Studies of poly(8‐hydroxy‐4‐azoquinolinephenol‐formaldehyde) and its metal complexes

Poly(8‐hydroxy‐4‐azoquinolinephenol‐formaldehyde) resin (8H4AQPF) was prepared by condensing 8‐hydroxy 4‐azoquinoline phenol with formaldehyde (1 : 1 mol ratio) in the presence of oxalic acid. Polychelates were obtained when the DMF solution of poly(8H4AQPF) containing a few drops of ammonia was treated with the aqueous solution of Cu(II) and Ni(II) ions. The polymeric resin and polymer–metal complexes were characterized with elemental analysis and spectral studies. The elemental analysis of the polymer–metal complexes suggested that the metal‐to‐ligand ratio was 1 : 2. The IR spectral data of the polychelates indicated that the metals were coordinated through the nitrogen and oxygen of the phenolic ? OH group. Diffuse reflectance spectra, electron paramagnetic resonance, and magnetic moment studies revealed that the polymer–metal complexes of the Cu(II) complexes were square planar and those of the Ni(II) complexes were octahedral. X‐ray diffraction studies revealed that the polymer metal complexes were crystalline. The thermal properties of the polymer and polymer–metal complexes were also examined. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1506–1510, 2006     

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     

Synthesis,spectral, thermal,and chelation potentials of polymeric hydrazone based on 2,4‐dihydroxy benzophenone

A chelating polymer, poly(2,4‐dihydroxy benzophenone hydrazone–formaldehyde) [poly(DHBPH–F)], was synthesized by the polycondensation of 2,4‐dihydroxy benzophenone hydrazone with formaldehyde in the presence of oxalic acid as a catalyst. Poly(DHBPH–F) was characterized by Fourier transform infrared and ¹H‐NMR spectral data. The molecular weight of the polymer was determined by gel permeation chromatography. Polychelates were obtained when the dimethylformamide solution of the polymer containing a few drops of ammonia was treated with an aqueous solution of metal ions. Elemental analysis of the polychelates indicated that the metal–ligand ratio was 1 : 2. The IR spectra of the polymer–metal complexes suggested that the metals were coordinated through the oxygen of the phenolic? OH group and the nitrogen of the azomethine group. The electron paramagnetic resonance and magnetic moment data indicated a square planar configuration for Cu(II) chelate and an octahedral structure for Ni(II) chelate. The thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction data indicated that the incorporation of the metal ions significantly enhanced the degree of crystallinity. The polymerization initiation, electrical conductivity, and catalytic activity of the polychelates are discussed. Heavy‐metal ions [viz., Cu(II) and Ni(II)] were removed with this formaldehyde resin, and the metal‐ion uptake efficiency at different pH's, the nature and concentration of the electrolyte, and the reusability of the resin were also studied. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization, and catalytic study of polymeric metal complexes derived from divalent transition metal ions with 2,4‐dihydroxy benzophenone and 2,4‐dihydroxy acetophenone

The polymeric metal complexes of poly (3‐hydroxy‐4‐((Z)‐1‐(phenylimino)ethyl)phenyl‐3‐methylbut‐2‐enoate) designated as [poly(3H4‐1PEPMB)] and poly (3‐hydroxy‐4‐((Z)‐phenyl(phenylimino)methyl)phenyl‐3‐methylbut‐2‐enoate designated as [poly(3H4‐PPMPMB)] containing Cu(II), Ni(II), Co(II), Cd(II), Mn(II), Ca(II), and Zn(II) ions were synthesized. The ploymer ligands and metal complexes were charcterized by Fourier transform infrared, nuclear magnetic resonance (NMR), thermogravimetric analysis, differential scanning calorimeter (DSC), and X‐ray diffraction (XRD) techniques. The XRD study of the complexes revealed highly crystalline nature of polychelates. The polymeric complexes were active for the oxidation of aldehyde group. The oxidation activity of Cu (II) complex of poly (3H4‐1PEPMB) was studied for the oxidation of benzaldehyde and its derivaties to corresponding carboxylic acids. The oxidation products were confirmed by GC‐MS analysis. The oxidation of aldehydes was quantitative with 100% selectivity for benzioc acid. Thermal analysis of complexes indicated reasonably good thermal stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis,characterization and antimicrobial activity of transition metal chelated thiourea‐formaldehyde resin

