The Preliminary Research Of The Synthesis Of Vinyl Terminated Water-based Polyurethane Modifiedly Acrylate And Its Application In Anion Releasing Material

Water-based polyurethane owns many excellent properties such as dramatic low temperature resistance, terrific flexibility, perfect abrasion resistance, non-toxic, and so on. water-based polyurethane was modified by acrylate, not only to retain the outstanding properties of polyurethane, but also to improve water-resistance, chemical resistance, weather resistance of the film, which improves the properties of the emulsion and the film significantly. Unfortunately, water-based polyurethane modified acrylate still has some problems, such as poor stability of emulsion and deficient water-resistance for advanced paint.In this thesis, polyurethane-polyacrylate copolymer composite emulsion was prepared by means of seed emulsion polymerization to improve the drawbacks of the acrylate modified water-based polyurethane. By controlling the process of polymerization, the composite emulsion was prepared, and its apparent viscosity decreased gradually along with the increase of its solid content. The problems of the composite emulsion such as poor mobility and paste phenomenon can be solved successfully, and the emulsion can be applied as advanced paint.During the experiment, water-based polyurethane which was dimethylol propionic acid (DMPA) as the hydrophilic chain extender and hydroxymethyl acrylamide (N-MAM) as capping agent. The influences of the reaction temperature,-NCO/-OH molar ratio, the types polymer of polyols and relative molecular mass, and the amount of DMPA, different types of neutralizer, and the ratio of neutralization on coating properties were investigated thoroughly. Determination by latex particle size showed that:with the increased use of DMPA, emulsion particle size decreases and stability increases.Polyurethane polyacrylate composite emulsion was synthesized while vinyl termi-nated polyurethane was used as seed emulsion, acrylate monomer was added to it using semi-continuous. During the copolymerization process, the influences of polymerization parameters, including reaction temperature, different initiators,ratio of emulsifier SDS-OP10 and the amount of them, acrylic monomers and vinyl weight ratio of polyurethane were investigated thoroughly. Polyurethane-polyacrylate's structure was analyzed by using FTIR, 13C-NMR spectra, DSC spectra and other analytical instruments, the results show that Polyurethane-polyacrylate copolymer were synthesized, and with the amount of methyl methacrylate (MMA) increased, composite latex particle size water contact angle of the coating increased, and its water-resistant improved. Under optimal conditions, the composite emulsion was prepared with solid content of 48.3% and the apparent viscosity 91.2 mPa.s. In view of the role of negative ions on the human body health, the coating agent was synthesized by adding anion additives to water-based polyurethane composite latex which was obtained in this study. In this thesis,the best optimum condition under this negative ions were released from the emulsion was determined, which was also used in the cotton cloth and polyester-cotton fabric processing.the results show that those kind of cotton cloth and polyester-cotton fabric can release negative ions, up to 1390/cm3 and 1200/cm3 respectively.