Rheology of Polymer Melts—A Correlation of Dynamic and Steady Flow Measurements

    Published: Oct 1959

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    The response of a viscoelastic fluid to a shearing stress varying sinusoidally with time can be described in terms of a complex dynamic viscosity. The real part of the complex viscosity thus obtained from dynamic measurements is observed to decrease with increasing frequency of the deformation in much the same way that the apparent viscosity of the material diminishes with increasing rate of shear in a steady flow test. Also, the dynamic and steady state viscosities approach the same limiting value as frequency and shear rate, respectively, approach zero. Therefore, it is natural to speculate on analogies between the role of frequency in dynamic tests and that of shear rate in steady flow measurements and to seek correlations between dynamic and steady state measures of viscosity.

    Author Information:

    Cox, W. P.
    Monsanto Chemical Co., Plastics Division, Springfield, Mass

    Merz, E. H.
    Monsanto Chemical Co., Plastics Division, Springfield, Mass

    Committee/Subcommittee: D20.10

    DOI: 10.1520/STP44206S

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