bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strahlenchemische Antielektrostatik‐Ausrüstung
Authors: Rätzsch M. , Ihme B. , Heger A. , Hässler R. 
Published: April 2003

AbstractDie antielektrostatische Ausrüstung von textilen Flaächengebilden aus Poly(ethylenterephthalat) erfolgte durch strahlenchemische Beschichtung mit Poly(ethylenglycolacrylaten). In Abhängigkeit von der Modifikatorzusammensetzung (Mono‐/Diacrylat‐Verhältnis, Molmasse), Tränkdauer und ‐temperatur, Restfeuchte und Massezunahme sowie Energiedosis und Dosisleistung wurde der erzielte Modifizierungseffekt hinsichtlich seiner Permanenz insbesondere durch Verfolgung des spezifischen elektrischen Oberflächenwiderstandes untersucht. Anhand umfangreicher analytischer und mikroskopischer Untersuchungen wurden wichtige Hinweise über Art und Form der Modifizierung gewonnen. Aus den vorliegenden Ergebnissen konnten günstige Modifizierungsparameter für eine ausreichende Permanenz des Effektes vorgeschlagen werden.
Polymerization of carboxyl group containing monomers with chemical initiators. Part III. Polymerization of acrylic acid induced by the persulphate/sulphite redox system
Authors: Hafiz S. A. Abdel , El‐Sisi F. , Higazy A. , Hebeish A. 
Published: April 2003

AbstractThe polymerization of acrylic acid by the redox system ammonium persulphate/sodium sulphite was studied under a variety of conditions. The obtained results indicate that the total conversion is determined by the concentrations of (NH4)2S2O8 and Na2SO3, as well as by the degree of neutralization of acrylic acid and the duration of polymerization. The apparent viscosity of the formed poly(acrylic acid) decreases as the shear rate increases due to the deformation of the poly(acrylic acid) macromolecules under the influence of higher shear rate. A tentative mechanism for the polymerization reaction is suggested.
Poly(butyleneterephthalate‐co‐isophthalate)s – new secondary coating materials for optical fibres
Authors: Dietrich K. , Rafler G. , Schaaf E. , Versäumer H. , Böhm J. , Gruber K. 
Published: April 2003

AbstractThe shrinkage of copolyesters from terephthalic acid, isophthalic acid, and butanediol during injection molding and the after‐shrinkage during annealing exhibits a minimum at 20 mole‐% isophthalic acid. Polyesters of this composition have proved to be new outstanding materials for secondary coating of quartz glass optical fibres. They allow the production of optical fibre constructions without any increase in optical damping down to − 50°C.
Investigations on the photodegradation of a PVC coil‐coating system
Authors: Zimmermann H. , Behnisch J. 
Published: April 2003

AbstractThe photostability of a coil‐coating composite consisting of layers of plasticized PVC and a methylmethacrylate/ethylacrylate/acrylic acid copolymer as well as of several model systems was investigated. Changes of the UV irradiated samples were characterized by UV‐vis spectroscopy, the determination of the remaining thermal stability of PVC, and checking the adhesion strength. Photooxidation may cause failure of the coating especially by degradation in the interface layer of the primer to the metal.
Synthese und Eigenschaften von aromatischen Polyamiden, die durch Matrizen‐Polykondensation bei niedrigen Temperaturen erhalten wurden
Authors: Vinogradova S. V. , Vygodskij Ja. S. , Koršak V. V. , Slonimskij G. L. , Askadskij A. A. , Čuročkina N. A. , Kazanceva V. V. , Raubach H. , Falk B. 
Published: April 2003

AbstractPolymermischungen aus Poly(phenylenbenzimidazolterephthalamid) und Poly(anilinfluorenterephthalamid) wurden durch Synthese eines Polyamids in der Matrix des anderen hergestellt. Der Einfluß des Matrix‐Polymers auf das Kriech‐, Deformations‐ und Festigkeitsverhalten von Folien aus den Polymermischungen wurde untersucht.
High‐resolution electron microscope observations of carbon fibre structures
Authors: Schaper A. , Fink H.‐P. 
Published: April 2003

