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  • 1
    ISSN: 1063-7826
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The polarization method for studying photoactive absorption is used to investigate the photoconversion processes in CdS/InP heterojunctions as a function of the orientation of the indium phosphide substrate. The results of these investigations demonstrate the sensitivity of the photoelectric processes to several factors, including the crystallographic orientation of the p-type InP substrate and the optical quality of the CdS layer. The induced photopleochroism coefficient of these heterojunctions increases proportionally to the square of the angle of incidence (P I ∼Θ2). Such CdS/InP heterojunctions can be employed as polarization-photosensitive devices.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Neue thermostabile heterocyclische Polymere, die phenylsubstituierte Chinoxaline sowie Amid- und Imidstruktureinheiten enthalten, wurden durch Polykondensation in Lösung bei niedriger Temperatur aus Diaminophenylchinoxalinen und Disäurechloriden verschiedener aromatischer Carbonsäuren, die Imidgruppen enthielten, hergestellt. Sowohl die thermische Stabilität als auch die elektrischen Eigenschaften dieser Polyphenylchinoxalin-Amid-Imide werden diskutiert.
    Notes: New thermostable heterocyclic polymers containing phenylsubstituted quinoxaline and both amide and imide units have been synthesized by low temperature solution polycondensation of diaminophenylquinoxalines with diacid chlorides of certain aromatic acids containing preformed imide rings. The thermal stability as well as electrical properties of these polyphenylquinoxaline-amide-imides are discussed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch Menschutkin-Reaktion wurden Polyurethane mit kationischen Viologen-gruppen hergestellt. Die photochromen Eigenschaften dieser Polymeren in einer Poly(vinylalkohol)-Matrix wurden mit UV- und Laserlicht untersucht.
    Notes: The Photochromic properties by UV and laser irradiation of cationic polyurethanes with viologen groups introducted by Menschutkin reaction were studied and poly(vinylalcohol) was used as matrix.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Viskositätsverhalten verdünnter Lösungen von Sulfobetain-Polyurethanen in Dimethylformamid sowie der Einfluß von Salzen einiger ein- und zweiwertiger Metalle auf die Viskosität wurden untersucht. Dabei zeigte sich, daß sich diese Polyurethan-Zwitterionomeren wie Polyelektrolyte verhalten.In aus diesen Polymeren hergestellten und mit zweiwertigen Metallen komplexierten Filmen bilden sich im Schwefelwasserstoffstrom Metallsulfide. Die höhere Leitfähigkeit der mit H2S behandelten Filme deutet auf eine Struktur mit Mikrophasenseparation hin.
    Notes: The viscosimetric behaviour of diluted DMF solutions of some sulfobetaine polyurethanes and also the influence of some mono- and bivalent metal salts were studied. The study showed that polyurethane zwitterionomers behave as polyelectrolytes.Films of these polymers complexed with bivalent metals can form, in situ, particles of metal sulfides by exposure to slow H2S flow. Preliminary results show an increased conductivity of films treated with H2S, suggesting a microphase segregation structure.
    Additional Material: 5 Ill.
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  • 5
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die mechanischen und dielektrischen Relaxationseigenschaften von Sulfobetain-Polyurethanionomeren auf Polyesterbasis wurden mit Zug-Dehnungs-Versuchen und thermisch stimulierten Depolarisationsstrom-Methoden (TSDC) untersucht und mit den Eigenschaften von nichtionischen Polyurethanen sowie Derivaten mit Pb2+ bzw. Co2+ verglichen. Die Einführung ionischer Zentren in die Polyurethankette verbessert die Zugfestigkeiten und verändert die TSDC-Spektren. Diese Effekte werden auf eine Verbesserung der Mikrophasensegregation zurückgeführt. Eine Komplexierung mit Pb2+ bzw. Co2+ vermindert die Zugfestigkeiten, was darauf hindeutet, daß durch eine teilweise Neutralisierung ionischer Zentren eine homogenere Phasenmischung erreicht wird. Die Behandlung mit H2S führt durch Clusterbildung der Metallsulfide PbS bzw. CoS zur Entstehung halbleitender Mikrophasen, wodurch die Zugfestigkeiten leicht erhöht und die TSDC-Spektren verändert werden.
