| 摘要 |
PURPOSE:To readily obtain finely powdered polymer without causing mutual welding or aggregation of the particles in the drying on heating, by reversed phase suspension polymerization or reversed phase emulsion polymerization in the presence of such an amount of inorganic salt as to represent the concentration above the saturated one in the system. CONSTITUTION:Either acrylamide monomer or its mixture with a water-soluble monomer copolymerizable therewith (e.g. acrylic acid, styrenesulfonic acid) is brought, in the form of an aqueous solution, to reversed phase suspension polymerization or reversed phase emulsion polymerization at 50-70 deg.C, normally in the presence of a polymerization initiator such as 2,2'-azobis(N,N'-dimethylene isobutylamidine) dihydrochloride, also in the presence of such an amount of inorganic salt (e.g., Na2SO4) as to represent the concentration above the saturated one, pref. up to double the weight of the monomer(s). The resulting polymer dispersion is dried on heating to obtain the objective finely powdered polymer.
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