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Flow method for study of gas transport in polymers. Application to the study of oxygen, nitrogen, and carbon dioxide permeation through cellulose acetate membranes
Author(s) -
Nguyen X. Q.,
Šipek M.,
Hynek V.,
Nguyen Q. T.
Publication year - 1994
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1994.070541205
Subject(s) - permeation , cellulose acetate , chemistry , solubility , carbon dioxide , solvent , oxygen , membrane , polymer , nitrogen , ethanol , cellulose , polymer chemistry , chemical engineering , thermodynamics , organic chemistry , physics , biochemistry , engineering
Transient permeation of oxygen, nitrogen, and carbon dioxide through certain cellulose acetate (CA) dense membrances made from solutions in dioxane and dioxane‐added ethanol were studied by the flow method. In order to explain the overshoots for transient permeation rates in the latter case, a new model is proposed. It postulates a time‐dependence solubility coefficient, in the form of a series of exponential terms, which is combined in Fick's second law and solved. The model fits well the obtained permeation kinetics, leading to values of the diffusion, and permeation coefficients, and the structure change‐related time. The overshoots are explained by the formation of unstable structure from dioxane‐ethanol solvent mixtures, a memory effect of aggregated chains, which undergoes consolidation upon gas penetration. The stable state which results from the consolidation process is the same as that of membrances obtained from pure dioxane solutions. © 1994 John Wiley & Sons, Inc.