The Polymerization Of Fluoro Olefins In New Emulsion Systems

New fluorocarbon surfactants were synthesized by free-radical addition reaction under the different experimental conditions. The influence of reaction conditions on yield was studied, structures of products were characterized by IR, 19FNMR and 1HNMR.The thermal stability was researched, which showed that the initial decomposition temperatures was 229℃, and the end decomposition temperature was 574℃.The results explained the fluorocarbon surfactant have good thermal stability. Surface tensions of solution and interfacial tensions of cyclohexane were quantitatively measured by the method of stationary rings, and the critical micelle concentrations(CMC) were measured by the methods of conductance and surface tension. The results showed that surface tensions of ammonium were low, such as 20.5mN/m, the interfacial tension was 6.67mN/m and cmc was 7.65mmol/L. The effects of length of fluorocarbon chains were studied in theory, interfacial tensions increased and surface tensions and cmcs reduced gradually with growth of fluorocarbon chains. The saturated adsorption amounts (Γ∞)were calculated in the water(25℃), such as 2.99×10-10mol·cm-2. The average area of the single molecule was 0.56nm2.The emulsifier-free emulsion copolymerization of tetrafluoroethylene(TFE) , ethylene (E), and 3,3,3-trifluoropropene (TFP) was carried out, forming a stable emulsion with 33% solid content. The effects of polymerization conditions on emulsion polymerization were investigated. The influence of reactive surfactant content on the emulsion polymerization and emulsion property was discussed. Laser particle size analyzer(LPS), fourier infrared(FTIR), scanning electron microscope (SEM), differential scanning calorimetry(DSC) were used as the main methods to analyze and characterize the polymer emulsion .The best process conditions were determined: TFE/E/TFP monomer mass ratio was 1/1/0.20, reactive emulsifier amount was 5%, reaction temperature was 75℃and initiator amount was 0.4%. Under this condition, the convertion could reach 94%, and the emulsion was stable.On the basic study of the P(TFE/E/TFP) ,we studied quinary emulsion system. Emulsion with different hydroxyl value was prepared by adding cross-linking agent 4-hydroxybutyl vinyl ether or ethylene glycol monoallyl ether.We could get stable emulsion under the condition of reactive surfactants amount between 1% and 9%. The latex particle size decreased at first and then increased when the content of reactive surfactants increased. It went to the minimum value at the amount of 5%, the property of the emulsion is excellent, which showed that when the latex particle size decreased, the latex particle would be stable.