A polymeric ligand (thiourea‐formaldehyde resin ‐ TUFR) bearing nitrogen and sulfur donor groups was synthesized by the polycondensation of thiourea and formaldehyde in acidic medium and its polychelates were prepared in alcoholic solution of metal ions such as Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The TUFR polymeric ligand and its TUFR‐M(II) polychelates were characterized with micro‐analytical analysis and spectral studies. The FTIR spectra of polychelates indicated that the metal ions were coordinated through the sulfur of the thionyl (C?S) groups and formed a covalent bond with the nitrogen of the NH groups. Electronic spectra, electronic spin resonance (ESR) spectra and magnetic moments revealed that the polychelates of Mn(II), Co(II) and Ni(II) were octahedral; however, Cu(II) and Zn(II) polychelates were square‐planar and tetrahedral, respectively. The thermogravimetric analysis data indicated that the polychelates were more stable than the corresponding ligand. The antimicrobial activities of all the compounds against several bacteria and fungi were also investigated by using the agar well diffusion method. Copyright © 2006 Society of Chemical Industry     

Semiflexible random thermotropic copolymers from 8‐(3‐hydroxy phenyl) octanoic acid and 3‐chloro‐4‐hydroxy benzoic acid/3,5‐dibromo‐4‐hydroxy benzoic acid

Two series of semiflexible random thermotropic copolymers containing 8‐(3‐hydroxy phenyl) octanoic acid (HPOA) with either 3‐chloro‐4‐hydroxy benzoic acid or 3,5‐dibromo‐4‐hydroxy benzoic acid were prepared by melt polycondensation techniques. The copolyesters were characterized with Fourier transform infrared spectroscopy, dilute solution viscometry, hot‐stage polarized light microscopy, differential scanning calorimetry, thermogravimetric analysis, and wide‐angle X‐ray diffraction. Studies revealed that the amount of HPOA as a disruptor incorporated into the backbone of substituted 4‐hydroxy benzoic acids had a detrimental effect on the liquid‐crystalline behavior. Mesophase‐transition temperatures were observed between 210 and 250°C, and the optical textures were of typical nematic phases. The degree of crystallinity decreased with an increase in the HPOA content. The thermal stability of the copolymers was in the range of 310–370°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Synthesis and characterization of poly(1,3‐thiazol‐2‐yl‐carbomoyl) methyl methacrylate: Its metal complexes and antimicrobial activity studies

Poly(1,3‐thiazol‐2‐yl‐carbomoyl) methyl methacrylate [poly(TCMMA)] is prepared in dimethyl sulfoxide using 2,2′‐azobisisobutyronitrile as an initiator at 60°C. Poly(TCMMA) is characterized by IR and ¹H‐NMR spectroscopic techniques. Cadmium(II), copper(II), and nickel(II) chelates of poly(TCMMA) were synthesized. An elemental analysis of the polychelates suggests a metal/ligand ratio of 1:2. The polychelates are further characterized by IR and magnetic susceptibility measurements. The thermal properties of the polymer and metal chelates are also discussed. The molecular weights of the poly(TCMMA) are determined by the gel permeation chromatography technique. The antimicrobial activities of the polymer and metal chelates are tested against Staphylococcus aureus COWAN I (bacteria), Escherichia coli ATCC 25922 (bacteria), Listeria monocytogenes SCOTTA (bacteria), Bacillus subtilis LMG (bacteria), Enterobacter aeroginosa CCM 2531 (bacteria), Klebsiela pneumania FMCS (bacteria), Candida albicans CCM 314 (Mayo yeast), and Saccharamyces cerevisiae UGA 102 (Mayo yeast). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3244–3251, 2003     

Polymer complexes: LIX. Supramolecular structural,spectral and thermal analysis of N‐[2‐(6‐aminopyridino)] acrylamide polymer complexes

