MOLECULAR-TRANSPORT OF ORGANIC ESTERS INTO FLUOROPOLYMER MEMBRANES

The effects of different fluorine contents of the Du Pont VITON fluoropolymers have been studied in the presence of esters such as methyl acetoacetate, ethyl acetoacetate, methyl benzoate, ethyl benzoate, and 1-butyl acetate in the temperature interval of 25-degrees-60-degrees-C. The sorption and diffusion of these liquids into the polymer membranes tend to deviate slightly from the Fickian mechanism; however, the diffusion data have been calculated from the Fickian model. It is suggested that the hindered chain segmental motion and the structural differences in the polymer membranes contribute to the overall sorption process, in addition to strictly thermodynamic considerations. The activation parameters for the transport processes have been estimated and the results are discussed in terms of the nature of polymer-solvent interactions.