POTENTIOMETRIC AND VISCOMETRIC STUDY OF THE ALKALIZATION OF LATEX DISPERSIONS OF ETHYL ACRYLATE - METHACRYLIC-ACID COPOLYMERS IN THE PRESENCE OF SALT

The behavior of latices of ethyl acrylate - methacrylic acid copolymer s during alkalization was investigated using potentiometric titration and viscometry. In the presence of NaCl in dispersion medium pH and vi scosity were lower compared to salt-free dispersions. Due to strong el ectrostatic interactions at low salt concentration the apparent dissoc iation constant of the carboxylic groups is small and the polymer segm ents bearing these groups are in extended conformations. The screening effect at higher salt concentration increases the apparent dissociati on constant and decreases the extension of the polymer segments. The p H and viscosity of latex dispersions alkalized in the presence of salt are thus smaller.