AbstractThe layer structure of an experimental 1400°C carbon fibre is revealed by high‐resolution electron microscopy and by electron diffraction of fibre fragments obtained by mechanical disintegration. Besides the typically wrinkled turbostratic texture, large crystalline aggregates were found exhibiting almost straight lattice lines and high lattices order. It is suggested that these crystals are induced by the catalytic action of impurity particles, particularly containing transition metals and silicon, included into the fibre mainly during precursor manufacture. The conclusion may be drawn that further improving the tensile strength of the carbon fibre requires to rigorously exclude any impurities from the manufacturing process.
NMR‐Untersuchungen zu Struktur und Beweglichkeit von substituierten Polyacetylenen
Authors: Hempel G. , Richter A. M. , Fanghänel E. , Schneider H. 
Published: April 2003

AbstractPoly(bis‐methylthio‐acetylen) und Poly(bis‐ethylthio‐acetylen) wurden hinsichtlich der Struktur der Hauptkette und der Beweglichkeit der Seitenketten mittels 13C‐NMR‐Spektroskopie untersucht. Die Hauptkette bestecht aus sp2‐ hydridisierten C‐Atomen. Die 1,2‐Bisalkythioethylen‐Einheiten bilden ein nicht‐Planares Polymerrückgrat, für das keine distreten Konfigurationen nachzuweisen sind. In Poly(bis‐methylthio‐acetylen) führen die MeS‐Einheiten eine Rotationsdiffusionsbewegung von etwa 70 kHz aus. Innerhalb der Hauptkette hat die Elektronenspindynamik keine Bedeutung.
Synthesis of new metal‐containing diols for polyurethanes
Authors: Rajalingam P. , Radhakrishnan G. , Devanathan S. B. , Selvy K. T. , Rao K. Venkata 
Published: April 2003

AbstractA new series of metal‐containing polyurethanes containing ionic links in the main chain were synthesized by the reaction of hexamethylene diisocyanate with Zn, Cd and Hg salts of mono(hydroxyethyl)phthalate. The structures of the monomeric diols were confirmed by IR, 1H‐NMR, UV spectroscopy, elemental analysis, and solubility studies. The obtained diols are white powders or solids. The prepared polyurethanes were characterized by IR and UV spectroscopy, solubility, and viscosity measurements.
Grafting of methyl methacrylate onto wood pulp with the KBrO3redox system
Authors: Yousef M. A. , Nada A. M. A. 
Published: April 2003

AbstractPaper wood pulp was grafted with methyl methacrylate using the potassium bromate redox system. The effects of monomer concentration, reaction time, initiator concentration, and liquor ratio on the graft yield, polymer loading, and water retention value of the grafted samples were studied. The optimum conditions of the grafting reaction were determined.
Charge transport mechanism in poly(vinyl alcohol) ‐ poly(vinyl pyrrolidone) polyblend films
Authors: Rao V. V. R. Narasimha , Kumar C. Ramesh , Laxminarayana K. , Rao B. Subba 
Published: April 2003

AbstractPolyblend films of poly(vinyl alcohol) and poly(vinyl pyrrolidone) were prepared from solutions of the homopolymers. The steady‐state electrical conduction was studied in the temperature range from 309 K to 450 K at the field strength of 0.75 to 46.5 · 106 V/m using different electrode materials. The charge transport is attributed to the injection of charge carriers from the electrode materials into the dielectric according to the Richardson‐Schottky mechanism and their subsequent trapping and release according to the Poole‐Frenkel mechanism.
Problems connected with the evaluation of the perfection of polymer crystalline structure with poly(ethylene terephthalate) as an example
Authors: Jeziorny A. 
Published: April 2003

AbstractThe perfection of the crystalline structure of PETP fibres was evaluated by means of two different X‐ray methods. The values of the perfection index of the crystalline structure obtained with the method proposed by Ruland were correlated with the parameters characterizing the fold surface layers of the crystallites, particularly with the free energy of these layers. On the basis of the found correlation, the conclusion was drawn that the value of the perfection index depends on the order of the macromolecules within the fold surface layers of the crystallites.
Liquid crystallinity of main chain polyurethanes based on 4,4′‐azobenzenediisocyanate
Authors: Kossmehl G. , Hirsch B. 
Published: April 2003

