Preparing Monodisperse PMMA Microspheres By Semi-polymerization Seed Swelling Polymerization

In this article, the technique of seed swelling that based on the emulsion polymerization is studied, which can be used to prepare large diameter monodispersed poly(methyl methacrylate) (PMMA).First, by using the method of soap free emulsion polymerization, potassium sulfate (K2S2O8) as the initiator, water as the dispersing medium to synthesize the PMMA seed-microspheres.And the whole reaction system is under the atmosphere of nitrogen. Then by changing the dosage of initiator, agitation rate, reaction temperature, and amount of thiol to research the factors that may affect the particle size and distribution of the PMMA seed-microspheres. In this part of experiment, the average particle size of monodisperse PMMA seed-microspheres in the range of 300nm-400nm was prepared.In the next part, we use the PMMA seed-microspheres to swelled in the emulsion environment. In this reaction system, the deionized water as the dispersion medium, the amber two alkyl sulfonate and octyl nonylphenol polyoxyethylene ether phosphate as emulsifiers.Finally, we prepared the monodisperse PMMA microspheres whose average particle size in 10μm. And we study the factors that may affect the particle size and particle distribution of PMMA swelling microspheres such as the ratio of the conversion, monomer and seed dosage.