Poly(methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid) Hydrogels: Investigation of pH- and Temperature-Dependent Swelling Characteristics and Their Characterization

Novel poly(methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid) (poly(MAAm-co-AMPS)) hydrogels were synthesized by free radical polymerization of methacrylamide (MAAm) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in deionized water at 60 degrees C by using ammonium peroxydisulfate (APS), N, N'-methylenebisacrylamide (MBAAm) and N, N, N', N'-tetramethylethylenediamine (TEMED) as initiator, crosslinker, and activator, respectively. To investigate the effects of feed content on the pH-and temperature-dependent swelling behavior of poly(MAAm-co-AMPS), molar ratio of MAAm to AMPS in feed was varied from 90/10 to 10/90. Structural characterization of gels was performed by Fourier transform infrared (FTIR) spectroscopy using attenuated total reflectance (ATR) technique. Thermal and morphological characterizations of gels were performed by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. Although an apparent pH-sensitivity was not observed for the poly(MAAm-co-AMPS) gels during the swelling in different buffer solutions, their temperature-sensitivity became more evident with the increase in AMPS content of copolymer. Thermal stability of poly(MAAm-coAMPS) gels increased with MAAm content. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2497-2508, 201

Novel Poly(N-vinylcaprolactam-co-2-(diethylamino)ethyl methacrylate) Gels: Characterization and Detailed Investigation on Their Stimuli-Sensitive Behaviors and Network Structure

Poly(N-vinylcaprolactam-co-2-(diethylamino)ethyl methacrylate), P(VC-co-DEAEMA), gels were synthesized in ethanol by using free radical cross-linking polymerization method at 60 degrees C for 24 h in the presence of azobis(isobutyronitrile) (AIBN) as initiator. Homopolymer gels of N-vinylcaprolactam (PVC) and 2-(diethylamino)ethyl methacrylate (PDEAEMA) were also synthesized at the same conditions and used for comparison purposes. In the synthesis of homopolymer and copolymer gels, ethylene glycol dimethacrylate (EGDMA) and allyl methacrylate (AMA) cross-linking agents were employed in order to determine the effects of crosslinker type on the equilibrium swelling value (ESV) and percentage of gelation (PG). pH and temperature sensitivities of gels were investigated for both cross-linkers, and network parameters of gels were also found. In addition, detailed characterization studies were performed by Fourier transform infrared and scanning electron microscopy techniques. It was observed that PVC gel had the lowest PG and highest ESV. Compared to EGDMA, AMA increased thee percentage of gelation and decreased the equilibrium swelling value of gels. pH-sensitive profiles of gels were substantially different from each other and strongly dependent on DEAEMA content. Copolymer gels containing the highest mole percentage of N-vinylcaprolactam (95%) showed non-Fickian and Fickian swelling behavior at pH 7.4 for EGDMA and AMA cross-linkers, respectively. It was found that both monomer concentration and cross-linker type affected the polymer-solvent interaction parameters (chi), mesh size (zeta), and experimental average molecular mass between the cross-links (M-c(E)) of gels

Noncompetitive Removal of Heavy Metal Ions from Aqueous Solutions by Poly[2-(acrylamido)-2-methyl-1-propanesulfonic acid-co-itaconic acid] Hydrogel

Noncompetitive removal of Pb2+, Cu2+, and Cd2+ ions from aqueous solutions by the copolymer of 2-(acrylamido)-2-methyl-1-propanesulfonic acid with itaconic acid and its homopolymer poly [2-(acrylamido)2-methyl-1-propanesulfonic acid] was investigated. Both poly[2-(acrylamido)-2-methyl-1-propanesulforlic acid] and poly[2-(acrylamido)-2-methyl-1-propanesulfonic acid-co-itaconic acid] removed the maximum and same amounts (1.74 mmol Pb2+/g polymer) of Pb2+ ion among the ions investigated in this work. The equilibrium swelling values of poly (2-(acryl amido)-2-methyl-1-propanesulfonic acid] and poly [2-(acrylamido)-2-methyl-1-propanesulfonic acid-co-itaconic acid] showed that the swelling of the copolymer is dominated by its completely ionizable constituent 2-(acrylamido)-2-methyl-1-propanesulfonic acid. Although the incorporation of itaconic acid into poly [2-(acrylamido)-2-methyl-1-propane sulfonic acid] did not affect the removal rates of poly [2-(acrylamido)-2-methyl-1-propanesulfonic acid-co-itaconic acid] for Pb2+ and Cd2+ ions, it considerably enhanced the removal rates of the copolymer for the Cu2+ ion. The trends in the single-ion sorption of ions on poly [2-(acrylamido)-2-methyl-1-propanesulfonic acid] and poly [2-(acrylamido)-2-methyl-1-propanesulfonic acid-co-itaconic acid] followed the orders Pb2+ > Cd2+ > Cu2+ and Pb2+ > Cu2+ > Cd2+ respectively. Noncompetitive adsorption profiles of Pb2+, Cu2+, and Cd2+ ions on both polymers were demonstrated to fit the pseudo-second-order-type kinetics

