bluuebunny/crossref_metadata_2025_split huggingface dataset:
Graft copolymerization of anhydro sugar derivatives from macromolecular halides
Authors: Uryu Toshiyuki , Hagino Arata , Terui Keiko , Matsuzaki Kei 
Published: April 2003

AbstractCationic graft copolymerizations of bicyclic acetals, 1,6‐anhydro‐2,3,4‐tri‐O‐benzyl‐β‐D‐glucopyranose (LGTBE) and 1,6‐anhydro‐2,3,4‐tri‐O‐methyl‐β‐D‐glucopyranose (LGTME), were investigated with macromolecular carbenium ions formed from polymers that contain reactive halogens. Macromolecular complex catalysts formed from chlorosulfonated polyethylene or poly(isoprene‐co‐chloromethylstyrene) by the action of phosphorus pentafluoride yielded graft copolymers with low proportions (0.6–16%) of poly(LGTBE) or poly(LGTBE‐co‐epichlorohydrin) branchings. It was found that macromolecular complex catalysts formed from poly(styrene‐co‐fluoromethylstyrene) or poly(methyl methacrylate‐co‐fluoromethylstyrene) by the action of boron trifluoride etherate give graft copolymers with high proportions (up to 80%) of poly(LGTBE) or poly(LGTME) branchings. In addition, the model reactions for the graft copolymerization of LGTBE were examined with organic halide‐PF5, organic halide‐AgPF6, and organic fluoride‐BF3·OEt2 catalytic systems, of which the last two indicate that the polymerization is effected by a carbenium ion mechanism.
Polymer adsorption on platinum: Surface coverage determination using iodide‐125
Authors: Ellis Tamir M. , Van De Mark Michael R. 
Published: April 2003

AbstractAdsorption of iodide‐125, a γ emitter, was used as a quantitative methodology for polymer adsorption surface coverage analysis. Adsorption of I‐125 on clean platinum produced surface elemental ratios of I:Pt of 1:4. The technique was applied to the adsorption of polyethylene glycol terephthalate from trifluoroacetic acid on platinum flags with a 2‐cm2 surface area. This polymer adsorption is approximated by a logarithmic relationship similar to the Temkin isotherm. Polymer coverage attained up to 99.6% of the surface.
Vinyl polymerization. 403. Polymerization of vinyl monomer initiated with sodium poly‐p‐vinylphenolate
Authors: Ouchi Tatsuro , Inamura Masaharu , Kobayashi Akinobu , Imoto Minoru 
Published: April 2003

AbstractThe polymerization of vinyl monomer initiated by poly‐p‐vinylphenol (PVPh) in NaOH aqueous solution was carried out at 85°C with shaking. Methyl methacrylate (MMA) was polymerized, whereas styrene and acrylonitrile were not. PVPh, which is dissociated into phenolate form (PVPh−Na+) in NaOH aqueous solution, was effective for the polymerization. The effects of the amounts of MMA, PVPh, NaOH, and H2O on the conversion of MMA were studied. The rate of polymerization of MMA increased with an increase in the molecular weight of PVPh‐Na. The overall activation energy was estimated as 54 kJ mol−1. The polymerization proceeded through a radical mechanism. The addition of tetra‐n‐butylammonium bromide increased the rate of polymerization.
Molecular weight control in polycondensation of hydroxyl diesters with hexamethylenediamine by polymer matrices
Authors: Ogata Naoya , Sanui Kohei , Tanaka Hozumi , Matsuo Hajime , Iwaki Fusako 
Published: April 2003

