Consistency Test for Continuous Flow Permeability Experimental Data

Abstract

The steady-state permeability experiment is the method recom mended to evaluate the barrier properties of polymeric films which are ex pressed as a permeability coefficient (Hernandez et al., 1986). Besides the permeability coefficient, the diffusion coefficient can also be determined from the unsteady-state values of a permeability study. Since the correctness of the set of permeability data will affect the numerical values of both diffusion and permeability coefficients, a procedure to determine the consistency of a set of data obtained from a continuous flow permeability experiment is proposed in this article. The interest of a simple consistency test arises from the need to de tect variations of the system parameters such as temperature or concentration changes, during the permeation experiment. Further, an analysis of the consis tency of the data will provide information on the applicability of the Henry's law of solubility and the invariability and uniqueness of the diffusion coeffi cient, and may lead to a better understanding of the diffusion and solubility mechanisms that are controlling the permeation system.

Keywords

permeability diffusion sorption gas permeation barrier polymer films consistency test.

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References

Brandrup, J. and E. Immergut , editors. 1975. Polymer Handbook, Second Edition . NY: John Wiley & Sons.

Chapra, S.C. and R.P. Canale. 1985. Numerical Methods for Engineers with Personal Computer Applications. New York: McGraw-Hill, Inc.

Crank, J. 1975. The Mathematics of Diffusion, Second Edition Oxford: Oxford University Press.

Gavara, R. and R.J. Hernandez. 1992. "Bimodal Diffusion Process in the Oxygen Mass Transport through Nylon 6 at Different Temperature and Water Activity Conditions", Proceedings of the American Society for Composites 7th Technical Conference on Composite Materials, October 13-15, Pennsylvania State University, PA.

Hernandez, R.J. , J.R. Giacin and A.L. Baner. 1986. "The Evaluation of the Aroma Barrier Properties of Polymer Films", Journal of Plastic Film & Sheeting, 2:187.

Meares, P. 1965. "Transient Permeation of Organic Vapors through Polymer Membranes," J. Appl. Polymer Sci., 9:917.

Pasternak, R.A. , J.F. Schimscheimer and J. Heller. 1970. "A Dynamic Approach to Diffusion and Permeation Measurements", Journal of Polymer Science, Part A-2, 8:467.