Numerical examination of the dual‐mode sorption model for sorption rate experiments with an extension for a mobile langmuir component

Abstract

SynopsisNumerical methods were applied to the dual-mode sorption model for sorption rate experiments with an immobilized Langmuir component over broad ranges of polymer characteristics and experimental conditions. The variation of the diffusion coefficient evaluated using a single scaling procedure was examined. The numerical procedure was also applied to the model for infinite volume sorption and to sorption allowing for mobility of the Langmuir component of the penetrant.

Sorption and diffusion of water vapor in poly(ethylene terephthalate) film

“…The apparent diffusion coefficient increased with vapor pressure. In this case, different diffusion coefficients were assigned to the water vapor sorbed by each of the two mechanisms and obtained the following expression for the flux N as the partial immobilization model17–23 developed by Paul and Koros: where D D is the diffusion coefficient of the Henry part and D H is the diffusion coefficient of the Langmuir part. Our results for the PET/water system have been interpreted in terms of a concentration‐dependent diffusion coefficient, which is shown to be mathematically equivalent to the partial immobilization model.…”

Sorption and diffusion of water vapor in poly(ethylene terephthalate) film

“…The apparent diffusion coefficient increased with vapor pressure. In this case, different diffusion coefficients were assigned to the water vapor sorbed by each of the two mechanisms and obtained the following expression for the flux N as the partial immobilization model [17][18][19][20][21][22][23] developed by Paul and Koros:…”