Synthesis of poly(vinyl alcohol) derivatives containing amidoxime groups

The modification reaction of poly(vinyl alcohol) (PVAL) with acrylonitrile in alkaline medium was studied. The structure of the resulting polymers was determined by means of IR, ¹H and ¹³C NMR spectroscopy. The influence of solvent composition, catalyst and temperature was evaluated. ¹³C NMR spectroscopy was used for the determination of the sequence distribution of cyanoethylated PVAL (considered as a vinyl alcohol (VAL)-(2-cyanoethyl) vinyl ether (VCE) copolymer). The ¹³C NMR spectra of the methylene carbons in the main chain show three split peaks, the intensities of which change with copolymer composition. These peaks can be assigned to the three dyad sequences. The obtained results show that VCE units have an alternating tendency in the copolymer. Nitrile groups in cyanoethylated PVAL were converted to amidoxime groups by reaction with hydroxylamine. The reaction showed second order kinetics. The activation energy was found to be 51.6 kJ/mol. Soluble polymeric chelates between amidoximated PVAL and cupric ions have been prepared. It is noteworthy that not all the amidoxime groups participate in binding cupric ions.     

Poly(vinyl alcohol) modification with n-alkyl chloroformates

This work deals with the modification reaction of poly(vinyl alcohol) with n-alkyl chloroformates using pyridine as catalyst. The structure of the modified polymers was determined by means of IR, ¹H and ¹³C-NMR spectroscopy as well as by chemical analysis. Vinyl alcohol-vinyl n-alkyl carbonate copolymers were obtained. The presence of cyclic carbonates has not been observed. It has been found a linear dependence of reaction rate on polymer, n-alkyl chloroformates, and pyridine concentrations, respectively. The activation energy found was of 15.4 kcal/mol. The water absorbed in the copolymers made it reasonable to conclude that the hydrophilic character of the copolymers decreased progressively when either the carbonate groups content or the side chain length increased. Water insoluble alcohol-vinyl n-alkyl carbonate copolymers were hydrolyzed in an alkaline medium. They were found to recover their solubility in water after a certain hydrolysis extent was reached.     

Characterization of ethylene-1-butene copolymer by differential scanning calorimetry and 13C-NMR spectroscopy

Two kinds of ethylene-1-butene copolymers that were produced by the different procedures, that is, the slurry and the high-pressure polymerizations, were characterized by differential scanning calorimetry (DSC) and carbon-13 nuclear magnetic resonance (¹³C-NMR) spectroscopy. The melting points of both copolymers were found to be different in spite of the same 1-butene content. It was deduced that this phenomenon depended upon the subtly different chain structures between these two copolymers from the tetrad monomer sequence analysis by ¹³C-NMR method. In addition, the behavior of the composition fractionation by temperature rising elution technique was also considered to be affected by the chain structures.     

Glycidyl methacrylate and N-vinyl-2-pyrrolidone copolymers: Synthesis,characterization, and reactivity ratios

Free radical copolymerization of glycidyl methacrylate (GMA) and N-vinyl-2-pyrrolidone (VPD) was carried out using 2,2′-azobisisobutyronitrile (AIBN), in chloroform at 60°C. The polymers were characterized by IR and ¹³C-NMR spectroscopic methods. The percentage composition of the copolymers were established by microelemental analysis and by ¹³C-NMR spectroscopy. The copolymerization reactivity ratios were computed using the Fineman-Ross method, the Kelen-Tudos method, and the extended Kelen-Tudos method. The molecular weights of the copolymers were obtained by GPC measurements. Thermal properties of the homo- and copolymers were also studied by thermogravimetric analysis. The copolymers were tested as adhesives for leather-to-leather and leather-torubber bonding.     

Sulfur containing polymers

Summary Copolymers containing -S-CO-S-and/or -O-CO-S-groups have been synthesized mainly by interfacial polycondensation.Different chemical structures were obtained by reacting 1,3-benzene dithiol (BDT) respectively with phosgene alone, phosgene and bisphenol-A (BPA), bischloroformate of BPA, BPA polycarbonate oligomers and by reacting phosgene with the products of BPA polycarbonate degraded with BDT. The chemical structures of the copolymers were investigated by IR, ¹H-NMR and ¹³C-NMR; molecular weights were determined by viscometry and vapor pressure osmometry. Although no attempt was made to find the optimum conditions for high molecular weight, some copolymers with fairly high mol. weight were obtained.     

