bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dilute solution properties of polyoctene‐1. Analysis by the kurata‐stockmayer method
Authors: Kinsinger Jack B. , Ballard Larry E. 
Published: April 2003

AbstractDilute solution properties of polyoctene‐1 have been measured by light scattering, osmometry, and viscometry and Mark‐Houwink expressions determined in two thermodynamically good solvents and one solvent at the Flory (θ) temperature. The data have been interrelated and analyzed by the Kurata‐Stockmayer technique and are shown to have good correspondence with the theory in some cases and moderately poor in others. However, the data are not sufficiently precise to permit all aspects of the adequacy of such a two‐parameter theory to be judged.
Polymerization of vinylcyclohexane with TiCl3–Al(C2H5)3 catalysts
Authors: McCarty W. H. , Parravano G. 
Published: April 2003

AbstractThe polymerization of vinylcyclohexane was followed dilatometrically in cyclohexane and n‐heptane solvents with TiCl3–Al(C2H5)3 as catalyst. In n‐heptane constant rates were obtained, while in cyclohexane a slow change of the initial rate to a lower steady‐state value was found. Polymerization rates were first order to [TiCl3] and [monomer] for concentrations >0.80 mole/l., and second order for monomer concentrations <0.80 mole/l. The rate was highest at [Al(C2H5)3] 0.005 mole/l. (Al/Ti = 0.28). Polymer intrinsic viscosity increased with time, with increasing monomer concentration, and with decreasing temperature. It was independent of [Al(C2H5)3]. A kinetic model which can account for these observations involves the alkylation of the TiCl3 surface by reaction with Al(C2H5)3 as the site‐generating step. It is also suggested that monomer molecules partake in the site‐generating step by reaction with the partially reduced TiCl3 surface. This possibility demands a rate of polymerization dependent upon the monomer concentration to a power between 1 and 2. The lower the liquid phase monomer concentration the higher the exponent of the monomer concentration in the rate expression. The melting point of the polymer was 280–285°C. The solubility of polyvinylcyclohexane was investigated for fifteen paraffinic and aromatic hydrocarbons. Only two polymer fractions exhibited amorphous x‐ray spectra, and both of these occurred at [Al(C2H5)3] 0.005 mole/l. The rate of polymerization of vinylcyclohexane is compared with that of propylene, pentene‐1, and stryrene on similar catalyst.
Some anomalous viscosities of poly‐γ‐methyl‐L‐glutamate (PMLG) solutions and relations between the aging of the solutions and the structure of spherulites grown from them
Authors: Ishikawa Saburo 
Published: April 2003

AbstractPoly‐γ‐methyl‐L‐glutamate was obtained by the NCA method in chloroform with the use of triethylamine, diethylamine, and n‐hexylamine as initiators. After polymerization, the solution was allowed to stand at 20 ± 2°C., and thin films cast from solvent, with short aging periods (∼1 month), no spherulites formed in the films. Aging periods of 2–6 months yielded positive spherulites; after much longer aging periods (6–10 months), negative spherulites were observed. In the positive spherulites, the helical axes oriented along the radius, but in negative spherulites the helical axes oriented along the tangential direction. These positive and negative spherulites were constructed of microfibrils about 45–67 A. in diameter. The relative viscosity of the aged solutions was also measured. The longer the aging time, the lower the viscosities of these aged solutions; the viscosities decrease sharply to 3 months of aging, and with aging times of 4–20 months the changes in viscosity are very small. However, the viscosity changes in every measurement and always increases during the measurement. Details of changes in viscosity are different depending upon the initiator used and the aging time. These results indicate that the decrease in viscosity is caused by intermolecular aggregation, while the increase during measurement is due to a breakup of the aggregates. Thus, the changes in the soluble state of the polymer in the aged solution seem to be closely related to the growth of both types of spherulites. The initiator has a significant influence on the structure of these aggregates. Polymer prepared with nHA initiator formed no spherulites, regardless of the aging time. No evidence was observed of the presence of the folding orientation of these α‐helical molecules or microfibrils, which indicates that the crystallization habits of helical molecules, such as polypeptides, are different from those of polyethylene. The crystallization mechanism of polypeptides is not by the so‐called folding mechanism, but by the side‐by‐side crystallization mechanism, as proposed by Ishiara or Flory. A difference in the mechanism of growth of positive and negative spherulite is also proposed.
Fluorothiocarbonyl compounds. V. Polymerization of thiocarbonyl compounds
Authors: Middleton W. J. , Jacobson H. W. , Putnam R. E. , Walter H. C. , Pye D. G. , Sharkey W. H. 
Published: April 2003

