Studies On Synthesis And Application Of Aqueous Dispersion Of Cationic Polyacrylamide

On the basis of the relevant literature, the preparation rules, the swelling andrheology properties of the aqueous dispersion of cationic polyacrylamide, which wasan environment-friendly type, were investigated in this thesis. At the same time, theperformances of the coagulation-flocculation were discussed.1. According to the molecular design clues, this research selected acrylamide(AM) asmain raw material, dimethylaminoethyl methacrylate methyl chloride (DMC) as theassistant monomer, poly(dimethylaminoethyl methacrylate methyl chloride) (PDMC)as stabilizer and azo-compounds(VA-044) as initiator, the cationic polyelectrolyte ofP(DMC/AM) was synthesized by aqueous dispersion polymerization in the ammoniumsulfate solution.2. The effects of varying factors, i.e. the molar ratios of DMC/AM, the totalconcentration of monomers, the concentration and molecular weight of the dispersant,the concentration of ammonium sulfate, the dosage of initiator, the reaction time andthe temperature, the pH value, the solvent polarity, and the stirring speed on thepolymerization, the product characters (molecular weight, particle size, particle sizedistribution) and the stability of the system were investigated. By the orthogonalexperiment, the optimum conditions of synthesis were determined as follows: thedosage of dispersant 3.0%, the concentration of initiator 525mg·Kg^-1, the initiationtemperature 50℃, and the pH 5.5.3. The dispersion copolymers were characterized with Fourier Transform Infra-Red(FTIR), the Transmission Electronic Mirror (TEM), the Laser Particle-size Analyzerand the Laser Light Scattering Instrument.4. Utilizing the digital rotational viscometer and the optical microscope, the swelling and rheology properties of the dispersion polymer were studied. The apparent viscosityof the system in the swelling course was investigated with the variables of inorganicsalts concentration, rotation speed and polymer concentration. Under the same ionintensity, it was found that the swelling degree of the cationic polymer system wassmaller than the anionic one.5. The high molecular weight CPAM was used as flocculant to treat waste water. Theinfluences of the concentration, the moleculai weight, the cationic degree (CD) and thecooperation with PAC on the flocculation efficiency were investigated. It was foundthat two of the conglomeration values appeared in the flocculation, the optimalmolecular weight and the cationic degree were 10%-15% and 500×10⁴-700×10⁴,respectively. Good results could be obtained when they cooperated with inorganicflocculant PAC in the treatment of waste water.