bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polysiloxane. 6. Bestimmung und Charakterisierung des löslichen Anteils von PDMS‐Netzwerken
Authors: Schimmel K.‐H. , Trinh Pham The , Schröder E. 
Published: April 2003

AbstractDie aus endgruppenvernetzten Poly(dimethylsiloxanen) extrahierten löslichen Anteile sind in Abhängigkeit vom Ansatzverhältnis Vernetzer/Polymer durch Gravimetrie und GPC untersucht worden. Der Solanteil nimmt mit steigender Vernetzungsdichte ab. Die Molmassen der unvernetzten Polymere verringern sich bis zum Molmassenmittelwert des bifunktionellen PDMS.
Physical and spectroscopic studies on methyl methacrylate‐chromium acrylate bulk copolymers
Authors: Sayyah S. M. , Bahgat A. A. , Sabby A. I. , Said F. I. A , El‐Hamouly S. H. 
Published: April 2003

AbstractNew semiconducting copolymers were prepared by bulk copolymerization of methyl methacrylate with chromium acrylate. The pattern of the chemical reactions is discussed. The density and hardness of the samples decrease with increase of the chromium content. I n the infrared spectrum broadening of the carbonyl band a t 1710 cm−l is observed, which indicates the possibility of coordination of the CO group with the chromium ion. The electrical conductivity of the samples increases with increase of chromium acrylate content. The effect of y‐irradiation on the electrical conductivity of the copolymers was studied.
Modifizierte Poly(phenylchinoxaline)
Authors: Korshak V. V. , Krongauz E. S. , Belomoina N. M. , Babich S. S. , Jedliński Z. , Paliwoda A. , Raubach H. 
Published: April 2003

AbstractPoly(esterphenylchinoxaline) wurden durch Niedertemperatur‐Polykondensation von Bis(hydroxyphenylchinoxalinen) mit Säurechloriden aromatischer Dicarbonsäuren sowie durch Polykondensation von Bis(α‐diketonen), die eine Polyestergruppe in der Struktur enthalten, oder deren Gemische mit 1,4‐Bis(phenylglyoxyloyl)benzen mit aromatischen Tetraaminen gewonnen. Es wurde nachgewiesen, daß durch die Einführung von Polystergruppen das gute Eigenschaftsbild der Poly(phenylchinoxaline) weitgehend erhalten bleibt, aber keine Erhöhung der Temperaturbeständigkeit erfolgt. Dagegen bringt die Einführung von Ethinylgruppen, die bei Wärmebehandlung zur Vernetzung führen, eine beachtliche Erhöhung der Wärmeformbeständigkeit.
Some aspects of the carbonization of polyimides
Authors: Sazanov Yu. N. , Stepanov N. G. , Shibaev L. A. , Antonova T. A. , Gribanov A. V. , Bertoti I. , Toth A. , Blazso M. , Jakab E. , Szekely T. 
Published: April 2003

AbstractOn base of polyimides with various chemical structures, which are considered to be the main structure types of polyimides, some carbonized products were obtained. By means of pyrolyse gas chromatography and X‐ray photoelectron spectroscopy the chemical changes in the polyimides during heating were studied. A mechanism of the carbonization process is suggested.
Synthese von aromatischen Polyketonen durch Fällungspolykondensation
Authors: Gileva N. G. , Solotuchin M. G. , Salaskin S. N. , Sultanova V. S. , Hörhold H.‐H. , Raabe D. 
Published: April 2003

AbstractAromatische Polyketone wurden durch Fällungspolykondensation aus den Säurechloriden der Iso‐ und Terephthalsäure, des 3,3‐Bis(4′‐carboxy‐phenyl)phthalids, des Bis(4‐carboxy‐phenyl)ethers jeweils mit Diphenylether sowie direkt aus 4‐Phenoxybenzoylchlorid hergestellt. Der Einifluß von Katalysator, Lösungsmittel und Temperatur auf den Syntheseverlauf wurde untersucht und die Struktur der erhaltenen Polyketone aufgeklärt.
Novel bis(napthalic anhydrides) and polyheteroarylenes on their basis
Authors: Korshak V. V. , Bulycheva E. G. , Shifrina Z. B. , Berlin A. M. , Shalikiani M. O. , Butskhrikidze B. A. , Rusanov A. L. , Mironov G. S. , Moskvichev Yu. A. , Timoshenko G. N. , Titov V. I. , Jedliński Z. , Palivoda A. 
Published: April 2003

