bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel photoinitiator of cationic polymerization: Preparation and characterization of bis [4‐(diphenylsulfonio)phenyl]sulfide–bis‐hexafluorophosphate
Authors: Watt W. R. , Hoffman H. T. , Pobiner H. , Schkolnick L. J. , Yang L. S. 
Published: April 2003

AbstractEfforts to prepare triphenylsulfonium hexafluorophosphate by metathesis between commercially available “triphenylsulfonium chloride” and potassium hexafluorophosphate failed to yield the expected product but gave, instead, in approximately 50% yield, a crystalline substance with well‐defined properties readily distinguishable from triphenylsulfonium hexafluorophosphate. The unexpected substance is identified as bis‐[4(diphenylsulfonio)phenyl]sulfide–bis‐hexafluorophosphate, for which no previous reference has been found in the literature. Its identification is based on elemental analysis, NMR, mass spectrometry, and infrared analysis. Bis‐[4‐(diphenylsulfonio)phenyl]sulfide–bis‐hexafluorophosphate was also prepared by the reaction of benzene with sulfur monochloride in the presence of aluminum chloride and chlorine, followed by addition of potassium hexafluorophosphate. The product is an effective photonitiator for the crosslinking of epoxide resins.
Effect of γ radiation on certain non‐newtonian fluids
Authors: Roshdy M. H. , Haridi M. T. , Ibrahim I. A. , Yaacoub M. Sh. 
Published: April 2003

AbstractThe radiation degradation of viscoelastic solutions of a dialkyl monohydroxy aluminum polymer compound (AIR2OH)x is investigated. Radioactive cobalt‐60 is chosen for irradiation experiments. The viscosity of the polymer in six different solvents is measured after irradiation using a capillary viscometer at room temperature (25°C). The degradation effects on both the radiation dose and the solvent used.
Two‐component interpenetrating polymer networks (IPNs) from polyurethanes and epoxies. II. Effect of different charge groups in polyurethanes and epoxies on properties and morphologies of two‐component IPNs
Authors: Cassidy Edward F. , Xiao Han X. , Frisch Kurt C. , Frisch Harry L. 
Published: April 2003

AbstractTwo‐component interpenetrating polymer networks (IPNs) that contained charge groups in the backbones of the polyurethane and epoxy networks were studied. IPNs that contained opposite charge groups, similar charge groups, no charge groups, and corresponding pseudo‐IPNs were prepared. A comparison of mechanical properties, water‐resistance data, mechanical spectra, and electron microscopy showed that improved properties and morphologies resulted in IPNs that contained opposite charge groups. Presumably, interactions between the opposite charge groups in the constituent networks resulted in a forced compatibility between the two polymers which decreased the degree of phase separation.
Stereospecific polymerization of some methyl aryloxymethacrylates
Authors: Balakrishnan T. , Devarajan R. , Santappa M. 
Published: April 2003

AbstractBy exposure to ultraviolet and gamma radiation and by the usual methods of thermal polymerization, the stereospecific polymerization of methyl aryloxymethacrylates was carried out at different temperatures in several solvents. Triad tacticity values of the polymers obtained by free‐radical and ionic routes were computed from nuclear magnetic resonance spectral data. Results of this investigation support our earlier observationSee: K. Saunders, T. Balakrishnan, R. W. Lenz, and K. Hatada, Macromolecules, 12, 392 (1979).
that, under the conditions used, heterotactic content is the maximum in most of these polymers, thereby justifying the high steric effect of the bulky and polar aryloxy side chain which offers equal isotactic and syndiotactic placements.
Improved acetone‐adduct and acetylene‐terminated quinoxaline oligomers
Authors: Lin See , Marvel C. S. 
Published: April 2003

AbstractA series of acetone‐adducts of acetylene‐terminated quinoxaline oligomers and polymers was synthesized by using 3‐(4‐ethynylphenoxy) benzil as endcapping agent for possible adhesives in airplane manufacturing.
Preparation and properties of N‐phenylated aromatic polyamide‐esters from anilinophenols and aromatic diacid chlorides
Authors: Imai Yoshio , Kakimoto Masa‐Aki , Hamaoka Nobuo 
Published: April 2003