    Notes: Tensile and dielectric relaxation properties of sulfobetaine polyurethane ionomers based on polyesters were studied comparatively to the non-ionic polyurethane and derived compounds with Pb2+ and Co2+, using stress-strain and thermally stimulated depolarization currents (TSDC) methods. Introduction of ionic centers into polyurethane chain improves the tensile properties and modifies the TSDC spectra. These effects are assigned to an enhancement of the microphase segregation. Complexation with Pb2+ and Co2+ diminishes the tensile properties, suggesting that an increase of phase mixing occurs determined by a partial neutralization of ionic centers. Treatment with H2S slightly increases tensile properties and changes TSDC spectra owing to the presence of the semiconducting microphases formed by clustering of the metal sulfides PbS and CoS, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aus Poly(oxytetramethylen), 4,4′-Bibenzyldiisocyanat, N-Methyldiethanolamin als Kettenverlängerer und Acrylsäure/Polyacrylsäure als Quaternisierungsagens wurden Poly(etherurethan)-Kationomere hergestellt. In aus diesen Kationomeren hergestellten Filmen wurde Pyrrol (15 Gew.-%) in Gegenwart von CuCl2 polymerisiert. Die Filme wurden mittels dynamisch-mechanischer Analyse, Thermogravimetrie und Differentialthermoanalyse charakterisiert. Die elektrische Leitfähigkeit beträgt für den Film ohne Polypyrrol 7.5 · 10-12 Ω-1 cm-1 und mit Polypyrrol 4.5 · 10-6 Ω-1 cm-1.
    Notes: Poly(ether urethane) cationomers based on poly(oxytetramethylene), 4,4′-bibenzyldiisocyanate, N-methyldiethanolamine as chain extender, and acrylic acid/poly(acrylic acid) as quaternization agent were synthesized. Pyrrole (15 wt.%%) was polymerized in films of the ionomer containing CuCl2. The films were characterized by dynamic mechanical analysis, thermogravimetry and differential scanning calorimetry. The electric conductivity of the film without polypyrrole is 7.5 · 10-12 Ω-1 cm-1, while incorporation of polypyrrole increases the conductivity to 4.5 · 10-6 Ω-1 cm-1.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 24 (1990), S. 573-576 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The dielectric relaxation processes in poly(azourethaneurea) prepared from diphenylmethane-4,4′-diisocyanate (MDI) and poly(ethylene adipate) glycol were studied in the range 200–390 K using thermally stimulated depolarization currents (TSDC). The TSDC spectra obtained on original sample, annealed sample, and both annealed and stretched sample showed significant differences which were explained in terms of the supramolecular structure of polymers. It was accepted that the polymers have a multiphase supramolecular structure.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 20 (1988), S. 195-200 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The thermally stimulated depolarization currents(TSDC) from polyurethanes based on 4,4′-dibenzyle diisocyanate(DBDI) and both saturated and unsaturated polyesters were studied over the temperature range 240–410 °K. Pour relaxation peaks were observed. The structure of the TSDC thermograms, location and intensity of the constituent peaks depend both on the urethane content and thermal history of the polymerr The morphological structure of the samples was evidenced using electron microscopy method.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Ultrahigh molecular weight polyacrylamides (PAAM) were obtained by plasma-induced polymerization in water solutions. The influenceof monomer concentration, sealing pressure, initiation time and post polymerization period on polymer yield and molecular weight were investigated. The viscosity and “screen factor” measurements, as well as the thermally stimulated depolarization currents spectroscopic data of the synthesized polymers, indicate good properties as efficient viscosity modifiers in displacement of fluids for enhance oil recovery (EOR).
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  • 10
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The thermally stimulated depolarization currents from poly(2-ethynylnaphtalene) with cis-cisoidal and transcisoidal structures were studied over the temperature range 200–380 K. The single peak ρ of the cis-cisoidal isomer was assigned to the Maxwell-Wagner polarization. The β1 and β2 peaks of the trans-cisoidal isomer arise from a single dipolar relaxation process and respectively from a dipolar relaxation distributed in natural frequency. Certains assignements are based on comparative work on polyphenylacetylene.
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