bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen zur Auflösung der Cellulose in binären aprotischen Systemen. 3. Mitt. Untersuchungen über Wechselwirkungen zwischen einzelen Lösungsmittelkomponenten für Cellulose und Überlegungen zum Lösemechanismus
Authors: Berger W. , Kabrelian V. , Keck M. , Kressler J. , Herzog K. , Scheller D. , Sang U Mun , Philipp B. 
Published: April 2003

AbstractEs werden Aussagen zu den Wechselwirkungen zwischen N‐Methylmorpholin‐N‐oxid und einer zweiten protischen oder aprotischen Lösungsmittelkomponente für Cellulose getroffen. Als Untersuchungsmethoden dienten DSC‐,1H‐NMR‐,FTIR‐ und RWWS‐Messungen. Um den Celluloselösemechanismus zu erklären, wurden einige Modellsubstanzen mit OH‐Gruppen in binären Systemen mit NMMNO untersucht. Die hier und in früheren Mitteilungen erhaltenen experimentellen Ergebnisse werden hinsichtlich der Lösewirkung von Mischungen aus NMMNO·1H2O und unterschiedlichen Zweitkomponenten gegenüber Cellulose zusammenfassend diskutiert.
Poly(ether ester) fibres
Authors: Gogeva T. , Fakirov S. , Mishinev J. , Sarkisova L. 
Published: April 2003

AbstractThe conditions of fibre formation by melt spinning of a thermoplastic elastomeric poly(ether ester) based on poly(butylene terephthalate) and poly(ethylene oxide) glycol with molecular weight of 1000 are studied. Some properties of both the starting polymer and the final fibres are discussed. A highly regular structure of the fibre is observed by scanning electron microscopy.
Influence of calcium carbonate on the toughness of polypropylene
Authors: Nezbedova E. , Ponesicky J. , Sova M. 
Published: April 2003

AbstractThe reasons for macroscopic changes of the toughness of isotactic polypropylene filled with different types of calcium carbonate are studied. The changes are analyzed on the basis of unnotched and notched impact strength, and on microscopic observations of fracture surfaces. The results are discussed with respect to the matrix and amount and size of the filler particles.
TSDC studies on thermoelectrets of CR‐39(DOP)
Authors: Singh A. , Singh P. , Singh V. P. , Singh N. 
Published: April 2003

AbstractThermoelectrets of CR‐39(DOP) were formed and their thermally stimulated discharge current studied. In the present work, effects of different forming temperatures, polarizing fields and storage times have been studies with a view to understand the electret behaviour of this material. The polarization seems to have a dipolar origin. The activation energy and relaxation times have also been calculated.
Polymerization of carboxyl group containing monomers with chemical initiators. Part II. Polymerization of methacrylic acid
Authors: Ibrahim N. A. , Haggag K. , Shoushda M. Abou , Hebeish A. 
Published: April 2003

AbstractThe polymerization of methacrylic acid has been carried out using K2S2O8 in conjunction with different reducing agents as initiators. The effects of the type of reductant, concentrations of oxidant, reductant and methacrylic acid, as well as degree of neutralization of the monomer have been investigated in dependence on polymerization time and temperature.
Amino resin microcapsules. IV. Surface tension of the resins and mechanism of capsule formation
Authors: Dietrich K. , Bonatz E. , Nastke R. , Herma H. , Walter M. , Teige W. 
Published: April 2003

AbstractThe surface activity of aqueous solutions of melamine formaldehyde resins was investigated at different stages of the resin synthesis. Partially methanol etherigied melamine formaldehyde resins, which are able to form microcapsules, are reactive surface active compounds. The formation of capsuole walls with these resins proved to be a one‐component interfacial polycondensation reaction.
Untersuchungen zum Verhalten von Reaktionskompositen aus Poly(butadienepoxid) und Polykieselsäuuren in wäßrigen Elektrolytlöusungen unterschiedlichen pH‐Wertes
Authors: Erler U. , Heublein B. , Heublein G. 
Published: April 2003

