Preparation And Flocculation Property Of Aqueous Dispersion Of Amphoteric Polyacrylamide

Amphoteric polyacrylamide is a very important polyampholyte, with both positive and negative charge on its macromolecular chain, it possesses specific property and is broadly applied. Aqueous dispersion polymerization is a one of the latest technologies in the field of water-soluble polymer developing. Avoiding the secondary pollution caused by organic solvents, it conforms to the development direction of green chemistry.In this thesis, amphoteric polyacrylamide dispersion systems with excellent stability were synthesized with2-methylacryloylxyethyl trimethyl ammonium chloride (DMC) as cationic monomer,2-acrylamido-2-methyl-l-propane sulfonate (AMPS) as anionic monomer,2,2-azobis(2-methylpropionconidine) dihydrochloride (V-50) as initiator, and poly(2-methylacryloylxyethyl trimethyl ammonium chloride)(PDMC) as steric stabilizer. The products were characterized with NMR1H spectrum. The influence of concentration of ammonium sulfate, stabilizer, initiator, monomer and sodium chloride, of monomer ratio, molecular weight, temperature and pH value were investigated. Aqueous solution property of the products were investigated with rotational viscometer and ubbelohde viscometer.Fluid amphoteric polymer dispersion system with excellent stability were prepared with ammonium sulfate as reaction media. The synthesis condition were optimized and the suitable synthesis conditions were proved to be:concentration of ammonium sulfate23-27%, the concentration of stabilizer1-5%, the concentration of monomer8-15%, the concentration of initiator15-20×10-4g.g (monomers)-1, the temperature55-62℃, pH value4-8, and concentration of sodium chloride≤0.03%.The external pH value, concentration of salt, temperature and self-concentration were proved to have effects on the intrinsic viscosity of amphoteric polyacrylamide. The intrinsic viscosity reaches its maximum at the point of isoelectric. The intrinsic viscosity decreased with the reduction of temperature with a decelerated rate in the later stage. When dispersion solution was diluted with ammonium sulfate solution of different concentration, lower concentration turned out to be of greater influence on the apparent viscosity.The flocculation ability of self-made amphoteric polyacrylamide was tested with kaolin clay simulated wastewater, results show that the amphoteric polyacrylamide were effective within a broad extent of pH value. When the content of anionic monomer and cationic monomer are equal, amphoteric polyacrylamide exerts a better flocculation ability than ionic polyacrylamide, the flocculation effect is better. when the ionic monomer content of polymer is10%.