Kinetic theory of polymer melts. VIII. Rheological properties of polydisperse mixtures.

The Curtiss–Bird model of polymer melts has been extended to include polydisperse mixtures. The formula for the stress tensor derived in the last paper is used here to give explicit expressions for material functions in shear and elongational flow. Predictions are shown for viscosity, first normal stress coefficient, elongational stress growth viscosity, and steady elongational viscosity for Flory–Schulz and log–normal molecular weight distributions. It is also shown how generalizations that are observed experimentally for viscosity are predicted by the Curtiss–Bird model. In the next paper, these calculations are compared with experimental data. [ABSTRACT FROM AUTHOR]