POTENTIOMETRIC TITRATION OF ACRYLAMIDE ACRYLIC-ACID COPOLYMERS - INFLUENCE OF THE CONCENTRATION

Potentiometric titrations of acrylamide acrylic acid copolymers of hig h molecular weight were made at various polymer concentrations. C(p), and ionic strengths, I. At a given pH, the ionization degree of the ca rboxylate groups is found to increase when C(p) and I increase. In the absence of salt and for a fraction tau of acrylic units in the polyme r, the values of pK(a) at different C(p) lie on a single curve as a fu nction of (alphaC(p)-1/3) for a given tau. It is found that pK(a) obta ined for the various values of C(p) is a polynomial function of tau1/2 C(p)-1/3.