AbstractPolycondensation reactions of hydroxyl diesters such as dimethyl tartrate (DMT) and diethyl mucate (DEM) with hexamethylenediamine (HMD) were carried out in the presence of poly(vinyl pyridine) (P‐VPy) and its copolymers with styrene of different compositions as matrix polymers in order to investigate the difference in interaction forces with monomers or the resulting polyamides owing to hydrogen bonding. It was found that matrix effects of poly(4‐vinyl pyridine) (P‐4VPy) on the rate enhancement and solution viscosity of the resulting polyamide became more pronounced with decreasing solvent polarity. This result suggests that the matrix effects of P‐4VPy on polycondensation are due to hydrogen bonding interactions between hydroxyl diesters and P‐4VPy. The addition of P‐4VPy increased the molecular weight of the resulting polyamide to a higher extent than poly(2‐vinyl pyridine) (P‐2VPy), and the molecular weight of the resulting polyamide could be controlled according to the molecular weight of P‐4VPy. Copolymer composition of 4‐vinyl pyridine–styrene (4VPy/St) copolymers as matrix polymers also affected the molecular weight of the polyamide, which increased with increasing P‐4VPy unit contents in the copolymers.
Photoreduction of viologen‐containing vinyl polymers by 2‐propanol
Authors: Furue M. , Yamanaka S. , Phat L. , Nozakura S. 
Published: April 2003

AbstractIn order to study the role of viologen‐containing vinyl polymers in light energy conversion systems, the photoreduction of the polymer by 2‐propanol and the properties of the reduced polymer were studied in comparison with methylviologen. There were marked polymer effects in the initial rate of photoreduction as well as in the absorption spectra of the photoreduced species. Both effects were interpreted in terms of the local concentration effect of viologen units in the photoreduction step. The spectral difference was found to be due to the dimeric association of the reduced viologen units on the polymer.
Plasma polymerization. V. A systematic investigation of the inductively coupled RF plasma polymerization of the isomeric tetrafluorobenzenes
Authors: Clark D. T. , Abrahman M. Z. 
Published: April 2003

AbstractA systematic investigation has been made of the composition, gross structural features, and rates of deposition of plasma polymer films produced from the excitation of inductively coupled RF plasmas in the isomeric tetrafluorobenzenes. ESCA data reveal that the dominant reaction involves rearrangement such that under a wide variety of experimental conditions the composition of the crosslinked products remains essentially the same as that of the starting material. Small differences in rates of deposition are observed for the different isomers, and theoretical SCF MO studies at the MNDO level provides a basis for discussion of the experimental data.
Study of photopolymers. XVI. Novel syntheses of the polymers with azidonitrobenzoyl groups and their photochemical and thermochemical reactions
Authors: Nishikubo T. , Iizawa T. , Imagawa I. , Kobayashi K. 
Published: April 2003

AbstractPoly‐2‐(2‐azido‐5‐nitrobenzoyloxy)ethylmethacrylate (P‐II‐A) and poly‐2‐(4‐azido‐3‐nitrobenzoyloxy)ethylmethacrylate (P‐II‐B) were synthesized from the reactions of 2‐hydroxyethylmethacrylate with 2‐chloro‐5‐nitrobenzoic acid and 4‐chloro‐3‐nitrobenzoic acid, respectively, by substitution reactions of sodium azide with the corresponding chloronitrobenzoyl group. In addition, the degradation reaction of the 2‐azido‐5‐nitrobenzoyl group in P‐II‐A and the transformation of the 4‐azido‐3‐nitrobenzoyl group to 5‐carboxylbenzofurazane‐1‐oxide ring in P‐II‐B by irradiation with ultraviolet (UV) light or by heating were investigated in detail. In the photochemical reaction the reaction of the azide group in P‐II‐A was affected by the presence of a spacer in the polymer chain. Moreover, in the thermochemical reaction the rates of the reactions of azide groups in P‐II‐A and P‐II‐B were controlled by the facility of molecular motion and the conformation of polymer chains.
Cationic polymerizations by aromatic initiating systems. III. Model reactions for initiation and termination using the t‐BuCl/ϕ3Al and Clt‐R‐Clt/ϕ3Al systems
Authors: Kennedy Joseph P. , Chung David Y. L. , Reibel Leonard C. 
Published: April 2003

