bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of sulfonated poly(acrylene ether sulfones)
Authors: Johnson B. C. , Yilgör İ. , Tran C. , Iqbal M. , Wightman J. P. , Lloyd D. R. , McGrath J. E. 
Published: April 2003

AbstractIonic groups incorporated into a polymer have a decided effect on its physical properties. A number of ionomers and polyelectrolytes have been widely applied. In particular, sulfonated bisphenol‐A polysulfone (SPSF) has been used as a composite or single‐component membrane for the desalination of water. In this article, the synthesis and physical characteristics of sulfonated polysulfone are addressed. A detailed synthesis route is provided and methods that yield determinable levels of sulfonation are described. These ion‐containing polymers retain an excessive amount of residual salts, which, of course, are impurities to the system. Therefore, before any analyses were made the polymers were subjected to a thorough soxhlet extraction process with boiling water, which appeared to be quite effective. The degree of sulfonation was assessed by several methods such as 1H NMR and FT‐IR. A new 1H NMR method was derived because the method cited in the literature proved to be too inconsistent for our work. The new 1H NMR method used a quaternary ammonium counterion [N(CH3)4]. These methyl protons are easily measured and may be ratioed against the isopropylidene protons in the polymer backbone that act as an internal standard. Characterization of the physical properties of SPSF consisted of water uptake, differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and solubility studies. Its physical appearance and mechanical behavior were improved by the solution procedure. Also addressed were the effects of different counterions (Na+ & Mg++) with SPSFs of low levels of sulfonation. The variation in physical properties between the divalent and monovalent counterions is dramatic, especially when observed by TMA in the rubber plateau above the apparent glass temperature.
Photochemical reactions of polymers containing thiocyanatoacetyl groups and dyeing the resulting polymer films
Authors: Tsunooka Masahiro , Cha Younsik , Tanaka Makoto , Konishi Fumiya 
Published: April 2003

AbstractPoly(styrene‐co‐4‐thiocyanatoacetylstyrene) and poly(4‐acetylstyrene‐co‐4‐thiocyanatoacetyl‐styrene) were prepared and their photochemical reactions were studied in the solid state. It was found that the thiocyanatoacetyl groups were easily rearranged with the corresponding isothiocyanatoacetyl groups by ultraviolet (UV) irradiation and that the resulting isothiocyanatoacetyl groups underwent intramolecular cyclization when treated with triethylamine or ammonia to yield oxazole‐2‐thione moieties. The irradiated polymer films could be dyed selectively with cationic dyes in an appropriate dye bath because of the formation of anionic species by keto‐enol tautomerization of oxazole‐2‐thione moieties in an alkaline state.
Gamma‐radiolysis of polysalicylide
Authors: Gupta Mool C. , Deshmukh Vilas G. 
Published: April 2003

AbstractPolysalicylide, a condensation product of acetylsalicylic acid, was irradiated with 60Co‐γ‐rays. Viscosity, end‐group analysis, and ultraviolet (UV) spectral measurement technique, and electrical conductivity were used to study the changes that occurred during γ‐radiolysis. It was observed that polysalicylide undergoes chain scission caused by weak links. The enthalpy of fusion is 16.0 and 13.4KJ/mol−1 repeat units of polysalicylide in air and N2, respectively. The indirect effective band gap decreased and electrical conductivity increased after irradiation.
Diffusion‐controlled reaction. VI. Radiation graft polymerization of styrene to polyethylene
Authors: Odian George , Lee Dong‐Ho , Patel Vishnu , Rabje Abdelgewad , Zahran A. H. 
Published: April 2003

