By using mercaptosuccinic acid-cerium(IV) sulfate and mercaptosuccinic acid-KMnO4 redox systems in acid aqueous medium, the polymerization of acrylamide monomer was performed at room temperatures. Water soluble acrylamide polymers which contain mercaptosuccinic acid end-groups were synthesized. The dependence of polymerization yield and the molecular weight of polymer on the initiator concentration(nMSA = nCe(IV)) at different acid concentrations, polymerization time, temperature, and concentration of sulfuric acid was investigated. The decrease in the initiator concentration resulted in an increase in the molecular weight but a decrease in the yield. The increase of reaction temperature from 20 to 60°C resulted in an increase in the molecular weights and slight decrease of the yield of polymer. Cerium and manganese ions are reduced to Ce(III) and Mn(II) ions respectively in polymerization reaction. The existence of Ce(III) ion bound to polymer was investigated by UV-visible spectrometry and fluorescence measurements. The amount of Mn(II) which is incorporated to the polymer was determined.
Abstract. In this paper, meso-2,3-dimercaptosuccinic acid-Ce(IV) redox couple is used for crosslinking polymerization of acrylamide (AAm) with N,N′-methylene bis(acrylamide) (MBAA) in acid aqueous medium. We have investigated the effects of crosslinker ratio, acid concentration and the molar ratio of AAm/Ce(IV) on the swelling behaviors of the synthesized P(AAm-MBAA) hydrogels. The experimental results show that the increase in the nAAm/nMBAA and nAAm/nCe(IV) result in an increase in the swelling ratio and rate of resulting hydrogels. However, the swelling equilibrium ratio and rate have been decreased with increasing of acid concentration. The k and n values in the equation of swelling rate have been determined. The n exponent decreases with increasing crosslinker, initiator and acid concentrations whereas k values increase. Kinetics and equilibrium swelling values have been discussed in terms of reaction parameters.
Chemical polymerization of acrylamide at room temperature was examined by using thioglycolic acid-cerium (IV) sulfate and thioglycolic acid-KMnO 4 redox systems in acid aqueous medium. Water soluble polyacrylamides containing thioglycolic acid end groups were synthesized. The effects of the molar ratio of acrylamide to Ce(IV) n AAm /n Ce(IV ) , the polymerization time, the temperature, the monomer concentration, the molar ratio of cerium (IV) sulfate to thioglycolic acid and the concentration of sulfuric acid on the yield and molecular weight of polymer were investigated. Lower molar ratios of acrylamide/Ce(IV) at constant monomer concentration resulted in an increase in the yield but a decrease in molecular weight of polymer. The increase of reaction temperature from 20 to 70 • C resulted in a decrease in the yield but generally resulted in a constant value for the molecular weight of polymer. With increasing polymerization time, the yield and molecular weight of polymer did not change substantially. Ce(IV) and Mn(VII) ions are reduced to Ce(III) and Mn(II) ions respectively in the polymerization reaction. The existence of Ce(III) ion bound to polymer was investigated by UV-visible spectrophotometry and fluorescence measurements. The amount of Mn(II) incorporated into the polymer was determined using graphite furnace atomic absorption spectrometry. The mechanism of this phenomenon is discussed.
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