latex synthesized above. And the comprehesively properties of the coating including the damping, rheometric and mechanical performance as well as the waterand heat resistances were evaluated. The coatings preparation process was optimized. Coatings with high solid contents and an excellent shear thinning properties were achieved by the synergestically use of several kinds of commerical thickeners. Furthermore, the detailed study was conducted on the influnence of compositions and construction conditions on the damping properties of the coatiing. It has been found that the higher latex amount, lower Y-13 size and larger Y-13 amounts would all have positive contribution on the damping properties of the coating. And the improvement on the coating thickness could also provide better damping performance. At the temperature range of 0 ℃～80℃, the coating showed excellent damping performancewith the largest composite damping factor of 0.18. In addition, the coating is easy to be applied with obviously shear thinning performance and would not sag under the thickness Of 3mm..