Unforseen factors influencing Fe(III)‐containing cations sorption on strongly basic anion exchangers

The sorption and partial destruction of the Fe(III)‐containing compounds in the aqueous medium in strongly basic anion exchangers AV‐17 and Varion‐AD phase have been investigated. It is shown that partial destruction of the Fe (III) compounds in acidulated water (pH = 2) and in K₂SO₄, Fe₂(SO₄)₃ solutions takes place. With increasing of temperature up to 50°C, the desorption degree of the iron ions from polymer phase decreases. In dried polymer, the structural and electronic state of iron compounds, according to their magnetic susceptibility, remains stable for a long time. The sorption of the Fe(III)‐containing cations at 50°C during 12 h depends essentially on the sizes of polymer granules. Sorption increases with growing of polymer granules. For comparison of sorptional capacities, the sorption of Fe(III)‐containing cations was determined on different cation and anion exchangers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Sorption of Cr(III)‐containing cations on strongly basic anion exchangers

It is shown that strongly basic anion exchangers AV‐17 and Varion‐AD in definite conditions are able to retain Cr(III)‐containing ions from Cr(III) sulfate solution. It is found that the sorption of Cr(III)‐containing ions on the polymers is essentially dependent on the pH, temperature, and Cr(III) sulfate concentration. The maximum temperature dependence of sorption was found to be about 60°C. The sorption isotherms are well described by Langmuir's equations. The sorption kinetics is determined by the diffusion of Cr(III)‐containing ions into polymer's phase. It is assumed that the Cr(III)‐containing ions are retained through formation, in polymer's phase, of the jarosite‐type mineral compounds: R₄N[Cr₃(OH)₆(SO₄)₂], H₃O[Cr₃(OH)₆(SO₄)₂], and K[Cr₃(OH)₆(SO₄)₂]. For comparison of sorptional capacities, the sorption of Cr(III)‐containing ions was determined on different cation and anion exchangers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3978–3985, 2006     

Morphological study on the reactivity of styrene‐divinylbenzene copolymers in a chloromethylation reaction

Styrene‐divinylbenzene (S‐DVB) copolymers with different kinds of porous structures were synthesized by aqueous suspension polymerization using n‐heptane as the pore forming agent. The amount of this solvent (monomer dilution degree) and the DVB content in the organic phase were varied. The combination of three different dilution degree values and three DVB contents yielded three series of copolymers with a variety of porous structures. The three series were composed by copolymers with pore diameters (D) in the following ranges: D < 500 Å, 500 < D < 1000 Å, and D > 1000 Å, respectively. The effect of synthesis conditions on the pore size distribution and on the copolymer matrix rigidity was evaluated. These copolymers were submitted to a chloromethylation reaction with a paraformaldehyde/gaseous HCl mixture in the presence of zinc chloride as a Lewis acid catalyst and 1,2‐dichloroethane as solvent. The effect of the copolymer porosity on the chloromethylation reaction extension was evaluated. It was possible to observe that a gel copolymer with a high swelling capacity in the reaction medium achieved the same chloromethylation yield observed for a high porous copolymer. This result thus indicates that, in the case of the chloromethylation reaction studied here, the high swelling capacity of the gel copolymer can counterbalance its limited surface area, turning this type of polymer structure as reactive as a macroporous one. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Glass transition temperature of methyl methacrylate–ethyl α‐benzoyloxymethylacrylate copolymers

Poly(ethyl α‐benzoyloxymethylacrylate) (EBMA) and copolymers of methyl methacrylate (MMA) with EBMA have been prepared by free radical polymerization. Monomer precursors of ethyl α‐benzoyloxymethylacrylate have likewise been polymerized. Glass transition temperatures (T_g) of homo and copolymers have been determined by differential scanning calorimetry. The Johnston equation, which considers the influence of monomeric unit distribution on the copolymer glass transition temperature, has been used to explain the T_g behaviour. T_g12 has been calculated by the application of the Johnston equation, which gave a value markedly lower than the average value expected from the additive contribution of the T_g of the corresponding homopolymers. © 2000 Society of Chemical Industry     

