bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sulfur‐containing vinyl monomers. XII. Charge transfer complexes of thioethylene derivatives with π‐electron acceptors
Authors: Inoue Hiroshi , Otsu Takayuki 
Published: April 2003

AbstractThe absorption spectra of charge‐transfer (CT) complexes of thioethylene derivatives with p‐chloranil (CA), tetracyanoethylene (TCNE), and 7,7,8,8,‐tetracyanoquinodimethane (TCNQ) were measured in methylene chloride. Since the CT bands of alkyl vinyl sulfides having bulky substituents such as isopropyl, cyclohexyl and tert‐butyl were similar to that of methyl vinyl sulfide, the complexing site of these sulfides to acceptor was assumed to be the vinyl group rather than the sulfur atom. In the case of the TCNE complex of phenyl vinyl sulfide, however, a new second CT band at 378 nm was observed, and the first CT band was also close to that of ethyl phenyl sulfide, indicating that the TCNE formed a complex with this vinyl sulfide mainly at its phenyl group. To investigate further the conformation of the complex, CT spectra of bis‐, tris‐ and tetrakis (phenylthio) ethylenes were measured. These compounds showed markedly different CT bands, and the changes in these CT bands with the number of the phenylthio substituents appears to be attributable to the change in complexing site with the acceptors used.
Synthesis of polyenamines by vinylogous nucleophilic substitution polymerization of 2,2′‐disubstituted bis(4‐ethoxymethylene‐5‐oxazolone) with diamines
Authors: Ueda Mitsuru , Kino Kohsuke , Hirono Takeo , Imai Yoshio 
Published: April 2003

AbstractA new class of polyenamines was synthesized by the vinylogous nucleophilic substitution polymerization of 2,2′‐p‐phenylenebis(4‐ethoxymethylene‐5‐oxazolone) with diamines in polar aprotic solvents under very mild conditions. The polymers derived from aliphatic diamines were soluble in these solvents and had inherent viscosities in the range of 0.3–0.9. The dilute solutions showed marked decrease in viscosity with time, presumably due to hydrolytic chain scission of the enamine structures in the polymer backbone. The polymers exhibited no melting temperature, and onset of breakdown under thermogravimetric analysis in a nitrogen atmosphere occurred at 250–300°C.
Synthesis and polymerization of (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐propiothiolactone
Authors: Jerman B. , Fleš D. 
Published: April 2003

Abstract(R)‐(+)‐2‐Methyl‐2‐ethyl‐3‐propiothiolactone was synthesized by debenzylation and cyclization of (−)‐2‐methyl‐2‐ethyl‐3‐benzylmercaptopropionyl chloride under the conditions of Friedel‐Crafts synthesis, and by dehydration of (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐mercaptopropionic acid with dicyclohexyl carbodiimide. The configuration of the (+)‐propiothiolactone was determined by chemical interconversion with (−)‐2‐methyl‐2‐ethylsuccinic acid, the absolute configuration of which is known to be (R). The polymerization of (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐propiothiolactone was performed in bulk with tetrabutylammonium versatate as catalyst. The specific rotation of the polymer ([α]D +151.7°) compared with the rotation of the low molecular weight model compound (R)‐(+)‐2‐methyl‐2‐ethyl‐3‐acetylmercapto‐thiolpropionic acid methyl ester ([α]D +55.0°) shows a significant enhancement, thus suggesting the possibility of the presence of rigid conformations in polymer chain.
Equilibrium anionic polymerization of n‐valeraldehyde
Authors: Hashimoto Kazuhiko , Sumitomo Hiroshi , Ohsawa Shinji 
Published: April 2003

AbstractThis paper describes an anionic polymerization of n‐valeraldehyde (VA) in tetrahydrofuran (THF) initiated by benzophenone‐monolithium complex in a high vacuum system. In spite of the deposition of the resulting polymer an equilibrium state between the monomer and the polymer was observed at a temperature range of −90 to −68°C. From the linear relationship between the equilibrium monomer concentration and the polymerization temperature, values of −5.3 ± 0.3 kcal/mole and −25.7 ± 1.4 cal/mole‐deg, respectively, were evaluated for the enthalpy change and the entropy change in the present system. The effect of polar substituents on the polymerizability of aldehydes is discussed from the comparison of these values with those in the case of β‐methoxypropionaldehyde.
Kinetics of anionic polymerization of α‐methylstyrene in tetrahydrofuran and toluene mixed solvents
Authors: Hui K. M. , Ong Y. K. 
Published: April 2003