AbstractThe radiation graft polymerization of styrene to polyethylene was studied under diffusion‐controlled conditions of radiation intensity I, monomer concentration M1, and polymer sample thickness L. The results of the present study together with previous work under diffusion‐free conditions verify our theoretical model for the diffusion‐controlled reaction. The grafting rate is inverse first order in L for diffusion‐controlled reaction and independent of L for diffusion‐free reaction. The order of dependence of grafting rate on radiation intensity for diffusion‐controlled reaction is one‐half that for diffusion‐free reaction. Diffusion control leads to a decrease in the order of dependence of grafting rate on monomer concentration. The decrease is greater than theoretically predicted; possible reasons for this effect are described.
Syntheses and properties of cured epoxy resins containing the perfluorobutenyloxy group. I. Epoxy resin cured with perfluorobutenyloxyphthalic anhydride
Authors: Sasaki S. , Nakamura K. 
Published: April 2003

AbstractPerfluorobutenyloxyphthalic anhydride (PFPA) has been synthesized as a new curing agent for epoxy resins, and the properties of epoxy resin cured with PFPA have been investigated. Good PFPA synthesis yields were realized by a dehydrating ring closure of perfluorobutenyloxyphthalic acid, which was obtained through the reaction of hexafluoropropene trimers with 4‐hydroxyphthalic acid. Epoxy resin cured with PFPA was found to have several excellent properties. Its boilding water absorption was 0.45%, which is about a one‐fourth that for conventionally cured epoxy resin. Its heat resistance was excellent, and its critical surface tension was almost the same as for PTFE.
Phosphorus‐containing polyurethanes and copolyurethanes based on 1,2‐dihydroxy‐1,2‐bis(diethoxyphosphinyl)ethane
Authors: Mikroyannidis John A. 
Published: April 2003

AbstractThe reactions of 1,2‐dihydroxy‐1,2‐bis(diethoxyphosphinyl)ethane (DBE) with various diisocyanates, such as tolylene diisocyanate, methylenebis(4‐phenylisocyanate), and hexamethylene‐1,6‐diisocyanate, were studied for the synthesis of phosphorus‐containing polyurethanes. In addition, DBE and ethyleneglycol or butanediol‐1,4 were copolymerized with the diisocyanates. The synthesized poyurethanes were characterized by Fourier transform‐infrared (FT‐IR), proton nuclear magnetic resonance spectroscopy (1H‐NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Their thermal properties were compared with those of the corresponding common polyurethanes. The fire resistance of the copolyurethanes was evaluated by determining their limiting oxygen index and smoke evolution.
Aminopropylcellulose, synthesis and derivatization
Authors: Daly William H. , Munir Arshad 
Published: April 2003

AbstractThe preparation of 3‐aminopropylcellulose from cyanoethylcellulose is readily achieved. Reduction of the cyano groups with borane‐dimethyl sulfide in tetrahydrofuran or a borane‐tetrahy‐drofuran complex proceeds quantitatively in 3 h to a corresponding 3‐aminopropylcellulose. The presence of primary amine functions is confirmed by spectroscopy and a positive ninhydrin test; the concentration of amino substituents, as ascertained by titration, ranged from 1.2 to 6.4 meq/g. Because the derivatives are neither soluble nor excessively swollen in water, applications as ion‐exchange resins or chromatographic supports can be envisioned. Treatment of 3‐aminopropyl‐cellulose with acetyl chloride, phenyl isocyanate, or p‐toluenesulfonyl isocyanate produced 3‐acetamido‐, 3‐(N′‐phenyluredo)‐, or 3‐(N′‐p‐toluenesulfonyluredo)‐N‐propylcellulose. Alkylation with methyl chloride yielded a water‐soluble quaternary ammonium salt.
Synthesis of aromatic polythioamide‐oxothioxoquinazolines from bis(1,3,4‐thiadiazoline‐5‐thione) and aromatic bis‐o‐amino esters
Authors: Saegusa Yasuo , Iida Sakayu , Nakamura Shigeo , Chau Nguyen , Iwakura Yoshio 
Published: April 2003

