bluuebunny/crossref_metadata_2025_split huggingface dataset:
6‐O‐methacryloyl‐D‐galactose: A reactive, water‐soluble monomer
Authors: Black W. A. P. , Colquhoun J. A. , Dewar E. T. 
Published: April 2003

AbstractDeacetonation of the crystalline monomer, 1.2:3.4‐di‐O‐isopropylidene‐6‐O‐methacryloyl‐α‐D‐galactopyranose(DGM, I) in 80% formic acid solution at 20°C gave the syrupy, water‐soluble monomer 6‐O‐methacryloyl‐α‐D‐galactopyranose (α‐GM) was a white crystalline compound which showed characteristic infrared absorption. The NMR spectrum of α‐GM in deuterium oxide was complicated by two variable: (i) mutarotation and (ii) gradual polymerisation. Syrupy GM was polymerised with ammonium persulphate to a water‐insoluble, cross‐linked hydrogel.
Thermal degradation of polyacetaldehyde having polyvinylalcohol‐type structure
Authors: Matsubara Tsutomu , Imoto Tatsuya 
Published: April 2003

AbstractIt was reported that an acetaldehyde polymer (PACH) having the polyvinylalcohol type structure was obtained by polymerization of acetaldehyde with alkali metal amalgam as catalyst. The thermal degradation of this polymer was carried out at 81.5, 110.8, 136.5, 170.0, 2104.0, and 219.5°C by thermogravimetric analysis. The two samples studied had molecular weights of 487 and 530 resp. At an early stage the rate of thermal degradation is of the first order with respect to polymer concentration. At a later stage, the degradation rate is not first order, because of some side‐reactions. At 219.5°C, the thermal degradation rates are 9.5·10−2%/sec. (Mol. wt. = 530), and 1.3·10−1%/sec. (Mol. wt. = 487). Activation energy is 13 kcal/mole for both polymers.
The mean activity coefficient of polystyrenesulphonic acid
Authors: Dolar D. , Leskovšek H. 
Published: April 2003

AbstractThe electromotive force of the concentration cell (Pt) H2/polystyrenesulphonic acid polystyrenesulphonic acid/H2 (Pt) with liquid‐liquid junction was measured in the concentration range of the polystyrenesulphonic acid from 0.1 to 0.001 monomolal. The values of the mean activity coefficient, derived from these measurements, were compared with those calculated on the basis of the rodlike model. A very good agreement between theory and Zxperiment has been found.
Polymer deformation. XIII. Deformation of thin films of polyoxymethylene
Authors: O'Leary K. , Geil P. H. 
Published: April 2003

AbstractThe deformation of four types of thin films of polyoxymethylene is discussed. Failure, even at elevated temperatures, occurred by micronecking or in a brittle manner. Slip bands were observed in some of the samples. Moiré patterns from portions of the sample indicated little internal distortion of the lamellae during the brittle failure. Micronecking with fibril formation occurred primarily during draw at temperatures near the α transition temperature. The results are in general agreement with concepts of the deformation process previously developed on the basis of work with thin films of polyethylene but cannot be applied directly to the mechanism of deformation of bulk samples.
Calorimetric studies of drawn polyethylene terephthalate
Authors: Koenig J. L. , Mele M. D. 
Published: April 2003

AbstractDynamic differential calorimetry and density measurements have been made on drawn polyethylene terephthalate. The crystallinity and heats of fusion depend on the type of molecular rearrangements produced by the extent of draw and the temperature of draw. At low temperatures (near the glass transition) the molecules relieve strain by uncoiling with little sliding or alignment occurring. At temperatures above 100°C the molecules glide past one another to relieve strain with little uncoiling Strain‐induced crystals are formed in the samples drawn more than 160% at temperatures near the glass transition; at high strain, both chain alignment and uncoiling occur and produce crystallization at these temperatures. At higher temperatures and high strain, the uncoiling is too small to allow crystallization. Annealing a drawn sample under strain resulted in an increase in uncoiling which is proportional to the strain.
Permeation, diffusion, and solution of gases and water vapor in unplasticized poly(vinylchloride)
Authors: Tikhomirov B. P. , Hopfenberg H. B. , Stannett V. , Williams J. L. 
Published: April 2003

