Polymerization of acrylamide initiated with Ce(IV)- and KMnO4–mercaptosuccinic acid redox systems in acid-aqueous medium

Abstract

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.

Polyacrylamide-based polyampholytes and their applications

“…Acrylamide easily polymerizes in the presence of free radical initiators (Mortimer 1991) (Scheme 1). Free radical sources including peroxides, persulfates, redox catalysts, azo compounds, ultrasonic energy, ultraviolet (UV) light, ionized gas plasma, and ionizing radiation can be used as initiators in the polymerization (Suen et al 1958, Rigg and Rodrigues 1967a,b, Misra and Bhasilal 1978, Lin 2001, Özeroglu and Sezgin 2007, Bai et al 2008.…”

Swelling properties of acrylamide-N,N’-methylene bis(acrylamide) hydrogels synthesized by using meso-2,3-dimercaptosuccinic acid-cerium(IV) redox couple

“…These parameters are: the molar ratios of acrylamide/ cerium(IV) sulfate (n AAm /n Ce(IV) = 100 and 200) at constant crosslinker and acid concentrations, the concentration of sulfuric acid (C H 2 SO 4 = 0.0125 and 0.025 mol/l) at the n AAm /n MBAA = 40 and the molar ratios of acrylamide to N,N′-methylene bis(acrylamide) for different acid and initiator concentrations. The radical generation in the redox reaction of meso-2,3-dimercaptosuccinic acid and cerium(IV) sulfate in acid-aqueous medium is supposed to occur by one electron transfer from meso-2,3-dimercaptosuccinic acid to Ce(IV) according to the reactions given in Figure 1 as reported in the literature [18][19][20][21][22]. Because of low S-H bonding energy, the formation of free radicals in reaction I in Figure 1 is more likely than other reactions to initiate crosslinking polymerization of acrylamide and N,N′methylene bis(acrylamide) and oxidative termination of polymer radicals is also possible by ceric ions [18,20,21].…”

“…The radical generation in the redox reaction of meso-2,3-dimercaptosuccinic acid and cerium(IV) sulfate in acid-aqueous medium is supposed to occur by one electron transfer from meso-2,3-dimercaptosuccinic acid to Ce(IV) according to the reactions given in Figure 1 as reported in the literature [18][19][20][21][22]. Because of low S-H bonding energy, the formation of free radicals in reaction I in Figure 1 is more likely than other reactions to initiate crosslinking polymerization of acrylamide and N,N′methylene bis(acrylamide) and oxidative termination of polymer radicals is also possible by ceric ions [18,20,21]. In previous investigations, it is described that the formation of radicals on carboxyl groups may be possible [18][19][20][21][22].…”

“…Because of low S-H bonding energy, the formation of free radicals in reaction I in Figure 1 is more likely than other reactions to initiate crosslinking polymerization of acrylamide and N,N′methylene bis(acrylamide) and oxidative termination of polymer radicals is also possible by ceric ions [18,20,21]. In previous investigations, it is described that the formation of radicals on carboxyl groups may be possible [18][19][20][21][22]. However, the radical formation on carboxyl groups may appear less than that of the other radical formation reactions given in Figure 1, as the formation of free radicals on carcoxyl groups requires more energy.…”

“…However, ceric saltorganic reducing agent containing thiol functional group or groups are also new sources to initiate copolymerization of vinyl monomers at low tem-peratures. When reducing agent with thiol functional group is used in redox system of ceric saltorganic reducing agent, the formation of -S. radical is energetically most favorable due to low S-H bonding energy to initiate copolymerization of gel particles in acid-aqueous medium at lower temperatures [18][19][20][21][22][23]. The swelling of polymeric networks is influenced by the composition of the polymer i.e.…”