Studies On Synthesis And Properties Of Namo-SiO₂/fluorine Contented Polystyrene-Acrylate Core-shell Emulsion-free Composite Emulsion

The features of emulsion polymerization, polystyrene acrylic emulsion and namo-silica, and recent progress on modification of polystyrene acrylic emulsion were reviewed in this thesis. The preparation and properties of core-shell emulsion-free polystyrene-acrylic emulsion were discussed, It is expected that the excellent namo-SiO2 contenting fluorine core-shell emulsion-free polystyrene-acrylate composites emulsion can be synthesized.The present studies could be divided into the following two parts.First, a fluorine contented emulsion-free polystyrene-acrylate emulsion was synthesized by per-emulsified technology with SE-10N as the emulsifier, the fluorine containing methyl acrylate as modifier. The core-shell emulsion-free polystyrene acrylate emulsion with (St+MAM+BA+MAA) as the core and (St+BA+MAA+F) as the shell was synthesized. The effect of factors such as polymerization process, temperature, the effect of the mass ratio of core-shell, the ratio of soft and hard monomer, and the amount of reactive emulsifier on the multiple properties of the latex film were studied. The water resistance of soap-free core-shell emulsion was better compared with the general core-shell emulsion. It was shown that the comprehensive properties of the emulsion and its film were better when the amount of fluorine-containing methyl acrylate was 0.2g, the quality of reactive emulsifier was 2.0%, the polymerization temperature at 80～85℃and the reaction time was 4～6 hours. The structure of the copolymer was characterized by IR. The positive core-shell structure was observed by TEM, DSC analysis also shows the core-shell structure was formed.Second, the namo-SiO2/polystyrene acrylic emulsion composites were successfully synthesized by a sol-gel method using tetraethylorthosilicate (TEOS) as the silica precursor, the non-soap copolymer emulsion of namo-silica and styrene-acrylate was synthesized by per-emulsified technology.with namo-silica, styrene, methyl acrylate monomers, APS as the initiator, SE-10N as the emulsifier. The model and amount of reactive emulsifier as well as the namo-silica amount on the comprehensive properties of the emulsion and its film were investigated. The structure of the copolymer was characterized by IR, TEM and DSC. The suitable polymerization process as follows:by pre-emulsification process, the quality score of reactive emulsifier and namo-silica was 2.0% and 5.0% respectively, the reaction temperature was 85～90℃, the reaction time was 4～6 hours. Under this condition, the comprehensive properties of the emulsion and its film were better.