AbstractUnterschiedliche Mengen Poly(butadienepoxid) wurden durch heterogene polymeranaloge Reaktion an der Oberfläche von Polykieselsäuren fixiert. Die Untersuchung der pH‐Stabilität in wäßrigen Pufferlösungen ergibt gute Stabilität im pH‐Bereich 2 bis 12 bei vollständig polymerbelegten Oberflächen. Niedrige Polymerbelegung der Polykieselsäureoberfläche mit Poly(butadienepoxid) äßert sich in pH‐Instabilität und Polymerverlust auf Grund der Hydrolyse von SiOCBindungen.
Structure of fibres prepared from polypropylene‐polycaproamide mixture 2. Drawn fibres
Authors: Ďurčová O. , Gróaf I. , Marcinčin A. 
Published: April 2003

AbstractThe structural and physical properties of drawn polypropylene‐polycaproamide fibres were investigated. A polycaproamide content up to 7 wt % improves some properties of the fibres. Higher content leads to the formation of porosity, decreases the uniformity of the dispersion of the polycaproamide phase, and deteriorates the mechanical properties. In comparison with polypropylene fibres higher sorption of humidity and lower electrical charge were observed with the polypropylene‐polycaproamide fibres.
Copolymerization of ethylene and vinyl chloride in the presence of Ziegler‐Natta catalysts I. Interrelation between the synthesis conditions and the physicochemical properties of the resultant copolymers
Authors: Belov G. P. , Solovyova T. I. , Smirnov V. I. 
Published: April 2003

AbstractThe homopolymerization of vinyl chloride and its copolymerization with ethylene in the presence of catalytic systems composed of transition metal organic compounds such as (C5H5)2TiCl2, vanadium, cobalt, nickel and chromium acetylacetonates, Ti(On‐C4H9)4 in combination with Al(C2H5)3, Al(C2H5)2Cl and Al(C2H5)Cl2 is studied. The effects of the solvent, e.g. heptane, toluene, benzene, ethyl chloride, and dichloroethane‐1,2, on the process of copolymerization in the presence of the catalytic system Ti(On‐C4H9)4/Al(C2H5)3‐nCln and on the physicochemical properties of the resultant copolymers are considered.
Study of the parameters affecting the emulsion polymerization of vinyl acetate
Authors: Badran A. S. , Yehia A. A. , Moustafa A. B. , Shendy S. M. M. 
Published: April 2003

AbstractThe kinetics of emulsion polymerization of vinyl acetate using the redox system potassium persulfate – acetone sodium bisulfite as initiator is studied. The effect of the reaction conditions on the rate of polymerization and on the number and size of the formed particles is established. The polymerization proceeded smoothly till high conversion and yielded stable emulsions. The apparent activation energy for the polymerization system has been calculated.
Semicontinuous emulsion polymerization of vinyl acetate. VIII. Copolymerization with di‐2‐ethylhexyl maleate
Authors: Donescu D. , Goşa K. , Languri J. 
Published: April 2003

AbstractThe semicontinuous emulsions copolymerization of vinyl acetate with 2‐ethylhexyl maleate has been studied. The amount of polymer obtained during the continuous addition of commonomers increases at first nonlinearly than linearly with time. During this period the viscosity of the obtained emulsion is not proportional to the polymer content. The conversions are affected by the reaction conditions, e.g. the stirring rate and the amount of the transfer agent n‐butanol and its distribution between the initial reactor charge und the continuously introduced comonomers.
Grafting of ethyl acrylate onto starch
Authors: Okieimen F. E. , Egharevba F. , Jideonwo A. 
Published: April 2003

AbstractGraft copolymerization of ethyl acrylate onto starch in aqueous medium was studied using various concentrations of ceric ions as initiator. It was found that termination of copolymerization occurred mainly by the interaction of ceric ions with the growing graft polymer chain. The value of the chain transfer constant was determined. Further the graft copolymerization of ethyl acrylate onto starch in the presence of small quantities of acrylonitrile was examined. An increase in the amount of acrylonitrile in the monomer mixture did not produce a corresponding increase in the amount of the monomer in the graft copolymer.
Zur Partialfraktionierung von Celluloseacetat
Authors: Ludwig J. , Philipp B. 
Published: April 2003

