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In this study, a terpolymer of acrylamide with (2-methacryloyloxyethyl) trimethyl ammonium chloride (DMC) and dimethyldiallylammonium chloride (DMDAAC) as cationic monomers was synthesized under the high-pressure Hg lamp with persulphate/bisulphite and 2, 2′-azobis (2-amidinopropane) dihydrochloride (V-50) as the hybrid photo-initiators. The compositions of the photopolymer were characterized by FTIR and 1H-NMR. The effects of main factors, i.e. monomers concentration, photo-initiators concentration, initial temperature, photo time and photo method on the photo-polymerization and intrinsic viscosity were investigated. The optimal reaction conditions were that the monomers concentration was 36 wt.%, photo-initiators concentration was 3.0 × 10−4 mol L−1, initial temperature was 6°C and photo time was 120 min (irradiate 30 min and halt 10 min). The flocculation effect of the terpolymer was evaluated using industrial sewage from wastewater manufacture in comparison with that of commercial flocculants. It was found that the photo-polymerized terpolymer had an excellent flocculation effect.

The copolymer of acrylamide (AM) and 2-acrylamide-2-methyl-propane sulfonate (AMPS) was synthesized through free radical dispersion polymerization in an aqueous solution of ammonium sulfate and poly(2-acrylamide-2-methyl-1-propane sulfonate) as a steric stabilizer. The average particle size of the copolymer ranged from 1.0 μm to 4.0 μm, and the molecular weight was 2.0 × 106 ~ 7.0 × 106 g mol−1. The swelling property of the dispersion copolymer was studied by characterizing the apparent viscosity and particle size distribution. When the dispersion was diluted with salt aqueous solution in which the ammonium sulfate concentration kept equal with that of the original dispersion, particle size and particle size distribution of the diluted dispersion changed little, compared with that of the original dispersion. While diluted with deionized water, particle size and particle size distribution could expand several times. The effects of the AMPS/AM molar ratios, the molecular weight of stabilizer, and the initiation temperature were investigated. It was found that with the increase of the AMPS/AM ratios, the molecular weight of copolymers increased, and then decreased. The particle size and conversion of monomers increased. The stability of the copolymer dispersion increased with increasing the molecular weight of stabilizer for a fixed stabilizer concentration. With the increase of the initiation temperature, the molecular weight of copolymer increased at first and then decreased gradually, but the particle size and conversion increased. The optimum conditions for the stable AMPS/AM dispersion were as follows: the AMPS/AM molecular ratio was 15/85, the molecular weight of the PAMPS stabilizer 3.0 × 105 ~ 4.0 × 105, and the initiation temperature 50 °С, respectively.