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  • 1
    Electronic Resource
    Electronic Resource
    Mapping of the relaxation patterns of polymer melts with linear flexible molecules of uniform length (1997)
    Springer
    Rheologica acta 36 (1997), S. 330-344 
    Details
    ISSN: 1435-1528
    Keywords: Relaxation time spectrum ; monodisperse polymers ; hypergeometric function ; incomplete gamma function ; linear viscoelasticity ; polymer dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The linear viscoelastic material functions of linear flexible polymers of uniform length are calculated from the BSW spectrum (Baumgaertel et al., 1990, 1992), and explicit analytic expressions are presented for several of the most common material functions for transient and dynamic experiments. However, numerical calculations are presented whenever needed. The BSW spectrum was determined from experimental G″, G″ data of two sets of molten polymers of narrow molecular weight distribution, polystyrene and polybutadiene. The purpose of the mapping is to show a wide range of viscoelastic behavior which otherwise is not available in such comprehensive form. Experimental check of these predictions is still needed in most cases. Also, some insight into the predictions for the non-linear (including the non-equilibrium) viscoelastic behavior is achieved by studying two particular experiments: the start-up of uniaxial extension at constant rate and the start-up of shear flow at constant rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366674
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Mapping of the relaxation patterns of polymer melts with linear flexible molecules of uniform length (1997)
    Springer
    Rheologica acta 36 (1997), S. 330-344 
    Details
    ISSN: 1435-1528
    Keywords: Key words Relaxation time ; spectrum ; monodisperse polymers ; hypergeometric function ; incomplete gamma function ; linear viscoelasticity ; polymer dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The linear viscoelastic material functions of linear flexible polymers of uniform length are calculated from the BSW spectrum (Baumgaertel et al., 1990, 1992), and explicit analytic expressions are presented for several of the most common material functions for transient and dynamic experiments. However, numerical calculations are presented whenever needed. The BSW spectrum was determined from experimental G′,G″′ data of two sets of molten polymers of narrow molecular weight distribution, polystyrene and polybutadiene. The purpose of the mapping is to show a wide range of viscoelastic behavior which otherwise is not available in such comprehensive form. Experimental check of these predictions is still needed in most cases. Also, some insight into the predictions for the non-linear (including the non-equilibrium) viscoelastic behavior is achieved by studying two particular experiments: the start-up of uniaxial extension at constant rate and the start-up of shear flow at constant rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366674
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The relaxation of polymers with linear flexible chains of uniform length (1990)
    Springer
    Rheologica acta 29 (1990), S. 400-408 
    Details
    ISSN: 1435-1528
    Keywords: Relaxation spectrum ; monodisperse polymers ; scaling ; glass transition ; plateau modulus ; recoverable compliance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The analysis of dynamic mechanical data indicates that linear flexible polymer chains of uniform length follow a scaling relation during their relaxation, having a linear viscoelastic relaxation spectrum of the formH(λ) = n 1 G N 0 × (λ/λ max) n1 forλ≤λ max. Data are well represented with a scaling exponent of about 0.22 for polystyrene and 0.42 for polybutadiene. The plateau modulusG N 0 is a material-specific constant and the longest relaxation time depends on the molecular weight in the expected way. At high frequencies, the scaling behavior is masked by the transition to the glassy response. Surprisingly, this transition seems to follow a Chambon-Winter spectrumH(λ) = Cλ−n2, which was previously adopted for describing other liquid/solid transitions. The analysis shows that the Rouse spectrum is most suitable for low molecular-weight polymersM ≈ M c , and that the de Gennes-Doi-Edwards spectrum clearly predicts terminal relaxation, but deviates from the observed behavior in the plateau region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01376790
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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