AbstractA series of novel bis(naphthalic anhydrides) has been prepared through acenapthene interaction with the dichloroanhydrides of dicarboxylic acids under the conditions of the Friedel‐Crafts reaction or with chloral and bromal followed by oxidation of bis‐acenaphthyls and anhydrization of the tetracarboxylic acids synthesized. Poly(naphthoylene benzoimidazoles) combining advantageous thermal properties and solubility in organic solvents have been obtained through interaction between the synthesized anhydrides and bis(o‐phenylene diamines).
Statistische Thermodynamik von Polymernetzwerken mit eingebauten Makromolekülcyclen
Authors: Heinrich G. , Helmis G. 
Published: April 2003

AbstractEin einfaches molekular‐statistisches Modell eines Polymernetzwerkes mit permanent eingefangenen Ringpolymeren wird vorgeschlagen. Die Kopplung der Cyclen an die Netzmatrix wird durch topologische Invarianten beschrieben. Die Zustandsgleichung wird abgeleitet und die Zahl der zum Elastizitätsmodul beitragenden elastischen Freiheitsgrade der Cyclen berechnet.
Graft copolymerization of acrylamide onto polycapromide with the redox system K2S2O8/Na2S2O3
Authors: Bogoeva‐Gatseva G. , Gabrielyan G. A. , Galbraikh L. S. 
Published: April 2003

AbstractKinetics and mechanism of the graft copolymerization process of acrylamide onto polycaproamide, initiated by the redox system K2S2O8/Na2S2O3 in the presence of the heptaazocyclohexadecine complex of Cu(I) fixed on the polyamide matrix, were studied. The process of graft copolymerization takes place with maximum rate and efficiency at a molar ratio of [Na2S2O3]:[K2S2O8]=4.3. The kinetical parmeters of the graft copolymerization as well as of the homopolymerization during the process of grafting have been determined.
New concept of kinetic description of simple copolycondensation process
Authors: Boryniec S. 
Published: April 2003

AbstractThe course of interbipolycondensation, i.e. the copolycondensation of a bifunctional monomer with two other monomers not reacting with each other, has been analyzed on the basis of dependences of formal kinetics. A kinetic equation of interbipolycondensation is derived for the case of invariable reactivity of functional groups. By introducing a new variable it was possible to describe the process by means of one differential equation of one variable. The equation of interbipolycondensation product composition was also derived in a new form.
Untersuchungen zur Isoprenpolymerisation mit dem Ziegler‐Natta‐Katalysator Nickeloctoat/Bortrifluoridetherat/Aluminiumtriethyl. I. Einfluß der Katalysatorbereitung
Authors: Gebauer U. , Engelmann S. , Gehrke K. 
Published: April 2003

AbstractBei der Isoprenpolymerisation mit dem Katalysatorsystem Nickeloctoat/BF3 · Et2O/AIEt3 wurden das Molverhältnis Ni: B: Al und die Alterungszeit variiert und Umsatz, die viskositätsmittlere Molmasse und die Mikrostruktur des Polyisoprens verfolgt.
Netwerkcharakterisierung mittels Dampfdruckosmometer. IV. Experimentelle Bestimmung des Netzwerkanteils am Chemischen Potential
Authors: Arndt K.‐F. , Hahn I. 
Published: April 2003

AbstractMit einem Dampfdruckosmometer wird die Lösungsmittelaktivität im gequollenen polymeren Netzwerk und im entsprechenden unvernetzten Polymer gemessen. Aus der Differenz beider kann der Netzwerkanteil am chemischen Potential in Abhängigkeit von der Polymerkonzentration bestimmt werden. Er weist bei einer bestimmten Polymerkonzentration ein Maximum auf, dessen Ort und Höhe von der Lösungsmittelgüte und der Vernetzungsdichte abhängen.
Experimental and theoretical analysis of viscoelastic behaviour of different polymer networks
Authors: Havránek A. , Heinrich G. 
Published: April 2003

