Random and Graft Cationic Polyacrylamide Microgel Flocculants

Graft and random microgel copolymeric flocculants of quaternary salt of N,N-dimethylaminoethylacrylate methyl chloride (DMAEA.MCQ) and acrylamide (AM) were synthesized via a free radical mechanism using the γ-radiation technique, and their performance was evaluated on a model dilute titanium dioxide (TiO2) colloid suspension. The time required to form graft and random microgel copolymers increased with increasing DMAEA.MCQ content in the copolymer, indicating the formation of graft copolymers and the crosslinking of linear random copolymers to form microgels (or soft gels). Both graft and random microgel copolymers showed improved reduction in the relative turbidity of the colloid suspension over their nonirradiated counterparts.