AbstractThiocarbonyl fluoride, fluoroalkylthio acid fluorides, and fluorothioketones are converted to high molecular weight polymers by anionic initiation at low temperatures. Amorphous poly(thiocarbonyl fluoride), (CF2S)n, is a tough elastomer that is highly resilient. Poly(thiocarbonyl fluoride) has a melting point of 35°C. and slowly crystallizes at room temperature to an opaque, stiff plastic. The glass transition point of the polymer is very low, being −118°C. as determined by the torsion pendulum method. Poly(trifluorothioacetyl fluoride) and polyhexafluorothioacetone are also elastomeric, but neither has the high resilience that is characteristic of poly(thiocarbonyl fluoride). Polyhexafluorothioacetone slowly depolymerizes at room temperature.
Preparation and characterization of some star‐and comb‐type branched polystyrenes
Authors: Altares T. , Wyman D. P. , Allen V. R. , Meyersen K. 
Published: April 2003

AbstractStar‐type polystyrenes, polymers with p branches attached to a common multifunctional center, and comb‐type polystyrenes, polymers with an average of p branches attached at random to a polymeric backbone, have been prepared by the reactions, respectively, of polystyryllithium of narrow chain length distribution with appropriate p‐functional molecules or with backbone polystyrene chains of narrow chain length distribution, containing the prerequisite number of benzylic‐type chloromethyl groups. The synthesis, isolation, and characterization of these types of polymers are illustrated by specific examples. Problems which are inherent to the system, e.g., metal–halogen interchange reactions, different reactivities of the chloromethyl groups, isomerization of the polystyryllithium, and other possible reactions and their consequences are discussed.
Electrically controlled anionic polymerization of methyl methacrylate
Authors: Funt B. L. , Bhadani S. N. 
Published: April 2003

AbstractMethyl methacrylate was polymerized in solutions of dimethylformamide containing quaternary ammonium salts. The course of the reaction was controlled by an electrolytic current passed through the solution. Results over a wide range of initial monomer concentrations at seven selected constant currents served to delineate the dependence of polymer yield on the control parameters. Polymer formation was directly dependent on monomer concentration and on the square root of the impressed current. The propagation reaction is anionic, and this was confirmed through inhibitor and copolymerization studies. Different solvents were tested and of these, dimethylacetamide was found to provide the best reaction medium. Molecular weights of approximately 50,000 were obtained. They were independent of salt, current, and monomer concentration, but were affected by the type of solvent and the temperature.
Dependence of the association of poly(methacrylic acid) with divalent cations on the stereoregularity of the polymers
Authors: O'Neill J. J. , Loebl E. M. , Kandanian A. Y. , Morawetz H. 
Published: April 2003

AbstractThe complexation of Cu2+ and Mg2+ with isotactic and syndiotactic poly(methacrylic acid) was studied by dialysis equilibrium over a range of degrees of ionization of the polymeric acid. It was found that the isotactic polymer has the higher affinity for Cu2+, while Mg2+ is bound more strongly to the syndiotactic species.
Heterogeneous polymer systems. II. Mechanism of stabilization of polymeric oil‐in‐oil emulsions
Authors: Molau Gunther E. 
Published: April 2003

AbstractPolymeric oil‐in‐oil emulsions (POO‐emulsions) are a new class of emulsions comprising two immiscible polymer solutions and a graft copolymer as an emulsifying agent. A mechanism of stabilization of POO‐emulsions has been proposed which explains why graft copolymers act as POO‐emulsifiers, why they accumulate in the interface of POO‐emulsions, and why they provide coalescence barriers. The basic hypothesis is that the emulsifying graft copolymers accumulate in the interface as a result of the phenomenon of phase separation of polymers in solution, and that this phenomenon also provides the repulsive forces between colliding droplets which stabilize POO‐emulsions. The formation of micelles of graft and block copolymers as a result of phase separation has been discussed, and a literature survey on the behavior of graft and block copolymers in solution has been included to support the proposed mechanism.
Effects of concentration of urethane linkage, crosslinking density, and swelling upon the viscoelastic properties of polyurethanes
Authors: Shibayama Kyoichi , Kodama Minekazu 
Published: April 2003