AbstractThe transport behavior of a number of permanent gases of varying molecular size and of water vapor was studied in calendered films of unplasticized poly(vinylchloride). Permeabilities, diffusivities, and solubilities were measured over a range of temperatures traversing the glass transition. A discrete change in the activation energy for diffusion was observed for Ar and Kr. No change in the activation energy for diffusion for He, Ne, CH4, N2, CO2, O2, and H2O was observed, as the glass transition was traversed. This appeared to be the first polymer system studied in detail in which the change in activation energy for diffusion is related to penetrant size rather than to a unique dependence upon polymer fine structurej
The polymerization of acrolein
Authors: Kitahama Yoshiharu , Ishida Shinichi 
Published: April 2003

AbstractThe polymerization of acrolein was carried out using the coordination Complexes of metallic salts with organic ligands. The polymer obtained had the same infrared spectrum and properties compared to that prepared by R. C. SCHULZ, who used sodium, and whose polymer consisted mainly of the structure produced by the aldehyde group polymerization of acrolein.Active catalysts for the polymerization consist of metallic salts such as CdI2, ZnCl2 and ligands such as pyridine and triphenyl phosphine.Rate of polymerization was considerably dependent on temperature, solvent and kinds of catalysts. These effects indicated that the polymerization proceeded through ionic mechanism.
Cationic copolymerization of trioxane with styrene. II. Some factors effect on the copolymerization of trioxane with styrene
Authors: Minoura Yuji , Mitoh Motonort , Mabuchi Yoshiki 
Published: April 2003

AbstractThe homogeneous copolymerization of trioxane with styrene was carried out using various catalysts and solvents. The copolymerization rate increased with increase in the dielectric constant of the solvent used and decreased with increase In the acidity of the catalyst used. The reactivity of styrene increased and on the contrary, the reactivity of trioxane decreased with increase in the dielectric constant of the solvent.
Vinyl polymerization. 221. Polymerization of methyl methacrylate in the presence of cellulose triacetate
Authors: Kubushiro Kanemitsu , Takemoto Kiichi , Imoto Minoru 
Published: April 2003

AbstractA kinetic study on the polymerization of methyl methacrylate (MMA) was made in the presence of cellulose triacetate (CTA) and water. In this case, water was found to be not necessary for the initiation of polymerization. The reaction proceeds by a radical mechanism, and the rate of polymerization can be expressed by the following equation:

The overall activation energy for the polymerization was estimated as 7.9 kcal/mole. The grafting efficiency of polymethyl methacrylate (PMMA) to CTA decreased with increase in polymerization temperature. The molecular weight of the extracted PMMA decreased also slightly with increase in polymerization temperature and was independent on the concentration of CTA. These results suggest that the molecular weight of PMMA is mainly affected by the transfer of growing radical to monomer molecule.
Unperturbed dimension of polymer molecules from viscosity measurements
Authors: Deb P. C. , Chatterjee S. R. 
Published: April 2003

AbstractBased on the theory of rate process for viscous flow, an expression for Φ (FLORY constant) has been given according to which Φ should depend on the polymer‐solvent pair and temprature. The variation of Φ, [η], and k, the latter two being fundamental terms of the equation c/ηsp = l/η − kc, has been utilised for the determination of unperturbed dimension of polymer molecules in solution. The importance of k and the alternative expressions for the same are discussd. The values of
\documentclass{article}\pagestyle{empty}\begin{document}$\[ \left( {{{\overline {\text{r}_\text{0}^\text{2} } } \mathord{\left/ {\vphantom {{\overline {\text{r}_\text{0}^\text{2} } } \text{M}}} \right. \kern&#x02010;\nulldelimiterspace} \text{M}}} \right)^{1/2} $\end{document}
are found to be in good agreement with the literature values.
Über die herstellung von tris‐O‐trimethylsilylpolysacchariden
Authors: Keilich Von G. , Tihlarik K. , Husemann E. 
Published: April 2003

