Study On Water-in-water Type Cationic Polyacrylamide Emulsion

Water-in-water emulsion polymerization can remedy those defectsthat traditional polymerization methods is of:high viscosity, the heat ofreaction which is difficult to remove, the final product is difficult todissolve in water when using it. The product which made by this waycan dissolve in water in ten seconds, moreover, it can avoid secondarypollution by the organic solvent. The process and technology about thepreparation of the water-in-water CPAM emulsion are notdisclosed.Related research is of great significance.In this research,a third monomer-N,N′-methylenediacrylamide(MBA) was added to the conventionalreaction monomers,it is helpful to obtain a stable water-water emulsion,it can be stable for more than a year.In addition, no inorganic salts orpolyelectrolyte was and to the water-water emulsion so as to avoidingnegative impact on the use of the product.Water-in-water type cationic polyacrylamide (CPAM) emulsionswith low viscosity, high polymer content and high stability wassynthesized in the polyethylene glycol20000(PEG20000) solution byradical copolymerization of acrylamide (AM), Methacrylatoethyltrimethyl ammonium chloride(DMC)andN,N′-methylenediacrylamide(MBA).Theeffects ofinitiator,polymerization temperature, monomers on the viscosity hasbeen researched. TEM is used to research the Micromorphology, FIRand1H NMR is used to determine the molecular in structure of CPAM,GPC is used to determine the molecular weight; XRD is used tocrystalline properties.Moreover,rheological behavior is studied, Kaolinflocculating tests is acted. Our main tasks are as follows: (1) Using water-water emulsion stability as an indicator, the optimalprocess conditions of water-in-water polymerization is determined: thepolymerization temperature is between20℃and60℃, w(MBA)=0.01%to0.03%, w(PEG20000)=60%~80%, w(DMC)=5%~20%, w(KPS)=4%to8%, w(MBA)=0.1%.(2) The structure of cationic polyacrylamide had been identified viaFTIR and1H NMR, GPC tests showed that the molecular weight is ashigh as2,400,000. TG-DTA shows that thermal decompositiontemperature is at260°C, XRD proved the prepared the CPAM latexfilm-based amorphous structure. TEM showed spherical droplets andstripe shape droplets dispersed throughout the aqueous dispersion;(3) The emulsion rheological properties of tests showed that awater-in-water CPAM emulsion is of shear thinning characteristics; w(PEG20000)≤100%, with the increase in the amount of PEG,the viscosityof emulsion has also been increase; w(PEG20000)≥100%, with theincrease in the amount of PEG, viscosity of the emulsion will bereduced up to tend to a specific value.(5) The effect of NaCl salt on steady state of polymer solutiontesting showed: the salt tolerance of the prepared emulsion needimprovement.(6) water-water CPAM emulsion Viscoelasticity tests showed thatthe homemade emulsion has a strong adhesive. Kaolin flocculating testsshowed: the reaction conditions for obtaining a product with betterflocculating performance were as follows: polymerization temperature=40℃~50℃, the reaction time=5h~8h， w(PEG20000)=80%， w(KPS)=0.8%,w(MBA)=0.3%, w(DMC)=10%.