Competitive heavy metal removal by poly(2-acrylamido-2-methyl-1-propane sulfortic acid-co-itaconic acid)

The competitive removal of Pb2+, Cu2+, and Cd2+ ions from aqueous solutions by the copolymer of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and itaconic acid (IA), P(AMPS-co-IA), was investigated. Homopolymer of AMPS (PAMPS) was also used to remove these ions from their aqueous solution. In the preparation of AMPS-IA copolymer, the molar percentages of AMPS and IA were 80 and 20, respectively. In order to observe the changes in the structures of polymers due to metal adsorption, FTIR spectra by attenuated total reflectancetechnique and scanning electron microscopy (SEM) pictures of the polymers were taken both before and after adsorption experiments. Total metal ion removal capacities of PAMPS and P(AMPS-co-IA) were 1.685 and 1.722 mmol Me2+/g(polymer), respectively. Experimental data were evaluated to determine the kinetic characteristics of the adsorption process. Competitive adsorption of Pb2+, Cu2+, and Cd2+ ions onto both PAMPS and P(AMPS-co-IA) was found to fit pseudo-second-order type kinetics. In addition, the removal orders in the competitive adsorption of these metal ions onto PAMPS and P(AMPS-co-IA) were found to be Cd2+ >Pb2+ > Cu2+ and Pb2+ >Cd2+ > Cu2+, respectively. Copyright (C) 2008 John Wiley & Sons, Ltd

Poly(ethylene glycol)/poly(2-acrylamido-2-methyl-1-propane sulfonic acid) gel electrolytes: a detailed investigation of their conductivity and characterization

Poly(ethylene glycol)/poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PEG/PAMPS) with a transparent appearance were prepared in the presence of ammonium persulfate (APS) as an initiator at 70 degrees C for 24 h. PEG/PAMPS-based polymer gel electrolytes in a motionless and uniform state were obtained by adding the required amount of liquid electrolytes to a dry PEG/PAMPS polymer. Liquid electrolytes include organic solvents with high boiling points (-1-methyl-2-pyrrolidone (NMP) and gamma-butyrolactone (GBL)) and a redox couple (alkali metal iodide salt/iodine). The optimized conditions for PEG/PAMPS-based gel electrolytes based on the salt type, the concentration of alkali metal iodide salt/iodine, and solvent volume ratio were determined to be NaI, 0.4 M NaI/0.04 M I-2, and NMP:GBL (7:3, v/v), respectively. The highest ionic conductivity and the liquid electrolyte absorbency were 2.58 mS cm(-1) and 3.6 g g(-1) at 25 degrees C, respectively. The ion transport mechanism in both the polymer gel electrolytes and liquid electrolytes is investigated extensively, and their best fits with respect to the temperature dependence of the ionic conductivity are determined with the Arrhenius equation

Synthesis and Characterization of Novel Poly(N-vinylcaprolactam-co-itaconic Acid) Gels and Analysis of pH and Temperature Sensitivity

Poly(N-vinylcaprolactam-co-itaconic acid), P(VC-co-IA), gels were synthesized in ethanol by using the free radical cross-linking polymerization method at 60 degrees C for 24 h in the presence of azobis(isobutyronitrile) (AIBN) and ally] methacrylate (AMA) as the initiator and the cross-linking agent, respectively. In order to determine the effect of the synthesis medium on the percentage of gelation (PG) and equilibrium swelling value (ESV), an ethanol/distilled water mixture (80:20, v/v) was also used as the synthesis medium for poly(N-vinylcaprolactam) (PVC) and P(VC-co-IA) gels. The swelling behaviors of the gels were investigated in distilled water at various temperatures and in different pH buffer solutions. Structural, morphologic, and thermal characterization studies of the gels were carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA), respectively. The lowest PG and highest ESV were obtained for the gel including 5 mol % IA, which was the gel synthesized in the ethanol/distilled water mixture. PVC synthesized in ethanol/water mixture had the highest percentage of gelation. All the gels displayed pH- and temperature-sensitive swelling behavior. The swelling kinetics of the copolymer gels synthesized in ethanol was investigated at pH 10.0, and it was determined that gels containing 5 and 10 mol % of IA indicated non-Fickian and case II swelling behavior, respectively

Swelling of N-vinylcaprolactam-dodecyl methacrylate gel in {heptane plus toluene} mixtures