Synthesis and simple method of estimating macroporosity of methyl methacrylate–divinylbenzene copolymer beads

Macroporous methyl methacrylate–divinylbenzene copolymer beads having diameter ～ 300 μm were synthesized by free radical suspension copolymerization. The macroporosity was generated by diluting the monomers with inert organic liquid diluents. The macroporosity was varied in the range of ～0.1 to ～ 1.0 mL/g by varying a number of porosity controlling factors, such as the diluents, solvent to nonsolvent mixing ratios when employing a mixture of the two diluents, degree of dilution, and crosslinkage. Increase in pore volume from 0.1 to 0.45 mL/g resulted in a sharp increase in mesopores having diameters in the range of 3–20 nm whereas the macropores remained negligible when compared with mesopores. Increase in pore volume from 0.45 to 1 mL/g resulted in a sharp increase in macropores, whereas mesopores having diameters in the range of 3–20 nm remained almost constant. The mesopores having diameters in the range of 20–50 nm showed an increase with the increase in pore volume throughout the whole range of pore volume studied. Macroporosity characteristics, i.e., pore volume (V_m), surface area (SA), and pore size distributions were evaluated by mercury penetration method. Statistical analysis of the data obtained in the present study shows that the macroporosity characteristics can be estimated with a reasonable accuracy from the pore volumes, which in turn are determined from the densities of the copolymers. These results are explained on the basis of pore formation mechanism. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Adsorption properties of novel chelating resins containing 2‐amino‐5‐methylthio‐1,3,4‐thiadizole and hydrophilic spacer arms for Hg2+ and Ag+

The adsorption properties, including the adsorption kinetics, adsorption isotherms, and adsorption selectivity, of newly formed chelating resins that contained a heterocyclic functional group and a hydrophilic spacer arm of poly(ethylene glycol) [polystyrene–diethylene glycol–2‐amino‐5‐methylthio‐1,3,4‐thiadizole (PS–DEG–AMTZ) and polystyrene–triethylene glycol–2‐amino‐5‐methylthio‐1,3,4‐thiadizole (PS–TEG–AMTZ)] were studied in detail. The results show that the adsorption kinetics of PS–DEG–AMTZ and PS–TEG–AMTZ for Hg²⁺ and Ag⁺ could be described by a pseudo‐second‐order rate equation. The introduction of a spacer arm between the polymeric matrix and functional group was beneficial for increasing the adsorption rates. The apparent activation energies of the resins for Hg²⁺ and Ag⁺ were within 20.89–32.32 kJ/mol. The Langmuir model could describe the isothermal process of Hg²⁺ and Ag⁺. The competitive adsorption of the resins for Hg²⁺ and Ag⁺ in binary mixture systems was also investigated. The results show that Hg²⁺ and Ag⁺ were adsorbed before the other metal ions, such as Cu²⁺, Zn²⁺, Fe³⁺, Cd²⁺, and Pb²⁺, under competitive conditions. Five adsorption–desorption cycles were conducted for the reuse of the resins. The results indicate that these two resins were suitable for reuse without considerable changes in the adsorption capacity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Glass‐transition temperatures and rheological behavior of methyl methacrylate–styrene random copolymers

Poly(methyl methacrylate‐ran‐styrene) copolymers were synthesized under monomer‐starved conditions by emulsion copolymerization. The glass‐transition temperatures (T_g's) of the copolymers were measured by differential scanning calorimetry (DSC) and torsional braid analysis (TBA). The results showed that the methyl methacrylate–styrene random copolymers produced an asymmetric T_g versus composition curve, which could not even be interpreted by the Johnston equation with different contributions of dyads to the T_g of the copolymer considered. A new sequence distribution equation concerning different contributions of triads was introduced to predict the copolymer's T_g. The new equation fit the experimental data exactly. Also, the T_g determined by TBA (T_gTBA) was higher than the one determined by DSC (T_gDSC) and the difference was not constant. The rheological behavior of the copolymers was also studied. T_gTBA ? T_gDSC increased with increasing flow index of the melt of the copolymer, and the reason was interpreted. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2891–2896, 2003     

