Premium
Combined experimental and computer simulation study of the kinetics of solute release from a relaxing swellable polymer matrix. I. Characterization of non‐Fickian solvent uptake
Author(s) -
Papadokostaki K. G.,
Petrou J. K.
Publication year - 2004
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.20289
Subject(s) - fick's laws of diffusion , swelling , kinetics , polymer , diffusion , absorption (acoustics) , solvent , relaxation (psychology) , thermodynamics , thermal diffusivity , matrix (chemical analysis) , materials science , polymer chemistry , chemistry , chemical engineering , organic chemistry , composite material , psychology , social psychology , physics , quantum mechanics , engineering
This article is concerned with a combined experimental and computer modeling study aimed at the characterization of the non‐Fickian absorption of liquid water by cellulose acetate (CA) matrices (in the form of thin films) on the basis of a strictly limited number of parameters. The observed kinetics exhibited two distinct non‐Fickian features, resulting from short‐term and long‐term viscous structural relaxations of the swelling glassy polymeric matrix. These relaxation processes were modeled by the extension of a previous model of micromolecular diffusion in a polymer subject to a single relaxation process. The successful simulation of the experimental kinetic curves then enabled the determination and cross‐checking of the relevant model parameter values. This work had the dual purpose of providing (1) input related to solvent absorption for the quantitative computer simulation (in part II of this series) of a model monolithic, solvent‐activated, controlled‐release device, consisting of a swellable glassy polymeric matrix (CA) loaded with an osmotically active solute (NaCl), and (2) an example of a general strategy of extracting meaningful values of micromolecular diffusivity in glassy polymers from non‐Fickian absorption kinetic data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2458–2467, 2004