Abstract
Graft copolymers of methyl acrylate-g-(2-vinylpyridinium bromide-co-vinylalcohol) were prepared by the reaction of (2-vinylpyridinium bromide-co-vinylalcohol) with methyl acrylate. The flocculating abilities for 5% aqueous kaolin suspension were investigated in the reiation to the structures by measuring the sedimentation rate, the sedimentation volume, and the turbidity. The results obtained are as follows. 1) For every graft copolymer, the optimum copolymer concentration required to flocculate 5% kaolin suspension was 6-50ppm, and under these conditions, the electrophoretic mobility of kaolin was relatively small. 2) Suitable mole fraction of vinylalcohol (FVA) and that of ionization group (FI2VP) in copolymer were 0.15 and 0.25 respectively. 3) Flocculating action increased with increase of mole fraction of methyl acrylate (FMA) in copolymer. 4) Flocculating ability of each copolymer increased with increasing inherent viscosity. 5) Suitable pH values for the flocculating action were in the range of about 2-12. 6) An isoelectric point was found in the vicin ity of pH 4 and optimum flocculating ability was observed in the pH range of 4-10. 7) Copolymers were more effective for typical commercial flocculants such as Sumifioc-FC, PAS-A, and Himoloc Neo 600.
