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Phenomenological relations for viscoelastic properties of polymer-diluent systems; the relative dissipation index N21

1969; Taylor & Francis; Volume: 3; Issue: 2 Linguagem: Inglês

10.1080/00222346908205092

1525-609X

Kazuhiko Ninomiya, John D. Ferry,

Polymer crystallization and properties

Abstract A previous phenomenological description of viscoelastic properties of polymer blends with different molecular weights has been extended to polymer-diluent systems. The most important parameter in this description is the relative dissipation index, N21, expressing the ratio of energy dissipations per unit volume of the solute and solvent in steady flow. Several methods for obtaining N21 from experimental data are given: from viscosity data far above the glass transition, from a combination of viscoelastic data in the transition and terminal zones, from high-frequency dynamic viscosities, from viscosity data in dilute solution, and from steady-state compliance data. These are illustrated with various data from the literature. With decreasing concentration, N21 approaches a limiting value which is approximately directly proportional to molecular weight. At high concentrations, N21 becomes proportional to the 2.4 power of molecular weight, provided the latter exceeds the critical value for entanglement coupling. For a given molecular weight, N21 ordinarily increases with concentration. The molecular interpretation of N21 is discussed.