AbstractN‐Phenylated aromatic polyamide‐esters with high molecular weights were synthesized by the high‐temperature solution polycondensation in nitrobenzene at 200°C from combinations of m‐ and p‐anilinophenol and isophthaloyl and terephthaloyl chloride. Reaction variables such as monomer concentration, solvent, temperature, and time were studied to optimize the reaction conditions for the preparation of high molecular weight polymers. Some of the N‐phenylated aromatic polyamide‐esters have glass transition temperatures around 190°C and good solubility in chlorinated and amide solvents. These polymers gave transparent flexible films by solution‐casting. Copolymers from p‐anilinophenol and the two diacid chlorides were also synthesized and characterized.
Conformation of poly(S‐(2‐N‐carbazolylethyl)‐L‐cysteine) in the solid state
Authors: Oshima Ryuichi , Wada Tatsuo , Kumanotani Ju 
Published: April 2003

AbstractThe β‐forming characteristics of poly(S‐(2‐N‐carbazolylethyl)‐L‐cysteine), (CELC)n, were examined by infrared (IR) spectroscopy. The film of (CELC)39 cast from tetrahydrofuran (THF) showed the typical spectrum of the antiparallel β‐form with the amide I band at 1630 cm−1, whereas that of (CELC)200 from dimethylformamide (DMF) or pyridine exhibited the amide I band at 1640 cm−1 which shifted to 1630 cm−1 on heating at 100°C for 5 min. As a result of the examination of the spectral variation due to the degree of polymerization, casting solvents, casting temperatures, and heat treatment, together with the evaluation of interaction constants for intermolecular hydrogen bonds, the band at 1640 cm−1 was attributed to the antiparallel‐chain pleated sheet (designated as β′‐form) with weaker hydrogen bond strength than that of the usual antiparallel β‐form. The β′‐β‐transformation is discussed in terms of the rigidity of the side‐chain region.
Substituent effects of methoxy, methyl, and vinyl groups on glow discharge polymerization
Authors: Inagaki N. , Koyama M. , Igaki H. 
Published: April 2003

AbstractGlow discharge polymerizations in systems of trimethoxymethylsilane, trimethoxyvinylsilane, tetramethylsilane, and trimethylvinylsilane were compared by elemental analysis, infrared (IR) spectroscopy, and ESCA to reveal effects of methoxyl, methyl, and vinyl substituents. The substituent effects appeared in the chemical composition of the polymers formed especially at low W/FM values. Methoxy groups depressed the C/Si and H/Si ratios of the polymers rather than the methyl groups, whereas vinyl groups increased the C/Si and H/Si ratios. On IR spectra the polymers formed from silanes that contained methoxy groups showed fewer absorptions due to SiH groups and strong absorptions due to SiOH groups. The polymers from those that contained no methoxy groups showed absorptions of SiH groups and no absorptions of SiOH groups. These differences in the environment of Si atoms of polymeric chains also appeared in the Si2p core level spectra, thus indicating the different fragmentation patterns of the starting materials in glow discharge.
An MNDO SCF MO investigation of some structural isomers of the perfluoro diazines (pyrimidine, pyrazine, and pyridazine) of relevance to their plasma polymerization
Authors: Clark D. T. , Johnson S. A. , Brennan W. J. 
Published: April 2003

AbstractExtensive MNDO SCF MO calculations were made to determine the heats of formation of the ground state of geometry‐optimized perfluorodiazabenzenes (pyridazine, pyrimidine, and pyrazine) and some of their structural isomers (Dewar benzene, benzvalene, prismane, fulvene, and hexadienyne). The heats of formation of the cation, singlet, and triplet states, were derived for the ground‐state geometry of 1,3‐diaza isomers to gain some insight into the excited state manifolds. These results were used to interpret various experimental observations that relate to the plasma polymerization of the diazines. In particular, the interconversion of the parent heteroaromatic, the relative energies of interconversion and polymerization, and the possibility of the elimination of a small stable molecule were considered. Comparison is made with results reported for the tetrafluorobenzenes.
Selective separation of water–alcohol binary mixture through poly(maleimide‐co‐acrylonitrile) membrane
Authors: Yoshikawa Masakazu , Yokoi Hideto , Sanui Kohei , Ogata Naoya 
Published: April 2003

