H. Kumazawa et al., PERMEATION BEHAVIOR FOR MIXED GASES IN POLY(4-METHYL-1-PENTENE) MEMBRANE NEAR THE GLASS-TRANSITION TEMPERATURE, Journal of membrane science, 97, 1994, pp. 7-12
Permeabilities to CO2 in an equimolar mixture of CO2 and air for a hom
ogeneous poly(4-methyl-1-pentene) membrane were measured at various up
stream gas pressures. The permeability to CO2 for the mixed gas was sm
aller than that for pure CO2 at the same CO2 upstream pressure. The pe
rmeability to O-2 for the mixed gas increased with increasing upstream
gas pressure, although for pure O-2 the permeability was independent
of pressure. Such experimental evidence is consistent with the free-vo
lume model prediction. The increase in permeabilities for the coexisti
ng O-2 might result from the membrane plasticization action of sorbed
CO2. The depression of CO2 permeability in the gas mixture case might
be ascribed to the hydrostatic pressure effect applied to the system,
as suggested by the free-volume model.