AbstractThe experimentally observed short time and long time relaxational behaviour of different types of crosslinked polymer networks is analyzed. The origin of the first process will be attributed to the glass‐rubber transition. The origin of the second one has been often attributed to the relaxation of dangling ends. We assume that beside these mechanism topological constraint release effects of network strands with both ends fixed in crosslinks have to be taken into account. We propose a theory of the slow relaxation process and introduce a fractional‐exponential time dependence of the constraint release parameter. Its equilibrium value characterizes the deformation dependence of the lateral dimensions of the configurational constraining tubes around the network chains.
Some aspects on the constitution of egyptian bagasse pith‐phenol polycondensate resins. Part I. Elemental analysis and thin layer chromatography‐ultra violet combined technique
Authors: Saad S. M. , Sayyah S. M. , Metwally N. E. , Mourad A. A. 
Published: April 2003

AbstractIn order to investigate the chemical constitution of bagasse pith‐phenol polycondensate resin, different resins were prepared by condensation of phenol with compounds that may be produced during the acid hydrolysis of bagasse pith and with different constituents of bagasse pith. The optimum conditions for thin layer chromatographic separation of these polycondensate resins were determined. The proposed chemical structure and the pattern of chemical reactions were discussed on the bases of elemental analysis, TLC and UV spectroscopic studies.
Some aspects on the constitution of egyptian bagasse pith‐phenol polycondensate resins. Part II. Spectroscopic analysis
Authors: Sayyah S. M. , Saad S. M. , Metwally N. E. , Shaaban S. M. 
Published: April 2003

AbstractInfrared spectroscopic studies on some phenolic resins prepared by condensation of phenol with furfural, xylose, glucose, holocellulose, resistant cellulose, pure soda lignin, and bagasse pith, were carried out. The IR spectrum of soda ligninphenol resin proves the presence of aliphatic methyl, methylene, methine and strong bonded OH groups. Drastic changes in band position and intensity are observed in the IR spectra of pure soda lignin or bagasse pith and the respective phenolic resins, indicating that degradation processes could take place during the condensation reactions. The IR spectra of fractions of the bagasse pith‐phenol resin give an insight in the complicated structure of this resin. NMR and UV spectroscopic studies confirm the IR data.
Preparation and mechanical properties of polypropylene foils with different structure
Authors: Bogdanov B. , Michailov M. , Uzov Ch. 
Published: April 2003

AbstractStructural transformations of quenched polypropylene foils have been investigated during heating of the melt at different temperatures or annealing at room temperature. In both cases a transition from smectic (paracrystalline) to the partially crystalline state was observed. A correlation between the structure and the mechanical properties of the initial unoriented and uniaxially stretched foils was established.
Sprunghafte Eigenschaftsänderungen von im gedehnten Zustand kristallisiertem vernetzten Polychloropren
Authors: Belaev O. F. , Aloev B. Z. , Zelenev Ju. V. 
Published: April 2003

AbstractDurch Anwendung eines Komplexes von Untersuchungsmethoden wird gezeigt, daß bei einem kritischen Reckgrad der Polychloroprenproben eine scharfe Änderung einer Reihe von Eigenschaften auftritt. Die Richtung der Molekülachsen in den Kristalliten ändert sich dabei nicht. Eine Erklärung der erhaltenen Resultate wird gegeben.
Complexation of poly(ethylene glycol) with 4‐nitrophenol in solutions and melts
Authors: Bekturov E. A. , Khamzamulina R. E. , Gusakova G. V. , Smolyanskii A. L. 
Published: April 2003

AbstractComplex formation between poly(ethylene glycol) and 4‐nitrophenol in solutions and melts was investigated by potentiometric and conductometric titration, IR spectroscopy and thermal analysis. It is shown that the interaction of the polymer with the low molecular compound is carried out through hydrogen bonds between the oxygen atoms of the polymer and the hydroxyl groups of 4‐nitrophenol. It depends on the molar ratio of the components and on the temperature of the solution.
Thermodynamik konzentrierter Poly(methylmethacrylat)‐Lösungen
Authors: Regener E. , Wohlfarth Ch. , Rätzsch M. T. , Höring S. 
Published: April 2003