Abstract2.3.6‐Tris‐O‐trimethylsilyl‐amylose, ‐cellulose und Tris‐O‐trimethylsilyl‐pullulan entstehen durch heterogene Umsetzung der entsprechenden Polyglucane in Pyridin mit Trimethylchlorsilan; eine vollständige Substitution der verzweigten Polyglucane Dextran und Amylopektin wird dagegen nicht erreicht.
The structure of beryllium di‐n‐butyphosphinate poymer
Authors: Giancotti Vincenzo , Giordano Federico , Ripamonti Alberto 
Published: April 2003

AbstractThe results of the interpretation of the X‐ray fibre photograph of the copolymer

isomorphous with the homopolymer

are reported. The unit cell has a monoclinic symmetry with

.The molecular chains are characterized by a backbone strucure with tetrahedral metal atoms bonded by alternate single and triple bridging phosphinate groups. The best agreement between observed and calculated intensities was obtained assuming the space group P21/m. Pairs of parallel chains are packed so that the triple bridged cages of one chain fall midway those of the other chain in a way similar to that found in the β‐form of the polymer
The second virial coefficient of polyelectrolytes
Authors: Patel J. R. , Patel R. D. 
Published: April 2003

AbstractA critical analysis of the data, obtained by NAGASAWA et al. for the second virial coefficient (A2) determined by light scattering measurements have been carried out for sodium polystyrene sulfonate (NaPSS). The result are analyzed in light of the different theories for the second virial coefficient. Finally, a critical discussion has been made of the theory proposed for the separate determination of the electrostatic interactions and the chain character of the polyelectrolyte by means of which the deviation from ideality are meansured.
Mercaptale als spezifische inhibitoren für mit dibenzoylperoxid initiierte polymerisationen. Untersuchung von O‐, S‐ und N‐vinylverbindungen. IX.
Authors: Gollmer Von Kl. , Ringsdorf H. 
Published: April 2003

AbstractBei Versuchen zur radikalischen Polymerisation von S‐Vinylverbindungen haben sich Mercaptale als spezifische Inhibitoren für Dibenzoylperoxid (BPO) erwiesen. DieSCH2SGruppe bedingt einen induzierten Peroxidzerfall unte Bildung von Benzoesäure und Acyloxymercaptalen. Diese konnten durch Modellversuche mit gesättigten niedermolekularen und makromolekularen Mercaptalen isoliert bzw. nachgewiesen werdern.
Zur kinetik der polyreaktion von styrol mit löslichen ziegler‐natta‐katalysatoren. I.
Authors: Reichert Von K. H. , Berthold J. , Dornow V. 
Published: April 2003

AbstractDie Polyreaktion von Styrol mit dem löslichen ZIEGLER‐NATTA‐Katalysator

wird kinetisch untersucht.Durch Verwendung einer 14C‐markierten Katalysatorkomponente kann nachgewiesen werden, daß unter den gegebenen Reaktionsbedingungen die Polyreaktion von Styrol fast ausschließlich durch Insertion des Monomeren zwischen eine Metall‐Kohlenstoff‐Bindung erfolgt. Auf Grund der kinetischen Befunde lassen sich folgende Aussagen über das Reaktionsgeschehen dieser Polyreaktion machen:In einer Folgereaktion des Mischkatalysators wird die eigentliche polymerisationsaktive Spezies gebildet, wobei die Bildungsgeschwindigkeit in Gegenwart von Styrol proportional der Aluminiumalkyl‐und Monomerkonzentration ist. Dieser aktive Zwischenkomplex kann die Polyreaktion des Styrols initiieren und gleichzeitig in einer Parallelreaktion unter Reduktion desaktiviert werden. Wachstum erfolgt, unter weitgehendem Ausschluß von Verunreinigungen und nur unter den gegebenen Katalysator‐Konzentrationsverhßältnissen, fast ausschließlich durch Insertion des Monomeren zwischen eine übergangsmetall‐Kohlenstoff‐Bindung des aktiven Komplexes. Als Abbruchreaktionen sind drei verschiedene Reaktionen anzunehmen, und zwar mit Monomerem, überschüssigem Aluminiumalkyl und dem aktiven Komplex selbst. Entsprechend ergibt sich, daß die maximale Bruttopolymerisationsgeschwindigkeit nur proportional der Monomerkonzentration im Quadrat und praktisch unabhängig von der Katalysatorkonzentration ist. Auf Grund der Befunde mit vorreagiertem Katalysatorsystem kann dem Komplex \documentclass{article}\pagestyle{empty}\begin{document}$ ({\rm C}_{\rm 5} {\rm H}_{\rm 5} )_2 {\rm C}_{\rm 2} {\rm H}_{\rm 5} {\rm TiCl} \cdot {\rm ClAlC}_{\rm 2} {\rm H}_{\rm 5} {\rm Cl,} $\end{document} oder einem im Gleichgewicht mit ihm stehendem Produkt die Polymerisationsaktivität zugesprochen werden.
Partielle spezifische refraktionen von polymethylmethacrylat und polystyrol. II. Eine methode zur endgruppenanalyse
Authors: Bodmann Von Otto 
Published: April 2003