Synthesis and metal ion adsorption studies of chelating resins derived from macroporous glycidyl methacrylate‐divinylbenzene copolymer beads anchored schiff bases

Two novel chelating resins are prepared by anchoring diethylenetriamine bis‐ and mono‐furaldehyde Schiff bases onto the macroporous GMA‐DVB copolymer beads and utilized for the adsorption towards Cu(II), Co(II), Ni(II), and Zn(II). FTIR spectra show that Schiff base groups have been successfully introduced into the polymer matrix and the chelating resins can form complexes with the metal ions. The chelating resins show a higher adsorption capacity toward Cu(II). The conductivity method can be used for determining the adsorption kinetics of the resins towards metal ions. The results show that the adsorption rates towards Cu(II) are much higher than those towards other ions and pseudo second‐order and intraparticle diffusion models can be applied to treat the adsorption amount‐time data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of poly[methyl methacrylate‐co‐2‐ethylhexyl acrylate‐co‐poly(propylene glycol diacrylate)] latices

The emulsion polymerization of the monomers methyl methacrylate (MMA) and 2‐ethylhexyl acrylate (EHA) was studied to investigate the effect of the crosslinkable monomer poly(propylene glycol diacrylate) (PPGDA). IR spectroscopy, NMR, differential scanning calorimetry, gel permeation chromatography, and scanning electron microscopy were used to characterize the synthesized polymers. These polymers were coated on glass panels and cured at appropriate temperatures to study the physical properties, swelling behavior, surface tension, and contact angle of these polymer latices. The results show that as the concentration of EHA monomer increased, the surface tension of the latices decreased. The copolymers were characterized by ¹H‐NMR spectroscopy to ensure the absence of unreacted monomer, and the results confirm the incorporation of EHA units in the copolymer. The contact angle of the latices on the glass substrate was smaller than that on the metal. The swelling mechanism of the film showed that the Fickian diffusion coefficient with 10 wt % PPGDA was at a minimum value and was the most highly crosslinked polymer among the samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Syntheses and properties of carboxymethyl chitosan/urea–formaldehyde snake‐cage resins

A series of novel snake‐cage resins were synthesized using carboxymethyl chitosan (CM‐CTS) as the snake resin and urea–formaldehyde resin (UF) as the cage resin. Such factors as the optimal synthesis conditions, content of the crosslinking agent, and sorption capacities for metal ions of the above‐mentioned resins were investigated. The experimental results show that these resins have appropriate swelling properties and good mechanical stability. They do not run off in water, HCl, and NaOH aqueous solutions. To form a stable network system, NH₄Cl was used as a crosslinking agent to crosslink urea and formaldehyde in synthesis. The sorption experiment showed that the sorption properties of the resins in the presence of the crosslinking agent NH₄Cl are better than those without a crosslinking agent. The investigation of the FTIR spectra indicated that the chelate groups, such as —OH, —CO and NHCH₂CO, in snake‐resin molecules participated in the coordination with the metal ions, but the —C?O bonds in the cage resin UF did not. The snake resin CM‐CTS in the snake‐cage resins was the major contributor of sorption. The sorption dynamics showed that the sorption was controlled by liquid film diffusion. The isotherms can be described by Freundlich and Langmuir equations. The saturated sorption capacities of the resins for Cu²⁺, Ni²⁺, Zn²⁺, and Pb²⁺ were 1.48, 0.78, 0.13, and 0.02 mmol g^?1, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 310–317, 2002; DOI 10.1002/app.10331     