AbstractPolyurethanes were synthesized from 4,4′‐azobenzenediisocyanate with mono‐, di‐, tri‐ and tetraethylene glycol and their thermal properties were investigated. One of the resulting polymers, poly(oxycarbonylimino‐4,4′‐azobenzenediyliminocarbonyloxyethyleneoxyethyleneoxyethylene) shows a liquid crystalline phase higher than 225°C, determined by DSC and polarizing microscopy.
Modification of the physical properties of paper wood pulp by grafting with α,α‐dihydroperfluoroheptyl methacrylate
Authors: Yousef M. A. 
Published: April 2003

AbstractPaper grade wood pulp was grafted with α,α‐dihydroperfluoroheptyl methacrylate by using a KMnO4 redox system. The effects of different reaction parameters on the grafting process are investigated. The prepared samples exhibit excellent oil and water repellency.
The structural effects of cold crystallization of poly(ethylene terephthalate)
Authors: Jeziorny A. 
Published: April 2003

AbstractPoly(ethylene terephthalate) fibres of different drawing ratio were investigated. The parameters of cold crystallization were determined from the DSC thermograms. The parameters of the supermolecular structure of the samples were determined by X‐ray technique. On the base of the suitable linear regression relations it was stated that cold crystallization occurs within the fold surface layers of the crystallites. The effects of cold crystallization are changes of the molecular order within the surface layers. Direction and magnitude of these changes decide the initial melting temperature of the sample.
Homo‐ und Copolymerisation von Butadien und Isopren mit Ni/Ti/Al‐ und Ni/B/Al‐Katalysatorsystemen. III. Copolymerisation Butadien/Isopren mit einem Ni/B/Al‐Katalysator
Authors: Gebauer U. , Oberdörfer A. , Schütz M. , Gehrke K. 
Published: April 2003

AbstractDie Copolymerisation von Butadien und Isoprcn mit dem ZIEGLER‐NATTA‐Katalysator Nickeloctoat‐Bortrifluoridetherat‐Aluminiumtriethyl in Toluen wurde untersucht. Diese Copolymerisationsreaktion ist über den gesamten Bereich der Ausgangsmonomenusammensetzung realisierbar. Dic Bestimmung der Copolymerzusammensetzung erfolgte mittels 1H‐NMR‐Spektroskopie. Die Bestimmung der r1‐ und r2‐Werte erfolgte iiber eine integrierte Form der Grundgleichung nach MEYER und SKEIST. Isopren wirdlangsamer eingebaut als Butadien (rBD > rt), bewirkt eine Abnahme des Umsatzes und hat transregulierende Wirkung.
Zum Einfluß von Gelkörpern auf die Symplexbildung von Na‐Carboxymethylcellulose
Authors: Kötz J. , Borrmeister B. , Philipp B. 
Published: April 2003

AbstractMittels turbidimetrischer und konduktometrischer Titration wurde die Symplexbildung zwischen verschiedenen kationischen Polyelektrolyten und Carboxymethylcellulose‐Lösungen unterschiedlichen Gelpartikelgehaltes untersucht. Der Gelgehalt beeinflußt im Falle von Poly‐DMDAAC als kationischer Komponente die Form der Trübungskurve, wobei sich ein Zusammenhang zwischen der Länge des steil verlaufenden Anfangsteils der Kurve und der Höhe des Gelanteils ergibt. Präparative und analytische Anwendungsmöglichkeiten dieser Beobachtungen werden diskutiert.
The governing factors in heterogeneous matrix monequilibrium copolyesterification
Authors: Kuznetsov A. I. , Ignatov V. N. , Vasnev V. A. , Gribova I. A. , Vinogradova S. V. , Gureeva G. I. , Lavrukhin B. D. 
Published: April 2003

AbstractA systematic study has been carried out on the kinetic and structural matrix effects in acceptor‐catalytic polyesterification conducted in the presence of fillers. The filler exerts a different influence on the reactivity of aromatic and aliphatic hydroxylated compounds, which is reflected in the microstructure of the synthesized copolyesters. Filler introduction at the stage of polymer synthesis is established to raise its molecular mass characteristics and to improve the antifrication properties of filled systems.
Thermal conversion of filled polymer compositions of aminoplast
Authors: Mgeladze B. M. , Sh. Papava G. , Pkhakadze N. S. , Kvantrishvili G. E. , Dokhturishvili N. S. , Maisuradze N. A. 
Published: April 2003