AbstractPreparatory for the synthesis of terminally functional polyisobutylenes carrying one or two phenyl end groups, model experiments have been carried out using novel tert‐butyl chloride/triphenylaluminum and 2,6‐dichloro‐2,6‐dimethylheptane/triphenylaluminum initiating systems. As anticipated, t‐BuCl was phenylated by ø3Al and the product is tert‐butylbenzene. The reaction is extremely rapid and temperature has little effect on it in the 0 to −60°C range. The interaction between the 2,6‐dichloro‐2,6‐dimethylheptane and ø3Al was found to be complicated by a proximity effect which leads to proton elimination in addition to phenylation. The formation of the desired diterminally phenylated product is not quanititative even at −60°C.
Kinetics of polymerization of acrylonitrile initiated by acidic permanganate/thioacetamide redox system
Authors: Samal Rajani K. , Nayak M. C. , Suryanarayan G. V. , Panda G. , Das D. P. 
Published: April 2003

AbstractThe kinetics of vinyl polymerization of acrylonitrile (AN) initiated by an acidic permanganate/thioacetamide (TAm) redox system have been investigated in aqueous media at 30 ± 0.2°C in nitrogen, and the rate of polymerization measured. The effect of additives like organic solvents, neutral electrolytes, and complexing agents on the rate have been assessed. Based on the experimental results, a suitable reaction scheme involving initiation by organic free radicals generated by the interaction of Mn(IV) with protonated thioacetamide and termination by Mn(III) has been suggested. Various rate and energy parameters have been evaluated.
Aromatic polyamides. I. Synthesis and characterization of some aromatic polyamides and their model diamides
Authors: Khanna Y. P. , Pearce E. M. , Forman B. D. , Bini D. A. 
Published: April 2003

AbstractThe synthesis of some wholly aromatic polyamides based on unsubstituted and chloro‐ and nitro‐substituted diamines by low temperature solution polymerization is described. Poly(1,3‐phenylene isophthalamide) and poly(chloro‐2,4‐phenylene isophthalamide) were selected for further investigation. To study the two polyamides on a systematic basis their model diamides were synthesized. These materials were characterized with respect to chemical structure and purity by elemental analysis, infrared (IR), and nuclear magnetic resonance (NMR) spectroscopic techniques. The usefulness of the model compounds in the interpretation of the polymer spectra is also demonstrated.
Aromatic polyamides. II. Thermal degradation of some aromatic polyamides and their model diamides
Authors: Khanna Y. P. , Pearce E. M. , Smith J. S. , Burkitt D. T. , Njuguna H. , Hindenlang D. M. , Forman B. D. 
Published: April 2003

AbstractThermal degradation behavior of poly(1,3‐phenylene isophthalamide) and poly(chloro‐2,4‐phenylene isophthalamide) was investigated with the aid of some appropriate model compounds. The pyrolysis products of these materials were identified by gas chromatography (GC), gas chromatography/Fourier transform infrared spectroscopy (GC/FT‐IR), and gas chromatography/mass spectrometry (GC/MS). The residual chars were characterized by IR spectroscopy. Thermogravimetric analysis (TGA) was applied to study the effect of end‐group concentration on the degradation characteristics of the two polyamides. Kinetic parameters that describe the thermal degradation of the polyamides were also evaluated by TGA. The results of this investigation suggest that the thermal decomposition of these aromatic polyamides involves homolytic as well as hydrolytic cleavages of the amide units.
Synthesis and properties of poly(dimethylxylylenylamides)
Authors: Rajendran G. P. , Mahadevan V , Srinivasan M. 
Published: April 2003