Novel ligand N‐[2‐(6‐aminopyridino)] acrylamide (APA) is prepared via amidation of 2,6‐diaminopyridine with acryloyl chloride in dry benzene as solvent. The ligand is characterized on the basis of elemental analysis, infra‐red (IR) analysis and ¹H nuclear magnetic resonance. Metal–polymer complexes are reported and characterized based on elemental analysis, molar conductance, magnetic susceptibility measurements, IR, ¹H nuclear magnetic resonance, electronic spectra and thermal analysis. The molar conductance of the polymer complexes in dimethylformamide corresponds to a 1:1/1:2 electrolyte, which is non‐electrolytic. IR spectra show that polyAPA is coordinated to the metal ions in a uni‐negatively bidentate manner with N, O donor sites of azomethine N and deprotonated enolic‐O. All the polymer complexes are of high spin type. On the basis of spectral studies an octahedral geometry may be assigned for Co(II) and Ni(II) polymer complexes. The thermal stabilities of the polymer complexes were studied and the activation energies of the degradation were calculated. Copyright © 2011 Society of Chemical Industry     

Synthesis,characterization, ion‐exchange,and antimicrobial study of poly[(2‐hydroxy‐4‐methoxybenzophenone) propylene] resin and its polychelates with lanthanides (III)

The polymeric ligand (resin) was prepared from 2‐hydroxy‐4‐methoxybenzophenone with 1,3‐propane diol in the presence of polyphosphoric acid as a catalyst on constant heating at 160°C for 13 h. The poly[(2‐hydroxy‐4‐methoxybenzophenone) propylene] (HMBP‐PD) form 1 : 2 metal/ligand polychelates (metal–polymer complexes) with La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), and Dy(III). The polymeric ligand and its polychelates (metal–polymer complexes) were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, IR‐spectroscopy, NMR, and thermogravimetric analyses. The molecular weight was determined using number average molecular weight (M_n) by a vapor pressure osmometry (VPO) method. Activation energy ( E ) of the resin was calculated from differential scanning calorimetry (DSC). All the polychelates are paramagnetic in nature except La(III). Ion‐exchange studies at different electrolyte concentrations, pH, and rate have been carried out for lanthanides(III) metal ions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Polymer complexes. XXXI. Potentiometric and thermodynamic studies of 2‐acrylamido‐2‐amino‐3‐hydroxy pyridine and its metal complexes

Proton ligand dissociation and metal ligand stability constants of 2‐acrylamido‐2‐amino‐3‐hydroxy pyridine (AAHP) with some transition metal ions in 0.1 M KCl and 50% (v/v) ethanol–water mixture were calculated potentiometrically. In the presence of 2,2′‐azobisisobutyronitrile as initiator the proton‐polymeric ligand dissociation and metal polymeric ligand stability constants were also evaluated. The influence of temperature on the dissociation of AAHP and the stability of its metal complexes in the monomeric and polymeric forms were critically studied. On the basis of the thermodynamic functions, the dissociation process of AAHP was found nonspontaneous, endothermic, and entropically unfavorable, although the formed metal complexes showed spontaneous, endothermic, and entropically favorable behavior. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2552–2557, 2000     

Removal of chromium,copper, and nickel ions using bidentate polymeric ligand derived from 4‐aminophenol and salicylaldehyde

The monomer 5‐(4‐acryloyloxyphenylazo)salicylaldehyde [5,4‐APASAL] was prepared and polymerized in dimethylformamide (DMF) at 70°C using benzoyl peroxide as free radical initiator. Poly5‐(4‐acryloyloxyphenylazo) salicylaldehyde [poly(5,4‐APASAL)] was characterized by infrared and nuclear magnetic resonance spectroscopic technique. The molecular weight of the polymer was determined by gel permeation chromatography method. Cu(II), Ni(II), Cr(III), and Cr(VI) complexes of poly(5,4‐APASAL) were prepared. Elemental analysis of polychelates suggests that the metal to ligand ratio is about 1 : 2. The polymer metal complexes were also characterized by XRD, magnetic moment, and thermal analysis. The effect of pH and electrolyte concentration in the metal uptake behavior of the polymer was also studied. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Chelation properties of poly(2‐hydroxy‐4‐acryloyloxybenzophenone) resins toward some divalent metal ions

