In order to investigate the property and concentration dependence of dissociation and hydrolysis of polyelectrolytes,acrylic acid-sodium acrylate copolymers 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 solutions 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 neutralization 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 through semi-permeable membranes in the corresponding concentration regions.
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