AbstractPoly(dimethylxylylenylamides) were synthesized from six different diphenylenediamenes and two dimethyl‐substituted xylylenyldiacid chlorides by solution polycondensation at low temperature. The model compound 2,5‐demethyl1,4‐benzediacetanilide was synthesized and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The polyamides were characterized by IR and viscosity measurements. Some of the polyamides showed crystalline behavior in the x‐ray diffractograms. The polyamdes have decomposition temperatures in the range 370–310°C in air and are soluble in all amide solvents. The effects of subsituents on crystallinity, thermal stability, and solubility of the polymides are also discussed.
Catalysis of α,β‐elimination of serine by pyridoxal phosphate–metal‐ion‐quaternized poly(4‐vinyl pyridine) system. A serine dehydratase model
Authors: Nakano Hidehiko , Nishioka Masahiro , Sangen Osamu , Yamamoto Yoshitake 
Published: April 2003

AbstractThe effect of quaternized poly(4‐vinyl pyridine)(QPVP) on the α,β‐elimination of series catalyzed to pyridoxall (PL) or pyridoxal phosphate (PLP) and metla ions was investigated. In PLP‐Al3+ and PLP‐Fe3+ systems QPVP showed simulation of about forefold; this stimulation was reduced in the presence of 0.5 M KCI. The catalytic activities of PL‐Al3+ and PL‐Fe3+ were lower compared to the corresponding PLP systems; stimulation by QPVP was also seen, through the extent of stimulation was smaller. The contribution of the electrostatic force between the polymer and the metal complex of the Schiff base was suggested to account for the stimulation. The pyridine moiety on the partialy quaternized PVP did not seen toparticpate in the catalysis. In PLP‐Cu2+, PL‐Cu2+, and PLP‐VO2+ systems, however, QPVP showed marked inhibition. This inhibition by QPVP was also mitigated in the presence of 0.5 M KCl.
Plasma polymerization of tetrafluoroethylene. III. Reproducibility and effects of substrate and reactor materials
Authors: Masuoka Toshio , Yasuda H. 
Published: April 2003

AbstractPlasma polylmerization occurs in plasmas surrounded by surfaces and polymer formation is one of the complicated interactions that take place between active species and molecules which constitute surfaces and gas phases. Effects of reactor wall, substrate materials, flow rate, and discharge power on polymer formation, and properties of polymer deposits were investigated by ESCA, IR (infrared) spectroscopy, and the measurement of system pressure. The effect of surface is important at the initial stage of plasma polymerization which can be easily detected by the system pressure change; however, integrated properties such as IR spectroscopy and the deposition rate show the effect in a less pronounced manner. ESCA, which reflects the properties of surface (approximately 20 A˚ in depth), showed the effect of surface in an even less sensitive manner. The amount and properties (including the effects of surfaces) are dependent on plasma polymerization parameter W/FM(W, wattage; F, volume flow rate; and M, molecualar weight of monomer) and the location of deposition within a reactor. IR and ESCA data clearly showed the dependence of polymer properties on W/FM; i.e., increase of W and decrease of M to be equivalent. When all these factors were kept under control, the reproducibility of plasma polymerization was found to be excellent.
Extinction of diffusion flames adjacent to flat surfaces of burning polymers
Authors: Sohrab S. H. , Williams F. A. 
Published: April 2003

AbstractExtinction of the diffusion flames in the stagnation‐point flow above the commercial polymers, poly(methyl methacrylate), polyoxymethylene (two types), polyethylene (three types), and polystyrene, is studied. The extinction data are used in a theory developed to obtain overall rate parameters for gas‐phase combustion of these fuels. Calculated overall rate parameters are corrected for surface heat loss by radiation. It is found that radiation corrections are most significant for polyethylene and polystyrene, in part because of their somewhat higher surface temperatures. Surface regression rates and corresponding surface temperatures are measured to aid in the radiation correction. The results are also used in an Arrhenius‐type rate expression to obtain overall activation energies for the thermal degradation of these polymers for comparison with the literature. Effects of surface losses on flame extinction are discussed.
Kinetics and mechanism of urethane formation catalyzed by organotin compounds. II. The reaction of phenyl isocyanate with methanol in DMF and cyclohexane under the action of dibutyltin diacetate
Authors: Van Der Weij Frederik Willem 
Published: April 2003

