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Sorption and diffusion of volatile organic compounds in polydimethylsiloxane membranes
Author(s) -
Chandak M. V.,
Lin Y. S.,
Ji W.,
Higgins R. J.
Publication year - 1998
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/(sici)1097-4628(19980103)67:1<165::aid-app19>3.0.co;2-0
Subject(s) - sorption , gravimetric analysis , chemistry , diffusion , thermodynamics , polydimethylsiloxane , thermal diffusivity , membrane , solubility , ethanol , chromatography , organic chemistry , chemical engineering , analytical chemistry (journal) , adsorption , biochemistry , physics , engineering
Sorption and diffusion of ethanol, 1,1,1‐trichloroethane (TCA), and trichloroethylene (TCE) were investigated in polydimethylsiloxane (PDMS) membranes using a gravimetric technique. The thermodynamic equilibrium and kinetic properties were evaluated at temperatures of 25, 100, and 150°C. The sorption isotherms for TCA and TCE can be correlated well using the Flory‐Huggins model. However, a three parameter Koningsveld‐Kleinjtens variation to the Flory‐Huggins equation is required for correlation of the ethanol isotherm. The solubility coefficients of TCA and TCE increase with activity, but it remains almost constant for ethanol. The calculated sorption energies reveal high positive heat of mixing for ethanol. TCA and TCE sorption in PDMS decreases strongly with temperature as opposed to ethanol. Clustering function analysis is used to explain the anomalous ethanol sorption and diffusion behavior in PDMS. TCA and TCE diffusivities do not exhibit large variations with volatile organic compound activity. However, ethanol demonstrates a maxima in its diffusivity at activities where it has minimum clustering tendencies. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 165–175, 1998