Concentration dependence of diffusivity for the styrene-polystyrene and ethylbenzene-polystyrene systems.

The concentration dependence of the mutual diffusivity is evaluated, using the concentration distributions obtained in the previous paper for both systems and comparing them with the free-volume theory of Vrentas and Duda. It is concluded that this theory is a correlative rather than a predictive method at a temperature extremely far above the Tg of the polymer