Electrolytic Properties of Aqueous Solutions of Polyacrylic Acid and Sodium Hydroxide. III. The Rate of Sodium Ion Exchange between Polyacrylate and Free Sodium Ions

Abstract

The exchange of free sodium ions with sodium ions bound to polyacrylate ion has been investigated by an electrolytic transference method. On the assumption that there is a single exchange process, rate constants have been computed and the theory has been found to provide a moderately good representation of the data. A much better correlation is obtained, however, if it is assumed that there are two exchange processes, one very rapid and the other very slow. Presumably the sodium ions that exchange rapidly belong to the polyacrylate ion atmosphere while those that exchange slowly are located within the coiled polymer ion. The distribution of sodium ions between these two groups has been computed.