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The degradation of polyacrylamide in basic solution has an extremely fast component characterized by the buildup and disappearance of an imide absorption band at 235 nm. Comparison with the behavior of low molecular weight model compounds shows that such imides are formed from monomer residues added head-to-head. Results suggest that 4.5% of amide groups belong to such pairs of residues and that about two-thirds of these have the racemic configuration. Initial amide hydrolysis rates of polyacrylamide and acrylamide-acrylic acid copolymers in 0.2 N NaOH at 53 °C showed that the reactivities of amide groups with one and two nearest-neighbor carboxyls are reduced by factors of 0.108 and 0.013, respectively, relative to amides flanked by two amide groups. Using these data to predict the course of polyacrylamide hydrolysis, we find that Keller's theory of polymer reactions with neighboring group effects is able to match experimental results in the early stages of the process but leads to low estimates for the conversion at high reaction times.The assumption that the electrical free energy of activation for the hydroxyl ion attack on chains with acrylamide and acrylic acid residues is equal to the electrical free energy of ionization for partially ionized poly(acrylic acid) with the same charge density leads to satisfactory predictions for the reactivity of random copolymers of acrylamide and acrylic acid but underestimates grossly the decrease in the rate constant with an increasing hydrolysis of polyacrylamide. The inadequacy of Keller's model to account fully for the course of polyacrylamide hydrolysis is due to long-range electrostatic effects and possibly to the effect of stereoisomerism.

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