AbstractSeparation of various alcohols and water through a membrane was carried out by means of a hydrogen‐bonding interaction. A membrane obtained from poly(maleimide‐co‐acrylonitrile) was effective for a selective separation of water from aqueous alcohol solution by pervaporation technique. Spectroscopic analyses verified that this high selectivity was attributed to the hydrogen‐bonding interaction between water and maleimide units in the membrane.
Polymer‐ bound flavins. III. Effects of coil dimension and substrate structure on reaction kinetics in water/2‐propanol mixtures
Authors: Bootsma Jan P. C. , Rupert Leo A. M. , Challa Ger , Müller Franz 
Published: April 2003

AbstractThe strong influence of medium composition (water/2‐propanol mixtures) on the rate of oxidation of 1‐substituted dihydronicotinamides by a flavin‐containing polyelectrolyte was studied. We found that the coil dimensions of the corresponding copolymer of styrene and vinylbenzyltriethylammoniumchloride without flavin groups dramatically depend on the solvent. Viscometric measurements revealed compact coil conformations in solvents of both high water and high 2‐propanol content, but pronounced coil expansion in intermediate mixtures. These changes of polyelectrolyte coil dimensions are related to changes in electrostatic potential of the microreactors. Addition of 2‐propanol also results in decrease of substrate enrichments, caused by weakening of nonpolar polymer–substrate interactions, as was demonstrated for 1‐carbamoylmethyl‐, 1‐benzyl‐, and 1 decyl‐substituted 1,4‐dihydronicotinamide substrates. The enormous decrease in rate constant for oxidation of DNAH by 2 upon increasing the 2‐propanol content from 10 to 40% (v/v), from k = 3120 to 21 M−1 s−1, can thus be explained as a cooperation of both effects. Evidence for the formation of a charge transfer complex between the polyelectrolyte‐bound flavin and the dihydronicotinamide having a long‐wavelength absorption is also presented.
Radical‐initiated homo‐ and copolymerization of methoxymethyl methacrylate
Authors: Ueda Mitsuru , Ishibashi Setsuo , Suzuki Toshiyuki , Masuko Toru , Pittman Charles U. 
Published: April 2003

AbstractThe kinetics of methoxymethyl methacrylate (MOMA) homopolymerization has been investigated in benzene, using azobis(isobutyronitrile) as an initiator. The rate of polymerization (Rp) could be expressed by Rp = k[AIBN]0.5 [MOMA]1.19. The overall activation energy was calculated to be 73.2 kJ/mol. Kinetic constants for MOMA polymerization were obtained as follows: kp/kt1/2 = 0.091 L1/2 · mol−1/2 · s−1/2; 2fkd = 1.37 × 10−5 s−1. The values of K and a in the Mark–Houwink equation, [η] = KMa, where K = 5.89 × 10−5 and a = 0.82 when M = Mn and the solvent was benzene. The relative reactivity ratios of MOMA (M2) copolymerizations with styrene (r1 = 0.40, r2 = 0.58) were obtained. Applying the Q‐e scheme led to Q = 0.78 and e = 0.67. The glass transition temperature (Tg) of poly(MOMA) was observed to be 64°C by DSC. Thermogravimetry of poly(MOMA) showed a 10% weight loss at 230°C in air.
13C nuclear magnetic resonance studies of cellulose acetate
Authors: Miyamoto T. , Sato Y. , Shibata T. , Inagaki H. , Tanahashi M. 
Published: April 2003