AbstractAromatic polythioamide‐oxothioxoquinazolines were synthesized by the polycondensation of 2,2′‐(m‐phenylene)bis‐1,3,4‐thiadiazoline‐5‐thione with aromatic bis‐o‐amino esters. The polymerizations were carried out at 160°C in acidic media such as m‐cresol, sulfolane, and polyphosphoric acid to produce polymers with reduced viscosities up to 0.5 dL/g. These polymers were soluble in polar aprotic solvents like N‐methyl‐2‐pyrrolidone and some acidic media including m‐cresol. The polythioamide‐oxothioxoquinazolines showed relatively good thermal stability with 10% weight loss at 344–394°C in air.
Interpenetrating polymer networks from polyurethanes and methacrylate polymers. II. Interpenetrating polymer networks with opposite charge groups
Authors: Xiao H. X. , Frisch K. C. , Frisch H. L. 
Published: April 2003

AbstractInterpenetrating polymer networks (IPNs) with opposite charge groups (tertiary amine and carboxyl groups) made from polyurethanes and methacrylate polymers have been synthesized and their properties and morphology, studied. With increasing carboxyl group concentration the mechanical properties and compatibility between the component networks were significantly improved, possibly because of the negative (or zero) free energy produced by the interaction contribution between the tertiary amine groups in the polyurethanes and the carboxyl groups in the methacrylate polymers determined by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The improved molecular mixing in these IPNs was thought to be due to the influence of the opposite charge groups in these systems.
Synthesis and investigation of polymers based on the nitriles of polycarboxylic acids and diamines
Authors: Vinogradova S. V. , Korshak V. V. , Siling S. A. , Solovyov V. N. 
Published: April 2003

AbstractThe influence of the reaction medium on the polycondensation of the tetranitriles of tetracarboxylic acids and diamines has been investigated. The reaction in phenol and cresols yields polymers with macroheterocycles in the chain—polyhexasocyclanes. If phenols with electron‐accepting substituents are used as reaction medium, nonmacrocyclic polymers with side aroxyl groups in the chain, polyisoindoxazenes—are formed. The properties of these polymers were studied. Macroheterocyclic compounds formed by condensation of phthalodinitrile with diamines can be used as one of the initial substances in polyhexasocyclane synthesis. Polyamidohexasocyclanes were prepared by polycondensation of macroheterocycles with dicarboxylic acid dichlorides. Some regularities of their formation and their properties were investigated.
Fire‐resistant polyimides and copolyimides based on 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes
Authors: Mikroyannidis John A. 
Published: April 2003

AbstractVarious phosphorus‐containing polyimides were prepared by the reaction of 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (1) with a tetracarboxylic dianhydride like pyromellitic dianhydride (PMDA) and benzophenone tetracarboxylic dianhydride (BTDA). In addition, copolyimides that contained approximately 3% phosphorus were prepared by the reaction of 1 and m‐phenylenediamine (MPD) with the aforementioned tetracarboxylic dianhydrides. Elemental analysis, inherent viscosity, infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) studies were performed to characterize the polymers. Their thermal properties were compared with those of the corresponding common polyimides. It was shown that the molecular weight and thermal stability of the polymers were reduced as the concentration of the phosphorus moieties increased. The fire‐resistance of the copolyimides was evaluated by determining their limiting oxygen index (LOI) value. Copolyimides that contained about 3% phosphorus showed an LOI value approximately 30% higher, than the value of the corresponding common polyimides. In addition, a model diamic acid and diimide was synthesized by the reaction of 1‐[di(2‐chloroethoxyphosphinyl)methyl]‐2,4‐ and ‐ 2,6‐diaminobenzene (DCEPD) with phthalic anhydride and characterized by elemental analysis, IR, proton nuclear magnetic (1H‐NMR) spectroscopy, DSC, and TGA. The pyrolysis behavior of the model compounds was investigated by gas chromatography‐mass spectrometry (GC‐MS). A direct cleavage of the PC bond and a possible rearrangement to diisocyanates occurred during their pyrolysis.
Anionic polymerization of norbornene trisulfide (exo‐3,4,5‐trithia‐tricyclo[5.2.1.02.6]decane)
Authors: Baran Teresa , Duda Andrzej , Penczek Stanisław 
Published: April 2003