AbstractFür Lösungen von Poly(methylmethacrylat) (PMMA) verschiedener Taktizität und Molmasse in Aromaten, Ketonen und Chlorkohlenwasserstoffen werden die Lösungsmittelaktivitäten im Temperaturbereich von 323 bis 403 K durch isopiestische Dampfdruckmessung, Dampfdruckosmose und inverse Gas‐Flüssig‐Chromatographie bestimmt und daraus die segmentmolaren freien Exzeßenthalpien \documentclass{article}\pagestyle{empty}\begin{document}$ \overline{\overline G} ^E $\end{document} und die χ‐Funktionen ermittelt. Die Resultate werden hinsichtlich der Einflüsse von Taktizität, Molmasse, Temperatur und Konzentration diskutiert. Es wird eine Modifizierung der Chain‐of‐rotators‐Zustandsgleichung für nichtstatistische Vermischung in Verbindung mit einer Brückenfunktion vorgestellt. Damit sind die komplexen Abhängigkeiten der χ‐Funktion in den Systemen mit syndiotaktischem PMMA zum größten Teil quantitativ beschreibbar.
Infrared spectra of lithium potassium copolyphosphates
Authors: Srivastava R. R. , Singh M. , Bhargava H. N. 
Published: April 2003

AbstractInfrared spectral analysis of lithium potassium copolyphosphates with various ratios of Li:K was carried out. The presence of an additional cation did not mask the characteristics of linear long‐chain polyphosphates. While the Li:K ratio or the average molecular weight had little influence on the spectrum, the absorbances of all peaks were found to increase with increase in the proportion of potassium.
Kinetische Charakteristika der anionischen Polymerisation von Acrylnitril
Authors: Erussalmisky B. L. , Berger W. 
Published: April 2003

AbstractDie bisher erschienenen Arbeiten zur anionischen Polymerisation von Acrylnitril in unpolaren und polaren Lösungsmitteln werden unter dem Gesichtspunkt der Kinetik dieses Aufbauprozesses analysiert. Die kinetischen Daten für die homogene Acrylnitrilpolymerisation (in DMF mit t‐BuOLi) lassen den Schluß zu, daß freie Ionen die geschwindigkeitsbestimmenden aktiven Zentren darstellen. Bei Verwendung chromorganischer Initiatoren (Tris‐π‐allylchrom mit 2,2′‐Dipyridyl) wurde für kw ein um drei Größenordnungen niedrigerer Wert gefunden. Es wird versucht, die Polymerisationskinetik verschiedener polarer Monomere (MMA, MAN, AN, Acrylate) zu vergleichen.
Polymer complexes. III. Stability and degradation of acrylonitrile‐transition metal bromide polymer complexes
Authors: El‐Sonbati A. Z. , Diab M. A. 
Published: April 2003

AbstractThermal stabilities and degradation behaviour of PAN homopolymer and AN‐CuBr, AN‐CuBr2, AN‐CoBr2, AN‐NiBr2 and AN‐CdBr2 polymer complexes were investigated. The stability of the polymer complexes is less than that of PAN. The main degradation products of the polymer complexes are ammonia and hydrogen cyanide, besides some monomer and methane. The activation energies for the degradation of PAN and the AN‐CuBr, AN‐CuBr2 and AN‐CoBr2 polymer complexes are higher than those of the AN‐NiBr2 and AN‐CdBr2 polymer complexes.
Organotin polymers. XIII. Binary copolymerization reactions of tri‐n‐butyltin acrylate and methacrylate with itaconic acid and dimethyl itaconate
Authors: Shaaban A. F. , Salem M. A. , Azab M. M. , Messiha N. N. 
Published: April 2003

AbstractThe copolymerization reactions of tri‐n‐butyltin acrylate and methacrylate with itaconic acid and dimethyl itaconate, respectively, in solution with AIBN as initiator were studied. The composition of the copolymers was determined by tin analysis. The copolymerization parameters were calculated and discussed. The structure of the copolymers was investigated by infrared spectroscopy.
Supermolecular organization and polymerization of compressed ethylene
Authors: Stoiljkovic D. , Jovanovic S. 
Published: April 2003

