bluuebunny/crossref_metadata_2025_split huggingface dataset:
γ‐Radiation‐produced supported metal complex catalysts. 3. Phosphinated polypropylene supports
Authors: Hartley Frank R. , Murray Stephen G. , Nicholson Philip N. 
Published: April 2003

Abstractp‐Styryldiphenylphosphine was grafted onto polypropylene by γ‐radiation. However, olefinic phosphines in general do not readily undergo such grafting. Among the many other olefinic phosphines examined only 1‐(4‐diphenylphosphinophenyl)‐prop‐1‐ene and vinyldiphenylphosphine were grafted successfully and both had low grafting yields. The optimum conditions for grafting involve low dose rates and high total doses of γ‐radiation in dimethylsulfoxide as solvent. This grafting is sensitive to impurities and inhomogeneity in the product readily results, especially at high grafting yields. Oxygen must be rigorously excluded if oxidation of grafted phosphorus(III) to phosphorus (V) is to be avoided. Phosphine oxides can be reduced to phosphines when grafted to the polymer with trichlorosilane. Mass spectrometry has shown that more than one olefinic phosphine binds to a single site in the polymer. Solid‐state, high‐resolution 31P‐NMR is a valuable technique for characterizing the grafted polymer. The preparation and characterization of the following hitherto unreported phosphines is described:
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In addition, the precursor halides
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none of which has been reported, were prepared and characterized.
Reaction rate of crosslinkings by using a metallated polymer. II. Intermolecular and intramolecular crosslinkings at the second state
Authors: Ishizu Koji , Ino Kazuhide , Fukutomi Takashi , Kakurai Toshio 
Published: April 2003

AbstractLithium‐metallated styrene–p‐benzylstyrene copolymer was reacted with the branched polymer with chlorine groups at the pendant chain ends (multifunctional branched polymer) in tetrahydrofuran (THF) at 25°C. The rate constant was estimated from the changes in the concentration of metallated polymer by using photometrical measurements. The various reaction conditions were chosen and it became clear that the rate constants of intermolecular (k20) and intramolecular (k3intra) crosslinkings were derived separately at the second stage. k20 showed a constant value in spite of the molecular weight of crosslinker chains and was about equal to the rate constant of the grafting. The rate of intramolecular crosslinking at the second stage increased with decreasing the molecular weight of pendant chains of multifunctional branched polymer.
Polymerization of oriented monomers. VI. Polymerization of monomeric di(undecenyl) phosphate vesicles to stable polymeric vesicles
Authors: Paleos C. M. , Christias C. , Evangelatos G. P. , Dais Photis 
Published: April 2003

AbstractThe synthesis of a novel vesicle‐forming surfactant monomer, i.e., of di(undecenyl) phosphate is reported. Vesicles formed from this monomer were irradiated by γ rays for the production of polymeric vesicles. Polymerization was studied in conjunction with the model of the monomeric vesicles and the structure of the polymers was primarily studied with 1H‐NMR spectra. It was further established that polymerized vesicles retain the structure of their monomeric counterparts while exhibiting higher stability than the unpolymerized vesicles.
13N‐NMR spectroscopy. XXXV. Sequence analysis of alternating and random copolyamides made up of aliphatic and aromatic ω‐amino acids
Authors: Kricheldorf Hans R. , Joshi Sharda V. , Hull William E. 
Published: April 2003

