| This paper was aimed at preparing the micro-size mono-disperse PMMA Particles by dispersion polymerization. Firstly, some pretty polymerization systems was chosen, and then, The influences of Polymerization parameters on particle size and particle size distribution were investigated to find out the reasonable polymerization way of PMMA mono-disperse particles.A series of experiments were conducted to get the effects of Polymerization parameters on particle size and mono-dispersion. The particle size was found to increase with increasing polymerization temperature, concentration of the initiator and monomer and prolonged reaction time. It also increased with decreasing concentration of the polymeric stabilizer-poly(vinyl pyrrolidone)(PVP). The influences of various polymerization parameters were explained by the proposed particle formation mechanism. Meanwhile we have found that different media system has a different influence on polymerization conversion rate and polymer particle size and polymer molecular weight distribution.From the results of the IR and XPS, it is concluded that PMMA-PVP graft-copolymer has been formed during the dispersion polymerization. A mechanism for particle formation and growth in dispersion polymerization is presented. The particle formation stage in dispersion polymerization consists of two steps: nuclei generation and aggregation. The oligomer chains grow in the continuous phase and precipitate to form the nuclei by either a self or aggregative mechanism. The nuclei are unstable and quickly aggregate with each other; concurrently, they adsorb the stabilizer molecules, and finally become mature(stable) particles. As long as enough mature particles are formed to capture all of the oligo-radicals and nuclei generated in the continuous phase, no more particles form and the particle formation stage will finish.The standard recipes for preparing 2.8 μm 5μm 7 μm 8 μm PMMA particles have been gotten.
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