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Effect of relative humidity and temperature on the gas transport properties of 6FDA–6FpDA polyimide: Experimental study and modelling
- Source :
- Journal of Membrane Science. 485:60-68
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- The transport of CO2, CH4, N2 and He in films of polyimide 6FDA–6FpDA was studied at different temperatures, from 25 to 45 °C, and Relative Humidity (RH) from 0% to 90%. The permeability of all gases decreases with increasing RH, by factors as high as 44% for CH4 and 35% for the other gases; moreover, the relative decrease of gas permeability with respect to the dry polymer value is constant with temperature and just weakly dependent on the gas type. Pure water vapour sorption experiments were also conducted on the polymeric films in the same RH and temperature range, showing that water solubility in 6FDA–6FpDA is almost temperature-independent. A strong correlation therefore seems to exist between gas permeability decrease and water content in the membrane, due to the fact that absorbed water molecules occupy a portion of the polymer free volume, that is no longer available for gas permeation. Based on these considerations, the humid permeation results were analysed quantitatively and modelled with a simple approach based on free volume theory.
- Subjects :
- POLYIMIDES
Aqueous solution
Permeability modelling
Chemistry
Analytical chemistry
Filtration and Separation
Sorption
Permeation
Atmospheric temperature range
Biochemistry
humid gas permeation
Permeability (electromagnetism)
Polymer chemistry
General Materials Science
Relative humidity
Physical and Theoretical Chemistry
Water content
Water vapor
GLASSY POLYMERS
Subjects
Details
- ISSN :
- 03767388
- Volume :
- 485
- Database :
- OpenAIRE
- Journal :
- Journal of Membrane Science
- Accession number :
- edsair.doi.dedup.....efe4c4c4dd03a28d0b6df6511c9d3a8c