AbstractViscoelastic properties of unswollen and swollen specimens of homologous series of polyurethanes were studied in the glass‐to‐rubber transition region. In the case of unswollen specimens, a large discrepancy was found to exist between the thermal expansion coefficient of specific volume and that of free volume derived by comparing the WLF equation with Doolittle's equation in which the parameter B was assumed to be unity. As a possible way to account for this discrepancy, B is assumed to be a decreasing function of temperature supposing that the thermal dissociation of secondary linkage between polar groups may have a decreasing effect on the size of elemental unit of molecular motion. In the case of swollen specimens, this discrepancy was found to disappear. Differences between specimens swollen in ethyl acetate and n‐propanol were observed in the spread of the array of relaxation modulus versus temperature curves in a homologous series. As a cause of this phenomenon it is suggested that the mechanisms of imparting free volume to the system are different for ethyl acetate and n‐propanol because of characteristic interactions between swelling agents and polymers.
Epoxy compounds. VIII. Stereoregular and stereorandom polymerization of phenyl glycidyl ether with tertiary amines, and infrared spectra of poly(phenyl glycidyl ether)
Authors: Tanaka Yoshio , Kakiuchi Hiroshi 
Published: April 2003

AbstractCrystalline and amorphous polymers have been obtained from the polymerization of phenyl glycidyl ether in the presence of tertiary amines. The crystalline fraction is high melting and insoluble at room temperature. The amorphous fractions are soluble at room temperature and their molecular weights are found to be ∼950 in benzene at 30°C. The yields of the crystalline fraction and the amorphous paste fraction decreased considerably with increasing the catalyst concentration and reaction temperature above 50°C. The yield of the liquid fraction, however, increased with increasing concentration of the catalyst and the reaction temperature. The x‐ray diffraction analysis of the crystalline fraction shows that the fraction has 47–50% crystallinity and that its diffraction pattern is similar to that of poly(phenyl glycidyl ether) obtained by Noshay and Price. The infrared spectra of these fractions have been obtained in the region of 650–4000 cm.−1. These data are compared with those of polystyrene and poly(styrene oxide) and are used to make an assignment of the normal modes of the poly(phenyl glycidyl ether) molecule. On the basis of analyses of polystyrene and poly(styrene oxide), and a study of the combination bands, it has been possible to make a fairly satisfactory assignment of all of the benzene ring fundamentals of the CH2, CH, and skeletal modes.
Polyaddition reactions of bisethyleneureas and 1,1,3,3‐diethyleneurea with polymethylene dimercaptans in LiCl‐dimethylformamide
Authors: Iwakura Yoshio , Sakamoto Munenori , Yoneyama Michio 
Published: April 2003

AbstractPolyaddition reactions of 1,1′‐tetramethylenebis(3,3‐ethyleneurea) (IIa), 1,1′‐octamethylenebis(3,3‐ethyleneurea) (IIb), 1,1′‐p‐phenylenebis(3,3‐ethyleneurea) (IIc), 1,1′‐(4,4′‐diphenylmethane)bis(3,3‐ethyleneurea) (IId) and 1,1,3,3‐diethyleneurea (III) with polymethylene dimercaptans were investigated. 1,1′‐Polymethylenebis(3,3‐ethyleneureas) and polymethylene dimercaptans successfully reacted at 80–95°C. in the presence of triethylamine to give poly(urea sulfides) with intrinsic viscosities up to 1.1 in about 90% yield when dimethylformamide, dimethylacetamide, or N‐methyl‐2‐pyrrolidone containing lithium chloride as a solvent were used. The other ethyleneureas, however, failed to give high molecular weight polymers.
Characterization of ethylene–propylene block copolymers by proton magnetic resonance
Authors: Porter Roger S. 
Published: April 2003

AbstractA high‐resolution proton magnetic resonance compositional analysis has been developed for propylene polymers containing 0–40 wt.‐% ethylene as either homopolymer or copolymer blocks. The test is independent of tacticity and provides qualitative information on copolymer sequencing and propylene chain structure. The analysis was developed using a series of standard reference polymers synthesized to contain various ratios of C14‐tagged ethylene and propylene. The compositional standards were established by radiotracer analysis for C14 and by preparing weighed physical mixtures of homopolymers. Spectra were obtained at 200 ± 10°C. by placing externally heated polymer solutions into a conventional probe of a Varian A‐60 proton spectrometer. All measurements were made on ± 10% polymer solutions in diphenyl ether. Analyses are accurate to about ± 10% at higher ethylene concentrations. The method is sensitive, with less precision, to below 1% for ethylene either as blocks or homopolymer.
Alternative copolymerization of aziridines and carbon monoxide by γ‐ray irradiation
Authors: Kagiya Tsutomu , Narisawa Shizuo , Ichida Taizo , Fukui Kenichi , Yokota Hisao , Kondo Masatsune 
Published: April 2003

