TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The living radical polymerization initiator is of formula: R4-P(-R3)(-R5)=C(-SR1)(SR2) (V).R3-R5=linear or branched alkyl or optionally substituted phenyl;andR1,R2=monovalent group corresponding to radical which arises radical generating agent.    TECHNOLOGY FOCUS - POLYMERS - Preparation (disclosed): Parastyrene sulfonic acid (salt) containing impurities, is added to water-soluble solvent such as pure water or acetone and isopropanol, heated and dissolved at 40-70 degrees C, cooled to room temperature and recrystallized to obtain high-purity parastyrene sulfonic acid (salt). Preferred Component: The polystyrene sulfonate is of formula (II)-(IV).n'=n;andm'=m.Preferred Properties: The polystyrene sulfonate has weight average molecular weight of 2000-1 million. The ratio of weight average molecular weight of polystyrene sulfonate with respect to number average molecular weight of polystyrene sulfonate is less than 2. Preferred Process: High-purity parastyrene sulfonic acid (salt) is added after living radical polymerization which is carried out in aqueous solvent, and living radical polymerization is continued. Preferred Definitions:    Q=styrene residue, styrene derivative residue, methacrylic acid residue, methacrylic acid-2-hydroxy ethyl residue, glycidyl-methacrylate residue, (meth)acrylamide residue, N-vinyl pyrrolidone residue, N-phenyl maleimide residue or maleic anhydride residue.    EXAMPLE - Parastyrene sulfonic acid sodium salt (1000 g), pure water (950 g) and sodium nitrite (1 g) were added to a separable flask, completely dissolved, heated, and stirred at 60 degrees C for 1 hour. The resultant mixture was cooled at 10 degrees C at the cooling rate of 10 degrees C per 1 hour, and centrifugally filtered after depositing crystals. Sodium bromide (0.19 wt.%), sodium sulfate (0.04 wt.%), and ( beta )-bromo ethylsodium benzene sulfonate monomer (90.57) were added to resultant mixture, and polymerized to obtain aqueous solution of polystyrene sulfone sodium salt having number average molecular weight of 57000 and weight average molecular weight of 160000.