| 摘要 |
PURPOSE:To prevent formation of fine particles, to thereby produce a water- soluble polymer of a desired particle diameter and excellent solubility, by effecting the polymerization with the aid of a specified polymerization initiator in carrying out the reversed phase suspension (emulsion) polymerization of a water- soluble monomer. CONSTITUTION:Use is made of a polymerization initiator having a rate constant of decomposition of 0.1X10<-2>-2X10<-2>/min at a temperature which is by 10 deg.C below the azeotropic point of a mixture of water with an organic solvent used, e.g., 2,2'-azobis(2-amidinopropane) dihydrochloride when cyclohexane is used as the organic solvent. Namely, an aqueous solution of a water-soluble unsaturated monomer, e.g., acrylamide, is dispersed in an organic solvent which is immiscible with water but is azeotropically distillable with water in an aqueous solution to organic solvent ratio (by weight) of about 6/4-4/6. The resulting dispersion is polymerized in the presence of the above catalyst at a temperature which is by about 5-20 deg.C below the azeotropic point to a conversion of 10%, and the polymerization is continued under a condition of azeotropic distillation (refluxing accompanied by removal of formed water).
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