AbstractAlternating copolyamides of various ω‐amino acids were synthesized by base‐catalyzed polycondensation of N‐isothiocyanatoacyl ω‐amino acids in solution. Derivatives of the following amino acids were used: glycine, β‐alanine, γ‐aminobutyric acid, δ‐aminovaleric acid, ε‐aminocaproic acid, D,L‐β‐aminobutyric acid, trans‐4‐aminocyclohexane 1‐carboxylic acid, 4‐aminophenyl acetic acid, 3‐aminobenzoic acid, 4‐aminobenzoic acid, 3‐amino‐4‐methyl benzoic acid, and 4‐amino‐3‐methyl benzoic acid. The base‐catalyzed polycondensation at lower temperatures gave purer products than the bulk condensation at 180–200°C. 13C‐NMR and natural‐abundance 15N‐NMR spectra measured in trifluoroacetic acid demonstrate that in most cases undisturbed alternating sequences were obtained. Strong neighboring residue effects and long‐range sequence effects were found in the 15N‐NMR spectra, and structure/shift relationships are discussed. The sequences of copolyamides obtained by copolymerizations of lactams or β‐amino acid N‐carboxyanhydrides were investigated by both 15N‐NMR and 13C‐NMR spectroscopy. 13C‐NMR spectroscopy was found to be more useful if the copolyamides consist of ω‐amino acid units of different chain length. However, 15N‐NMR spectroscopy is more suited if the monomer units differ exclusively by their substituents.
Grafting polyesters onto carbon black. I. Polymerization of β‐propiolactone initiated by alkali metal carboxylate group on the surface of carbon black
Authors: Tsubokawa Norio , Funaki Akira , Hada Yukio , Sone Yasuo 
Published: April 2003

AbstractBy use of carbon black that contained alkali metal carboxylate (COOM; MLi, Na, K, Rb, or Cs) group as catalyst the anionic polymerization of β‐propiolactone (PL) was carried out at 50°C and the grafting of polyester onto the carbon black surface was investigated. Carbon black that contained COOM group was prepared by the reaction of carboxyl group on the surface with corresponding alkali metal hydroxide and was able to initiate the anionic ring‐opening polymerization of PL. The carbon black obtained from the reaction gave a stable colloidal dispersion in an organic solvent. It was confirmed that the polyester formed was grafted effectively onto the surface; for instance, by using carbon black that contained COOK group as catalyst the grafting ratio was increased to 145% (viz., 1.45 g of polyester was grafted/1 g of carbon black) with an increase in conversion. Furthermore, the effect of alkali metal countercation (M+) on the polymerization was studied. The initiating activity of COOM group on the surface increased in the following order: COOLi < COONa < COOK < COORb < COOCs. This order was in agreement with that of increasing electropositivity of these alkali metals.
Study of the curing of an acetylene‐terminated polyphenylene resin with thermal expansion measurements
Authors: Baise A. I. 
Published: April 2003

AbstractThe curing of an acetylene‐terminated polyphenylene resin (Hercules H‐Resin) was followed by thermal expansion measurements. This approach proved useful in optimizing the curing conditions of the resin. Curing the polymer in air led to the formation of carboxyl groups, whereas curing under nitrogen did not. The thermal expansion coefficient is a minimum (32 ppm deg−1) for a cure cycle of 250°C for 30 min, followed by 350°C for 30 min. Heating at temperatures above 350°C led to degradation of the crosslinked polymer and an increase in the thermal expansion coefficient.
Influence of monomer composition on certain factors affecting the light‐transmitting properties of MBS terpolymers
Authors: Karaenev S. S. , Chilingirjan M. K. 
Published: April 2003

AbstractThis article is a report of the investigation of the influence of monomer composition within optimum limits on the light‐transmitting properties of MBS terpolymers obtained by the mass‐suspension method. The high and nearly constant light‐transmitting properties of the MS copolymer matrix have no effect on the light‐transmitting properties of MBS with a MMA content up to about 20 mol % higher than that at the azeotropic point. The refractive index of the MS copolymers decreases uniformly as the mole ratio of MMA increases and becomes equal to the index of the SBR. Particle concentration in sizes up to 0.6μm increases as the MMA content increases to a given point at which the concentration remains constant as MMA continues to increase. The light‐transmitting properties of MBS with a MMA content of 57 mol % are improved significantly. This fact is explained by a decrease in variation on the refractive index between the two phases to 0.0014 and by the increasing percentage of particles with sizes smaller than 0.6 μm up to 70%.
Comparisons of glow‐discharge polymerizations among tetramethylsilane, dimethyldimethoxysilane, and tetramethoxysilane
Authors: Inagaki N. , Koyama M. 
Published: April 2003

