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  • 1
    Electronic Resource
    Electronic Resource
    Copolymers of pyrrole and bithiophene by oxidative electropolymerization (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 1379-1385 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrrole (PY) and 2,2′-bithiophene (BT) have been electropolymerized at various feed ratios in LiClO4/Propylene carbonate (PC) and the mer ratios in the copolymer determined by N and S. microanalysis. A strong correlation was observed between the copolymer compositions and the monomer feed ratios using the copolymer equation, and reactivity ratios were determined by a nonlinear error-in-variables approach. Although PY predominates in these copolymers, the proportion of BT increases with increasing applied potential. It is shown that reactivity ratios do not have to be understood in the traditional sense, but may be simply a measure of the relative ease of oxidation of the monomers at the electrode.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080291002
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  • 2
    Electronic Resource
    Electronic Resource
    Mechanistic studies of the electrochemical polymerization of pyrrole: Deuterium isotope effects and radical trapping studies (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 451-464 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of the electrochemical polymerization of pyrrole and pyrrole-d4 has been studied by an examination of the kinetic deuterium isotope effect. The kinetic rate constants of the reaction were measured by cyclic voltammetry, UV/visible specrophotometric analysis of polymer growth, and quantitative gas chromatographic analysis of monomer uptake. All three techniques demonstrated no primary isotope effect, from which it is concluded that proton loss or abstraction is not involved in the rate-determining step of the polymerization. Furthermore no consistent secondary effect could be observed, suggesting that the rate-determining step is free of hybridization changes or hyperconjugative effects in the transition state. A radical trap experiment revealed that polymer formation is completely inhibited by the presence of a radical trap and thus a reaction with the scavenger is more favorable than coupling with another radical cation or a neutral monomer molecule. Previously proposed mechanisms are examined and compared in light of the present study. Oxidative coupling is favored as the mechanism for electrochemical polymerization of pyrrole and related compounds. For this mechanism the rate-limiting step must be either oxidation of monomer or radical cation coupling.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1990.080280301
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  • 3
    Electronic Resource
    Electronic Resource
    Characterization of conducting copolymers of 2,2′-bithiophene and pyrrole by cyclic voltammetry and UV/visible spectroscopy (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1891-1898 
    Details
    ISSN: 0887-624X
    Keywords: polypyrrole ; poly(2,2′-bithiophene) ; copolymer ; conducting polymer ; electrochemical polymerization ; cyclic voltammetry ; UV/visible spectroscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several polymers have been prepared by electropolymerization of mixtures of pyrrole (PY) and 2,2′-bithiophene (BT). Cyclic voltammetry on prepared polymer films shows three anodic oxidation peaks, two of which match the oxidation potentials of homopolymeric PY and BT, and a third which is intermediate. UV/visible spectroscopy displays a unique spectrum for each of the reduced and oxidized forms of these polymers. Nernstian plots from UV/visible data exhibit three well-defined redox couples in polymer films produced at 1.3 V. Overall, the data strongly support the formation of a copolymer, consisting of three distinct oxidizable units. Two of these can be attributed to short blocks of either PY or BT, and a third to random and alternate groupings of PY and BT. The polymers produced are electrically conductive, but the conductivity drops rapidly as BT units are introduced into a homopolymer of PY. © 1992 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300911
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  • 4
    Electronic Resource
    Electronic Resource
    Thermogravimetric study of polyacrylamide with evolved gas analysis (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1807-1823 
    Details
    ISSN: 0887-624X
    Keywords: polyacrylamide ; thermal analysis ; thermogravimetry ; evolved gas analysis ; infrared ; mass spectrometry ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dried samples of polyacrylamide in an He atmosphere have been subjected to thermogravimetric analysis in the 30-600°C range, and the evolved gases were monitored by FTIR. Water, ammonia, and small quantities of carbon dioxide are released in the first stages of decomposition (220-340°C), where the polymer chains remain intact and the reaction occurs on the pendant amide groups. In the second stage of decomposition (340-440°C), the majority of the weight loss occurs, and main chain breakdown occurs, releasing carbon dioxide, water, nitrile compounds, and imides. Trapping of the gases in this stage and analysis by GC-FTIR and GC-MS reveals the presence of more than 20 decomposition products, and confirms that a large proportion of these can be assigned to glutarimide and its substituted analogs. Imidization and dehydration reactions on the amide groups, as well as free radical breakdown of the main chains, with inter- and intramolecular hydrogen transfer, can account for many of the products of the decomposition. © 1993 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310720
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