AbstractThermal treatment of polymer compositions of aminoplast on the basis of diatomite leads to the increase of the rate and depth of curing due to the catalytic action of the filler. These polymer compositions are capable to injection moulding and yield plastic materials with good dielectric properties.
Zum Löseverhalten von Polyester‐Polyurethanen
Authors: Hettrich W. , Joel D. , Gnauck R. , Pohl G. 
Published: April 2003

AbstractDer Einfluß des Hartsegmentgehaltes linearer Toluen‐2,4‐diisocyanat‐Polyester‐PUR mit M̄n < 50000 auf deren Lösungseigenschaften wird untersucht und mit dem thermoanalytisch bestimmten Zustand der Phasensegregation verglichen. Die Morphologie dieser Formstoffe wird durch schwach polare Lösungsmittel signifikant verändert. Zeitliche sowie thermische Alterung unterhalb 70°C bewirkt dagegen keine Veränderung des Entmischungszustandes.
Untersuchungen zur Kondensation von Harnstoff mit Formaldehyd in konzentrierten wäßrigen Lösungen
Authors: Starzyńska K. 
Published: April 2003

AbstractZwei‐ und Dreistufenprozesse zur Kondensation von Harnstoff‐Formaldehyd‐Harzen bei Einsatz von Harnstoff bzw. Harnstoff‐Formaldehyd‐Konzentraten wurden untersucht. Die Änderungen des Gehaltes an unreagiertem Formaldehyd, Hydroxymethyl‐, Dimethylenether‐ und Methylengruppen in den einzelnen Stufen der Kondensation wurden bestimmt. Unterschiede im Verlauf des Kondensationsprozesses wurden beim Einsatz eines Gemisches von Harnstoff und Harnstoff‐Formaldehyd‐Konzentrat bzw. eines Gemisches von Harnstoff und Formalin mit ähnlicher Zusammensetzung gefunden.
Macrocyclic compounds as polymer light stabilizers
Authors: Siling S. A. , Margolin A. L. , Ya. Kalontarov I. , Vinogradova S. V. , Niyazi F. F. , Chaiko Yu. V. , Dzhumayev Sh. S. 
Published: April 2003

AbstractThe efficiency and mechanism of light stabilization have been investigated for macroheterocyclic compounds (hexazocyclanes) and for polymers with macroheterocycles in the chain (poly(hexazocyclanes)). The hexazocyclane based on phthalodinitrile and p‐phenylene diamine proved to be the most active UV stabilizer for acetyl cellulose. It acts by the mechanisms of UV screening and photosensitization. The photostabilizing activity depends on the structure of the macrocyclic compound.
Slow reversible collapse of gels based on copolymers of acrylamide and acrylic acid
Authors: Budtova T. V. , Belnikevich N. G. , Buyanov A. L. , Revelskaya L. G. , Petropavlovsky G. A. , Frenkel S. Ya. 
Published: April 2003

AbstractThe behaviour of highly swelling hydrogels based on a copolymer of acrylic acid and acrylamide has been studied in solutions of low molecular weight salts. An explanation of the mechanism for gel collapse and swelling in solutions of various metals is presented. The dependences of the sorption rate and the amount of sorbed copper ions on the particle size of the dry powder and on the swelling coefficient were established.
Lichtinduzierte Polymer‐ und Polymerisationsreaktionen. 40. Untersuchungen zur direkten Photopolymerisation von Methylacrylat durch aromatische Ketone – Wirkung von 1,4‐Diradikalen und Ketylradikalen
Authors: Timpe H.‐J. , Krohfeld K.‐P. 
Published: April 2003