AbstractAnhand von 9 Cellulose‐2,5‐acetat‐Proben wurden verschiedene Arbeitsweisen der Partialfraktionierung durch Extraktion mit einem Aceton‐Wasser‐Gemisch (55:45 Masse‐%) und durch Fällung aus Acetonlösung mit der entsprechenden Wassermenge verglichen. Bei Längerer Standzeit vor der Aufarbeitung der Franktionen wurde eine erhebliche Deacetylierung beobachtet. Der unter sonst vergleichbaren Bedingungen in Lösung befindliche Polymerianteil war bei der Fällfraktionierung stets größer als bei der Extraktion. Die Aussagemöglichkeiten der angewandten Methoden für die Charakterisierung von Celluloseacetaten werden diskutiert.
Investigation of some physico‐chemical properties of vinyl acetate‐itaconic acid copolymers
Authors: Mateva R. , Kotzeva L. , Gitzov I. 
Published: April 2003

AbstractThe influence of the quantity and the method of introduction of itaconic acid in the polymerization system on the molecular mass and the molecular mass distribution of the obtained vinyl acetate‐itaconic acid copolymers and some of the physico‐chemical properties of the resulting products are studied. It is established that quantities up to 2 to 3 mole % itaconic acid do not change essentially the reaction rate and the average molecular mass of the copolymers, but the content of itaconic acid improves the adhesion to metals and the surface activity of the poly(vinyl alcohol) which was obtained from the products.
Thermal studies on isotactic polypropylene. Measurements of Tg, Tm and ΔHf
Authors: Sadiku E. R. 
Published: April 2003

AbstractMeasurements of the glass transition temperature Tg, the melting temperature Tm and the enthalpy of fusion ΔHf were made with three types of polypropylene with different orientation by means of differential scanning calorimetry and dynamic mechanical analysis. The difference in the Tg values determined with the two techniques is ca. 30 K. Tm and ΔHf increase with increase of the draw ratio of the filaments. These increases indicate an increase in the crystallinity between the undrawn and drawn specimen as the result of better chain alignment, and hence the cooperative resistance of the main chain segments of thermal motions.
The antielectrostatic properties of imidazolium chlorides
Authors: Pernak J. , Biernacka R. , Skrzypczak A. , Pasternak A. 
Published: April 2003

AbstractThe antielectrostatic properties of a series of imidazolium chlorides were investigated. The surface resistance, half decay time, and the induced maximum voltage of polyethylene films treated with these chlorides were measured. From among 64 studied compounds 28 revealed an excellent antielectrostatic effect.
Electrical conductivity and stability of polymeric \documentclass{article}\pagestyle{empty}\begin{document}$\hbox{TCNQ}^{- \atop \cdot}$\end{document} salts
Authors: Koropecký I. , Nešpůrek S. , Šorm M. 
Published: April 2003

AbstractPoly[1‐methyl‐3‐(2‐methacryloyloxyethyl)] imidazolium \documentclass{article}\pagestyle{empty}\begin{document}$\hbox{TCNQ}^{- \atop \cdot}$\end{document} and poly(methacryloyloxyethyl) trimethylammonium \documentclass{article}\pagestyle{empty}\begin{document}$\hbox{TCNQ}^{- \atop \cdot}$\end{document} were obtained by a metathesis of the corresponding polymeric ammonium bromides with LiTCNQ. The electrical conductivity of simple salts at room temperature was about 10−6 to 10−4 S · m−1, that of the complex salts about 10−2 to 101 S · m−1. The respective activation energy values were 0.35 to 0.50 eV and 0.11 to 0.26 eV. The stability of the salts is low, and it is affected by the decomposition of \documentclass{article}\pagestyle{empty}\begin{document}$\hbox{TCNQ}^{- \atop \cdot}$\end{document}.
Polymeranaloge Umsetzungen an Ethylen‐Vinylalkohol‐Copolymeren
Authors: Henning K. , Göhle G. , Fedtke M. 
Published: April 2003