AbstractThe anionic polymerization of norbornene trisulfide initiated with sodium thiophenoxide (sodium cation solvated with dibenzo‐18‐crown‐6 ether) was studied. Polymers with high molecular weights were obtained (Mn up to 105, osmometrically). Molecular weights calculated for living polymerization conditions (i.e., one molecule of initiator yields one macromolecule) agree well with Mn measured by osmometry. 1H‐NMR, 13C‐{1H}‐NMR, and Raman spectra of the polymer are given. Thermodynamics of polymerization in toluene solvent is described. Enthalpy ΔHss = −(1.39 ± 0.17) kcal mol−1 and entropy ΔSss = −(7.52 ± 0.55) cal mol−1 deg−1 coefficients of polymerization were evaluated from the temperature dependence of the equilibrium monomer concentration determined dilatometrically.
Fire‐ and heat‐resistant polymer based on maleimido‐substituted 2,2‐bis(anilino)‐4,4,6,6‐tetrakis‐(4‐aminophenoxy)‐cyclotriphosphazene
Authors: Kumar Devendra , Fohlen George M. , Parker John A. 
Published: April 2003

AbstractA fire‐ and heat‐resistant polymer was obtained by the thermal polymerization of bismaleimido‐substituted 2,2‐bis(anilino)‐4,4,6,6‐tetrakis‐(4‐Aminophenoxy)‐cyclotriphosphazene. The thermal stabilities of the polymer were evaluated in nitrogen and in air by thermogravimetric analysis. This polymer was stable to 345°C and had char yields of 78% at 800°C in nitrogen and of 71% at 700°C in air. The structures of cyclotriphosphazene precursors and the polymer were characterized using Fourier‐transform infrared and proton nuclear magnetic resonance spectroscopy.
Living reversible anonic polymerization of N,N‐diethylamine‐1,3,2‐dioxaphosphorinan
Authors: Pretula Julia , Kałużyṅski Krzysztof , Penczek Stanisław 
Published: April 2003

AbstractPolymerization of the cyclic amide of PIII is described for the first time. The N,N‐diethylamine‐1,3,2‐dioxaphosphorinan was shown to give living reversible polymerization with anionic initiators. Lithium and sodium derivatives were found to be inactive. 1H‐, 13C‐, and 31P‐NMR indicated that the polymer strictly reflects the monomer structure and is formed without any isomerization, the polymer chain being $\rlap{--} ({\rm OP}\left( {{\rm NR}_{\rm 2} } \right){\rm O(CH}_{\rm 2} \rlap{--} )_3 )_n $. Initiation involves attack of the anion on the P atom. From the dependence of the equilibrium monomer concentration on temeprature ΔH1s = 1.5 ± 0.2 kcal·mol−1 and ΔS1s = 4.6 ± 0.6 cal·mol−1·°K−1.
Preparation and properties of high transition temperature aromatic polyphosphonates by phase‐transfer‐catalyzed polycondensation of phenylphosphonic dichloride with bisphenols
Authors: Imai Yoshio , Kamata Hiroshi , Kakimoto Masa‐Aki 
Published: April 2003