AbstractAls Methode zur Endgruppenanalyse bei polymerhomologen Reihen werden die Spezifische Refraktion und ihre Dispersion untersucht. Am Beispiel von Polymethylmethacrylat‐ und Polystyrolpräparaten, die mit Dibenzoylperoxid polymerisiert wurden, wird gezeigt, daß sowohl auf die Art wie auch auf die Zahl der Endgruppen pro Molekül Schlüsse gezogen werden können. Voraussetzung ist, daß (1) die spezifischen Refraktionen und Dispersionen von Kette und Endgruppen verschieden sind und (2) keine störenden Exaltationseffekte vorliegen.
Untersuchungen über den endgruppeneinfluß bei oligomeren. 1. Mitt.: Die abhängigkeit des enthalpiekoeffizienten vom polymerisationsgrad
Authors: Sotobayashi Von Hideto 
Published: April 2003

AbstractFür Die Abhängigkeit des BH‐Wertes vom Polymerisationsgrad wurde mit Hilfe des Gittermodells eine neue Theorie aufgestellt, die einen Konformations‐ und Endgruppeneffekt berücksichtigt. Dabei wird angenommen, daß die internmolekularen Kontakte im Gitter statistisch verteilt und die Polymermoleküle steif sind.Mit Hilfe enies Computers wurde die Konformation oligomerer Moleküle untersucht.Für alle Konformationen wurde die glelche Auftrittswahrscheinlichkeit vorausgesetzt. Mit Hilfe der Theorie wurde die Abhängigkeit der BH‐Werte vorn Polymerisationsgrad für verschiedene Systeme berechnet. Die Übereinstimmung mit dem Experiment ist über einen großen Bereich des Polymerisationsgrads befriedigend.
Oligoester. III. The synthesis of oligohydroxypivalates having unprotected terminal groups
Authors: Iwakura Yoshio , Hayashi Katsumi , Iwata Kaoru , Matsuo Shunji 
Published: April 2003

AbstractLinear oligohydroxypivalates terminated with a hydroxy and a carboxy group

were synthesized by the catalytic hydrogenolysis of the corresponding oligohydroxypivalate benzyl esters. The oligohydroxypivalate benzyl esters, in turn, were prepared by a stepwise method which involved the condensation of dichloroacetoxypivaloyl chloride with a preceding hydroxy terminated oligohydroxypivalate followed by removal of the dichloroacetyl group by mild alkaline hydrolysis. Melting points, infrared spectra and nuclear magnetic resonance spectra of the oligomers were studied.
Studies on the charge‐transfer complex and polymerizations. Part XIX. Spontaneous copolymerization of 1.2‐dimethoxyethylen and p‐dioxene with maleic anhydride
Authors: Kokubo Takashi , Iwatsuki Shouji , Yamashita Yuya 
Published: April 2003

AbstractThe kinetics of spontaneous copolymerization of 1.2‐dimethoxyethylene and p‐dioxene with maleic anhydride were studied and found to obey the following relation:

These results were explained by regarding the charge‐transfer complex between ethers and maleic anhydride as a single monomer and assuming the participation of the charge‐transfer complex in both the initiation and propagation steps.The activation energies of thermal (spontaneous) polymerization were calculated for the p‐dioxene‐maleic anhydride system as follows:
The effect of hydroxyl ion concentration and ionic strength on the intrinsic viscosity of hydroxyethyl cellulose at high velocity gradients
Authors: Elmgren Hans , Norrby Sverker 
Published: April 2003

