Fractionation of a polydisperse polymer using an antisolvent. Application of continuous thermodynamics

Authors

  • Albert H. Wu,

    1. Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory and Chemical Engineering Department, University of California. Berkeley, California 94720
    Current affiliation:
    1. Mobil Research and Development Corporation, Paulsboro, NJ 08066
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  • John M. Prausnitz

    1. Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory and Chemical Engineering Department, University of California. Berkeley, California 94720
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Abstract

Continuous thermodynamics is used to calculate liquid-liquid equilibria in a ternary system containing polydisperse polymer, one good solvent and one poor solvent (antisolvent). The polymer has a semiinfinite molecular-weight distribution which can be described by a gamma distribution. From Flory-Huggins theory, the logarithm of the distribution ratio of the polymer is a linear function of the molecular weight. Because the distribution of polymer between the two liquid phases is very sensitive to the choice of binary Flory parameters. The Flory parameters must be fitted to the ternary data. Results are given for the system benzene, ethanol, and polydisperse polystyrene.

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