| 摘要 |
PURPOSE:A dispersion stabilizer for preventing suspended beads from adhering to each other during the suspension polymerization of a vinyl monomer and for forming polymer beads of a sharp particle size distribution, comprising a copolymer containing specified vinyl alcohol derivative units and vinyl alcohol units. CONSTITUTION:A dispersion stabilizer for suspension polymerization, comprising a copolymer containing 0.1-20mol% vinyl alcohol derivative units of formula I (wherein R is H or a 1-6C alkyl) and 99.9-80mol% vinyl alcohol units of formula II. When the above dispersion stabilizer is used in suspension-polymerizing a vinyl monomer (mixture) in an aqueous medium, substantially no adhesion of suspended beads occurs during polymerization because of its good suspension stabilizing effect, and polymer beads of a sharp particle size distribution can be obtained. Especially, in the suspension polymerization of a vinyl chloride monomer (mixture), it brings about advantages such as good moldability, high porosity, good plasticizer absorption and formation of substantially no fish eye during molding, in addition to the above merits.
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