AbstractBei Umsetzungen an Ethylen‐Vinylalkohol‐Copolymeren mit verschiedenen Hydroxycarbonsäuren in Lösung traten Reaktivitätsunterschiede in Abhängigkeit von der Stellung der Hydroxylgruppe auf. Die modifizierten Produkte enthalten polymerfixierte phenolische und sekundäre Hydroxylgruppen, die mit bifunktionellen Epoxidverbindungen in der Schmelze zu Kettenverlängerungsprodukten reagieren.
Copolymers of styrene and maleic anhydride formed in the presence of a heterogeneous initiator
Authors: Chrástová V. , Citovický P. , Alexy P. , Rosner P. 
Published: April 2003

AbstractThe copolymerization of styrene with maleic anhydride initiated with hydroperoxides of isotactic powdered polypropylene in the presence of an activator and a nonionic emulsifier was studied. In the investigated system the initiator forms a solid phase, which could be separated from the emulsion during the styrene polymerization. After addition of maleic anhydride solved in a polar solvent to the polymerizing styrene a block copolymer containing a pure styrene block and a styrene/maleic anhydride block is formed. The copolymer composition can be influenced by the polymerization time of the first polymerizing monomer. The obtained block copolymers are characterized.Die Copolymerisation von Styren mit Maleinsäureanhydrid bei Initiierung durch Hydroperoxide von isotaktischem, pulverförmigen Polypropylen wurde in Gegenwart eines Aktivators und eines nichtionischen Emulgators untersucht. In dem System liegt der Initiator in fester Phase vor, die während der Polymerisation des Styrens von der Emulsion abgetrennt werden kann. Nach Zugabe des Maleinsäureanhydrids in einem polaren Lösungsmittel zu dem polymerisierenden Styren wird ein Blockcopolymer gebildet, das einen reinen Styrenblock und einen Styren‐MaleinsäureanhydridBlock enthält. Die Zusammensetzung des Copolymers kann durch Variation der Polymerisationszeit des zuerst polymerisierten Monomers beeinflußt werden. Die erhaltenen Blockcopolymeren werden charakterisiert.
Formation of latex particles during the batch emulsion polymerization of vinyl chloride
Authors: Boieshan V. 
Published: April 2003

AbstractThe quantitative dependences between the emulsifier concentration in the emulsion water and the total surface area of the latex particles at the emulsion polymerization of vinyl chloride are investigated. From this it is possible to calculate the average volume/surface diameter. The exponent of emulsifier concentration in this relation reflects the variation of surface tension of the latex during the polymerization. This fact is due to the adsorption in time of the emulsifier on the surface of the latex particles.
Starch size in loomstate cotton fabric accelerates grafting of methacrylic acid induced by KMnO4/citric acid system
Authors: El Sisi F. , Hafiz S. A. Abdel , El Rafie M. H. , Hebeish A. 
Published: April 2003

AbstractThe use of loomstate cotton fabric (starch sized fabric) as a substrate for grafting of methacrylic acid using KMnO4/citric acid as initiator provided an effective method with greater potentiality. Presence of starch size on the fabric helps the deposition of MnO2 over the fabric with subsequent acceleration of the grafting reaction. Major factors affecting polymerization of MAA, such as KMnO4, citric acid and MAA concentrations, as well as reaction time and temperature of polymerization were studied. A tentative mechanism for the polymerization reaction is suggested.
Biologisch abbaubare polymere. 1. Mitt. Viskositäts‐molmassen‐beziehung für poly‐d,l‐lactid und poly(glycolid(50)‐co‐lactid(50))
Authors: Rafler G. , Dahlmann J. , Wiener K. 
Published: April 2003

AbstractDurch Ringöffnungspolymerisation hergestellte Poly‐D,L‐lactide wurden durch Viskosimetrie, Osmometrie, Streulichtphotometrie, Gelchromatographie und Endgruppenbestimmung umfassend charakterisiert. Auf der Grundlage membranosmometrisch ermittelter M̄n‐Werte wurden die Viskositäts‐Molmassen‐Beziehungen für Polylactid in Chloroform und Dimethylformamid sowie für ein äquimolar zusammengesetztes Lactid‐Glycolid‐Copolymer in Dimethylformamid bestimmt. Für Polylactid wurde das M̄w/M̄n‐Verhältnis zu ca. 2 bestimmt.
Photooxidation retardants. II. Spectra‐structure correlations of new additives from 3‐oxo‐3‐phenyl‐N‐(2‐pyridyl)propanamide for use as photooxidation retardants in polymers
Authors: Hanna M. A. , Girges M. M. 
Published: April 2003