AbstractAromatic polyphosphonates of high molecular weights were prepared from phenylphosphonic dichloride and bisphenols having rigid ring structures by the two‐phase polycondensation in organic solvent–aqueous alkaline solution system with phase‐transfer catalyst at 0°C or below. The effects of reaction solvent and catalyst on the inherent viscosities of the polymers formed are studied. The glass transition temperatures of the polyphosphonates with biphenyl, phenylindane, and diphenylfluorene units are 120, 124, and 188°C, respectively. These polymers are self‐extinguishing and are readily soluble in solvents such as N,N‐dimethylacetamide, pyridine, tetrahydrofuran, and chloroform. They began to lose weight above 300°C in air. Copolyphosphonates from combinations of bisphenols and phenylphosphonic dichloride are also prepared and characterized.
Photochromism of 4‐acryloxyazobenzene/(−)‐menthyl acrylate copolymers
Authors: Altomare A. , Carlini C. , Ciardelli F. , Solaro R. , Rosato N. 
Published: April 2003

AbstractCopolymers of trans‐4‐acryloxyazobenzene (AAB) with (−)‐menthyl acrylate (MtA) have been prepared by free radical initiation; comonomer reactivity ratios have been found to be rAAB = 0.89 and rMtA = 0.53. Dependence of chiroptical properties on copolymer composition has been investigated and contribution to circular dichroism by azobenzene chromophores of isolated and sequence AAB units, as well as the influence of the trans to cis photoisomerization, have been determined. Kinetics of photoinduced trans → cis and thermally induced cis → trans isomerization of azobenzene side chains have also been examined and the kinetic parameters evaluated with relation to copolymer structure. The results have been discussed in terms of light‐induced secondary structure reversible modifications.
Functional metal‐porphyrazine derivatives and their polymers. VIII. Catalase‐like activity of Fe(III)‐ and Co(II)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene)
Authors: Shirai H. , Higaki S. , Hanabusa K. , Kondo Y. , Hojo N. 
Published: April 2003

AbstractThe decomposition reaction of hydrogen peroxide by Fe(III)‐ and Co(III)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene) and the quaternized one, was studied at pH 7.0 in aqueous media. The kinetics of this reaction was also investigated at pH 7.0 by measuring the initial velocity V0 of the increasing concentration of O2 with a Warburg respirometer. The reaction proceeded according to the catalaselike mechanism. Fe(III)‐2,9,16,23‐tetracarboxyphthalocyanine supported on poly(2‐vinylpyridine‐CO‐styrene) was a remarkably effective catalyst for a H2O2 decomposition reaction. The coordination sphere around the Fe(III)‐phthalocyanine ring was characterized by electronic and ESR spectroscopy. Fe(III)‐phthalocyanine supported on the copolymer dispersed in water was the five‐coordinated, high‐spin type. A typical competitive inhibition in respect of H2O2 by CN‐ was observed. ESR spectrum of this system showed the low spin iron(III) in the octahedral ligand field. The polymer coils hindered undesirable dimerization of metal‐phthalocyanine molecules by the shielding effect.
Graft polymerization of acrylic monomers onto starch fractions. III. Effect of carbohydrate structure
Authors: Goñi I. , Gurruchaga M. D. , Valero M. , Guzman G. M. 
Published: April 2003

AbstractGrafted PMMA was isolated by the acid hydrolysis method. Weight‐average and number‐average molecular weights were determined by gel permeation chromatography. The number‐average molecular weight of the grafted chains was about 475,000 for amylopectin and 403,000 for amylose. The number of grafted chains (mmol) ranged from 2.4 × 10−3 to 4.6 × 10−3 for amylopectin graft copolymers and from 2.9 × 10−3 to 6.8 × 10−3 for those of amylose. These results were related to others obtained from ceric ion consumption studies. The values suggest that amylopectin, because of its complex structure, favors a higher consumption of ceric ion in homopolymerization reactions and inhibits the initiation reactions of the copolymerization.
Functionalization of an amorphous ethylene‐propylene copolymer by free radical initiated grafting of unsaturated molecules
Authors: De Vito G. , Lanzetta N. , Maglio G. , Malinconico M. , Musto P. , Palumbo R. 
Published: April 2003