AbstractDie durch Lichtanregung von Benzophenon (BP), Fluorenon (FI), Xanthon (X), Thioxanthon (TX), 3,6‐Bis(dimethylamino)thioxanthon (BTX), Acridon (Ac) oder N‐Methylacridon (MAc) in Acetonitril/Methylmethacrylat‐Mischungen erhaltenen Polymere wurden isoliert und bezüglich ihrer Endgruppen analysiert. Dazu dienten UV/VIS‐Spektren in Kombination mit Protonierungs‐ und Hydrolysereaktionen. Es konnte bewiesen werden, daß im Falle des Fl ein 1,4‐Diradikal, gebildet durch Addition des Ketontripletts an das Monomer, die Polymerisationskette initiiert. Bei TX, BTX, Ac und MAc ist diese Reaktion im untergeordneten Maße an der Polymerbildung beteiligt. Es überwiegt, bei BP und X ausschließlich, eine Initiierung durch Radikale, die durch Wasserstoffabstraktionsreaktionen des Ketontripletts entstehen. Die so entstchenden Ketylradikale zeigen ein sehr differenziertes Verhalten. Während sie bei Ac und MAc in der Abbruchreaktion Wasserstoffatome übertragen, erfolgt bei Fl überwiegend Radikalkombination.
Untersuchungen zur Bildung wasserlöslicher Cellulosephosphate durch homogene Acylierung im System Cellulose N2O4/DMF. 1. Mitt.: Problemstellung und Ergebnisse zur Acylierung mit POCl3
Authors: Wagenknecht W. , Philipp B. , Nehls I. , Schnabelrauch M. , Klemm D. , Hartmann M. 
Published: April 2003

AbstractNach Auflösung in einem N2O4/DMF‐Gemisch unter partieller Bildung des Nitritesters wurde Cellulose unter homogenen Reaktionsbedingungen mit POCl3 in Gegenwart von Triethylamin bis zu DSp‐Werten von etwa 1 phosphoryliert. Wasserlösliche Produkte wurden im DSp‐Bereich zwischen 0,3 und 0,6 nach einer Behandlung des Reaktionsproduktes in einem protischen Medium erhalten.
13C‐NMR‐spektroskopische Untersuchungen zur Phosphatierung von Celluloseprodukten im System H3PO4/Harnstoff
Authors: Nehls I. , Loth F. 
Published: April 2003

AbstractAuf Basis von gemahlenem Fichtensulfitzellstoff, mikrokristalliner Cellulose und Perlcellulose sowie Carboxymethyl und Hydroxyethylcellulose wurden unterschiedliche Cellulosephosphate hergestellt und mittels 13C‐NMR‐Spektroskopie untersucht. Die Phosphatgruppen wurden in das Cellulosematerial durch trockene Erwärmung mit einer Mischung von Phosphorsäure und Harnstoff eingeführt. Bei allen nach diesem Verfahren erhaltenen Proben wurde eine bevorzugte Substitution der C‐6‐Stellung gefunden.
Theoretical analysis of the processes of heat exchange and relaxation of a polymer melt at the formation of highly oriented polymer films
Authors: Karpov E. A. , Elyashevich G. K. , Neelov I. M. , Ro E. A. 
Published: April 2003

AbstractA mathematical model is proposed to describe the processes of cooling and relaxation of an oriented polymer melt on a tempering surface. On the basis of this model an algorithm is established that makes it possible to calculate the temperature distribution in the melt from the given external parameters and characteristics of the material. With the aid of of this algorithm the rate of melt cooling at tempering is evaluated. The relationship between the tempering time and the degree of relaxation of macromolecules under predetermined conditions was established.
Transformations of poly(methacrylonitrile) in solutions at the addition of alkali
Authors: Rumynskaya I. G. , Romanova E. P. , Agranova S. A. , Frenkel S. Ya. 
Published: April 2003

AbstractThe kinetics of changes of electronic spectra of poly(methacrylonitrile) in DMSO on addition of alkali was studied. The spectral picture depends on the amount of alkali corresponding to one chain unit, the amount of water in the solution, and the alkali/water ratio. Besides, the maximal attainable effective length of conjugation of cyclic sequences is all the more the lower is the rate of initiation of cyclization. A slow and unsubstantial decrease of the intrinsic viscosity excludes the occurrence of a sharp coil‐globule transition on alkaline hydrolysis of poly(methacrylonitrile).
Melting of oligo(ethylene terephthalate)‐oligo(oxyethylene) block copolymers
Authors: Bogdanov B. , Mihailov M. , Gavrailova G. , Panev Pl. 
Published: April 2003

