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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 33 (1998), S. 3391-3400 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The elastic constants C 11, C 13, C 33 and C 44 of oriented poly-4-methyl-1-pentane (P4M1P) films were measured with Brillouin scattering. The photoelastic constants p 11, p 13, p 31 and p 33 were measured by evaluating the integral intensities of the phonon lines. The correlation of the photoelastic constants p 13 and p 31 with the degree of stretching was determined by evaluating the relative integral intensities of the Brillouin lines with the phonon propagation vector into and perpendicular to the stress direction. The other photoelastic constants were measured by comparing the angle-dependent relative integral intensities of the transverse and longitudinal Brillouin lines. The elastic constants, as well as birefringence, were surprisingly found to be unaffacted by further stretching of the sample above the necking region. The density was constant for all degrees of stretching. The photoelastic constants p 11 and p 33 showed significant variation during deformation. The results have been compared with former measurements of polypropylene (PP) by Cavanaugh and Wang. Because the elastic constants are unchanged during deformation, the modulation of the intensities is due to the variation of the photoelastic constants for this material.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 1661-1676 
    ISSN: 0887-6266
    Keywords: elastomers ; Brillouin spectroscopy ; oriented polymers ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We present a new method to interpret data obtained by Brillouin-scattering from oriented networks. Because in rubberlike samples the transverse sound waves are normally not observable, it is not possible to extract the complete set of elastic constants. We will show that by combining a model of the orientation process with the lattice-model from Kondo and Igarashi, force constants can be determined from the sound velocities. These force constants can be discussed in terms of molecular conformations and interactions. The anisotropic hypersound velocity was measured in polyurethane- and polysiloxane networks. With the help of the combined orientation-lattice-model evaluation, different kinds of forces can be distinguished. By comparing the force constants with Raman- or infrared spectroscopic data, information about the conformation of the polymer chains can be determined. The effective force constants of the segments are an order of magnitude lower than that of the polymer main chains and the ratio of force constants along and between the segments lies between 1 : 1 to 5 : 1. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1661-1676, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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