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Determination of diffusion coefficients of water in cellulose acetate membranes
Author(s) -
Palin Michael J.,
Gittens Gerald J.,
Porter G. Brian
Publication year - 1975
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.1975.070190421
Subject(s) - cellulose acetate , membrane , diffusion , gravimetric analysis , cellulose , polymer , sorption , chemistry , chemical engineering , porosity , materials science , thermodynamics , analytical chemistry (journal) , polymer chemistry , chromatography , organic chemistry , adsorption , biochemistry , physics , engineering
The determination of the diffusion coefficient for water in various porosity cellulose acetate membranes by a gravimetric method, using a humidified carrier gas, is described. It was found to be impossible to obtain meaningful results for very porous membranes, although dense membranes gave limiting values of diffusion coefficient at high carrier gas velocities. This phenomenon is explained in terms of the dissipation of the heat of sorption by the forced convection provided by the carrier gas. The variation of diffusion coefficient with concentration of water in dense cellulose acetate is explained in terms of clustering of water molecules in the polymer at high concentration.