Microemulsion polymerization Compared with conventional […]
Microemulsion polymerization Compared with conventional emulsion polymerization, the monomer content in the microemulsion polymerization system studied was very low (less than 10%), and the concentration of the emulsifier was very high (greater than 10%). These obvious shortcomings limit the industrial application of microemulsion polymers. The emulsifier and emulsion system used in the polymerization of styrene-acrylic emulsion have great influence on the polymerization and emulsion properties of styrene-acrylic emulsion. Studies have shown: the structure of the emulsifier, the critical micelle concentration (CMC) or the amount of emulsifier and the ratio of emulsifier to monomer in the initial stage to the particle size and distribution of the emulsion, viscosity and film formation temperature, polymer stability and coating The continuity, integrity, water resistance, adhesion, etc. have a very important impact. Further research shows that in the polymerization process of styrene-acrylic emulsion, the combination of anionic emulsifier and non-ionic emulsifier or using the composite emulsifier chemically synthesized by these two emulsifiers is more excellent than the emulsion prepared by using anionic emulsifier alone. Because the two are used reasonably or as a composite, the two emulsifier molecules can be alternately adsorbed on the surface of the latex particles, reducing the electrostatic repulsion between the ions on the same colloidal particles, and enhancing the adsorption fastness of the emulsifier on the colloidal particles. Reducing the charge density on the surface of the latex particles makes the negatively charged radicals more easily enter the latex particles and increase the emulsion polymerization rate.