Poly[N-(hydroxyethyl)ethyleneimine-co-phenyl succinic anhydride] Synthesis and structure

Summary Five copolymers from N-(hydroxyethyl)ethyleneimine as nucleophilic monomer and phenylsuccinic anhydride (PhSAn) as electrophilic monomer, were synthesized according to the spontaneous copolymerization concept. These copolymers were characterized by elemental analysis, FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopy. The copolymer composition determined from the ¹H-NMR spectra showed that the copolymers are not alternating. According to all the data, it was suggested a copolymer structure which includes ester and anhydride bonds. The molecular weights determined by vapor pressure osmometry ranged between 5.100 and 6.100 g/mol. Received: 12 February 1999/Revised version: 5 October 1999/Accepted: 5 October 1999     

Synthesis and characterization of chelating resins with amino moieties and application on removal of copper(II) from EDTA complexes

Strong‐field ligands (amino moieties) are introduced into a hydrogel resin to obtain a chelating resin via inversion suspension polymerization. The characteristics of chelating copolymers are measured by using Fourier transform IR spectroscopy (FTIR), elemental analysis (EA), and scanning electron microscopy (SEM). After chelating copolymers adsorb cupric ions, the absorption peak of stretch N? H is shifted to higher frequency because of a coordination reaction from the FTIR spectra. Furthermore, the mechanism of metal complex adsorption on the chelating copolymer is that the strong‐field chelating ligand decomposes the bonding of the metal complexes and recoordinates the cupric ion to a chelating polymer, which is examined via FTIR, SEM with EA, and ionic chromatography analysis. The maximum adsorption capacity of cupric ions is 1.08 mmol/g and the adsorption capacity increases with the increase of the pH of the solution. The stability constant of the Cu chelating copolymer is 10^18.72, and it can have competition adsorption with EDTA in aqueous solution. These amino chelating copolymers can be used not only to recover metal ions but also to move anion pollution in wastewater. It is interesting that parts of the cupric ions adsorbed on the chelating copolymer are reduced into cupreous ions and/or copper atoms after electron spectroscopy for chemical analysis measurement. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2457–2468, 2005     

Spontaneous copolymerization of 2-phenyl-2-oxazoline with cyclic carboxylic anhydrides

Summary The copolymers obtained by the spontaneous reaction between 2-phenyl-2-oxazoline (PhOx) and different anhydrides (succinic-SA, maleic-MA and phthalic-PA) in the absence of an added initiator have been studied. The copolymers were characterized by FTIR and ¹³C-NMR spectroscopies. Compositions were determined by quantitative elemental analysis and average molecular weights were obtained by GPC. The PhOx/MA and PhOx/PA were found to be alternating copolymers, whereas the PhOx/SA copolymer was a statistical one, rich in PhOx.     

Synthesis of novel functionalized methacrylate copolymers and their copolymerization kinetics,thermal stability,and biocidal properties

In the first step of this study, 2-[(methoxy-1,3-benzothiazole-2-yl)amino]-2-oxoethyl methacrylate (MBAOM) monomer was synthesized and characterized. Then, a series copolymers were obtained by free-radical copolymerization method of MBAOM and glycidyl methacrylate, which is a commercial monomer at 65°C in 1,4-dioxane solvent. Structural characterizations of synthesized monomer and copolymers were carried out using Fourier transform infrared spectrophotometer and nuclear magnetic resonance spectroscopy (¹H and ¹³C-NMR) instruments. The composition of the copolymers was estimated by elemental analysis. The thermal behaviors of all the polymers have been investigated using the differential scanning calorimetry and the thermogravimetric analysis. A kinetic study of the thermal decomposition of copolymers was investigated using thermogravimetric analyzer with non-isothermal methods selected for analyzing solid-state kinetics data. The activation energy (E_a) values were calculated via Kissinger and Ozawa models in a period of α = 0.10–0.80. Photostability of the copolymers was investigated. Also, the biological activity of the copolymers against different bacterial and fungal species has been investigated.     

Synthesis and characterization of methacrylic acid–ethyl acrylate copolymers

Copolymerization of methacrylic acid (MAA) and ethyl acrylate (EA) was performed in aqueous medium in the presence of an emulsifier with MAA as the major component (53.7–82.3 mol %). Emulsion stability was studied as a function of concentration and the nature of the emulsifier (ionic or nonionic). Copolymers were characterized using IR and ¹H-NMR spectroscopy. ¹³C-NMR spectra of MAA–EA copolymers have been discussed in terms of their triad monomer sequence distributions. Reactivity ratios of the MAA–EA pair were determined using a nonlinear least-square errors in variables method. Partition of the monomers in aqueous and organic phases was studied using a gas chromatographic technique. A two-loci polymerization mechanism was proposed on the basis of this partition behavior and the calculated composition of the oligomeric radicals formed in the initial stages of polymerization. © 1994 John Wiley & Sons, Inc.     