AbstractThe kinetics of the dibutyltin diacetate (DBTDA)‐catalyzed reaction of phenyl isocyanate with methanol in DMF and cyclohexane have been studied by monitoring the rate of change of the absorbance of the reaction mixture at 281.6 and 280.9 nm, respectively. Our results indicate that the mechanism of the reaction is independent of the nature of the (inert) solvent. The subsequent reaction steps are (i) complexation of methanol to DBTDA, (ii) dissociation of the complex into a proton and an anion of composition [(n‐C4H9)2Sn(OCOCH3)2(OCH3)]−, (iii) insertion of the isocyanate into the tin—alkoxy bond (the rate‐determining step), and (iv) methanolysis of the thus‐formed urethane precursor with simultaneous regeneration of the anion. The rate of the catalyzed reaction increases on goin from coordinating to noncoordinating solvents. The following sequence in order of increasing rate constant was observed: DMF < dibutyl ether < cyclohexane. This is because in coordinating solvents, DBTDA and methanol, apart from forming a complex with each other, also form complexes with the solvent.
C3 cyclopolymerization. IV.1 Cationic polymerization of 1,3‐bis(4‐vinylnaphthyl) propane and the polymer structure yielded
Authors: Nishimura J. , Furukawa M. , Yamashita S. , Inazu T. , Yoshino T. 
Published: April 2003

AbstractThe compound 1,3‐bis(4‐vinylnaphthyl)propane was prepared by a convenient dehydration of 1,3‐bis[4‐(1‐hydroxyethyl)naphthyl]propane. The structure was confirmed by nuclear magnetic resonance (NMR) spectroscopy. The monomer was polymerized by antimony pentachloride, tin tetrachloride, titanium tetrachloride, or boron trifluoride etherate at 0°C in toluene, 1,2‐dichloroethane, or a mixed solvent of 1,2‐dichloroethane and nitromethane. Most of runs except for antimony pentachloride–catalyzed ones gave mainly benzene‐soluble polymers. The structures of the polymers were studied by several spectroscopic methods. Comparison of NMR and fluorescence spectroscopic data of the polymers with those of syn‐and anti‐[3.3](1,4)napthalenophane was especially valuable in leading to the conclusion that they were cyclopolymers containing predominantly syn‐[3.3]‐(1,4)naphthalenophane units in the main chain.
The preparation and reactions of polymeric azides. II. The preparation and reactions of various polymeric azides
Authors: Cohen H. L. 
Published: April 2003

AbstractPolymeric haloethyl acrylates, methacrylates, and methacrylamides, poly(vinyl chloride), poly‐(epichlorohydrin), and halohydrins prepared from poly(glycidyl methacrylate), poly(butadiene), and poly(pentenamer) were converted to the corresponding azides. These azides reacted with a variety of acetylenic and olefinic derivatives to give, in most cases, good conversions to the corresponding triazole derivatives.
Preparation and properties of aromatic polyamide‐esters from aminophenols and aromatic diacid chlorides
Authors: Imai Yoshio , Abe Shigemitsu , Ueda Mitsuru 
Published: April 2003

AbstractAromatic polyamide‐esters of moderately high molecular weight were prepared from various combinations of three aminophenols (m‐ and p‐aminophenol, and 4‐(4′‐aminophenoxy) phenol) and two aromatic diacid chlorides (isophthaloyl and terephthaloyl) by interfacial polycondensation in a cyclohexanone/water system and two‐phase polycondensation in a dichloromethane/water system with phase‐transfer catalysts. The solution polycondensation in dichloromethane/N,N‐dimethylacetamide was also successful for the production of high‐molecular‐weight polymers. The solubility of the aromatic polyamide‐esters varied markedly with polymer structure. Except for two polyamide‐esters derived from terephthaloyl chloride, all the other polymers were almost amorphous. These polymers had glass transition temperatures at around 200°C and showed 10% weight losses at about 400°C in both air and nitrogen atmospheres.
Buoyancy and relative flow rates in ultrcentrifugation
Authors: Elmgren Hans 
Published: April 2003