Abstract13C‐NMR spectra of ring carbons and O‐acetyl carbonyl carbons of cellulose acetate (CA) in dimethyl sulfoxide‐d6 were analyzed. The CA samples with the degree of substitution (DS) ranging from 0.84 and 1.91 were prepared by homogeneous acetylation of cellulose with acetic anhydride in a 10% LiCl/dimethyl acetamide solvent. It was found that the use of these low DS samples permitted easier assignments not only of the ring carbon but also of the O‐acetyl carbonyl carbon signals. The assignments were confirmed by comparing with the 1H‐NMR spectra of the samples obtained by complete acetylation of the corresponding CA samples with acetyl‐d3 chloride. Two methods for determining the distribution of O‐acetyl groups of CA, i.e., the relative DS at the three different types of hydroxyl groups, were developed. One is based on the measurements of the relative intensities of the signals for the ring carbons and the other is based on the measurements of the relative intensities of the signals for the O‐acetyl carbonyl carbons.
Direct synthesis of polyamides by N‐acyl phosphoramidites
Authors: Kawanobe Wataru , Yamaguchi Kazuo , Rokicki Gabriel , Mei Sha Kei , Yamazaki Noboru , Nakahama Seiichi 
Published: April 2003

AbstractA variety of N‐acyl phosphoramidites were prepared from chlorophosphites and amide derivatives, and their structures were determined with the aid of 1H‐, 13C‐, and 31P‐NMR, and IR spectroscopies. These phosphoramidites were employed in direct polycondensation reaction of dicarboxylic acids and diamines under various conditions resulting in polyamides with inherent viscosities of 0.1 to 1.13. The best results were obtained when aliphatic dicarboxylic acids and aromatic diamines were condensed by 2‐(N‐methylacetamido)‐1,3,2‐dioxaphospholane in nitriles.
Synthesis of functionalized linear poly(divinylbenzene). II. Synthesis of poly(divinylbenzene) with hydroxyl pendants and/or endgroups
Authors: Aoshima Sadahito , Higashimura Toshinobu 
Published: April 2003

AbstractPoly(divinylbenzene) [poly(DVB)] derivatives having hydroxyl terminals and/or pendants were synthesized by chemical modifications (hydration and hydroxylation) of unsaturated linear poly(DVB) (I), which was prepared by the polymerization of DVB catalyzed by acetyl perchlorate. Hydroboration of both terminal and in‐chain carbon–carbon double bonds in I with BH3.THF complex yielded a fully hydrated poly(DVB) II, in which hydrophilic and hydrophobic groups are placed alternately. Selective hydroboration of the vinyl endgroups in I with 9‐borabicyclo[3.3.1]nonane led to an α,ω‐dihydroxy‐poly(DVB) (III). Reaction of I with m‐chloroperbenzoic acid gave fully epoxidated poly(DVB) IV, which was subsequently hydrated to yield polymer V consisting of glycol repeat units and terminals. The physical properties and reactions (chain extension and crosslinking) of these polymers were also studied.
Poly(alkylene oxide) ionomers VIII. Synthesis of methyl ω‐alkenoates and methyl ω‐epoxyalkanoates
Authors: Muggee John , Vogl Otto 
Published: April 2003

Abstractω‐Alkenoic acids, either commercially available or synthesized, were esterified to their corresponding methyl esters. They were characterized by their infrared, 1H‐, and 13C‐NMR spectra. The ω‐alkenoates prepared were: propenoate (acrylic acid), butenoate, pentenoate, hexenoate, heptenoate, octenoate, nonenoate, and decenoate. These compounds were epoxidized with m‐chloroperoxybenzoic acid to the corresponding methyl ω‐epoxyalkanoates. The rate of epoxidation of the double bond is found to increase as the double bond is separated from the carbomethoxy group by increasing numbers of methylene groups. When at least three methylene groups are inserted, the rate of epoxidation becomes constant and is similar to the epoxidation of ω‐olefins. The methyl ω‐epoxyalkanoates were characterized by their infrared, 1H‐, and 13C‐NMR spectra. Methyl ω‐alkenoates and methyl ω‐epoxyalkanoates were prepared and characterized, and their purification was studied in preparation for their investigation as monomers for olefin or epoxide polymerization using corrdination initiators.
Controlled release by polyelectrolyte microcapsule membranes
Authors: Tsai Ming‐Fu , Levy Moshe 
Published: April 2003

