PROCESS FOR PREPARING MONODISPERSE POLYMER PARTICLES BY DISPERSION POLYMERIZATION

摘要

A method for preparing a vinyl-based polymer through dispersion polymerization is provided to obtain spherical vinyl-based polymer particles having a uniform micro-scaled particle size distribution, various particle sizes and a high syndiotactic ratio. A method for preparing a vinyl-based polymer through dispersion polymerization includes a step of adding an unsaturated vinyl-based monomer, a stereo-stabilizer and a hydrophobic polymerization initiator to a dispersion medium containing a mixture of an organic solvent and water. The dispersion medium is an organic-aqueous dispersion medium comprising methanol or ethanol and water in a weight ratio of 1:0.1-1 and is used in an amount of 100-2,000 parts by weight based on 100 parts by weight of the unsaturated vinyl-based monomer. As the stereo-stabilizer, 0.01- 10 parts by weight of polyvinyl alcohol or polyvinyl pyrrolidone is added to 100 parts by weight of the dispersion medium. The polymer particles obtained by the method are spherical particles having an average particle diameter of 2.5-7.0 micrometers and have a syndiotactic ratio of at least 50% in terms of stereoregularity.