Study On Dispersion Polymerization Of Acrylamide In Ionic Liquids

In this thesis, Ionic Liquids,1-Butyl-3-methylimidazolium Tetrafluoroborate（[bmim]BF4）, was introduced into dispersion polymerization of acrylamide as a newsolvent. The preparation rules of high-molecule-weight polyacrylamide dispersionwere investigated.1.1-Butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids（[bmim]BF4）wassynthesized using N-methyl imidazole and1-bromobutane as the raw materialsthrough a two-stage method. Firstly,1-Butyl-3-methylimidazolium bromide（[bmim]Br）was synthesized from N-methylimidazole and1-butylbromide. Effects ofreaction time，reaction temperature and molar ratios of N-methyl imidazole to1-butylbromide on [bmim]Br yield were investigated. The optimum conditions were asfollows：the reaction temperature was65℃, reaction time16h and molar ratio ofN-methyl imidazole to1-butylbromide1:1.1. The intermediate yield was94.6%. Andthen，ionic liquids [bmim]BF4was obtained after the anion-exchanged process. Effectsof ion-exchanged time and ion-exchanged temperature on the yield were examined.The optimum conditions of targeted product were as follows：the ion-exchangedtemperature was65℃and ion-exchanged time16h. Finally, the product wascharacterized by infrared spectroscopy．2. The stable polyacrylamide (PAM) dispersions were synthesized via dispersionpolymerization in the ionic liquid using acrylamide (AM) as the monomer,azo-compounds (AIBN) as the initiator, and polyethylene glycol (PEG2000) as thedispersant stabilizer. The factors which affected the relative molecular weight,conversion of the monomer, average particle size and apparent viscosity of thepolyacrylamide were investigated including the reaction time, reaction temperature, theconcentration of initiator. The optimum conditions of synthesis of PAM weredetermined by the orthogonal experiment and as follows: The react time was10h, theinitiation temperature70℃, the concentration of monomer1.6mol/L, and the dosage of initiator2%.3. The structure of polymer was confirmed by Fourier Transform Infra-Red (FT-IR).By Laser Particle-size Analyzer and the digital rotational viscometer, the rheologyproperties and apparent viscosity of the dispersion polymer were studied. And therelative viscosity-average molecular weights of the polyacrylamides were measured byviscometer. The results showed that acrylamide can polymerize via dispersionpolymerization in ionic liquid [bmim]BF4. The polymer particles were homogeneous.And the molecular weights of obtained products were as high as1.05107g/mol withgood water solubility.