Syntheses and Electronic Behaviors of Networked Alternating Aluminum-organic Moiety Hybrid Copolymers

Hybrid copolymers with aluminum-organic moiety frameworks were successfully prepared by reacting aluminum tri-sec-butoxide with several organic diols. The compositions of the resulting copolymers were determined using IR spectroscopy, ICP, elemental analysis and CP/MASS ¹³C-NMR spectroscopy. The UV-VIS spectra of the copolymers were also obtained. ESR spectral examinations of the copolymers and ab-initio calculations of the copolymer models indicate that an electron transfer takes place from the organic moiety to the aluminum atom in the framework.     

Polymerization of lactams, 44. Molecular characterization of the copolymers of 6-caprolactam and 12-dodecanelactam

Equilibrium copolymers of 6-caprolactam and 12-dodecanelactam differing in chemical composition have been prepared, fractionated and characterized by light scattering, viscometry and ¹³C-NMR. It has been found that the copolymers have a statistical distribution of comonomer units and are practically homogeneous in chemical composition. Intrinsic viscosities for the copolymer fractions in m-cresol, regardless of their chemical composition, fit fairly well the same Mark-Houwink relationship whose constants K = 7.55.10^?4 and a = 0.71 have the values between those for polycaprolactam and polydodecanelactam.     

Metal ion retention using the ultrafiltration technique: Preparation,characterization of the water-soluble poly(1-vinyl-2-pyrrolidone-co-itaconic acid) and its metal complexes in aqueous solutions

Radical copolymerization of 1-vinyl-2-pyrrolidone with itaconic acid at different feed monomer ratios (75–25 mol %) were investigated. The copolymers were characterized by elemental analysis, Fourier transform infrared (FTIR), ¹H and ¹³C NMR spectroscopy. The copolymer composition was determined from elemental analysis and found to be statistical copolymers. Additionally, viscosimetric measurements, molecular weight, and polydispersity have been determined. The metal complexation of poly(1-vinyl-2-pyrrolidone-co-itaconic acid) for the metal ions such as Cr(III), Co (II), Zn(II), Ni(II), Cu(II), Cd(II), and Fe(III) were investigated at pH 3, 5, and 7 in aqueous solution. The metal ion interaction with hydrophilic polymers was determined as a function of the pH and filtration factor. Poly(1-vinyl-2-pyrrolidone-co-itaconic acid) showed a high affinity for the metal ions at pH 5 and 7. The poly(NVP-co-IA), with a copolymer composition of 29 : 71 mol % (PVA-3), presented the highest metal ion retention values, particularly at higher pHs, at which the carboxylic acid groups are nonprotonated and could easily coordinate with the metal ions. According to the interaction pattern obtained, Cr(II), Zn(II), Pb(II), and Ni(II) formed the most stable complexes at pH 7. The thermal behaviors of the copolymer and polymer metal complex were characterized using differential scanning calorimetry (DSC) and thermogravimetry techniques under nitrogen atmosphere. The copolymers present high thermal stability and do not present glass transition in DSC curves between 25 and 500°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Determination of the composition of common linear low density polyethylene copolymers by 13C-NMR spectroscopy

A comprehensive ¹³C-NMR method for the analysis of composition in the most common commercial polyethylene copolymers has been established. The method covers ethene copolymers with propene, butene-1, hexene-1, octene-1, and 4-methyl pentene-1 in the composition range of 1–10 mol %. The chemical shift assignments and T₁ values of the resonances of the copolymers are presented. Results of precision studies and interlaboratory analyses showed that the molar composition could be determined with a relative precision at 2δ of about 6%. This method is being proposed to ASTM as Method X70-8605-2.     

Thermoplastic elastomeric hydrogenated styrene-butadiene elastomer: Optimization of reaction conditions,thermodynamics, and kinetics