AbstractGlow‐discharge polymerizations among tetramethylsilane, dimethyldimethoxysilane, and tetramethoxysilane were compared by elemental analyses and infrared spectroscopy. The elemental composition of the polymers prepared from the three monomers depended strongly on the operational conditions necessary to sustain a glow discharge, i.e., the W/FM parameter, where W is the rf power, F is the flow rate of the monomer, and M is the molecular weight of the monomer. Methoxy groups were more susceptible to glow discharge than methyl groups. Differences in chemical structure among these monomers appeared in the polymer structures formed when the glow‐discharge polymerization was carried out at a low value of the W/FM parameter, while the differences disappeared at high values of the W/FM parameter, for analogous polymers. Substitution with methoxy groups was favorable for the formation of polymers of low carbon content only when the glow‐discharge polymerization was performed at low values of W/FM.
Preparation of viologen polymers from alkylene dipyridinium salts by cyanide ion
Authors: Ageishi Kentaro , Endo Takeshi , Okawara Makoto 
Published: April 2003

AbstractPolymers of viologen structure were prepared by oxidation of quinoid polymers obtained by the dimerization of alkylene dipyridinium salts with cyanide ion as catalyst. These polymers showed the behavior of polyelectrolytes and redox polymers that turn a deep blue when reduced chemically or electrically.
Siloxane‐containing polyenaminoesters
Authors: Moore J. A. , Mitchell T. D. 
Published: April 2003

AbstractPolyenaminoesters were prepared by condensation of succinyl succinic ester (SSE) and p‐bis‐carbomethoxy diacetyl benzene (CDB) with 1,3‐bis(3‐aminopropyl)‐1,1,3,3‐tetramethyldisiloxane. Conditions of solvent and temperature were discovered which yielded soluble polymer from SSE after heat treatment. CDB yields only tough, rubbery, insoluble products.
Distributions in nonself‐condensing polycondensations: A kinetic approach
Authors: Stafford J. W. 
Published: April 2003

AbstractThe size distributions of a number of different polycondensations with nonself‐condensing monomers were calculated by a kinetic method. The results of linear polycondensations with and without reversibility or stoichiometry and of multifunctional polycondensations are exactly the same as those obtained by Flory with probability methods and do not differ, when comparable, from the size distributions produced by the polycondensation of self‐condensing monomers. Size distributions were also obtained for reactions in which the order of reaction changes with conditions or during reaction. These results clearly show that a Flory distribution is obtained as long as the principle of equal reactivity applies at any given instant, although this reactivity may vary in the course of the reaction.
Metal‐containing coordination polymers. XIV. Relations between the structure and the melt viscosity of polyesters containing Mg ions
Authors: Vancsó‐Szmercsányi I. , Székely‐Pécsi Zs. 
Published: April 2003

AbstractRheological properties of coordination polymers formed in the reaction of low‐molecular‐weight (about 1000) polyesters with MgO were studied. The melt viscosity and activation energy of viscous flow were measured as functions of Mg content and temperature. Rheological behavior was discussed in view of the chemical structure of these systems and correlated with qualitative and quantitative conditions of the coordination bonds. Melts of Mg complexes of amorphous and semicrystalline polyesters showed identical rheological results.
HCN evolution from thermal and oxidative degradation of poly(diphenyl methane pyromellitimide) at high temperatures
Authors: Jellinek H. H. G. , Dunkle S. R. 
Published: April 2003

