Hydrolysis of polyacrylamide and acrylic acid-acrylamide copolymers at neutral pH and high temperature

The hydrolysis of acrylamide-acrylic acid copolymers has been studied as a function of pH and of the initial composition of the samples. Our experimental results confirm the intramolecular catalysis by neighbouring undissociated carboxylate groups for 3 < pH < 5, as already demonstrated by Smets et al., and the catalysis of OH− ions with autoretarded kinetics for pH > 11. In the range of neutral pH, the observed kinetics cannot be simply explained by the superposition of these two mechanisms. Nevertheless, some empirical laws can be established from experimental data. A simulation based on a Monte Carlo method is proposed in order to predict the hydrolysis of these copolymers in different conditions.