The chelation behavior of poly(2‐hydroxy‐4‐acryloyloxybenzophenone) [poly(2H4ABP) or polymer I ] obtained through the free‐radical polymerization of 2‐hydroxy‐4‐acryloyloxybenzophenone monomer and for crosslinked polymers prepared from the monomer and known amounts of the crosslinker divinylbenzene (DVB) [4 mol % of DVB for polymer II, 8 mol % of DVB for polymer III, and 16 mol 16% of DVB for polymer IV ] toward the divalent metal ions Cu²⁺, Ni²⁺, Zn²⁺, and Pb²⁺ in aqueous solution was studied by a batch equilibration technique as a function of contact time and pH. The effect of the crosslinker, DVB, was also studied. The metal‐ion uptake of the polymers was determined with atomic absorption spectroscopy, and the highest uptake was achieved at pH 7.0 for polymers I, II, III, and IV. The selectivity and binding capacity of the resins toward the investigated divalent metal ions are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

New polymeric Schiff base and its metal complexes

A novel polymeric Schiff base was synthesized by the reaction of a Schiff base from 2,4‐dihydroxy benzaldehyde and aniline with acryloyl chloride and was polymerized in methyl ethyl ketone at 70°C with benzoyl peroxide as a free‐radical initiator. Polychelates were obtained in an alkaline solution of poly(2‐hydroxy‐4‐acryloyloxy‐N‐phenylbenzylidine) with aqueous solutions of metal ions such as Cu(II), Ni(II), Co(II), Ca(II), Cd(II), Mn(II), and Zn(II). The polymeric Schiff base and polychelates were characterized with elemental analysis and spectral studies. The elemental analysis of the polychelates suggested that the metal‐to‐ligand ratio was 1:2. The IR spectral data of the polychelates indicated that the metals were coordinated through the nitrogen and oxygen of the phenolic ? OH group. Diffuse reflectance spectra, electron paramagnetic resonance, and magnetic moment studies revealed that the polychelates of the Cu(II) complex were square‐planar, those of the Ni(II), Mn(II), and Co(II) complexes were octahedral, and those of the Ca(II), Cd(II), and Zn(II) complexes were tetrahedral. X‐ray diffraction studies revealed that the polychelates were highly crystalline. The thermal properties of the Schiff base and polychelates were also examined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 494–500, 2004     

Chelating resins VI: Chelating resins of formaldehyde condensed phenolic Schiff bases derived from 4,4′‐diaminodiphenyl ether with hydroxybenzaldehydes—synthesis,characterization, and metal ion adsorption studies

Phenolic Schiff bases derived from o‐, m‐, and p‐hydroxybenzaldehydes and 4, 4′‐diaminodiphenyl ether were subjected to polycondensation reaction with formaldehyde. The resins were found to form polychelates readily with several metal ions. The materials were characterized by elemental analysis, GPC, IR, UV‐Vis, ¹H‐NMR, XRD, and thermal analyses like TG, DTG, and DSC studies. The ¹H‐NMR spectra of the resins provided evidence of polycondensation with well‐defined peaks for bridging methylene and terminal methylol functions. The metal‐ligand bonds were registered in the IR spectra of the polychelates. The thermal analysis data provided the kinetic parameters like activation energy, frequency factor, and entropy changes associated with the thermal decomposition. These data indicated the resins to be more stable than the polychelates. The DSC and XRD data indicated that the incorporation of metal ions significantly enhanced the crystallinity of the polymers. The resins could adsorb several metal ions from dilute aqueous solutions. Adsorption characteristics of the resins towards Cu(II) and Ni(II) were studied spectrophotometrically both in competitive and noncompetitive conditions. The effects of pH, contact time, quantity of the sorbent, concentration of the metal ions in a suitable buffer medium were studied. The resins were found to be selective for Cu(II) leading to its separation from a mixture of Cu(II) and Ni(II). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 967–981, 2000     

