ACRYLATE POLYMER COLLOIDS - KINETICS OF AUTO-CATALYZED HYDROLYSIS

The kinetics of the hydrolysis of alkyl polyacrylate latexes, in which the alkyl groups were methyl, cyclohexyl, benzyl, and β-naphthyl, and of polymethyl methacrylate latexes have been studied. The reaction is catalyzed by surface strong acid groups-sulfate and sulfonate-derived from the initiator. By varying the surface acid concentration it was found that the reaction is first order with respect to acid. Since the activation energies were found to be similar to those of analogous reactions in homogeneous media, it was concluded that it follows an AAC2 mechanism. Two constant-rate intervals are generally observed, the first rate being faster than the second. The constant rate is explained by a surface reaction zone model in which a steady-state concentration of the polymeric ester is maintained. © 1979.