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  • 1
    Electronic Resource
    Electronic Resource
    Effect of heat treatment on the structure and mechanical properties of polyacrylonitrile fibers (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 2409-2416 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Strucure and mechanical properties of untreated and thermally treated (at 110°C and 150°C) drawn polyacrylonitrile (PAN) fiber have been studied through IR spectroscopy, wide angle X-ray diffraction, and tensile and dynamic mechanical properties measurements. The results are interpreted in terms of the change in the degree of bound nitrile group pairs on heat treatment. The heat treatment at both the temperatures resulted in higher degree of bound nitrile groups (through their dipolar interactions) in the heat-treated PAN than that of the untreated PAN, as evidenced by IR spectroscopy, X-ray diffraction, and the mechancal properties. The difference between the results for the two heat-treatment temperatures are not sufficiently large, although the changes produced by heat treatment at 110°C seems somewhat more prominent than those produced by heat treatment at 150°C.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270711
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of heat treatment on the dielectric relaxation of polyacrylonitrile. II. Heat treatment under vacuum and in air (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 4101-4114 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Dielectric relaxation, infrared spectra, and X-ray diffraction data of polyacrylonitrile (PAN) heat treated at 120°C in air and under vacuum and of the untreated PAN are reported. The heat treatment resulted in (1) lowering of dielectric constant increment, dielectric dissipation factor, and increase in relaxation temperature and glass transition temperature; (2) lowering of the intensity of —C≡N stretching band in the infrared spectra; and (3) increase in degree of order of the X-ray diffraction results. The changes produced by heat treatment under vacuum are found greater than those produced by heat treatment in air, which suggests that the observed effect is not caused by chemical changes in the PAN molecule under heat treatment. Interpretation of these results is attempted on the basis of the difference in the degree of bound nitrille group pairs (bound through intermolecular dipole-dipole interactions) in the structure of PAN heat treated under the different conditions.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070271103
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Spectroscopic characterization and Langmuir-Blodgett films of N,N-symmetrical dialkyl-3,4:9,10-perylenebis(dicarboximide)s (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 351-356 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The electronic and vibrational spectra of N-R-N′-R-symmetrical dialkyl-3,4:9,10-perylenebis(dicarboximide)s (R = C5H11, C6H13 and C8H17) are reported. Langmuir monolayers were prepared and surface pressure-area isotherms were measured for three non-amphiphilic molecules. Langmuir-Blodgett (LB) films of mixed layers only were fabricated on solid substrates. Fundamental vibrational frequencies were observed using surface-enhanced resonance Raman scattering, transmission and reflection-absorption (RAIRS) Fourier transform infrared spectroscopy. The molecular orientation in the LB films was established from the transmission and RAIRs spectra. Molecular aggregation is reduced by the presence of bulky alkyl substituents. The adsorption of electron acceptor molecules and its effect on the fluorescence yield are also reported.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250240603
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  • 4
    Electronic Resource
    Electronic Resource
    Spectroscopic characterization and Langmuir-Blodgett monolayers of N,N′-unsymmetrical dialkyl-3,4:9,10-perylenebis(dicarboximide)s (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 24 (1993), S. 227-232 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The spectroscopic characterization of N-pentyl-N′-R-unsymmetrical dialkyl-3,4:9,10-perylenebis(dicarboximide)s (R = CH3, C2H5 and C3H7) is reported. Langmuir monolayers of all three non-amphiphilic molecules were successfully prepared and transferred to solid substrates. The absorption and fluorescence spectra of solutions and Langumuir-Blodgett (LB) films were studied. Vibrational fundamental frequencies were observed using surface-enhanced resonance Raman scattering and transmission and reflection-absorption Fourier transform infrared spectroscopy. The formation of aggregates in the ground and excited states (excimer formation) is also discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250240408
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    Paper (German National Licenses)
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