Synthesis,characterization, and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid)–metal complexes

The metal‐ion complexation behavior and catalytic activity of 4 mol % N,N′‐methylene bisacrylamide crosslinked poly(acrylic acid) were investigated. The polymeric ligand was prepared by solution polymerization. The metal‐ion complexation was studied with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) ions. The metal uptake followed the order: Cu(II) > Cr(III) > Mn(II) > Co(II) > Fe(III) > Zn(II) > Ni(II). The polymeric ligand and the metal complexes were characterized by various spectral methods. The catalytic activity of the metal complexes were investigated toward the hydrolysis of p‐nitrophenyl acetate (NPA). The Co(II) complexes exhibited high catalytic activity. The kinetics of catalysis was first order. The hydrolysis was controlled by pH, time, amount of catalyst, and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 272–279, 2004     

Part 8. Preparation,characterization and metal complexing of poly[(2‐hydroxyethyl)‐DL‐aspartamide] in aqueous solution

Poly[(2‐hydroxyethyl)‐DL ‐aspartamide] was synthesized by polyreaction of aspartic acid and subsequent polymer‐analogous functionalization with ethanolamine. The water‐soluble polymer was characterized by FTIR, NMR, TGA and light‐scattering measurements. The metal complexing properties of the polymer were studied for Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sr(II), Cd(II) and Pb(II) ions in aqueous solution using the liquid‐phase polymer‐based retention (LPR) method. According to the retention profiles of LPR, Cr(III), Fe(III), Cu(II) and Pb(II) showed a strong interaction with this polymer under these conditions, indicated by retention values of about 100 %. In contrast, Co(II), Ni(II), Zn(II), Sr(II) and Cd(II) exhibited retention values of only 50–60 % in dilute solution at pH 5. © 2000 Society of Chemical Industry     

Preparation,characterization, and metal ion retention capacity of Co(II) and Ni(II) from poly(p‐HO‐ and p‐Cl‐phenylmaleimide‐co‐2‐hydroxypropylmethacrylate) using the ultra filtration technique

p‐Chlorophenylmaleimide and p‐hydroxyphenylmaleimide with 2‐hydroxypropyl methacrylate were synthesized by radical polymerization, and the metal ion retention capacity and thermal behavior of the copolymers were evaluated. The copolymers were obtained by solution radical polymerization with a 0.50 : 0.50 feed monomer ratio. The maximum retention capacity (MRC) for the removal of two metal ions, Co(II) and Ni(II) in aqueous phase were determined using the liquid‐phase polymer based retention technique. Inorganic ion interactions with the hydrophilic polymer were determined as a function of pH. The metal ion retention capacity does not depend strongly on the pH. Metal ion retention increased with an increase of pH for a copolymer composition 0.50 : 0.50. At different pH, the MRC of the poly(p‐chlorophenylmaleimide‐co‐2‐hydroxypropylmethacrylate) for Co(II) and Ni(II) ions varied from 44.1 to 48.6 mg/g and from 41.5 mg/g to 46.0 mg/g, respectively; while the MRC of poly(p‐hydroxyphenylmaleimide‐co‐2‐hydroxypropyl methacrylate) for Co(II) and Ni(II) ions varied from 28.4 to 35.6 mg/g and from 27.2 to 30.8 mg/g, respectively. The copolymers and copolymer–metal complexes were characterized by elemental analysis, FT‐IR, ¹H NMR spectroscopy, and thermal behavior. The thermal behavior of the copolymer and polymer–metal complexes were studied using differential scanning calorimetry and thermogravimetry techniques under nitrogen atmosphere. The thermal decomposition temperature and T_g were influenced by the binding‐metal ion on the copolymer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of antibacterial polychelates of urea–formaldehyde resin with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) metal ions

