Synthesis of flocculant aids for cane sugar juice clarification* – Part III: Dependence of clarification efficiency on the composition of copolymers of acrylamide and trimethylammoniumethyl(meth)acryl

Copolymers of acrylamide with quaternary ammonium cationic monomers trimethylammoniumethylacrylate chloride (TMAEAC) and trimethylammoniumethylmethacrylate chloride (TMAEMAC) were prepared, characterized, and tested as flocculant aids to facilitate the clarification of primary cane sugar juice in the presence of an anionic flocculant. The effectiveness of these copolymers was compared with selected commercially available cationic copolymers. At dosages of 10 and 40 mg/kg, certain of the synthesized polymers were found to be more effective in reducing juice turbidity and increasing juice settling rate than commercial polymers. The differences between the effectiveness of TMAEAC and TMAEMAC copolymers were not marked, with the intrinsic viscosity of the copolymers (related to the size of the random polymer coil in solution) likely to be a more important parameter than copolymer composition. Clarification was found to be generally more effective and rapid if the flocculant aid was added after rather than before addition of calcium saccharate to the primary sugar juice. The results obtained are consistent with the flocculant aid operating by a bridging mechanism, and support the hypothesis that a separate population of particles, smaller than those targeted by the anionic flocculant, primarily interact with the flocculant aid.

I:2000,101–105; II:2001,259–263