AbstractThe intrinsic viscosity of a fractionated hydroxyethyl cellulose sample (HEC) in solvents of various ionic strengths and pH (≥ 7) was measured at high rates of shear by means of a capillary viscometer. The results show that the cellulose molecule is a polyelectrolyte at pH values greater than 13, and that the charge density on the cellulose chain increases with increasing pH. The intrinsic viscosity decreases with increasing pH with its strongest pH dependence at pH ≈ 13.7. The results also show that the stiffness of HEC in neutral solvents is about the same as that of cellulose trinitrate in ethyl acetate1. The flexibility of HEC increases with increasing pH of the solvent. By means of the empirical method of hyperbolic extrapolation1 to infinite rate of shear, the same value of the intrinsic viscosity of the sample was obtained in all solvents except for those in which polyelectrolyte effects were not swamped out by an excess of salt. All these results are explained by a model which describes the extended configuration of cellulose molecules as partly due to intramolecular hydrogen bonds via the 6‐position hydroxyl proton to an adjacent anhydroglucose unit2.
The oligomerization of isoprene with modified ziegler catalysts
Authors: Itakura Jo , Tanaka Hisao 
Published: April 2003

AbstractThe oligomerization of isoprene with modified ZIEGLER catalysts was studied. Dimers of isoprene were obtained in 70–90% yield using combined catalysts of diethylaluminum chloride, dimethyl sulfoxide, and a titanium(IV) compound, such as titanium di‐(p‐toluenesulfonate) dichloride and N‐vinylpyrrolidone or alkylene carbonate complexes of titanium tetrachloride. Two isomeric dimers, produced in approximately equal molar ratio, were found as the main product accompanied by small amounts of a third dimer and of trimers. Each dimer was separated by means of preparative gas chromatography and subjected to analyses. The two predominant compounds were identified as 2.4‐dimethyl‐4‐ethenyl‐1‐cyclohexene and 2.7‐dimethyl‐1.3.6‐octatriene, respectively. Possible mechanisms are discussed in relation to the oligomerization of butadiene on the basis of the product analysis.
Radical reactions initiated by chelate complexes of transition metals. I. The kinetics of the reaction of bis‐(–)ephedrine copper(II) chelate with halogen containing compounds
Authors: Bartoň J. , Szöcs F. , Nemček J. 
Published: April 2003

AbstractThe kinetics of the reaction of bis‐(–)ephedrine copper(II) chelate with halogen containing compounds and carbon tetrachloride in benzene and/or cyclohexane solutions were studied. The course of chelate reaction with carbon tetrachloride is in agreement with the kinetic law for a pseudomonomolecular reaction, with the rate constant k′=8.60·10−5 mole−1 l. sec−1 at 20°C. In solutions of carbon tetrachloride in benzene and/or cyclohexane there was an increase of the rate constant with decreasing carbon tetrachloride concentration in the first case, while a decrease was observed in the second case. The variation of the rate constant of chelate reaction with carbon tetrachloride in presence of benzene and/or cyclohexane was interpreted by assuming the chelate molecule conformation to be influenced by the solvent. It was found that halogen compounds react the more readily with the chelate the more halogen atoms are present in the molecule. It was shown by means of ESR spectroscopy that in the course of the reaction of the chelate with carbon tetrachloride a reduction of the central metal of the chelate takes place. The rate constant k″ of the reaction Cu2+ + CCl4 → Cu1+ + products has a value of 4.63·10−6 mole−1 l. sec−1 at ambient temperature.
Monte‐carlo‐rechnungen an makromolekülmodellen. 1. Mitt.: Der quadratische mittelwert des fadenendenastands
Authors: Bruns Von Wolfgang 
Published: April 2003