We studied the reaction between urea and formaldehyde with the purpose of preparing new polychelates of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) metal ions. These compounds were characterized by elemental analysis, IR spectroscopy, ¹H‐NMR, electronic spectroscopy, thermogravimetric analysis (TGA), and molar conductance measurements. The percentage of metal in all of the polychelates was found to be consistent with 1:1.5 (metal/ligand) stoichiometry. The thermal behaviors of these coordination polymers were studied by TGA in a nitrogen atmosphere up to 750°C. The TGA results reveal that the complexes had higher thermal‐resistance properties compared to the common urea–formaldehyde resin. The molar conductivity and magnetic susceptibility measurements of the synthesized polychelates confirmed the geometry of the complexes. The antibacterial activity of the polychelates was also investigated with agar diffusion methods. The antibacterial activity of these polychelates was found to be reasonably good compared with standard drugs, namely, ciprofloxacin, ampicillin, and kanamycin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 928–936, 2006     

Synthesis,characterization, and metal ion uptake studies of chelating resins derived from formaldehyde/furfuraldehyde condensed phenolic schiff base of 4,4′‐diaminodiphenylmethane and o‐hydroxyacetophenone

The synthesis, characterization, and metal ion uptake studies of two chelating resins with multiple functional groups are reported. The chelating resins were synthesized by condensing a phenolic Schiff base derived from 4,4′‐diaminodiphenylmethane and o‐hydroxyacetophenone with formaldehyde or furfuraldehyde. The resins readily absorbed transition metal ions, such as Cu²⁺ and Ni²⁺, from dilute aqueous solutions. The Schiff base, resins, and metal polychelates were characterized by various instrumental techniques, such as elemental‐analysis, ultraviolet–visible spectroscopy proton and carbon‐13 nuclear magnetic resonance spectroscopy (¹H‐NMR and ¹³C‐NMR, respectively), X‐ray diffraction (XRD), and thermogravimetric–differential thermogravimetric analyses (TG–DTG). The ¹H‐NMR and ¹³C‐NMR studies were used to determine the sites for aldehyde condensation with the phenolic moiety. Fourier transform infrared data provided evidence for metal–ligand bonding. Thermogravimetric analysis was employed to compare the relative thermal stabilities of the resins and the polychelates. The TG data were fitted into different models and subjected to computational analysis to calculate the kinetic parameters. The XRD data indicate that the incorporation of metal ion into the resin matrix significantly enhanced the degree of crystallinity of the material. The extent of metal‐ion loading into the resins was studied in competitive and noncompetitive conditions, varying the time of contact, metal ion concentrations, and pH of the reaction medium in a suitable buffer medium. The furfuraldehyde‐condensed resin was more effective in removing metal ions than the formaldehyde‐condensed resins. The resins were selective for Cu²⁺, resulting in separation of Cu²⁺ and Ni²⁺ from the mixture at pH 5.89. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 570–581, 2003     

Removal of heavy metal ions using the chelating polymers derived by the condensation of poly(3‐hydroxy‐4‐acetylphenyl methacrylate) with different diamines

A series of methacrylate‐based chelating polymers was synthesized by the reaction of 3‐hydroxy‐4‐acetylphenyl methacrylate with amines (e.g., ethylenediamine, propylenediamine, and phenylenediamine) in tetrahydrofuran. The chelating polymers were characterized by infrared (IR) and carbon‐13 nuclear magnetic resonance (¹³C–NMR) spectroscopic techniques. The thermal stabilities of these polymers were investigated by thermogravimetric (TG) and differential thermal analyses (DTA). Heavy metal ions [viz., Pb(II), Hg(II), Cd(II), and Cr(VI)] were removed with these chelating polymers, and metal ion uptake efficiency, reusability of the resins, and effects of pH and time on the metal removal were also studied. The chelating polymers possess appreciable selectivity for Pb(II) and Hg(II) compared with Cd(II) and Cr(VI). The chelating ability of the polymers towards the heavy metal ions is a sensitive function of the nature of the substituent on the nitrogen atom. The amount of metal uptake by the chelating polymer was determined by atomic absorption spectrophotometry (AAS). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 414–421, 2003