AbstractIt is shown that the buoyancy factor (1–v̄ρ), used in sedimentation studies, is the product of the true buoyancy factor (1–v̄ρ0) and a backflow factor. In two‐component systems, the latter is the volume fraction (1–Φ) of the solvent. The corresponding factor for the case of multicomponent systems is also given.
Reverse osmosis separation of alkaline metal ions through hydrophobic membranes
Authors: Igawa Manabu , Nakamura Yoshinori , Takahashi Kōsei , Tanaka Masao , Senō Manabu 
Published: April 2003

AbstractA very thin hydrophobic membrane separated alkaline metal ions under a pressure gradient. The membrane was prepared by coating polystyrene or other polymers on a Teflon membrane filter. The permeabilities of alkaline metal ions under a pressure gradient decreased with increasing ion radius, while the diffusion fluxes in a dialysis experiment increased with increasing ion radius. The selectivity was enlarged in the mixed salts solution of a low concentration at a high pressure.
Intramolecular charge transfer complexes. 16. Copolymers of N,N‐dimethyl‐p‐aminobenzyl methacrylate with acryloyl‐ and methacryloyl‐β‐hydroxyethyl‐3,5‐dinitrobenzoate
Authors: Simionescu C. I. , Percec V. , Natansohn A. 
Published: April 2003

AbstractA new electronodonor monomer, N,N‐dimethyl‐p‐aminobenzyl methacrylate (DMABM), was synthesized and radical copolymerized with two electronoacceptor monomers, acryloyl‐ (DNBA) and methacryloyl‐(DNBM) β‐hydroxyethyl‐3,5‐dinitrobenzoate, in order to obtain intramolecular charge‐transfer‐complex copolymers. Also, the small‐molecular models of poly(DMABM), poly(DNBA), and poly(DNBM), the respective acetates, were synthesized and used to measure the values of ionization potential Ip of the donor and the electronic affinity Ea of the acceptor. They are Ip = 7.15 eV and Ea = 1.41 eV. The lower value of Ip as compared with that of carbazole derivatives is taken as evidence of a nonterminal mechanism of copolymerization. Also, from the 1H‐NMR and electronic spectra, the intramolecular complexation is discussed in terms of total transfer of the electron from donor to acceptor structural units.
Polyureas from carbon dioxide and diamines by means of triphenyl phosphite and pyridine hydrochloride
Authors: Higashi Fukuji , Murakami Tomoyoshi , Taguchi Yuji 
Published: April 2003

AbstractThe reaction of carbon dioxide with aniline using triphenyl phosphite in pyridine is greatly facilitated by the addition of hydrochlorides of tertiary amines such as pyridine and triethylamine, and has been successfully applied to the preparation of polyureas of high molecular weight from carbon dioxide and aromatic diamines. The presence of a catalytic amount of pyridine hydrochloride significantly increased the inherent viscosity of the resulting polymers, the highest value being obtained with about an equivalent of the chloride. Optimal temperatures and pressures varied with diamines used, and were 60–80°C and 40–50 atm of carbon dioxide. The polycondensation reaction was also affected by the solvent compositions of pyridine and N‐methylpyrrolidone, its optimum being dependent on diamines used.
Pyrolysis mass spectrometry of terephthalate polyesters using negative ionization
Authors: Adams Robert E. 
Published: April 2003

AbstractThe usual method of studying thermal degradation mechanisms of polymers in vacuo is to use electron ionization pyrolysis mass spectrometry. This can lead to mass spectral fragmentation from the 70 eV electrons used. Low energy electrons (10–15 eV) produce a low abundance of positive ions. However, if a molecule is prone to capture a thermal energy electron, then negative ions are produced in high abundance. This report describes the negative ion pyrolysis mass spectrometry of polyethylene terephthalate and polybutylene terephthalate.