AbstractMonte‐Carlo‐Methoden wurden benutzt, um mit Hilfe einer Rechenmaschine Zufallsketten zu erzeugen, die als Vorlage für reale Makromoleküle dienen können. Dabei wurden zwei gitterfreie Modelle, bei denen entweder Valenz‐ und Rotationswinkel (A) oder die Rotationswinkel allein (B) frei wählbar waren, verwendet; die Wirkung des „ausgeschlossnen Volumens”︁ wurde berücksichtigt. Die Abhängigkeit des mittleren Quadrats des Fadenendenabstands von der Segmentzahl wurde an Hand von zwei aus der Literatur bekannten Gleichungen diskutiert. Sie läßt sich in guter Näherun, durch die Bezichungen h̄2= 1,68 n1,203bzw. h̄2= 1,21 n1,248wiedergeben.
Butene‐1/propylene copolymers. Influence of the comonomerie units on polymorphism
Authors: Gianotti Giuseppe , Capizzi Amedeo 
Published: April 2003

AbstractButene‐1/propylene copolymers at different compositions have been studied by differential scanning calorimeter (D.S.C.) and dilatometric techniques in order to ascertain the influence of the comonomeric units on polymorphism.The results suggest that the phase transitions of these copolymers have the peculiar trend of polybutene‐1, whereas remarkable changes are observed in the kinetic parameters. Contrary to what known so far, for the himopolymer, they can also crystallize from the melt directly in a low‐melting form called modif. 1′.
Isotactic polybutene‐1: Internal pressure measurements
Authors: Turturro Antonio 
Published: April 2003

AbstractSome internal pressure (Pi) measurements on modification 1 and 2 of isotactic polybutene‐1 are reported.They confirm the solid‐solid transition at 65°C for form 2 and show Pi of 1, at room temperature, to be higher than that of both form 2 and the melt; the molten polymer has an internal pressure intermediate between form 1 and form 2.
Über eine neue Methode zur kinetischen Untersuchung der Perlpolymerisation
Authors: Gunesch Von Heinz , Schneider I. A. 
Published: April 2003

AbstractEs wird in vorliegender Arbeit eine kinetische Untersuchungsmethode der Perlpolymerisation vorgeschlagen, wobei der isotherme Ablauf der Reaktion dadurch gewährleistet wird, daß die Polymerisationswärme von temperiertem Wasser aufgenommen wird, das in das Reaktionsgemisch einfließt.Die zugeflossen Wassermenge als Funktion der Zeit ermöglicht nach einer vorherigen Eichung, kinetische Umsatzkurven für den ganzen Reaktionsablauf abzuleiten.Es werden die verwendete Apparatur und die Überprüfung der Methode während der Perlpolymerisation des Vinylacetats beschrieben.
Vinyl Polymerization. 246. Polymerization of Vinyl Chloride with Monoethanolamine and Carbon Tetrachloride System
Authors: Takemoto Kiichi , Sasabe Masazumi , Imoto Minoru 
Published: April 2003

AbstractReaction of amines with carbon tetrachloride has received considerable attention1–3, and it has been pointed out that the presence of copper metal is substantial for the reaction4,5. On the other hand, oligomerization of ethylene was studied by amine and carbon tetrachloride system, and discussed whether any metal or metal salts can play a role for initiating the reaction6,7. Polymerization of vinyl monomers was also carried out by imidazole and carbon tetrachloride system8,9.
Über die Darstellung und Polymerisation von 4‐Vinyldiphenyl, 11‐Vinyl‐p‐terphenyl und 1 2‐Vinyl‐p‐terphenyl
Authors: Kern Von W. , Heitz W. , Jäger M. , Pfitzner K. , Wirth H. O. 
Published: April 2003

AbstractFür die Darstellung von 4‐Vinyldiphenyl und 11‐Vinyl‐p‐terphenyl wurden einfache, verallgemeinerungsfähige Synthesen ausgearbeitet. Durch Umsetzung entsprechender Carbinole mit Methansulfonsäurechlorid in Pyridin gelang die Darstellung der Vinylverbindungen in einer einstufigen Reaktion.Die Untersuchung der radikalischen Copolymerization der Monomeren mit Styrol ergab bei 4‐Vinyldiphenyl und 12‐Vinyl‐p‐terphenyl einen bevorzugten Einbau in die Polymerketten, während 11‐Vinyl‐p‐terphenyl nur in untergeordnetem Maße in Polystyrolketten eingebaut wurde.