AbstractThe synthesis of 3‐oxo‐3‐phenyl‐N‐(2‐pyridyl)propanamide and twelve of its arylhydrazone derivatives for use as additives to resist photooxidation in polymers is described. The structure of these compounds is dominated by the presence of double hydrogen bonding. Intramolecular charge transfer occurs through the nonbonding electrons on the amino nitrogen atom of the hydrazone moiety as donor rather than through the amide group, and the benzoyl carbonyl group as acceptor. The mode of action of these products as UV absorbers is discussed.
Mechanism of deformation at large strains in semicrystalline polymers‐LDPE
Authors: Mayer J. , Schrodi W. , Heise B. , Kilian H. G. 
Published: April 2003

AbstractCrystallinity, mean crystal thickness, thickness distribution of crystal, and mean thickness of the amorphous layers in LDPE are deduced by treating it as a eutectoid copolymer. This knowledge is transferred into a van der Waals network theory which includes plastic shear deformation of crystals. The fit of stress‐strain pattern at different temperatures and of temperature induced relaxation and shrinkage informs about the deformation mechanism in semicrystalline polymers.
Poly(oxyethylen)‐poly(oxypropylen)‐poly(oxyethylen)‐triblockcopolymere. Struktur und dynamik
Authors: Wartewig S. , Alig I. , Bloss P. , Hergeth W.‐D. , Lange J. , Lochmann J. R. , Scherzer T. 
Published: April 2003

AbstractDas Löslichkeitsverhalten und die physikalische Natur des Trübungspunktes eines POE‐POP‐POE‐Triblockcopolymers in wäßriger Lösung werden mit verschiedenen experimentellen Methoden (Viskosimetrie, Grenzflächenspannungsund Dichtemessungen, Ultraschallgeschwindigkeits‐ und ‐absorptionsmessungen, statische und dynamische Lichtstreuung, Infrarot‐ und Ramanspektroskopie, DSC‐Messungen) untersucht. Die Hydratisierung der Moleküle und die Dimensionen der Molekülassoziate werden diskutiert. Experimentelle Befunde belegen, daß der Trübungseffekt mit kritischen Erscheinungen verbunden ist. Der Vergleich der spektroskopischen Ergebnisse mit Konformationsenergierechnungen zeigt, daß Konformationsübergänge das Verhalten am Trübungspunkt bestimmen.
Optical studies of chain orientation by thermal treatment and mechanical stretching of Teflon PFA foil
Authors: Kułek J. , Kroupa J. 
Published: April 2003

AbstractThe effect of thermal treatment and uniaxial stretching on the temperature dependence of optical birefringence, degree of crystallinity, thermally stimulated depolarization, and isothermal discharge of electrets obtained of Teflon PFA foil has been studied. The increase in stability of charge is related to changes in the polymer structure.
Dynamic mechanical anisotropy of undrawn polypropylene films
Authors: Sadiku E. R. 
Published: April 2003

AbstractUndrawn isotactic polypropylene films were studied for dynamic anisotropy. The rations of the loss moduli and of the loss tangent in the parallel and perpendicular directions, respectively, gave a better picture of the anisotropy effect than the ratio of the storage moduli. In both the loss moduli and loss tangent ratios a very sharp γ‐transition was observed at‐60°C. Two γ‐transitions at 15 and 60°C, respectively, which are not very strongly marked in the tests in the individual directions, showed up fairly sharp in the anisotropic parameters used for the characterization. A weak γ‐transition was observed in both test directions. The results are discussed with respect t o anisotropy of crystal imperfection and stability.
Einfluß der Temperung auf die Eigenschaften von modifizierten Polymeren
Authors: Kardanov Ch. K. , Ivanovskij V. A. , Ch. Kardanov A. , Zelenev Ju. V. 
Published: April 2003

