Applied Studies On Synthesis And Properties Of Polystyrene-acrylate Emulsion Modified By Organosilicone And Organofluorine

The features, conditions, and the recent progress on emulsion polymerization and the related technology researches were reviewed in this thesis. Also the modification of acrylic latex paints and their uses were discussed. The present study could be divided into the following three parts.Styrene-acrylic emulsion was modified with organic silicone by physical and chemical methods. The results showed that the chemical method could effectively improve the performance of emulsion. An organic silicone modified poly styrene-acrylic emulsion was synthesized by styrene, butyl acrylate, acrylic acid and vinyl triethoxysilane. The effect of factors such as polymerization process, temperature, the content and the introducing model of vinyl triethoxysilane as well as the emulsifier amount and ingredient proportion on the comprehensive properties of the emulsion and its film were investigated, the structure of the copolymer was characterized by IR and X-ray diffraction. The performances of the modified poly styrene-acrylics latex paint were also studied. By pre-emulsification process, the quality score of composite emulsifier was 3%～5%, the quality score of vinyl triethoxysilane was 2%～6%, the reaction temperature was 75-80℃. Under this condition, the diluting stability, Freeze-thaw stability and calcium stability as well as storage stability of the emulsion were better than the general one. The water absorption rate of its film was much lower than the general poly styrene-acrylics emulsion. Comparing with the film of polystyrene-acrylics latex paint, the organosilicone modified latex paint was superiority and it could be used as upscale coatings.A fluorine modified polystyrene-acrylate emulsion was synthesized by a semi-continuous process using fatty alcohol polyoxyethylene ether, sodium dodecyl sulfate, and non-ionic fluorine containing surfactants (OP-10/SDS/DF-10) as an emulsifier system. The structure and latex particles of the Copolymers were characterized by IR and TEM. The influence factors including the content of fluorine-containing methyl acrylate and fluorocarbon surfactants on the emulsion were investigated. The effects on the rate of monomer conversion and the stability of emulsion were also studied. It is shown that the rate of monomer conversion is 99.6% when the polymerization temperature at 75～80℃and the reaction time is 4.5～5 hours. Compared with other fluorine-containing polymer emulsions, the quality scale of organic fluorine is only 0.67% and DF-10 is 1.35%. The rate of monomer conversion is 99.6% and the water absorption is 6% by now.Organofluorine and organosilicone modified polystyrene-acrylate emulsion with excellent behaviors was prepared using the similar method. The effects of factors such as the stability, the type of the modified monomer and organofluorine were studied; the structure of the copolymer was characterized by IR and X-ray diffraction. Results showed that the water absorption rate of its film was much lower than that of the two formers, the lowest water absorption rate was 5.4%.