Thermoplastic elastomeric hydrogenated styrene—butadiene (HSBR) elastomer was prepared by diimide reduction of styrene-butadiene rubber in the latex stage. The products were characterized by infrared, ¹H-NMR, ¹³C-NMR spectroscopy, and differential scanning calorimetry (DSC). The standard free energy change, ΔG⁰ at 298°K is −44.7 × 10⁴ kJ/mol, indicating that the formation of HSBR is thermodynamically feasible. The value of heat change of the reaction at constant volume, ΔU_T is −41.6 × 10⁴ kJ/mol. The effect of different reaction parameters on the level of hydrogenation, calculated from nuclear magnetic resonance spectroscopy, was also investigated. The degree of hydrogenation increases with the increase in reaction time, temperature, the concentration of reactants and catalyst. A maximum of 94% hydrogenation was obtained under the following conditions: time, 4 h; temperature, 45 ± 2°C; pH, 9.36; cupric sulphate (CuSO₄ · 5H₂O) catalyst concentration, 0.0064 mmol; hydrazine concentration, 0.20 mol; and hydrogen peroxide concentration, 0.26 mol. The diimide reduction of SBR is first-order with respect to olefinic substrate, and the apparent activation energy is 9.5 kJ/mol. The glass transition temperature increases with the increase in saturation level due to development of crystalline segments. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1151–1162, 1997     

pH/temperature-responsive poly(dimethylaminoethyl methacrylate) grafted κ-carrageenan copolymer: Synthesis and physicochemical properties

κ-Carrageenan-graft-poly(dimethylaminoethyl methacrylate) (CRG-g-PDMA) was synthesized via free-radical copolymerization under microwave irradiation. ¹³C-Nuclear magnetic resonance spectroscopy (¹³C-NMR), fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and X-ray diffraction (XRD) methods were used for characterization of the CRG-g-PDMA structure. The effect of reaction variables including the concentrations of the initiator and dimethylaminoethyl methacrylate (DMA) as well as the microwave irradiation time and power on graft ratio and conversion was investigated, and their highest values were obtained to be 179 and 76%, respectively. The lower critical solution temperatures (LCSTs) of the CRG-g-PDMA copolymers were determined at various pH conditions, and their value in distilled water was found as 47°C. Besides, the swelling capacity of the copolymers under different pH levels was investigated and it was seen that the swelling capacity of the copolymer increased with the decrease in the pH value of the medium. The CRG-g-PDMA copolymer exhibited excellent swelling performance in acidic pH conditions and possessed responsiveness to pH and temperature stimuli.     

Spontaneous copolymerization of N-(2-hydroxyethyl)ethyleneimine with maleic anhydride

Summary The copolymerization of N-(2-hydroxyethyl)ethyleneimine, (HEEI) as nucleophilic monomer and maleic anhydride (MA) as electrophilic monomer in the absence of initiator in acetonitrile was investigated. Copolymers were characterized by IR, ¹H-NMR and ¹³C-NMR spectroscopy. The copolymer composition depends on the monomer ratio in the feed, determined by ¹H-NMR spectroscopy. The presence of MA bridges between copolymer chains was established by spectroscopic analysis. At lower temperature the yield and molecular weight of copolymers decrease as well as the MA unit content in the copolymer.     

Charge transfer copolymerization and properties of isopropyl methacrylate with acrylonitrile and methacrylonitrile

Isopropyl methacrylate (IPMA) with Acrylonitrile (AN) and Methacrylonitrile (MAN) copolymers of different copositions were prepared at 60°C and 80°C, respectively, using a mixture of n-Butylamine (nBA) and carbon tetrachloride (CCl₄) in dimethyl sulphoxide (DMSO) as a charge transfer (CT) initiator. The percentage composition of the copolymers was established by elemental analysis. The copolymerization reactivity ratios were computed by the Kelen–Tudos method. In both the systems, IPMA was found to be more reactive; the copolymers sequence was random in nature. The copolymers were characterized by IR, ¹H-NMR, ¹³C-NMR spectroscopy and intrinsic viscosity measurements in dimethyl formamide (DMF) at 30±0.1°C. The thermal behavior of the AN-IPMA copolymers was studied by thermogravimetry (TG) in air. The thermal stability increased, with increasing AN content in the copolymer chain. The solubility parameter of AN-IPMA copolymer was evaluated by studying the intrinsic viscosity in different solvents. The solubility parameter of the copolymer was found to be 9.7 (cal/cc)^1/2.     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

Synthesis and solubility of polylactide-co-poly(amino acid) random copolymer

Random copolymers of polylactide-co-poly(amino acids) with a molecule weight range of 5,000–20,000 g/mol were obtained by ring-opening polymerization of l-lactic acid O-carboxyanhydride with amino acid-N-carboxyl anhydride in the presence of DMAP as an initiator. The structures of the copolymers were characterized with IR, ¹H-NMR, ¹³C-NMR, and GPC. The results show that the polymerization activity of amino acid-N-carboxyl anhydride is higher than that of l-lactic acid O-carboxyanhydride. Copolymers of polylactide-co-poly(amino acid) can improve the solubility of poly(amino acid) in organic solvents.