AbstractIt was proposed in 1955 that ethylene molecules are closely packed and oriented in the course of polymerization at high pressures. Although many papers have been published since that time, there has been no attempt to explain this reaction accounting for the supermolecular organization of compressed ethylene. Recently, we have developed a model that explains this organization of monomer. It is shown that the supermolecular organization of compressed ethylene has decisive effects on the mechanism and kinetics of polymerization as well as on the molecular structure and properties of the polyethylene.
Acoustic emission from emulsion polymerization systems
Authors: Hergeth W.‐D. , Wartewig S. , Ranachowski Z. , Rzeszotarska J. , Ranachowski J. 
Published: April 2003

AbstractExperimental results are presented concerning the application of acoustic emission (AE) in order to monitor emulsion polymerizations. An AE signal was observed during a short period immediately after the addition of a water‐soluble solid initiator to the reaction mixture. This behaviour is discussed in terms of an enhanced dissolution of initiator crystals (i.e. the fracture of their surface) due to the polymerization reaction in the aqueous phase.
Some aspects on the polymerization of vinyl acetate in the presence of poly(methyl methacrylate) template
Authors: Tewari N. , Saini S. , Nigam S. K. , Srivastava A. K. 
Published: April 2003

AbstractThe kinetics and mechanism of radical polymerization of vinyl acetate in dimethyl formamide with syndiotactic poly(methyl methacrylate) as a polymer template was investigated. The reaction rates showed that complexation between the template and poly(vinyl acetate) was maximum when the template: polymer ratio was 1 : 1. The molecular weight of the daughter polymer was very close to that of the template. The order of reaction with respect to template, monomer, and initiator was 0.40, 1.10, and 0.44, respectively.
Struktur‐Eigenschafts‐Beziehungen in diolmodifizierten Epoxidharzen
Authors: Tänzer W. , Szestay M. , László‐Hedvig Zs. , Fedtke M. 
Published: April 2003

AbstractPhenylglycidether reagiert mit Butan‐1‐ol zu Produkten unterschiedlicher Struktur, wenn Mg(ClO4)2 oder N,N‐Dimethylbenzylamin als Reaktionsbeschleuniger eingesetzt werden. Im difunktionellen System Bisphenol‐A‐diglycidether/Butan‐1,4‐diol führt dies zur Bildung von Netzwerken unterschiedlicher Dichte. HPLC‐Untersuchungen an Modellverbindungen sowie DSC‐Untersuchungen und Sol‐Gel‐Messungen an den Netzwerken bestätigten den Zusammenhang zwischen der Struktur der Modellverbindungen und Netzwerkeigenschaften der ausgehärteten Finalprodukte.
Der Einfluß struktureller Veränderungen auf den Glasübergang in teilkristallinem Poly(ethylenterephthalat). 2. Charakterisierung der übermolekularen Struktur
Authors: Schick C. , Fabry F. , Schnell U. , Stoll G. , Deutschbein L. , Mischok W. 
Published: April 2003

AbstractMit Röntgenbeugungs‐, kalorimetrischen, NMR‐ und ramanspektroskopischen Untersuchungen werden Aussagen zur lamellaren Struktur von unterschiedlich kristallisierten PETP‐Proben gemacht. Die verwendeten Kristallisations‐regime ergeben Lamellendicken von 1,5 nm bis 2,5 nm, starre amorphe Bereiche (Randschichten) von etwa 2 nm und beweglich amorphe Bereiche von 1 nm bis 3 nm, in denen die mit dem thermischen Glasübergang verknüpften Umlagerungsprozesse ablaufen. Die Dicke dieser Bereiche entspricht den aus den Glasübergängen ermittelten Korrelationslängen der Umlagerungsprozesse.
Einfluß einer thermischen Vorbehandlung von Buchensulfitzellstoff und einer Variation von ausgewählten Viskosierparametern auf den Filterwert von Viskose
Authors: Erdmann R. , Philipp B. , Schleicher H. 
Published: April 2003

AbstractDer Einfluß einer thermischen Vorbehandlung von Buchensulfitzellstoff auf den Filterwert daraus hergestellter Viskosen wurde unter Variation einiger Viskosierparameter untersucht. Die beobachtete signifikante Filtrationsverbesserung ist um so ausgeprägter, je weiter man bei der Viskoseherstellung von den optimalen Viskosierparametern abweicht. Die Ergebnisse werden diskutiert sowohl im Hinblick auf die bei der thermischen Behandlung des Zellstoffs auftretenden Strukturveränderungen und ihrer Relevanz für die Viskosierung als auch im Hinblick auf ihre Anwendbarkeit beim technischen ViskoseProzeß.
Semicontinuous emulsion polymerization of vinyl acetate. IV. Homopolymerization with poly(vinyl alcohol)
Authors: Donescu D. , Gosa K. , Languri I. 
Published: April 2003