AbstractThe copolymerization of carbon monoxide and aziridines such as ethylenimine and propylenimine was carried out by γ‐ray irradiation. Aziridines and carbon monoxide were allowed to copolymerize under γ‐ray irradiation from a Co60 source and gave a crystalline solid copolymer. The yield of the copolymer increased with reaction temperature. The composition of copolymers obtained did not depend on the feed ratio of monomers and was found to be almost equimolar. The copolymer of ethylenimine and carbon monoxide melted at about 322–335°C. with decomposition and has an infrared spectrum identical with that of poly‐β‐alanine obtained by the hydrogen‐migration polymerization of acrylamide. The hydrolyzed product of the ethylenimine–carbon monoxide copolymer was confirmed to be β‐alanine by paper chromatography. These results lead to the conclusion that the copolymerization of aziridines and carbon monoxide took place alternatively by γ‐ray irradiation, and produced crystalline poly‐β‐alanines.
Relationship between viscosity and direct current conductivity in PVC
Authors: Kallweit Juerg‐Heinrich 
Published: April 2003

AbstractIn general, the d.c. conductivity σ has been considered to be inversely proportional to the viscosity η, but the relation ση = const. has not been proven in the case of the system poly(vinyl chloride)‐dioctyl phthalate. The experimental results can be described by σηm‐1/m = constant if the plasticizer content is not too high. The ion mobility seems to depend on a local effective viscosity, which differs from that viscosity which is derived from retardation experiments.
Donor–acceptor interaction in cationic polymerization. VI. Influence on the molecular weight of polyisobutylene of some anions derived from the complexes of aluminum trichloride with some electron donors
Authors: Zlámal Z. , Kazda A. , Ambrož L. 
Published: April 2003

AbstractThe concentration dependence of the specific conductivity of complexes of aluminum trichloride with ethanol, diethyl ether, and phenetole in a molar ratio of 1 : 1 and in 2EtOH·AlCl3 and EtOH·2AlCl3 complexes has been measured. Conductivity measurements were carried out in ethyl chloride at −78.5°C. Molar conductivity and the degree of dissociation of the complexes studied are concentration‐independent which proves an extensive association of ions. Polymerizations of isobutylene carried out in the presence of these complexes and under the same conditions as the conductivity measurements have shown that the molecular weight of polyisobutylene formed is inversely proportional to the concentration of the complex over the whole range of concentrations studied. It can be deduced from the relation between the specific conductivity and the molecular weight that only the ionized part of the complex asserts itself in the chain‐breaking processes. The chain‐breaking efficiencies of various anions are given and allow one to draw conclusions about the mode of ionization of donor molecules after the interaction with the acceptor, viz. aluminum trichloride.
Vinyl polymerization by cobaltic ions in aqueous solution: Part I. Polymerization of methyl methacrylate
Authors: Jijie K. , Santappa M. , Mahadevan V. 
Published: April 2003

AbstractPolymerization of methyl methacrylate initiated by cobaltic ions in perchloric, nitric and sulfuric acids was studied in the temperature range 15–25°C. In all three acids, water oxidation occurred as a side reaction. In HClO4 and HNO3 media monomer oxidation was shown to be an additional complicating feature. Rates of cobaltic ion disappearance, monomer disappearance, and chain lengths of polymers were measured with variations in [M], [Co3+], [H+], initially added [Co2+], and temperature. In HClO4 and HNO3 experimental results favored simultaneous initiation by Co3+ and CoOH2+ species, while in H2SO4, Co3+ ions alone were the active entities. An appropriate kinetic scheme to fit all the experimental observations is proposed. The various rate constants were evaluated.
Vinyl polymerization by cobaltic ions in aqueous solution. Part II. Polymerization of acrylonitrile and methyl acrylate
Authors: Jijie K. , Santappa M. , Mahadevan V. 
Published: April 2003

