The purpose of the present invention is to provide: a molecular-weight controlling agent for radical polymerization which enables controlled radical polymerization of a water-soluble monomer in an aqueous medium; a method for producing a polymer of a water-soluble vinyl monomer using the same; and a water-soluble vinyl monomer polymer. The present invention provides a molecular-weight controlling agent for radical polymerization characterized in that the agent comprises, as its active ingredient, an iodine compound represented by formula (1) and in that the solubility of the active ingredient in water is 0.5 weight % or more at 20 °C.
In the formula, R1 is -COOX, -CONR4R5, an aromatic group or a cyano group, X is a hydrogen atom, an aliphatic group, an alkali metal, an alkaline earth metal, an organic ammonium or an ammonium, and R2, R3, R4 and R5 are each independently a hydrogen atom, an aromatic group or an aliphatic group.
本发明的目的是提供:一种可使
水溶性单体在
水介质中进行受控自由基聚合的自由基聚合用分子量控制剂;一种用其生产
水溶性
乙烯基单体聚合物的方法;以及一种
水溶性
乙烯基单体聚合物。本发明提供了一种用于自由基聚合的分子量控制剂,其特征在于该控制剂包括作为其活性成分的由式(1)表示的
碘化合物,并且在20℃时活性成分在
水中的溶解度为0.5重量%或更高。
式中,R1 是-COOX、-CONR4R5、芳香族基团或
氰基,X 是氢原子、脂肪族基团、碱
金属、碱土
金属、有机
铵或
铵,R2、R3、R4 和 R5 各自独立地是氢原子、芳香族基团或脂肪族基团。