AbstractThe kinetics of anionic polymerization of α‐methylstyrene with Na+ as counterion have been studied in mixed solvents of tetrahydrofuran (THF) and toluene in various compositions at −25 to 5°C. The ion‐pair rate constant k(±) increases by about a factor of 50 at −10°C, whereas the activation energy decreases from 5.1 to −2.2 kcal/mole, when THF in the mixed solvent increases from 30 to 100 vol‐%. The plot of log k(±) against (D − 1)/(2D + 1) is a curve, where D is the dielectric constant of the medium. This deviation from linearity is explained in terms of propagation by two types of ion‐pairs.
19F‐ and 1H‐NMR spectra of tetrafluoroethylene–propylene copolymers
Authors: Kojima Gen , Wachi Hiroshi , Ishigure Kenkichi , Tabata Yoneho 
Published: April 2003

AbstractHigh resolution 94‐MHz 19F‐ and 100‐MHz 1H‐NMR spectra were measured on a series of tetrafluoroethylene (TFE)‐propylene (P) copolymers having a range of composition (TFE/P molar ratio = 37/63–55/45) and polymerized at different temperatures (−23, 25 and 65°C). The spectra were analyzed in relation to copolymer compositions. The assignment of 19F resonance in terms of tetrads proposed previously was confirmed, and the tentative assignment of 1H resonances was proposed in terms of triads. The spectra thus interpreted revealed the sequence distribution of the copolymers. Copolymer compositions calculated from NMR spectra and elemental analysis agreed rather well with each other. Monomer reactivity ratios were calculated from the sequence distributions and compared with those obtained from the elemental analysis. It was observed that highly alternating copolymers are obtained in this system over a wide range of monomer composition at lower temperatures and that a deviation from alternancy increases slightly with rising polymerization temperature.
Modification of poly(ethylene terephthalate) and nylon 66 surfaces by using organometallic polymerization catalysts
Authors: Dobbs B. , Jackson R. , Gaitskell J. N. , Gray R. F. , Lynch G , Thompson D. T. , Whyman R. 
Published: April 2003

AbstractZirconium hydrocarbyl catalysts react with nylon and poly(ethylene terephthalate) (PET) fibers to produce a supported species which may be used to polymerize a sheath of polyethylene around the fiber. Very high catalyst activities have been achieved over very short reaction periods on PET spinning threadlines. It is also possible to use these reagents to produce strongly adhered oxide and sulfide surface coatings. Infrared evidence is given for a mechanism in the case of reaction between catalyst and PET.
Kinetics and mechanism of the thermal reaction between tert‐butyl perbenzoate and n‐alkanes: A model system for the crosslinking of polyethylene
Authors: Van Drumpt J. D. , Oosterwijk H. H. J. 
Published: April 2003

AbstractThe thermal reaction between tert‐butyl perbenzoate and n‐alkanes has been studied under conditions as close as possible to those during actual crosslinking of polyethylene. Product analysis allowed a description of the fate of 90–95% of the peroxide fragments. Approximately 50–60% of the substrate radicals, formed upon hydrogen abstraction, were found to combine and give crosslinks, whereas about 30% showed disproportionation, thus leading to substrate unsaturation. The two competing reactions account for 85–90% of the generated substrate radicals. The model system provides a simple and convenient method for comparing the crosslink efficiencies of peroxides; these data are reported for some commercial peroxides. In order to facilitate an extrapolation of the results in liquid alkanes towards solid polyethylene (PE), the influence of substrate viscosity and temperature on the peroxide decomposition rate, product distribution, and crosslink efficiency was studied. In n‐alkanes peroxide decomposition follows first‐order kinetics well, with an Arrhenius activation energy of 32.9 ± 0.5 kcal/mole. In addition, the kinetics in the model system are compared with those calculated from Rheometer (torque vs. time) measurements on the curing of unfilled PE and ethylene‐propylene‐dicyclopentadiene terpolymer (EPDM). Only minor differences in peroxide decomposition rate and overall activation energy were found.
High‐resolution NMR studies on radiolytic reactions in polyethylene
Authors: Hayakawa N. , Kuriyama I. 
Published: April 2003

