Prepartion And Proerties For The Water-in-water Emulsion Of Polacramide

The water-in-water PAM emulsion with the feature of good solubilities in water,insensitive to salt, the green and pollution-free product has already been extensively keptattention. Because the process and technology about the preparation of the water-in-waterPAM emulsion are not disclosed, the studies of its synthesis and properties are of greatsignificance in theory and application.The cationic monomer MBDAC was synthesized, and the influence of synthesis conditionson MBDAC performances was discussed and the optimal synthesis conditions weredetermined. The effects of the concentrations of initiator, monomer, stabilizer, inorganic saltand temperature on synthesis and properties of water-in-water PAM emulsion in the twodifferent initiator systems with two different stabilizers were investigated.Comparing the initiating system of (NH₄)₂S₂O₈-NaHSO₃ and the VA-044 initiating system,we found that effects of various factors on molecular weight of PAM and monomerconversion are similar. However, a larger molecular weight of PAM and a higher monomerconversion as well as narrow particle size distribution were obtained with the VA-044 as aninitiator. Reducing w(initiator) and enhancing w(AM),w(PVP),w(AS) in the appropriaterange are helpful to improve the molecular weight of PAM. Increasing w(initiator) contributesto monomer conversion. However, in the (NH₄)₂S₂O₈-NaHSO₃ initiating system, moderatelyincreasing w(AM),w(PVP),w(AS) and raising temperature enhances AM conversion, Whilethese factors have less effects on AM conversion in the VA-044 initiating system.The optimal conditions of the process using ammonium persulfate-sodium bisulfite asthe initiator bave been obtained based on single-factor experiments: m(ammoniumpersulfate):m(Sodium Bisulfite) is 2:1, the mass fractions of monomer, ammonium sulfate,initiator, PVP, EDTA-2Na are 12%, 10%, 0.5%, 5%, 0.5% respectively, the reaction time is 2-3h at 30℃. The optimal conditions in the VA-044 initiating system is: the mass fractions ofmonomer, ammonium sulfate, initiator, PVP, EDTA-2Na are 11%, 10%, 0.5%, 3%, 0.5%respectively, the reaction time is 1-2h at 30℃.Discussing the influence of synthesis conditions on MBDAC performances, we foundthat raising temperature, enhancing V (reactants): V (solvent) and decreasing n (DMAM): n(benzyl chloride) benefit for improving the yield of products. The optimal synthesisconditions for MBDAC: the mass fraction of the inhibitor is 1.9% (relative to DMAM), n(DMAM): n (benzyl chloride) is1:2.5, V (reactants): V (solvent)=1:1.5, reaction time is 25h,reaction temperature is 40℃.The stabilizer P (MBDAC) was prepared by MBDAC as raw material, and we found thatthe smaller molecular weight benefits for preparation the water-in-water emulsion of largemolecular weight PAM. The optimal reaction condition: the mass fractions of monomer,ammonium sulfate, stabilizing agent, initiator, EDTA-2Na are 15%,10%,1%,0.5%,0.5%respectively, the reaction time is 5h at 50℃. The comparison of P (MBDAC)-salt solutiondispersion and PVP-salt solution dispersion showed that the PAM synthesized inP-(MBDAC)-salt solution dispersion have larger molecular weights and higher conventions.