AbstractPolyelectrolyte submicron microcapsules were prepared by interfacial crosslinking of an aqueous salt solution of poly(ethyleneimine) and a toluene solution of brominated poly‐(2,6‐dimethylphenylene oxide). The two solutions were brought together and mixed by sonication. As a result, a stable emulsion was obtained, which was subsequently cast into a membrane in which the microcapsules were embedded. The salt solution contained in the microcapsules could be released under controlled conditions. The rates of release were measured. They could be controlled by applying osmotic pressures, by additional quaternization of the membrane, or by modification of the structure of the capsule wall by introduction of a surfactant.
An ESCA study of the inductively coupled RF plasma polymerisation of 2,4,6‐trifluoro‐1,3,5‐triazine
Authors: Munro H. S. , Allaker R. S. , Clark D. T. , Recca A. 
Published: April 2003

AbstractESCA has been used to investigate the composition and structural features of plasma‐polymerized 2,4,6‐trifluoro‐1,3,5‐triazine. Polymer formation was studied as a function of power and post‐polymerisation treatment. All the polymer films revealed an intense peak at a binding energy of ∼290.2 eV probably arising from groups. A high sensitivity towards hydrolysis was observed resulting in substantial loss of fluorine and increase in oxygen content of the plasma polymers.
Grafting onto cellulose. VIII. Graft copolymerization of poly(ethylacrylate) onto cellulose by use of redox initiators. Comparison of initiator reactivities
Authors: Misra B. N. , Mehta I. K. , Khetarpal R. C. 
Published: April 2003

AbstractIn an attempt to compare the relative reactivities of different redox systems in graft copolymerization of vinyl monomers onto cellulose, we studied grafting of ethylacrylate (EA) in aqueous medium by using the well‐known redox intiator, ferrous ammonium sulfate–potassium persulfate (FAS–KPS) system, and its reactivity was compared with that of Fenton's reagent (Fe2+ −H2O2) towards grafting of EA onto cellulose. Optimum conditions for affording maximum grafting were evaluated and percent grafting is expressed as functions of different reaction variables. Evidence of grafting was obtained from IR spectroscopic measurements, SEM, and TGA studies of the grafted and ungrafted cellulose. A plausible explanation for the observed reactivity pattern shown by (FAS–KPS) and (FAS–H2O2) redox systems is offered. Fenton's reagent (Fe2+ −H2O2) was found to be several times more reactive than (FAS–KPS) redox system.
Synthesis and polymerization of optically active N‐α‐methylbenzylmaleimide
Authors: Oishi Tsutomu , Fujimoto Minoru 
Published: April 2003

AbstractOptically active N‐α‐methylbenzylmaleimide (MBZMI) was prepared with maleic anhydride and d‐(+)‐α‐methylbenzylamine. The polymerizations of MBZMI were carried out with α,α′‐azobisisobutyronitrile (AIBN) and n‐butyllithium (n‐BuLi) in tetrahydrofuran (THF). The specific rotations of the polymers obtained by AIBN and n‐BuLi initiator were +11.1° to +13.0° and −57.0° to −89.2°, respectively. The weight‐average molecular weights (Mw) for the polymers were between 4200 and 8000. Furthermore, MBZMI was copolymerized with styrene (ST) and methyl methacrylate (MMA) with AIBN in THF at 50°C to obtain optically active copolymers. The monomer reactivity ratios of MBZMI (M1) with ST (M2) were obtained as r1 = 0.027, r2 = 0.094 in the MBZMI–ST and r1 = 0.15, r2 = 1.54 in the MBZMI–MMA system. The Q‐e values for MBZMI were Q1 = 0.78, e1 = 1.62. All the polymers and copolymers were found to show a weakly negative circular dichroism (CD) peak at about 250 nm and a strongly positive CD peak at about 220 nm.
Compatibility in poly(ethylene oxide)–poly(methyl methacrylate) blends
Authors: Liberman Susana A. , Gomes Ailton De S. , Macchi Edgardo M. 
Published: April 2003