Studies on poly(8‐hydroxy‐4‐azoquinolinephenylmethacrylate) and its metal complexes

8‐Hydroxy‐4‐azoquinolinephenylmethacrylate (8H4AQPMA) was prepared and polymerized in ethyl methyl ketone (EMK) at 65°C using benzoyl peroxide as free radical initiator. Poly(8‐hydroxy‐4‐azoquinolinephenylmethacrylate) poly(8H4AQPMA) was characterized by infrared and nuclear magnetic resonance techniques. The molecular weight of the polymer was determined by gel permeation chromatography. Cu(II) and Ni(II) complexes of poly(8H4AQPMA) were prepared. Elemental analysis of polychelates suggests that the metal‐ligand ratio is about 1 : 2. The polychelates were further characterized by infrared spectra, X‐ray diffraction, spectral studies, and magnetic moments. Thermal analyses of the polymer and polychelates were carried out in air. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1516–1522, 2006     

Pore structure of water‐wettable hydrophobic resins based on divinylbenzene and methyl acrylate

Hydrophobic, but water‐wettable porous resins based on divinylbenzene (DVB) and methyl acrylate (MA) were prepared with a wide range of pore structures by suspension copolymerization under different conditions. By using purified DVB (98.8%), the specific surface area for the resulting MA/DVB resins could reach high values at high DVB levels, while these resins are wettable by direct contact with water. An increased content of MA significantly increases the porosity of the resins, whereas the solvating power of the porogen affects both pore structure and water‐wettability of the MA/DVB resins profoundly. Treating these MA/DVB resins with ferric chloride in the presence of dichloroethane gives products with larger surface areas and an enhanced water‐wettability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2681–2688, 2004     

The influence of the diluent system on the porous structure formation of copolymers based on 2‐vinylpyridine and divinylbenzene. Diluent system. III. heptane/methylethylketone

The effects of the diluent mixture's composition and crosslinking degree [divinylbenzene (DVB)] on the porous characteristics of the anion‐exchange resins based on 2‐vinylpyridine (2VP) and DVB, synthesized by suspension polymerization, in the presence of a diluent mixture constituted of heptane (HEP) and methyl ethyl ketone (MEK) at different proportions, were evaluated. The resins were characterized by mercury porosimetry, nitrogen adsorption (Brunauer–Emmett–Teller (BET) method surface area determination), apparent density, and swelling in methanol. The optical appearance of the copolymer beads was examined by optical microscopy. It was found that the development of porosity was attained whenever the content of methyl ethyl ketone in the diluent mixture was increased for all DVB contents employed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 666–669, 2004     

Preparation,characterization, and adsorption properties of cellulose acetate‐polyaniline membranes

Four lots of cellulose acetate (CA) membranes, modified with polyacrylic acid, using various plasticizers, and coated with polyaniline (PANI) were prepared. The morphology of the membranes was evaluated by using scanning electron microscopy, and the membranes showed larger pore size when the plasticizers were used. The electrical conductivity of the modified membranes and coated with PANI increased by two orders of magnitude when the plasticizer triphenyl phosphate was used. The strain at break improved by an order of magnitude and the glass transition temperature (T_g) showed an average decrease of 36°C when the membranes were plasticized. Finally, these membranes were tested as ion‐exchange materials of a gold‐iodide complex. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Studies on γ‐Fe2O3–high‐density polyethylene composites and their additives

γ‐Fe₂O₃–high‐density polyethylene (HDPE) composite films are prepared by a gel‐casting technique. To understand the effect of additives, rice husk ash and thiourea are made to disperse in the HDPE matrix to obtain the composite films with additives. The as‐prepared γ‐Fe₂O₃–HDPE composite films with their additives are subjected to characterization and study through X‐ray diffraction, thermal, scanning electron microscopy, and dielectric measurements. The results are qualitatively treated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1527–1533, 2004     