AbstractHigh‐resolution NMR spectra was obtained for linear polyethylene powder irradiated by 60Co γ‐rays in vacuo or in air. For the sample irradiated in vacuo, the spectra consist of two components having different line width. The narrow component was assigned to soluble molecules and the broad one to gel. When samples are irradiated in air, their spectra show no broad component. The GPC curves obtained for the samples irradiated in air shift to high elution counts (low molecular weight) upon increase of the irradiation dose. It is concluded that oxidative degradation is the predominant reaction in the sample irradiated in air.
Polyimidines, a new class of polymers. II. Polyhexamethylenetetraphenyldithiopyromellitimidine
Authors: Cassidy Patrick E. , Lee Frankie W. C. 
Published: April 2003

AbstractPolyimidines have been shown to be soluble, thermally stable polymers. In searching for an alternate synthetic method the thio analog of this system has been discovered. The brightly colored (red‐orange) perthio derivatives of 3,3‐diphenylphthalide and 3,3,5,5‐tetraphenyipyromellitide were synthesized from their oxo analogs with P2S5. The model compound thioimidines were synthesized by reacting 3,3‐diphenyldithiophthalide with aniline and with 1,6‐hexane diamine and by reacting 3,3,5,5‐tetraphenyltetrathiopyromellitide with aniline and n‐hexylamine. The polymerization of tetraphenyltetrathiopyromellitide occurred readily with 1,6‐hexanediamine in boiling carbon tetrachloride with complete cyclization. This reaction gave an 80% yield with inherent viscosities up to 0.89 and molecular weights up to approximately 11,000. Thermogravimetric analysis showed a 2% weight loss at 200°C and 10% weight loss at 300°C with rapid decomposition above 300°C. Although the polythioimidine was less thermally stable than its oxo analog, it was much more soluble in common solvents (aromatic and chlorinated aliphatic hydrocarbons) and more readily synthesized in higher yield.
Préparation de polyesteramides alternés
Authors: Akçatel P. , Jasse B. 
Published: April 2003

AbstractThe polycondensation of hydroxyamido acids of general formula HO‐R1‐CO‐NH‐R2‐COOH provides alternating polyesteramides only when R1 and R2 are alkyl groups. These aliphatic alternating polyesteramides, according to their structural high regularity, possess a more important content of interchain hydrogen bonds than the random copolymers. The higher melting point of the random copolymers is attributed to the heterogeneity of amide group partition in the chain. The existence of a benzyl group in the structure of the hydroxyamido acids reduces the polycondensation ability and the molecular weights of the products are low. These aromatic monomers are thermally degraded, p‐toluic acid evolving; ester and amide functions stoechiometric ratio is not maintained, but infrared and differential thermal analysis show that these aromatic polyestermides keep a reasonable structural regularity.
Vinyl chloride–propylene copolymerization
Authors: Ravey M. , Waterman J. A. , Shorr L. M. , Kramer M. 
Published: April 2003

AbstractBecause of the allylic nature of propylene, the vinyl chloride–propylene system exhibits polymerization behavior markedly different from that of vinyl chloride, even at relatively low propylene concentrations. Propylene acts as a degradative chain‐transfer agent, and as a result, both the polymerization rate and the molecular weight of the resultant copolymers are lower than those of the homopolymer, decreasing with increasing propylene content. Even at propylene concentrations as low as 10% the rate of polymerization is proportional to the initiation rate, indicating kinetic control by the propylene. The reactivity ratios of these monomers given by Cain were verified. The reciprocal intrinsic viscosity of the copolymer was found to be linearly related to the monomer feed composition.
Applications of ESCA to polymer chemistry. X. Core and valence energy levels of a series of polyacrylates
Authors: Clark D. T. , Thomas H. R. 
Published: April 2003

AbstractThe core and valence levels of a series of poly(alkyl acrylates) have been studied by ESCA. From an analysis of the individual component peaks for the C1s and O1s core levels and from comparison of relative area ratios it is shown that ESCA may be applied to the study of surface compositions. The evidence presented strongly suggests that on the ESCA depth‐profiling scale the technique statistically sample the repeat units with no evidence for preferential orientation of side chains at the surface. For some samples, ESCA provides evidence for a degree of surface oxidation and hydrocarbon contamination. The valence energy levels are shown to be characteristic of the polymer system. The measured absolute and relative binding energies of the core levels have been compared with model calculations using the charge‐potential model in the CNDO/2 SCF MO formalism.
Synthesis of monomers that expand on polymerization. Synthesis and polymerization of 3,9‐dimethylene‐1,5,7,11‐tetraoxaspiro[5.5]undecane
Authors: Bailey William J. , Endo Takeshi 
Published: April 2003

