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  • 1
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 193 (1991), S. 13-20 
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Strom-Spannungs-Charakteristik eines Bisphenol-A-Polycarbonats im Span-nungsbereich 50-1000 V und der Einfluß von UV-Bestrahlung (λ = 225 und 300 nm) und Tempern auf die elektrische Leitfähigkeit (σ) des Polycarbonats wurden untersucht. Die Abhängigkeit von σ gegen 1/T deutet auf zwei verschiedene Leitfähigkeits-mechanismen hin. Aus den Ergebnissen wurden die Aktivierungsenergien der Leitfähigkeit und die Sprungdistanzen berechnet.
    Notizen: Current-voltage characteristics of polycarbonate samples (PC) have been studied in the voltage range 50-1000 V. The effect of UV-irradiation at λ = 225 and 300 nm, and thermal annealing on the electrical conductivity (σ) of PC was studied. The σ vs. 1/T relationship shows two slopes, i.e. two possible conduction mechanisms. The obtained results made it possible to determine a complete set of conduction parameters including activation energy and jump distance.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1587-1591 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The investigated samples were of cellulose nitrate CA-80-15. The dc conductivity (σ) and the dielectric permittivity decreasd with increasing time of annealing. The activation energy is 0.46 eV in a temperature range from 298 to 385 K. The thermally stimulated current (TSC), JD, was measured. The maximum value of the TSC (Jm) increases with increasing the rate of heating and shifts slightly toward higher values of temperature. The activation energy (0.25 eV) is independent of the variation of the rate of heating. In addition, the peak positions for the constant rate of heating were unaffected by increasing the polarization time, but the maximum value of the current increases and the activation energy decreases. The dipolar relaxation time was calculated theoretically and studied as a function of temperature. © 1994 John Wiley & Sons, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 2415-2421 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The dc electrical conductivity (σ) and permittivity (ε′) of polycarbonate (PC) discs doped with different concentrations of NiCl2 are studied. Both (σ) and (ε′) increase with increasing the concentration of NiCl2, with a maximum value at 30 wt %. The activation energies for pure and doped PC are 0.49 and 0.53 eV, respectively. The increase in the electrical conductivity with increasing NiCl2 concentration is attributed to the formation of chargetransfer complexes (CTC); the increase in ε′ may be due to the rise in the interfacial polarization which results from the increase in boundaries between PC and NiCl2 phases. The currents in PC discs, both pure and doped with NiCl2, in the high-field region are attributed to space charge limited conduction. The time dependence of conduction current before and after reversal of applied voltage is also investigated. Some parameters such as the density of mobile ions and their drift mobilities are estimated. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 935-942 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Cellulose nitrate (CA-80-15) films were exposed to UV and neutron irradiations. An increase of the electrical conductivity was observed. The values of the activation energy diminish with irradiation from 0.42 to 0.15 eV for UV and to 0.31 eV for neutron irradiation. A sharp increase in the current was observed after exposing CA-80-15 samples to fission neutron fluences of 1*107 n/cm2. The electrical conduction in cellulose nitrate is governed by the Shottky mechanism. The value of the electron affinity of the polymer used is 4.46 eV. This value is increased after both types of irradiation. The dielectric permittivity (ε′) of the above samples together with the dielectric loss factor (ε″) were measured over a range of temperatures (293-403 K) at fixed frequencies (1*103, 1*104, and 1*105Hz). Three neutron exposures (φ = 1*105, 1*106, and 1*107 n/cm2) were used. The obtained results made it possible to determine a complete set of conduction parameters including dielectric susceptibility χ, ac conductivity αac, and temperature coefficient of permittivity TCε′. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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