MULTICOMPONENT DIFFUSION IN POLYMERIC LIQUIDS

It is shown hom the phase-space kinetic theory of polymeric liquid mix tures leads to a set of extended Maxwell-Stefan equations describing m ulticomponent diffusion. This expression reduces to standard results f or dilute solutions and for undiluted polymers. The polymer molecules are modeled as flexible bead-spring structures. To obtain the Maxwell- Stefan equations, the usual expression for the hydrodynamic drag force on a bead, used in previous kinetic theories, must be replaced by a n ew expression that accounts explicitly for bead-bead interactions betw een different molecules.