AbstractHCN evolution from thermal and oxidative degradation of poly(diphenyl methane pyromellitimide) has been investigated over a range of temperatures from 500 to 1000°C; rate constants and Arrhenius equations have been determined. Kinetics and mechanisms have been proposed and quantitatively evaluated. They account well for the experimental results. The rate determining steps are CN scission for thermal degradation and H abstraction from the methylene bridge by O2 for oxidative degradation, respectively. At high temperatures, oxidation and thermal decomposition of the evolved HCN take place on its passage through the hot zone of the furnace in the highest range of temperatures (800–1000°C). Additional HCN is produced (>800°C) from the char obtained during thermal and oxidative degradation.
Gamma radiation‐initiated polymerization of styrene at high pressure. III. Emulsion polymerization with anionic emulsifiers
Authors: Moore P. W. , Clouston J. G. , Chaplin R. P. 
Published: April 2003

AbstractValues calculated for the activation volume for chain propagation, ΔV, for the polymerization of styrene in emulsions under a variety of conditions agree closely with that previously obtained in pure styrene (ΔV = −18.6 cm3 mol−1). The rate of initiation of emulsion polymerization by radicals produced in the water phase was independent of pressure; therefore ΔV is zero. This differs from initiation in pure styrene which is slightly retarded by pressure (ΔV = 2.0 cm3 mol−1). The activation energy for the reaction in emulsion, as in pure monomer, decreases slightly with pressure. Chain transfer to monomer occurs to a much greater extent in emulsions than in pure monomer under similar temperature and pressure conditions. Values for the dependence of the polymerization rate on the initiator (i.e., the irradiation dose rate) and emulsifier concentration are consistent with Smith–Ewart, Case II kinetics.
Preparation of aromatic polyesters by the direct polycondensation reaction with diphenyl chlorophosphate in pyridine
Authors: Higashi Fukuji , Hoshio Atsushi , Kiyoshige Jun 
Published: April 2003

AbstractThe direct polycondensation reaction of diphenyl chlorophosphate (DPCP) as a new condensing agent in pyridine was used for the preparation of polyarylene esters. High‐molecular‐weight polymers can be prepared by reacting a pyridine solution of dicarboxylic acids and DPCP in the presence of LiCl, followed by treating with a pyridine solution of bisphenols. About an equivalent of LiCl, and 30 mol % excess of DPCP were most favorably added. Effects of the initial reaction of the acids and DPCP, and of dropwise addition of bisphenols on the polycondensation were investigated. Polycondensations of several hydroxybenzoic acids were also carried out with limited success.
Radical copolymerization of acrylic monomers. V. Copolymerization of ortho‐ and para‐chlorophenyl acrylates with methyl methacrylate
Authors: San Román J. , Madruga E. L. , Del Puerto M. A. 
Published: April 2003

AbstractThe radical copolymerization of phenyl, ortho‐chlorophenyl, and para‐chlorophenyl acrylates with methyl methacrylate has been studied at low conversions. The reactivity ratios of these comonomeric pairs have been determined by the application of Fineman–Ross and Kelen–Tudös methods, and the inherent reactivities of phenyl acrylate derivatives toward methyl methacrylate radicals seem to be related to their availability of forming π complexes with methyl methacrylate. The scheme Q‐e for these systems clarifies that the higher the polar factor e of the phenyl acrylate derivative, the higher reactivity of the corresponding monomer. The stereochemistry of the prepared copolymers has been studied by NMR spectroscopy. In the analysis of the α‐CH3 resonance signals, considering methyl‐methacrylate‐centered triads, it becomes apparent that the introduction of ring aromatic substituents in the copolymer chains changes appreciably the tacticity of poly(methyl methacrylate).
Grafting of living poly(ethylene oxide) onto polystyrene via aromatic nucleophilic displacement of activated nitro groups
Authors: Shalati Mohamad D. , Overberger C. G. 
Published: April 2003