A copolymer gel has been synthesized from N-vinylcaprolactam and dodecyl methacrylate in ethanol using the free radical cross-linking polymerization method. Characterizations of the gel were performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA) techniques. Swelling behavior of the gel was investigated in heptane, toluene, and their binary mixtures with different compositions. Swelling value in toluene is higher than that in heptane and swelling value increases with the increasing initial content of toluene in the binary mixture with heptane. The swelling values are correlated by the first-and second-order differential equations, and the best model correlating the experimental results is a second-order one. Diffusion coefficients have also been calculated for heptane and toluene at each concentration by power-law and first-order equations. While the diffusion mechanism of the gel in heptane is a Fickian one, the gel swelled in toluene exhibits a non-Fickian character. Diffusion mechanisms of the gels in binary mixtures are much more complicated. Because of the higher swelling degree in toluene compared to that in heptane, selectivity of the gel in different {heptane + toluene} mixtures with selectivity close to 1 has also been taken into consideration. (C) 2014 Institute of Chemistry, Slovak Academy of Science

Liquid-Liquid Extraction of Linalool from Methyl Eugenol with 1-Ethyl-3-methylimidazolium Hydrogen Sulfate [EMIM][HSO4] Ionic Liquid

The liquid-liquid equilibrium (LLE) data for a ternary system {methyl eugenol + linalool + 1-ethyl-3-methylimidazolium hydrogen sulfate [EMIM][HSO4]} (Meu-Lin-IL) were measured at 298.2 K and atmospheric pressure. The Othmer-Tobias correlation was used to verify the reliability of the experimental tie-line data. The solubility curves were obtained using the cloud point titration indicating the liquid-liquid equilibrium of the ternary system was in Type II class where two immiscible curve pairs were attained. Distribution coefficients, separation factors and selectivity were calculated for the immiscibility regions. The calculated results were compared with the experimental data. Characterization studies were performed by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and proton nuclear magnetic resonance spectroscopy (H-1-NMR) techniques

Solvent dependent swelling behaviour of poly(N-vinylcaprolactam) and poly(N-vinylcaprolactam-co-itaconic acid) gels and determination of solubility parameters

Swelling behaviour of poly(N-vinylcaprolactam) (PVC) and poly(N-vinylcaprolactam-co-itaconic acid) (P(VC-co-IA)) gels was investigated in different solvents (water, ethanol, methanol, isopropyl alcohol (IPA), chloroform, toluene, acetone) and in binary solvent mixtures (ethanol/chloroform, ethanol/methanol, IPA/chloroform, ethanol/water, IPA/water). Gels were synthesised in ethanol by the free radical cross-linking polymerisation method at 60 degrees C for 24 h in the presence of azobis(isobutyronitrile) and allyl methacrylate as the initiator and cross-linker, respectively. And also, ethanol/distilled water mixture (phi(r) = 4 : 1) was used as the synthesis medium to determine its effect on the swelling of gels. It was found that the presence of water in the synthesis medium significantly affected the equilibrium swelling value (ESV) and the swelling tendency of gels both in solvents and in solvent mixtures. All gels synthesised in ethanol showed the highest swelling in chloroform. The gels synthesised in the ethanol/water mixture displayed different swelling behaviour. In this case, while chloroform was still valid for maximum swelling of PVC, P(VC-co-IA) had the highest swelling in methanol. Solubility parameters of gels were predicted by the van Krevelen-Hoftyzer (VKH) and Hoy methods (group contribution methods) and theoretical calculations verified the experimental swelling order. (C) 2015 Institute of Chemistry, Slovak Academy of Science

Synthesis and characterization of poly(vinyl alcohol) proton exchange membranes modified with 4,4-diaminodiphenylether-2,2-disulfonic acid

A proton-exchange membrane for a direct methanol fuel cell was prepared by modifying the chemical structure of poly(vinyl alcohol) (PVA) by means of sulfonation. We report the synthesis of a new proton-conducting polymer membrane with poly (vinyl alcohol) and diamine-containing organic molecules immobilized to PVA. The sulfonation was carried out by using 4,4-diaminodiphenyl ether-2,2-disulfonic acid (ODADS). A sulfonated diamine monomer, ODADS, was successfully synthesized by direct sulfonation of a commercially available diamine, 4,4-diaminodiphenyl ether (ODA), using fuming sulfuric acid as the sulfonating reagent. The chemical structure and thermal stability of the sulfonated PVA were studied by using FTIR and thermogravimetric analysis techniques, respectively. The proton conductivities of membranes were investigated as a function of ODADS content. The thermal decomposition of PVA-ODADS membranes started at 220 degrees C. Differential scanning calorimetry (DSC) results indicated the homogeneity of the blends. Proton conductivity values of the sulfonated PVA membranes ranged between 8.25 and 16.53 mS/cm and the conductivities of PVA-ODADS membranes increased with the increasing ODADS content