The effects of CO2 exposure on pure and mixed gas permeation behavior: comparison of glassy polycarbonate and silicone rubber
1987; Elsevier BV; Volume: 30; Issue: 2 Linguagem: Inglês
10.1016/s0376-7388(00)81351-4
ISSN1873-3123
AutoresS.M. Jordan, William J. Koros, G. K. Fleming,
Tópico(s)Membrane Separation and Gas Transport
ResumoPure and binary mixture permeabilities have been investigated for the C02/CH4 system in polycarbonate and silicone rubber. Upstream pressure conditions ranging from zero up to the critical point of CO2 were investigated. No permeability hysteresis was observed for the silicone rubber sample with pure or binary feeds of CO2 and CH4. On the other hand, perturbation treatments with CO2 resulted in long-lived increases in the permeability of the conditioned polycarbonate films compared to untreated films. Increases in CO2 permeability of 50% persisted for the polycarbonate sample over a period spanning more than two months. CO2/CH4 mixed gas measurements on the conditioned polycarbonate film also reflect changes in its permselection properties. The CO2 permeability in the mixed gas system is based on a fugacity driving force to provide a rigorous comparison with the pure gas system. The conditioning treatment caused reductions in permselectivity of 30% relative to the as-received film for mixed gas feed streams of CO2/CH4 under the conditions studied. The permselectivity effects also appear to be semi-permanent and continue if the conditioning medium is not totally removed after the conditioning treatment.
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