AbstractPolymerization of methyl acrylate in HClO4 and HNO3 was studied in the temperature range 10–15°C. The kinetics of the polymerization were found to be very simple, involving initiation and termination by cobaltic ions. Kinetic studies on polymerization of acrylonitrile in HClO4 and HNO3 revealed that water oxidation, and monomer oxidation were side reactions as in the case of methyl methacrylate. Experimental evidence favored the simultaneous initiation by Co3+ and CoOH2+ species. In H2SO4, certain unusual features were encountered. At low [Co3+], linear termination as well as termination by mutual combination occurred. Another interesting aspect was that CoSO4+ initiated at low [Co3+]. This was unlike the case of other monomers in H2SO4. The rates of polymerization and rates of cobaltic ion disappearance were measured with respect to changes in [M], [Co3+], [H+], temperature, etc. The various rate constants were evaluated.
Polymerization in liquid ammonia: Acrylate esters and vinyl thiolacetate
Authors: Leonard F. , Hanks G. A. , Kulkarni R. K. 
Published: April 2003

AbstractMethyl ethyl and n‐propyl acrylates when polymerized by sodium in liquid ammonia, contain an average of one amino group per polymer chain, which is indicative of amide anion initiation and chain transfer to the solvent ammonia. Isopropyl acrylate and the higher homologs contain considerably less nitrogen than required by one amino group per chain indicative of another initiating and terminating mechanism. Three alternate mechanisms are discussed. Of these, alkoxide initiation seems to be the most plausible. Vinyl thiolacetate polymers prepared under the same conditions also contain less nitrogen than required by one amino group per chain. The polymer structure is predominantly poly(vinyl thiol) with intramolecular or intermolecular disulfide bridges. The acetate part of the molecule is concomitantly split off to form acetamide.
Radiation‐induced cis–trans isomerization of polyisoprenes and temperature dependence of the equilibria
Authors: Tsurugi Jitsuo , Fukumoto Tsugio , Yamagami Masayuki , Itatani Hiroshi 
Published: April 2003

AbstractThe cis‐trans interconversion of polyisoprenes in solutions induced by γ‐radiation in the presence of a sensitizer, which is any one of organic bromides or n‐butyl mercaptan, was studied by using hevea and gutta percha as starting substances. The percentage cis remaining or converted after irradiation were determined by the infrared absorption. The equilibrium constants for the interconversion at 22, 60, and 100°C. were found to be 3.00, 5.25, and 7.33, respectively. The first‐order rate constants for cis → trans and trans → cis isomerizations at 22°C. were calculated to be 9.05 and 2.91, respectively. The results were interpreted by the mechanism proposed by Golub, according to which the double bonds from π complexes with radiolytic fragments from sensitizers give a radical transition state capable of interconversion. However, our results showing that heating shifts the equilibrium toward trans isomer are not in accord with the mechanisms of the radiation‐induced isomerization of polybutadiene of Golub and those for photoisomerization of aromatic azo compounds.
Inorganic coordination polymers. VIII. Cobalt(II) and zinc(II) phosphinate polymers and copolymers
Authors: Rose Selwyn H. , Block B. P. 
Published: April 2003

AbstractThe preparation, properties, x‐ray powder patterns, and TGA curves are given for cobalt(II) dimethyl‐, methylphenyl‐ and diphenylphosphinate. The polymeric character of cobalt(II) methylphenylphosphinate is demonstrated by its colligative properties and melt indexes. These cobalt(II) phosphinates along with hybrid copolymers of zinc(II) or cobalt(II) were prepared by the reaction of the metal acetate with the appropriate phosphinic acid or mixture of phosphinic acids. A consideration of the hybrid copolymers leads to the conclusion that both the zinc(II) and cobalt(II) dimethyl‐ and diphenylphosphinates are likewise polymeric. Thermal stability is discussed in terms of the structures suggested, and it is shown that crystallinity is related to polymer symmetry.
Permeation, sorption, and diffusion of water in ethyl cellulose
Authors: Wellons J. D. , Stannett V. 
Published: April 2003

AbstractThe permeability of ethyl cellulose to water vapor and liquid water was measured as a function of temperature. A change of slope was found in the Arrhenius plots at about 50°C., close to the glass transition. The sorption isotherms showed essentially zero heat of mixing in agreement with other workers. The diffusion constants were measured in four ways, viz., sorption, desorption, time lag, and by dividing the permeability constants by the equilibrium solubility coefficients. The time lag method gave diffusion constants which were independent of concentration, whereas the other three methods led to diffusion constants which steadily decreased with concentration. All the methods, however, extrapolated to about the same value at zero concentration. The decreasing diffusivities are believed to be due to the clustering of water molecules in the polymer. However, no clustering appeared to take place under the conditions of the time lag measurements.