AbstractResults obtained by calorimetric investigations on heating of oligo(ethylene terephthalate) (OETP) and oligo(oxyethylene) (OOE) block copolymers with different contents of the components are presented. The temperatures and enthalpies of melting of the crystalline phases, which are formed by the OETP and OOE blocks, are determined. An additional endothermic peak is observed on the DSC curves in a temperature range depending on the molecular weight of the OOE blocks and on the thermal prehistory of the samples. It is supposed that this transition is due to structural changes of the OETP‐OOE block copolymers on heating.
Bestimmung des Gleichgewichtswassergehaltes von Polycaprolactam
Authors: Schmalz E.‐O. 
Published: April 2003

AbstractAnhand bekannter Gleichungen wird die Rolle des Gleichgewichtswassergehaltes beim Spinnprozeß von Polycaprolactam abgeleitet und ein isochores Verfahren zu seiner Bestimmung angegeben. Für die isobare Verfahrensführung wird eine Gleichung abgeleitet, mit der sich der mittlere Polymerisationsgrad als Funktion des Wasserdampfpartialdruckes und der Kettenreglerkonzentration berechnen läßt. Die Gültigkeit dieser Gleichung wird experimentell überprüft und ein Verfahren zur isobaren Bestimmung des Gleichgewichtswassergehaltes mitgeteilt. Die Unterschiede zwischen einer isochoren und einer isobaren Reaktionsführung werden anhand experimenteller Ergebnisse diskutiert.
Seeded emulsion polymerization of butyl acrylate
Authors: Capek I. 
Published: April 2003

AbstractThe emulsion polymerization of butyl acrylate initiated by ammonium peroxodisulfate in the presence of poly(ethyl acrylate) seed particles was kinetically investigated. The dependence of the final particle number on the initiator concentration deviates from the predictions of emulsion polymerization. The rate of polymerization decreases with increasing monomer concentration. The polymerization behaviour was explained by the polymerization in both the monomer‐swollen emulsifier micelles and the monomer‐swollen polymer particles.
Graft polymerization of acrylamide onto cellulose acetate initiated by ceric ion
Authors: Egboh S. H. O. , Akonwu L. N. 
Published: April 2003

AbstractThe ceric ion method has been used to graft copolymerize acrylamide onto cellulose acetate. The effects of different reaction conditions on the graft yields were investigated. The activation energy and the order of reaction with respect to monomer and initiator concentration have been determined.
Passive isomers of the active center as its possible dormant states responsible for the retardation of propagation of the macroanion of poly(α‐methylstyren)
Authors: Ye. Eizner Yu. , Ushakova I. L. 
Published: April 2003

AbstractQuantum chemical calculation shows that apart from the formation of the canonical active center in the reaction of a macroanion with a monomer of α‐methylstyrene the formation of isomers of the active center is also possible. These noncanonical isomers seem to be passive in respect to addition of the next monomer molecule. Some other sequences of the calculation which can be checked experimentally are given.
Synthesis and characterization of some N‐vinyl carbazole containing copolymers
Authors: Curteanu S. , Simionescu C. I. , Talmaciu V. 
Published: April 2003

AbstractThe copolymerization of N‐vinyl carbazole with methyl methacrylate and styrene, respectively, was studied. 1H‐NMR spectra and elemental analysis were used to establish the composition of the copolymers. The composition data confirmed that solution radical copolymerization follows quite well the simple terminal copolymerization model.
Structure and properties of chitosan carboxymethyl ether
Authors: Vikhoreva G. A. , Gladyshev D. Y. , Bazt M. R. , Kuznetsova S. Y. , Gal'Braikh L. S. , Lavut E. E. , Ovsepyan A. M. , Panov V. P. 
Published: April 2003

AbstractPhysical, physicochemical and chemical methods were applied to the study of structure, fractional composition, and properties of carboxymethyl chitosan, a polyampholyte containing carboxyl and amino groups. As a result of the interaction of ionogenic groups in the carboxymethyl chitosan their dissociation degrees increase against the corresponding values in chitosan and carboxymethyl cellulose, which are polyelectrolytes containing only one type of functional groups. The viscosity properties of dilute solutions of carboxymethyl chitosan suggest to the polyampholytic nature of the substituted polysaccharide and to the intra‐salt formation in the pH range 2.5 to 7.5, where the ionization regions of opposite charged ionogenic groups overlap to a great extent.