AbstractPolystyrene of M̄ω = 2.2 × 104 was alkylated with 4‐nitrophthalimidomethyl groups as grafting sites. Several backbone polymers with various degrees of grafting sites (G = 2–100%) were prepared and characterized by elemental analysis, IR, 1H‐ and 13C‐NMR, and viscosity measurements. “Living” poly(ethylene oxide) with narrow molecular‐weight distribution was prepared in the presence of 15‐crown‐5, and grafted onto the 4‐nitrophthalimidomethylated polystyrene. The nitro displacement reaction was fast and the grafting yield was quantitative (100%). The graft copolymers are highly soluble in water and in organic solvents. The intrinsic viscosities of the graft copolymers are higher than those of the backbone polymers. The intrinsic viscosities show an initial increase followed by a decrease as the degree of grafting increase.
Photopolymerization initiated by charge‐transfer complex. VI. Photopolymerization of methyl methacrylate with the use of isoquinoline–chlorine charge‐transfer complex
Authors: Lenka Subasini , Nayak Padma L. , Nayak Sanjay K. 
Published: April 2003

AbstractPolymerization of methyl methacrylate in visible light was studied at 30°C using the isoquino‐line–chlorine charge‐transfer complex as the photoinitiator. Analyses of kinetic and other data indicate that the polymerization proceeds via a radical mechanism and the termination is initiator dependent. Chain termination via degradative chain (initiator) transfer appears to be significant.
300‐MHz 1H‐NMR spectra of p‐cresol‐formaldehyde condensates having regular repeating structures
Authors: Tong S. N. , Park Kyung Y. , Harwood H. James 
Published: April 2003

AbstractModel p‐cresol‐formaldehyde condensates having regular sequences of methylene ether and methylene linkages were prepared by the self‐condensation of dimethylol derivatives of p‐cresol‐formaldehyde condensates (2‐hydroxy‐5‐methyl‐1,3‐benzenedimethanol, 3,3′‐methylene‐bis[2‐hydroxy‐5‐methylbenzenemethanol] and 3,3′‐[(2‐hydroxy‐5‐methyl‐m‐phenylene)dimethylene]‐bis[2‐hydroxy‐5‐methylbenzenemethanol]). 300‐MHz 1H‐NMR spectra of these polymers and of their acylated derivatives were recorded and used to develop resonance assignments for the various types of protons present in these polymers. The spectra were found to be sensitive to end‐group and sequence distribution effects.
Plasma polymerization of trifluoromethyl substituted aromatic compounds
Authors: Diaz A. F. , Hernandez R. 
Published: April 2003

AbstractThin film coatings were prepared by polymerizing trifluoromethyl‐substituted aromatic compounds in a glow discharge with low power levels and medium pressures. Smooth, continuous films which are adherent and insoluble in conventional solvents were produced. A significant amount of the fluorine content from the monomer was retained in the polymer. The trifluoromethyl group was not removed by the plasma conditions and appeared in the film as trifluoromethyl and difluoromethylene groups. The films were slightly less wettable than those of the unfluorinated films.
Preparation and properties of N‐phenylated aromatic polyamides from N,N′‐diphenyl‐p‐phenylenediamine and aromatic diacid chlorides
Authors: Imai Yoshio , Hamaoka Nobuo , Kakimoto Masa‐Aki 
Published: April 2003

AbstractN‐Phenylated aromatic polyamides and copolyamides derived from N,N′‐diphenyl‐p‐phenylenediamine, isophthaloyl, and terephthaloyl chloride were prepared by high‐temperature solution polycondensation in anisole at 155°C. Factors that influenced the reaction, such as monomer concentration, solvent, temperature, and time, were studied to determine the optimum conditions for the preparation of high molecular weight polymers. Compared with analogous unsubstituted aromatic polyamides, the N‐phenylated polymers exhibited better solubility in chlorinated and amide solvents, reduced crystallinity, and lower glass transition temperatures (above 200°C). All polymers except the polyterephthalamide could be solvent‐cast, as well as hot‐pressed, into transparent flexible films.
Preparation and some properties of nylon‐4,2
Authors: Gaymans R. J. , Venkatraman V. S. , Schuijer J. 
Published: April 2003