AbstractA spiro ortho‐carbonate containing two double bonds, 3,9‐dimethylene‐1,5,7,11‐tetraoxaspiro[5.5]undecane (III) was prepared from 2‐methylene‐1,3‐propanediol (VI). The structure of the monomer was indicated by its elementary analysis as well as its infrared and NMR spectra. When the crystalline monomer was polymerized with Lewis acids such as trifluoride etherate as catalysts, soluble polymer with a high molecular weight was obtained. The infrared and NMR spectra indicated that the polymer was an alternating copolymer of ether and carbonate having double bonds. When the usual monomers such as vinyl chloride and styrene polymerize, shrinkage occurs. However, this monomer underwent expansion on polymerization.
Study of radiation‐induced polymerization of vinyl monomers adsorbed on inorganic substances. VII. Effect of pretreatment temperature of silica gel on styrene–silica gel system
Authors: Fukano Kazuyuki , Kageyama Eiichi 
Published: April 2003

AbstractTo investigate the reaction mechanism of radiation‐induced polymerization of styrene adsorbed on silica gel, the effect of pretreatment temperature of silica gel was studied. Preheating of silica gel was carried out at 200, 500, and 800°C. The number of silanol groups of silica gel surface decreased as preheating temperature increased. The rate of polymerization on the silica gel preheated at 500°C was faster than that at 200°C, but the polymerization rate on the silica gel preheated at 800°C was the lowest. These results suggest that rate of polymerization on the silica gel is affected by the conditions of silica gel surface such as the number of silanol groups and the pore size. At the same monomer conversion, percent grafting decreased as preheating temperature of silica gel increased. The GPC spectra of both graft polymers and homopolymers have two peaks at all preheating temperatures. The monomer conversion of low molecular weight peaks of graft polymers decreased as preheating temperature of silica gel increased. This result suggests that there is a probability that the grafting sites of low molecular weight peaks of graft polymers somehow interact with silanol groups.
Effect of surface swelling on diffusion on polymers. II. Delamination
Authors: Sefton Michael V. , Merill Edward W. 
Published: April 2003

AbstractSwelling in chloroform resulted in delamination of surface‐hydroxylated styrene‐butadiene‐styrene block copolymers, with the formation of three fractions: crosslinked gel, reacted sol, and unreacted chloroform‐soluble material. From the relative weights of these fractions, the depth of penetration of the reaction and the shape of the reaction front were determined. The weight of the gel fraction gave directly an estimate of the depth of penetration, λx which decreased with increasing film thickness. This was attributed to the increased amount of reacted polymer being noncrosslinked material (sol) in the interior compared to the 100% crosslinked nature of the surface region and to a reduction in the penetration of the reaction front resulting from the effect of stress transfer in lowering the permeation rate of peracetic acid. Comparison of the depth of penetration estimates λx and λs determined from the weight of the unreacted polymer demonstrated that, for the conditions used, the reaction front is quite broad. (For example, at 40°C, in 71% acetic acid for 80 min, the fully crosslinked portion is 15 μm thick and the partially reacted region extends for another 8.5 μm.) The combined influences of the increase in penetration of the reactants in the polymer and the relief of stress secondary to this increase in penetration were reflected in the time dependence of the depths of penetration λx and λs.
Interaction of several polymers with p‐substituted phenols in aqueous solution
Authors: Inoue Masami , Otsu Takayuki 
Published: April 2003

AbstractThe interactions between several water‐soluble polymers, i.e., polyethyleneimine (PEI), poly‐(ethylene glycol) (PEG), polyacrylamide (PAM), and poly(methacrylic acid) (PMAA), and p‐X‐substituted phenols (X = CH3O, CH3 C2H5, H, Cl, Br and NO2) in aqueous solution at 30°C were investigated by means of equilibrium dialysis. By applying the Klotz equation to the results obtained, the bonding constants between these polymers, including poly(vinylpyrrolidone) (PVP) which was reported previously, and phenol were determined; they decreased in the following order: PVP > PMAA > PEI > PAM > PEG. This order was in agreement with that reported from the solubility of naphthalene, biphenyl, and alkyl halides in aqueous solution of these polymers caused by a hydrophobic bonding interaction. In this case, therefore, a hydrophobic bonding seemed to be significant. The bonding constants of these polymers with p‐substituted phenols were also determined, and they were found to be approximately correlated with Hamett σ constants of the para substituents in phenols. Therefore, it was concluded that the interactions due to electrostatic and hydrogen‐bonding forces were also important.
Liquid crystal polymers. I. Preparation and properties of p‐hydroxybenzoic acid copolyesters
Authors: Jackson W. J. , Kuhfuss H. F. 
Published: April 2003

