TY - JOUR
T1 - Gas and vapor sorption and permeation in poly(2,2,4-trifluoro-5- trifluoromethoxy-1,3-dioxole-co-tetrafluoroethylene)
AU - Prabhakar, Rajeev S.
AU - Freeman, Benny D.
AU - Roman, Ian
PY - 2004/10/5
Y1 - 2004/10/5
N2 - The solubilities of N 2, CO 2, CH 4, C 2H 6, C 3H 8, and C 3F 8 and permeabilities of N 2, O 2, CO 2, CH 4, C 2H 6, and C 3H 8 were determined in a glassy, amorphous fluoropolymer prepared from 80 mol% 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD) and 20 mol % tetrafluoroethylene (TFE), commercially known as Hyflon AD 80. This polymer exhibits lower increases in hydrocarbon gas and vapor solubility with increasing penetrant critical temperature than conventional hydrocarbon polymers. On the basis of a best fit of the natural logarithm of solubility vs critical temperature, Hyflon AD 80 should have much lower solubility for high molar mass hydrocarbon compounds (e.g., n-decane) than conventional hydrocarbon polymers. Pure gas CO 2/CH 4 separation properties of this polymer are comparable with those of some hydrocarbon polymers considered for natural gas purification. When, exposed to a feed stream containing a mixture of CO 22 and CH 4, the polymer exhibits a CO 2 permeability of approximately 250 barrers and a CO 2/CH 4 mixed-gas selectivity of 10.6 at 1.6 atm CO 2 partial pressure. The mixed gas selectivity decreases minimally as CO 2 partial pressure increases to 10.6 atm. The mixed gas selectivity is also maintained when moderate amounts of toluene and n-hexane are present in the CO 2-CH 4 feed stream. Diffusion coefficients, calculated from pure gas permeability and solubility coefficients, suggest membrane plasticization at higher pressures of CO 2 and C 2H 6. The polymer also exhibits reversible hysteresis in C 3H 8 permeability with pressure.
AB - The solubilities of N 2, CO 2, CH 4, C 2H 6, C 3H 8, and C 3F 8 and permeabilities of N 2, O 2, CO 2, CH 4, C 2H 6, and C 3H 8 were determined in a glassy, amorphous fluoropolymer prepared from 80 mol% 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole (TTD) and 20 mol % tetrafluoroethylene (TFE), commercially known as Hyflon AD 80. This polymer exhibits lower increases in hydrocarbon gas and vapor solubility with increasing penetrant critical temperature than conventional hydrocarbon polymers. On the basis of a best fit of the natural logarithm of solubility vs critical temperature, Hyflon AD 80 should have much lower solubility for high molar mass hydrocarbon compounds (e.g., n-decane) than conventional hydrocarbon polymers. Pure gas CO 2/CH 4 separation properties of this polymer are comparable with those of some hydrocarbon polymers considered for natural gas purification. When, exposed to a feed stream containing a mixture of CO 22 and CH 4, the polymer exhibits a CO 2 permeability of approximately 250 barrers and a CO 2/CH 4 mixed-gas selectivity of 10.6 at 1.6 atm CO 2 partial pressure. The mixed gas selectivity decreases minimally as CO 2 partial pressure increases to 10.6 atm. The mixed gas selectivity is also maintained when moderate amounts of toluene and n-hexane are present in the CO 2-CH 4 feed stream. Diffusion coefficients, calculated from pure gas permeability and solubility coefficients, suggest membrane plasticization at higher pressures of CO 2 and C 2H 6. The polymer also exhibits reversible hysteresis in C 3H 8 permeability with pressure.
UR - http://www.scopus.com/inward/record.url?scp=6344244647&partnerID=8YFLogxK
U2 - 10.1021/ma048909f
DO - 10.1021/ma048909f
M3 - Article
AN - SCOPUS:6344244647
SN - 0024-9297
VL - 37
SP - 7688
EP - 7697
JO - Macromolecules
JF - Macromolecules
IS - 20
ER -