AbstractIn semicontinuous emulsion polymerization of vinyl acetate the system behaves as a flooded system in the first moment of the process. Then the polymerization rate becomes proportional to the introduced monomer. At moderate feed rate the polymerization rate is controlled by the addition rate. At a critical addition rate transition to a flooded system takes place. The conversion and particle diameter decrease with increasing stirring speed.
Effects of catalyst diffusion in the methanolysis of poly(vinyl acetate)
Authors: Brandsch J. 
Published: April 2003

AbstractThe relationship between catalyst concentation and the structure of the copolymers at partial methanolysis of poly(vinyl acetate) was studied. Based on a model earlier presented and meanwhile developed further, it was found that the penetration rate of the sodium hydroxide has a characteristic influence on the distribution of monomer units. The obtained vinyl alcohol — vinyl acetate copolymers were examined also as protective colloids for poly(vinyl acelate) latex particles.
Polymerisation von Styren und Copolymerisation mit Butadien mit dem Katalysatorsystem Nickel‐ll‐acetylacetonat/Ethylaluminiumsesquichlorid
Authors: Gehrke K. , Pohlmann H.‐W. , Harwart M. 
Published: April 2003

AbstractDie Styrenpolymerisation mit dem Ziegler‐Natta‐Katalysatorsystem Nickelacetylacetonat/Al2Et3Cl3 in Abhängigkeit von Zeit, Monomer‐ und Initiatorkonzentration sowie Temperatur wurde untersucht. Die Copolymerisationsparameter für die Copolymerisation von Butadien und Styren mit diesem Katalysatorsystem wurden bestimmt.
Determination of reactivity ratios of styrene and some alkyl acrylates with n‐tolylmaleimide at high conversion steps
Authors: Ryttel A. , Kucharski M. 
Published: April 2003

AbstractThe copolymerization of styrene, methyl acrylate, ethyl acrylate, and n‐butyl acrylate with N‐tolymaleimide initiated by benzoyl peroxide in benzene solution has been studied. At high conversion steps the reactivity ratios of the monomers were determined, using Kelen‐Tüdős method and briefly discussed. The Alfrey‐Price Q and e values of N‐tolylmaleimide were also calculated.
Synthesis of macroporous poly(methyl methacrylate) derivatives and their use in organic synthesis
Authors: Akelah A. , Hassanein M. , El‐Sakran M. , Kenawy E. R. , Abdel‐Galil F. 
Published: April 2003

AbstractCrosslinked poly(methyl methacrylate) beads were reduced with LiAlH4 or aminated with ethylenediamine followed by acylation of the hydroxymethyl or amine pendant groups with chloroacetal‐, p‐bromomethylbenzoyl‐, or 11‐bromoundecanoyl chloride to give the corresponding polymeric halogen derivatives. Treatment of these resins with triphenylphosphine gave the polymeric phosponium salts. The catalytic activities of the products were tested in various types of anion promoted reactions. The results show that polymeric phosphonium salts based on PMMA effectively activate the anions in liquid‐liquid two‐phase systems. In solid‐liquid systems the catalytic activity of these polymeric catalysts is greatly reduced.
Copolymerization of a multiallyl monomer with styrene
Authors: Jantas R. , Połówiński S. 
Published: April 2003

AbstractThe free‐radical copolymerization of the multiallyl monomer poly(N‐allylmethacrylamide) with styrene in diluted dioxane solutions was studied. The chain transfer constant of the polystyrene radical to the multiallyl monomer was determined. The effect of temperature, initiator concentration, and initial composition of the monomer mixture on the copolymerization yield was examined and the content of unreacted allyl bonds and molecular weight were determined. Based on IR spectroscopy, 1H NMR, and elemental analysis and on the examination of the products of hydrolysis, the structure of the copolymers is described. The polymerization resulted in the formation of branched copolymers with ladder‐type short blocks, linked through polystyrene blocks, and containing unreacted allyl groups.