The Mannich reaction of formaldehyde and dimethylamine with a polymeric substrate, poly (acrylamide), was studied with carbon-13 nuclear magnetic resonance spectroscopy (13C NMR). Reaction rates, equilibria, and the mechanism of conversion are characterized for the base-catalyzed reaction. The formation of the Mannich derivative is best described as a second-order process, involving the polymer and (dimethylamino)methanol, a rapidly formed product of dimethylamine and formaldehyde. The reaction exhibits a reversible equilibrium evidenced by a decrease in Mannich conversion with a molar excess of amine. A model equation describing this behavior gave estimates for the major equilibrium constants. Rate data, obtained in the absence of (dimethylamino)methanol, indicated that the reaction of the polymer with N, N, N', N'-tetramethvldiaminomethane does not play a prominent role in the kinetics. © 1979, American Chemical Society. All rights reserved.