AbstractHigh molecular weight copolyesters were prepared by the acidolysis of poly(ethylene terephthalate) with p‐acetoxybenzoic acid and polycondensation through the acetate and carboxyl groups. The mechanical properties of the injection‐molded copolyesters containing 40–90 mole‐% p‐hydroxybenzoic acid (PHB) were highly anisotropic and dependent upon the PHB content, polyester molecular weight, injection‐molding temperature, and specimen thickness. As the injection‐molding temperature increased and the specimen thickness decreased, the tensile strength, stiffness, and Izod impact strength increased when measured along the direction of flow of the polymer melt, and the coefficient of thermal expansion was zero. In some compositions these properties were superior to those of commercial glass fiber reinforced polyesters. Maximum tensile strengths, flexural moduli, notched Izod impact strengths, and minimum melt viscosities were obtained with polyesters containing 60–70 mole‐% PHB. Higher oxygen indicies (39–40) and heat deflection temperatures (150–220°C) were obtained with 80–90 mole‐% PHB.
Poly‐N‐methyliminotetrafluoro‐1,4‐phenylene
Authors: Koppang Rolf 
Published: April 2003

AbstractPoly‐N‐methyliminotetrafluoro‐1,4‐phenylene has been prepared. The polymer was insoluble in organic solvents, but dissolved in concentrated H2SO4. It started to melt at approximately 360°C with decomposition. The structure of the polymer is discussed on the basis of synthesized oligomers.
Kinetic study of the alternating copolymerization of butadiene and methyl methacrylate
Authors: Furukawa Junji , Arai Yoshihiro , Kobayashi Eiichi 
Published: April 2003

AbstractA kinetic investigation of the alternating copolymerization of butadiene and methyl methacrylate with the use of a system of ethylaluminum dichloride and vanadyl chloride as a catalyst was undertaken. The relation between the polymer yield and the molar fraction of methyl methacrylate in the feed was examined by continuous variation of butadiene and methyl methacrylate, the concentrations of total monomer, ethylaluminum dichloride, and vanadyl chloride being kept constant. This continuous variation method revealed that the polymer yield attains its maximum value with a monomer feed containing less than the 0.5 molar fraction of methyl methacrylate. This value of the molar fraction of methyl methacrylate affording the maximum polymer yield decreased on increasing the total monomer concentration but was not changed on varying the concentration of ethylaluminum dichloride. The number of active species estimated from the relation between yield and molecular weight of the polymer was almost constant, regardless of the molar fraction of methyl methacrylate in the feed. Consequently, it can be said that the maximum polymer yield depends mainly on the propagation reaction, not on the initiation reaction or the termination reaction. Three types of the mechanism have been discussed for this alternating copolymerization: polymerization via alternating addition of butadiene and methyl methacrylate complexed with ethylaluminum dichloride by the Lewis‐Mayo scheme; polymerization via the ternary intermediate of butadiene, methyl methacrylate, and ethylaluminum dichloride; polymerization via the complex formation of butadiene and methyl methacrylate complexed with ethylaluminum dichloride occurring only at the growing polymer radical. From the kinetic results obtained, it was shown that the first and third schemes are excluded, and polymerization by way of the ternary intermediate is compatible with the data.
Ring‐opening polymerization. V. Hydroxyl‐initiated polymerization of phenyl‐substituted 1,3‐dioxolan ‐2,4‐diones: A model study
Authors: Smith I. J. , Tighe B. J. 
Published: April 2003

AbstractThe reaction of C(5) phenyl‐substituted 1,3‐dioxolan‐2,4‐diones with a series of alcohols has been studied in order to obtain quantitative information relating to the role of hydroxyl initiation in the polymerization of these compounds. Results relating to both the effect of C(5) substitution and the structure of the attacking alcohol are presented. The reactions are secondorder (first‐order with respect to each component) and show some of the kinetic features associated with monosubstituted 1,3,2‐dioxathiolan‐4‐one‐2‐oxides. Structural effects are adequately represented in terms of Taft σ* and Es substituent constants. Of the parameters describing the properties of the reaction medium, the donicity concept was found to give the best correlation with rate data. It is considered that hydroxyl initiation will contribute to a relatively small extent in the polymerization of 5,5‐diphenyl‐1,3‐dioxolan‐2,4‐dione and 5‐methyl, 5‐phenyl‐1,3‐dioxolan‐2,4‐dione but will form the basis for the major chain‐growth process in 5‐phenyl‐1,3‐dioxolan‐2,4‐dione.