INVESTIGATIONS ON THE DISSOCIATION BEHAVIOR OF HYDROLYZED ALTERNATINGCOPOLYMERS OF MALEIC-ANHYDRIDE AND PROPENE .1. POTENTIOMETRIC TITRATIONS

The potentiometric behaviour of hydrolyzed copolymers of maleic anhydr ide and propene was studied as a function of added;salt (LiCl, NaCl, K Cl, CaCl2). The first and second apparent ionization values pK(a1) and pK(a2) obtained by the classical interpretation were found to depend on the ionic strength and the counterion, respectively. The influence of the two configurations of the succinic moieties causing four dissoc iation constants is discussed. The effect of added salt was observed t o be the greatest in the presence of CaCl2. Hence the addition of CaCl 2 enables determination of the concentration of other copolymers of ma leic anhydride obtained from the neutralisation of the second carboxyl ic group. Copyright (C) 1996 Elsevier Science Ltd.