ISSN:
0887-6266
Keywords:
glassy polymers
;
gas sorption
;
dual-mode sorption model
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Sensitivity of the parameters of the dual-mode sorption (DMS) model on the pressure range, in which sorption of gases in polymers have been studied, was analyzed. Different “gas-polymer” systems were considered but the most detailed analysis was performed for sorption of argon and nitrogen in poly[5,5-difluoro-6,6-bis(trifluoromethyl)] norbornene and polysulfone. It was shown that the model parameters depend upon the range of gas pressure studied. Expanding of the pressure range (0-pi) results in an increase in the Langmuir adsorption capacity C′H and in reduction of Henry's law solubility coefficient kD and Langmuir affinity parameter b. These behaviors does not depend on a choice of an experimental apparatus or software and procedure of nonlinear least squares treatment of the data. As statistical analysis indicated, a systematic error of the measurement cannot call forth the observed dependencies of the model parameters. Different physical reasons of these behaviors were considered, among them: the pressure dependence of the affinity parameter, and the dilation of a polymer. The results obtained showed that although the DMS model, as a rule, gives an excellent fit of the experimental curves, and, hence, can be used as a form of compact storage of information on gas sorption in polymers, one should be careful in using it outside the pressure range in which its parameters have been determined. © 1996 John Wiley & Sons, Inc.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
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