Copolymer resin. VII. 8‐hydroxyquinoline‐5‐sulfonic acid–thiourea–formaldehyde copolymer resins and their ion‐exchange properties

8‐Hydroxyquinoline‐5‐sulfonic acid–thiourea–formaldehyde copolymer resins were synthesized through the condensation of 8‐hydroxyquinoline‐5‐sulfonic acid and thiourea with formaldehyde in the presence of hydrochloric acid as a catalyst and with various molar ratios of the reacting monomers. The resulting copolymers were characterized with UV‐visible, IR and 1H‐NMR spectral data, employed to determine the reactivity of monomers. The average molecular weights of these resins were determined with vapor pressure osmometry and conductometric titration in a nonaqueous medium. The chelation ion‐exchange properties were also studied with the batch equilibrium method. The resins were proved to be selective chelating ion‐exchange copolymers for certain metals. The chelation ion‐exchange properties of these copolymers were studied for Cu²⁺, Ni²⁺, Co²⁺, Pb²⁺, and Fe³⁺ ions. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymers showed a higher selectivity for Fe³⁺ ions than for Cu²⁺, Ni²⁺, Co²⁺, and Pb²⁺ ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Water‐soluble copolymers of 1‐vinyl‐2‐pyrrolidone and acrylamide derivatives: synthesis,characterization, and metal binding capability studied by liquid‐phase polymer‐based retention technique

Radical copolymerizations of 1‐vinyl‐2‐pyrrolidone with acrylamide and N,N′‐dimethylacrylamide at different feed ratios were investigated. The copolymers were characterized by Fourier transform infrared spectroscopy, ¹H NMR, and ¹³C NMR spectroscopy. The copolymer composition was determined from the ¹H NMR spectra and found to be statistical. The metal complexation of poly(acrylamide‐co‐1‐vinyl‐2‐pyrrolidone) and poly(N,N′‐dimethylacrylamide‐co‐1‐vinyl‐2‐pyrrolidone) for the metal ions Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Pb(II), Fe(III), and Cr(III) were investigated in an aqueous phase. The liquid‐phase polymer‐based retention method is based on the retention of inorganic ions by soluble polymers in a membrane filtration cell and subsequent separation of low‐molecular compounds from the polymer complex formed. The metal ion interaction with the hydrophilic polymers was determined as a function of the pH and the filtration factor. Poly(N,N‐dimethylacrylamide‐co‐1‐vinyl‐2‐pyrrolidone) showed a higher affinity for the metal ions than poly(acrylamide‐co‐1‐vinyl‐2‐pyrrolidone). According to the interaction pattern obtained, Cr(III) and Cu(II) formed the most stable complexes at pH 7. Pb(II) and Zn(II) were not retained. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 741–750, 1999     

CO2‐responsive swelling behavior and metal‐ion adsorption properties in novel histamine‐conjugated polyaspartamide hydrogel

Novel polyaspartamide copolymers containing histamine pendants (PHEA‐HIS) were prepared from polysuccinimide, which is the thermal polycondensation product of aspartic acid, via a successive ring‐opening reaction using histamine (HIS) and ethanolamine (EA). The prepared water‐soluble copolymer was then crosslinked by reacting it with hexamethylene diisocyanate in order to provide a hydrogel with both good gel strength and reversible CO₂ absorption characteristics. PHEA‐HIS gel is also pH‐sensitive and eligible to coordinate to metal ions such as Pb²⁺, Cu²⁺, and Ni²⁺ due to the imidazole units in its structure. The CO₂‐responsive swelling behavior, metal‐ion adsorption, and morphology of the crosslinked gels were investigated. The approach described here results is a promising hydrogel with potential for a variety of industrial and biomedical applications including CO₂ capture, CO₂‐responsive and switchable sensors, and smart drug delivery systems. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43305.