Model cationic flocculants from the Mannich reaction of polyacrylamide

¹⁴C-Labeled cationic derivatives of polyacrylamide were prepared by the reaction of polyacrylamide with ¹⁴C-labeled formaldehyde and dimethylamine hydrochloride. The resulting Mannich base was reacted with dimethyl sulfate. Both reactions produced a yield of about 50% and the final product was a substituted polyacrylamide with tertiary and quaternary amine groups. Extensive dialysis removed the tertiary groups to give a stable radio-labeled polymer that was an effective flocculant. Treatment with mixed-bed ion exchange resin was effective in purifying polyacrylamide derivatives; however, counterions for the quanternary amine groups were not quantitatively exchanged for hydroxide groups.