MOLECULAR-TRANSPORT OF ORGANIC ESTERS INTO TETRAFLUOROETHYLENE PROPYLENE COPOLYMER MEMBRANES/

Diffusion, permeation, and equilibrium sorption coefficients have been determined using a sorption gravimetric technique for methyl acetoace tate, ethyl acetoacetate, methyl benzoate, ethyl benzoate, methyl sali cylate, isobutyl salicylate, and diethyl malonate into tetrafluoroethy lene/propylene copolymer membranes in the temperature range 25-70 degr ees C. The sorption kinetics process has been characterized by first-o rder rate constants and penetration velocities. From a temperature dep endence of the transport coefficients, the activation parameters have been estimated. It is observed that the values of the transport coeffi cients for the systems of this study depend on the nature of the penet rant molecules rather than on their molecular sizes. On the whole, the mechanism of solvent transport into the copolymer membranes used here follows nearly the Fickian trend. (C) 1994 John Wiley and Sons, Inc.