| The radical dispersion polymerization of styrene in ethanol/water medium in the presence of polyvinylpyrrolidone using azobisisobutyr -onitrile as initiator was carried out. The effects of stabilizer concen -tration, monomer concentration, initiator concentration and medium composition on the size and size distribution of polymer particles were investigated, the better reaction match is, monomer concentration 30(g/100g solution), stabilizer concentration 3.0(g/100g solution), initiator concentration 0.5(g/100g monomer), ethanol 90(g/100g me -dium), temperature 68.On the basis of the preceding work, the anionic dispersion polymerization of styrene in n-Hexane medium in the presence of steric stabilizer SEBS using n-butyllithium as initiator was mainly carried out. It was showed by experiments that the main factors of anionic dispersion polymerization, such as steric stabilizer concentration, initiator concentration, monomer concentration, the method of adding monomer, monomer multi-addition and promoter etc, influenced the particle size and size distribution, Some factors,such as monomer concentration and steric stabilizer concentration, influence the time for the onset nucleation. And through the study of the mechanism of particle formation andstabilization, it was proved that the mechanism of adsorbentstabilization is dominant during anionic dispersion polymerization and the mechanism of nucleation is the aggregation of living-polymers. The results indicate that anionic dispersion polymerization is considered living polymerization, the particle size and size distribution monomer can be controlled by altering the method of adding monomer. In the end, the particle formation process was pictured.
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