Synthesis Of Maleic Polymerizable Emulsifiers And Application In Miniemulsion/Microemulsion Polymerization

In recent years, the preparation of nanocapsule have attracted much research interest. However, there are still a lot of problems in the preparation of nanoscale polymer latex when using conventional emulsifiers. In this thesis several maleic polymerizable emulsifiers were synthesized and used in miniemulsion/microemulsion polymerization. Better emulsion properties were achieved by improving the emulsion composing. In this dissertation, four parts were studied:1.Having deeply studied the benefits of some kinds of polymerizable emulsifiers, we selected to synthesize maleic polymerizable emulsifiers:maleic hemiamide propylsulfonate,maleic hemiester propylsulfonate and a non-ionic emulsifier. By the method of orthogonal experiment the synthesis factors influencing the reaction were optimized. The struetues of the resulting emulsifiers were studied by FT-IR and 'H-NMR. The CMC was received by surface tension test and conductivity method. We also compared the emulsifying power of synthesized polymeric emulsifiers with traditional emulsifiers. The results indicated that, they have lower CMC and excellent surfactant activity.2. With suitable soft and hard monomers, maleic hemiamide propylsulfonate polymerizable emulsifiers were used in the St-BA miniemulsion polymerization. The influences of temperature, types of emulsifiers, mass concentration of polymerizable emulsifiers, mass concentration of cosurfactant on polymerization stability and conversion of emulsion polymerization were investigated. Compared with conventional emulsifiers(SDS and LAS), the cosurfactant cetyl alcohol (CA) in the system can be controlled in a smaller level while high rate of conversion (at 65℃), electrolytic stability and water resistance of the synthesized emulsion were markedly improved. Then miniemulsion polymerization of St-BA, initiated with a redox initiator ((NH4)2S2O8-NaHSO3), have been carried out at 45℃in the presence of HE-12 as surfactant and CA as cosurfactant. The effects of temperature and initiator on the polymerization rate and conversion were determined. Test results showed that, the polymerization conversion was high, and the gel could be prevented well.3. The best water-soluble polymezable emulsifier HE-12 was selected for the O/W microemulsion polymerization with the system of "St-BA/HE-12+n-pentanol/water'" Its pseudo-ternary phase diagrams of microemulsions were made by the test of conductivity. Based on the above experiment, some of the microemulsion compositions with an O/W droplet structure were polymerized to form microlatices. The influence factors, including initiator kinds, initiator concentration and emusfier concentration, was discussed. The results showed that when the situation was (NH4)2S2O8 as initiator, polymerizable emulsifier content was 3.57% and the ratio of emulsifier and monomer was 1:2, the obtained polymer particle size was smaller, microemulsion had better properties.4. Then the above microemulsion polymerization system was applied in the preparation of pesticide nanocapsules. The influence of the emulsifier content, the ratio of monomer and pesticide, the mixture ratio of emulsifiers(HE-12 and OP-10) on particle size, size distribution, structure of nanocapsules were studied. The results indicate that, the addition of pesticides will influence on microemulsion system. And a perfect nanocapsule can be obtained when the mixture ratio of HE-12:OP-10 is 1.5:1, the ratio of monomer and pesticide is 1:2.5.