In order to investigate the property and concentration dependence of dissociation and hydrolysis of polyelectmlytes

acrylic acid-sodium acrylate eopolymers with various degree of neutralization were prepared by adding calculated amounts of sodium hydroxide into the aqueous solutions of a poly (acrylic acid) sample

and the pH values of the solutions covering a wide concentration range were measured for each copolymer at 25℃．It was found that the pH values of the sofutions of a copolymer with degree of neutralization of 0.96 kept constant and equaled to 9.80 as c>0.001 mol/L．For another copolymer with degree of neutralizatlon of 0.30．the pH values of its solutions remained constant and equaled to 6.25 as c<0.001 mol／L．These two copolymers may serve as polymeric buffer reagents which couldn’t penetrate thmugh semi-permeable membranes in the corresponding concentration regions．