DIFFUSION OF METHYL ETHYL KETONE IN POLYISOBUTYLENE - COMPARISON OF SPECTROSCOPIC AND GRAVIMETRIC TECHNIQUES

In this study, vapor sorption FTIR-ATR (Fourier Transform Infrared Att enuated Total Reflectance) spectroscopy was combined with a convention al gravimetric sorption balance to examine diffusion in polymers. Mutu al diffusion coefficients of methyl ethyl ketone in polyisobutylene we re measured using both methods at various penetrant activities and tem peratures in the range 40-60 degrees C. Actual penetrant concentration s were determined from the sorption balance. The diffusion coefficient s from the two techniques agree very well with each other. In addition , the diffusivity data from both techniques could be correlated succes sfully as a function of temperature and concentration with the Vrentas and Duda free-volume model. (C) 1997 John Wiley & Sons, Inc.