AbstractDer Einfluß der Temperung auf die änderung der Eigenschaften von Polymeren wird mit Hilfe der Relaxationsspektrometrie untersucht. Als neuartige Untersuchungsmethode wird die Messung der elektrischen Fluktuationen bei Temperaturänderungen angewandt. Die Messungen wurden an Poly(methylmethacrylat) durchgeführt.
Water‐insoluble polyelectrolytes. 1. Polyampholytes by aminolysis of poly(acrylonitrile) with dicyandiamide
Authors: Gohlke U. , Dautzenberg H. 
Published: April 2003

AbstractBy aminolysis of poly(acrylonitrile) with dicyandiamide and a subsequent reaction with hydroxylamine, polyampholytes are formed, which exhibit different ranges of insolubility around the isoelectric point. The reason for the improved solubility of the twice modified polymer is its higher concentration of dissociable functional groups. The aggregation behaviour of the polyampholyte is discussed on base of the intrinsic viscosities measured in dependence on the pH value.
Athermische und thermische Keimbildung bei sphärolithischer Kristallisation
Authors: Dobbert P. , Fabry F. 
Published: April 2003

AbstractAnhand von Modellrechnungen wird gezeigt, wie sich athermische und thermische Keimbildung auf den zeitlichen Verlauf der Hauptkristallisation von Polymeren auswirken, wenn unterschiedliche Sphärolithmodelle zugrunde gelegt werden. Die Überlegungen machen deutlich, daß die aus Meßkurven α(t) zu ermittelnden Parameter Keimdichte, Sphärolithform und radiale Wachstumsgeschwindigkeit komplex über die Kristallisationszeit miteinander verknüpft sind. Eindeutige Aussagen über diese Größen sind deshalb nur in Sonderfällen oder durch Einbeziehung weiterer Informationen über die Kristallisationskinetik möglich.
Thermomechanical properties and chemical resistance of alkyl methacrylate‐N‐vinyl carbazole copolymers
Authors: Ryttel A. 
Published: April 2003

AbstractCopolymers of ethyl methacrylate and n‐butyl methacrylate with N‐vinyl carbazole were synthesized by bulk polymerization. The thermal stability, softerning point, chemical resistance, glass transition temperature, hardness, density, and shrinkage on polymerization of the copolymers were studied. The effect of N‐vinyl carbazolel content on the properties is discussed.
Zur Synthese von Polysilanen
Authors: Heinicke J. , Uhlig W. , Tzschach A. , Reinhold G. 
Published: April 2003

AbstractDer Einfluß der Reaktionsbedingungen und des Lösungsmittels auf die Molmassenverteilung von Polysilanen, hergestellt durch Umsetzung von Diorganodichlorsilanen mit Natrium, wurde untersucht. Einsatz von Paraffinöl als Solvens verkürzt die Reaktionszeten und liefert, wie für (MePhSi)n näher studiert, auch in Mischungen höhermolekulare Produkte. Die beobachteten Effekte lassen sich durch im wesentlichen diffusionskontrollierte Oberflächenreaktionen an Natrium erklärren.
Plasmaätzen dünner Schichten organischer Polymere. Teil III: Zum phänomenologischen Mechanismus des Schichtabtrags
Authors: Eggert L. , Friedrich J. , Wittrich H. , von Löwis M. , Abraham W. 
Published: April 2003

AbstractZwei unterschiedliche Vorstellungen zum Ablauf des Abtrags von Polymerschichten in einem nichtisothermen Sauerstoffplasma einer elektrischen Hochfrequenzentladung werden diskutiert: der successive Abbau an der Oberfläche und die plasmaphysikalische Verfestigung der Polymeroberfläche bei gleichzeitiger Verlagerung des Abbaus in des Polymervolumen. Das letztgenannte Modell von Valiev verlangt komplizierte Diffusionsprozesse von abbaufähigen Plasmaspezies und entsprechenden Abbauprodukten. Die hier durchgeführten Modellversuche sprechen in ihren Ergebnissen gegen das Modell von Valiey, wobei jedoch die plasmamodifizierte Polymeroberflächenschicht tatsächlich eine besondere Rolle beim Abbau der gesamten Polymerschicht spielt.