Abstract
The flow of high current densities (j > 20 mA cm−2 through aqueous solutions of acrylamide and NaNO3 from platinum electrodes promotes the generation of polyacrylamide. The polymer product remains soluble. The kinetics of the process was followed by gravimetric determination of polymer production. A straightforward polymerization occurs at times longer than 15 min. The empirical kinetics followed through the second region was proportional to [acrylamide]12[NaNO3]−34 and decreases linearly when the current density increases. The activation energy of the overall process was 79 k mol−1. These results, including the variations of the average viscosimetric molar mass of samples, the number of electrons consumed to generate a molecule of polymer and the number of monomeric units incorporated in the polymer per consumed electron, as a function of the chemical variables of synthesis, can be explained through the simultaneous presence of monomer, water and nitrate ion oxidation on the electrode. Gel formation occurs around the electrode for short times of current flow.
Published Version
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