Molecular migration of some industrial solvents into fluoropolymer membranes

The molecular migration of nine industrial organic liquids into Du Pontʹs VITON fluoropolymers has been studied over the temperature interval 25–60°C. Migration has been studied in terms of sorption and diffusion of liquids into the membrane materials. A gravimetric method is used to measure the solvent uptake. From the sorption results, diffusion coefficients have been calculated using Fickʹs equation. A numerical method has been employed to calculate the liquid concentration profiles in the polymers. The kinetic rate constants have also been calculated from the sorption results. Activation parameters for sorption, diffusion, and permeation have been estimated by a least-squares method using the Arrhenius equation.