Date of Award

Spring 1977

Document Type

Dissertation

Degree Name

Doctor of Engineering Science in Chemical Engineering

Department

Chemical Engineering and Chemistry

First Advisor

Ching-Rong Huang

Second Advisor

Teddy Greenstein

Third Advisor

Robert S. Morsbach

Fourth Advisor

Deran Hanesian

Fifth Advisor

Jerome J. Salamone

Abstract

The flow of molten polystyrene, poly(methyl methacrylate) and three blends of these polymers has been studied in a rheogoniometer and in packed beds of unconsolidated spherical glass beads. One primary purpose of the study was to determine the behavior of polymer melt blends in porous media flow. The second major purpose of the work was to develop and test a new and powerful model for packed bed flow based upon the Huang generalized rheological constitutive equations.

Rheological characterization of the pure polymers and blends was obtained using a Roberts-Weissenberg rheogoniometer. Shear and normal stresses were measured at shear rates from .002 to 20 sec-1 and temperatures from 180 to 220 °C. Both the four parameter Huang and three parameter Ellis equations of state provided excellent representations of the viscometric data.

The Huang rheological equation was combined with an hydraulic radius capillary model for a porous medium leading to a generalized Darcy's law. This expression defined an effective non-Newtonian viscosity applicable to packed bed fluid flow. A packed bed friction factor and Reynolds number were developed to correlate experimental data.

Pressure drop of the pure polymers and blends was measured over a range of flow rates through packed beds of various bead sizes and packing depths. Temperature was maintained at 204°C.

Data for each pure polymer and blend was successfully correlated using a friction factor-Reynolds number relationship, which specifies that the product of these dimensionless quantities is constant. The value of this constant for pure poly(methyl methacrylate) was approximately one half the value for pure polystyrene and the three blends.

No significant differences in the behavior of the pure polymers and blends was observed. The Huang equation of state provided excellent representation of molten polymer viscometric data and successfully correlated packed bed flow data. The difference in packed bed flow behavior of poly(methyl methacrylate) and the other materials was tentatively ascribed to unidentified surface interaction effects between the fluids and the packed beds. Using the defined expressions, pressure drop for packed bed flow can be estimated from the rheological properties of the fluid and the physical properties of the packed bed.

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