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.