Preparation Of Water-in-Water Acrylamide Copolymer Emulsion

As a common water-soluble polymer, polyacrylamide(PAM) is extensively used in several industries, such as oil extraction, water treatment, paper-making and mining. The PAM water/water emulsion possesses several advantages, such as low viscosity, quick solubility and little pollution. Water/water emulsion polymerization technology makes up the disadvantages of large solution viscosity in aqueous solution polymerization and hydrocarbon pollution in inverse emulsion polymerization. Therefore water/water emulsion polymerization would be the orientation of PAM industry.Based on the phase-separating principle of water/water copolymerization emulsion, the probability and feasibility of several systems used to prepare water/water emulsion were investigated, such as the systems containing polyglycol(PEG), polyethylpyrrolidone(PVP), 1-propanol, ethanol, N,N-dihexylacrylamide(DHA), methylα-methacrylate(MMA), ammonium sulphate and sodium sulphate. The appropriate phase-separating system for the preparation of cationic polyacrylamide(CPAM) water/water copolymerization emulsion was determined. The influence of salts, surfactant, stabilizer and lipophilic monomers of polymerization dosage on the solubility, viscosity, reaction rate and molecular weight of emulsion were studied, and the polymerization dosage was optimized. In order to increase the stability of emulsion, the copolymer of acrylamide(AM)/ethylα-methacrylate trimethyl ammonium chloride (DMC), chemically modified PEG20000, PVP, copolymer of DMC/ethyl pyrrolidone(NVP) were respectively used as the stabilizer and the suitable proportion of monomers was investigated.The results showed that the polymerization systems including PEG, ethanol or 1-propanol could not obtain water/water emulsion with high molecular weight, and the polymerization system containing salts and lipophilic monomers was economical and feasible to prepare the water/water emulsion. The CPAM water/water emulsion was prepared by adding emulsifiers and stabilizer to the polymerization system which was composed of the inorganic salts, lipophilic monomers and water. The influence of polymeric ingredient on the performance of emulsion was rather complicated. The modified PEG20000 could make the emulsion stable for a week and caused low molecular weight of copolymer. The copolymer of DMC/NVP could make the emulsion stable for about ten days and the peculiar viscosity equal to 460 mL/g was obtained.