AbstractThe compatibility of poly(ethylene oxide)‐poly(methyl methacrylate) (PEO‐PMMA) blends were examined covering the complete composition range. Up to 20% of PEO content films were transparent and glass transition temperatures were determined by DSC and by refractive index vs. temperature measurements. Only one Tg was obtained for these samples and the relationship between Tg and composition has been evaluated. At higher PEO content crystallization took place and the films were opaque. Melting temperatuures of PEO in blends were determined by DSC. Melting point depression was observed for increasing proportion of PMMA and the binary interaction parameter has been calculated.
A convenient photochemical method to immobilize enzymes
Authors: Ichimura Kunihiro 
Published: April 2003

AbstractA method to immobilize enzymes photochemically with use of photocrosslinkable poly(vinylalcohol) bearing stilbazolium groups is described. Irradiation of a film of the photosensitive polymer containing enzyme gave water‐insoluble, cellophane‐like transparent film demonstrating high enzyme activity. The dissolution of enzymes from the film was dependent upon the molecular weight of the proteins and the content of the photocrosslinking unit. It was found that various enzymes are sufficiently entrapped in the photocrosslinked polymer matrix when the content of the photosensitive group is more than about 1.0 mol%.
Superacid polymers from sulfonated poly(styrene‐divinylbenzene): Preparation and characterization
Authors: Dooley K. M. , Gates B. C. 
Published: April 2003

AbstractSuperacid polymers were prepared by bringing metal halides (AlCl3, SnCl4, TiCl4, BF3, or SbF5) in contact with macroporous sulfonic acid resins [sulfonated, crosslinked poly(styrene‐divinylbenzene)]. The resulting solids were characterized by chemical analysis, temperature‐programmed desorption, transmission electron microscopy, and X‐ray photoelectron spectroscopy. They were also tested as catalysts for n‐butane isomerization at 0.5 bar and 60 to 120°C. The polymers consist of supported metal oxyhalide particles, complexes of metal oxyhalides and sulfonate groups, and the remaining unreacted sulfonic acid groups. In the presence of HCl, these polymers were highly active catalysts for the butane isomerization reaction, the activity being a consequence of a high proton‐donor strength inferred to be associated with H2Cl+ groups stabilized on the polymer surface by negative charge delocalization over sulfonate–metal oxyhalide sulfonate groups.
Polyelectrolyte influences on the trans–cis isomerization of sodium m‐(4‐ethoxyphenylazo)benzene sulfonate
Authors: Ishiwatari Tsutomu , Tsuji Tadashi , Aoshima Kazuyuki , Mitsuishi Masaru 
Published: April 2003

AbstractInfluences of microenvironment of various polyelectrolytes, i.e., ionene polymers and polyamine sulfones, on the photo‐ and/or thermal isomerization between the trans and cis forms of sodium m‐(4‐ethoxyphenylazo)benzene sulfonate (SEPS) were studied. 6,6‐Ionene demonstrated larger enhancing effect on the cis–trans thermal isomerization than 3,3‐ionene, which indicated that the micropolarity or the pH around the polymer is important. In the Arrhenius plots for both photo‐ and thermal isomerizations, deviations from the linearity were observed. In the former case, a sharp bend and the negative apparent activation energy were obtained at the high temperature. Furthermore, they were sensitively affected by the polyelectrolytes.
A study of the mechanism of photocrosslinking polymers by quinones
Authors: Cha Younsik , Tsunooka Masahiro , Tanaka Makoto 
Published: April 2003

AbstractPhotocrosslinking of poly(methyl methacrylate) (PMMA) was studied in the solid state in the presence of various quinones. For the study of photocrosslinking mechanism, a PMMA film containing p‐benzoquinone (Q) was irradiated with UV light (λ > 370nm) and then purified by reprecipitation. It was found that the reprecipitated polymer has quinone‐type moieties, besides the hydroquinone‐type moieties, chemically bound to the polymer chain. The reprecipitated polymer film also crosslinking efficiency was higher than that of PMMA film containing Q. It was concluded that the formation of quinone‐type structure during irradiation played an important role in the photocrossing of PMMA containing Q.