AbstractAn attempt was made to produce a new short‐chain alphatic polyamide nylon‐4,2. This polyoxamide can be prepared by polycondensation of tetramethylene diamine and diethyl oxalate. A high molecular weight polymer (ηinh = 1.9 from 0.5% solutions in 96% sulphuric acid) has been obtained by employing a two‐step polycondensation method; the precondensation was carried out in solution at low temperatures (20–140°C) and the postcondensation in the solid state at high temperatures (250–300°C). The effect of solvent composition and reaction temperature on the prepolymerization and the effect of reaction time and temperature on the postcondensation was studied. We also investigated the influence of moisture during washing, storing, and the solid‐state reaction on the polymerizability by the postcondensation. Nylon‐4,2 is soluble only in highly polar solvents such as trifluoroacetic acid (TFA), dichloroacetic acid, and 96% sulphuric acid. Films were cast from TFA. With these films we studied the IR spectrum, WAXS pattern, water absorption, and melting behavior. Nylon‐4,2 was found to melt at 388–392°C, has a crystallinity of 70%, and a low water absorption (3.1% at 50% RH). The glass transition temperature of the dry sample was found to be at ∼120°C and for the wet sample at −15°C.
Vinyl polymerization. 422. Initiation mechanism of uncatalyzed polymerization by polyethyleneglycol
Authors: Ouchi Tatsuro , Hosaka Yoshifumi , Imoto Minoru , Konaka Ryusei 
Published: April 2003

AbstractThe initiation mechanism on the radical polymerization of vinyl monomers by polyethyleneglycol (PEG‐300) in aqueous solution was studied. The initiating radical species were determined by means of the spin trapping technique. They were concluded to be generated by the hydrogen atom transfer from the monomer adsorbed at the ether group of PEG‐300 to the free monomer.
Preparation of silicon containing polymers. II.. Effect of structure on the thermal stability of organosilicon aramids
Authors: Ghatge N. D. , Jadhav J. Y. 
Published: April 2003

AbstractTwo silicon‐containing acid dichlorides, bis(4‐chlorocarbonylphenyl)dimethylsilane and bis(4‐chlorocarbonylphenyl)diphenylsilane, were synthesized and reacted with 1,3‐phenylene diamine, 1,4‐phenylene diamine, 4,4′‐diaminodiphenyl, 4,4′‐diaminodiphenyl methane 4,4′‐diaminodiphenyl ether, and 4,4′‐diaminodiphenyl sulfone in the preparation of 12 structurally different high molecular weight aromatic polyamides. A low‐temperature interfacial polycondensation technique was used. Most of the polyamides formed tough, transparent, flexible films and were characterized by solubility, solution viscosity, infrared spectroscopy (IR), and glass transition temperature (Tg). The thermal behavior of these aramids was studied by dynamic thermogravimetry. The effect of diamine and acid dichloride structure on the aramids properties is also discussed.
Polymerization of trimethylsilylacetylene by WCl6‐based catalysts
Authors: Okano Yoshimichi , Masuda Toshio , Higashimura Toshinobu 
Published: April 2003

AbstractThe polymerization of trimethylsilylacetylene was investigated by using W and Mo catalysts. Mixtures of WCl6 with appropriate organometallic cocatalysts such as n‐Bu4Sn and Et3SiH at 1:1 molar ratio provided poly(trimethylsilylacetylene) in high yields. On the other hand, MoCI5 gave mainly methanol‐soluble oligomers even in the presence of these cocatalysts. The polymer formed was a partly insoluble yellow powder, and the molecular weight of the soluble fraction was about 7000. The IR, 1H‐NMR, and 13C‐NMR spectra supported the polymer structure, (CH = CSiMe3)n. Protodesilylation of poly(trimethylsilylacetylene) afforded a new polymer containing both acetylene and trimethylsilylacetylene units.