AbstractFunctionalization of an amorphous ethylene‐propylene copolymer, EPM, has been performed by means of homogeneous grafting reactions of unsaturated molecules such as dibutylmaleate, diethylfumarate, itaconic anhydride, and maleic anhydride, initiated by free radicals. Dicumylperoxide and dibenzoylperoxide have been used as a free radical source and their efficiency has been compared. A different reactivity of the unsaturated molecules has been evidenced. The influence of the nature of the solvent on the functionalization degree has been investigated, revealing a noticeable effect of the solvent either on the amounts of grafted molecules or on the secondary reactions which lead to partial degradation of the functionalized EPM chains.
The preparation and characterization of homogeneous copolymers of ethylene and 1‐alkenes
Authors: Hunter B. K. , Russell K. E. , Scammell M. V. , Thompson S. L. 
Published: April 2003

AbstractHomogeneous copolymers of ethylene and 1‐alkenes have been prepared using an ethyl aluminum sesquichloride–vanadium oxychloride catalyst system. Branches were varied from CH3 to C16H33 by appropriate choice of 1‐alkene. Size exclusion studies of copolymers of ethylene‐d4 and 1‐alkenes show that the comonomer content of a given sample is essentially constant over the whole molecular weight range. A random distribution of branches is inferred from the simplicity of the 13C‐NMR spectra and from the melting behaviour of the copolymers. Comonomer contents varying from 1 mol% to 15 mol% were readily determined by 13C‐NMR spectroscopy. The copolymers can be used to study the separate effects of branch length, branch frequency, and molecular weight on physical properties including melting point and crystallinity.
Addition polyimides. III. Thermal behavior of bismaleimides
Authors: Varma I. K. , Sangita  , Varma D. S. 
Published: April 2003

AbstractThis article describes the synthesis of N,N′‐bis(3,3′‐maleimidophenyl) sulfone (S) and its Michael addition products with (4,4′‐diaminodiphenyl) methane (S‐M), 4,4′‐diaminodiphenyl ether (S‐E), (3,3′‐diaminodiphenyl) sulfone (S‐DDSm), (4,4′‐diaminodiphenyl) sulfone (S‐DDSp), (3,3′,3″‐tris aminophenyl) phosphine oxide (S‐TAP), and 9,9‐bis(p‐aminophenyl) fluorene (S‐B). Curing behavior of these bisimides was investigated by differential scanning calorimetry. Activation energy of curing reaction was determined by using isothermal and multiple heating rate method. Thermal stability of bisimides was evaluated by thermogravimetric analysis. Better char yields were obtained in S‐TAP resins.
Molecular weight phenomena at high conversions in the Ziegler–Natta polymerization of butadiene
Authors: Honig J. A. , Burford R. P. , Chaplin R. P. 
Published: April 2003

AbstractA Comparison between two different feedstocks in the homogeneous polymerization of butadiene has been conducted. The conversion and molecular weight trends were essentially the same for both feedstock systems. Changes in polydispersity at high conversions could not be explained by a living polymerization mechanism. A reaction scheme involving reuse of active cobalt centres combined with termination has been proposed.
The crosslinking of epoxy resins at interfaces. I. Germanium, germanium dioxide, and silane‐treated germanium
Authors: Garton Andrew 
Published: April 2003

AbstractThe chemical changes that accompany the crosslinking of an epoxy resin by an anhydride curing agent were followed by internal reflection spectroscopy (IRS). The crosslinking process was carried out on the surface of a germanium IRS element and the effects of various surface treatments of the germanium (humid aging, oxidation, and silane coating) on the reaction kinetics were examined. The reaction kinetics in the first 3000–4000 Å of the resin adjacent to dry, freshly polished germanium were similar to the reaction kinetics in the bulk of the resin. However, humid aging or oxidation of the germanium surface produced a local acceleration in the rate of anhydride consumption and reduced the yield of ester products. The aminosilane coating accelerated the consumption of anhydride, decreased the yield of ester, and resulted in the formation of amide groups in the interfacial region.