TY - JOUR
T1 - Gas sorption and characterization of thermally rearranged polyimides based on 3,3'-dihydroxy-4,4'-diamino-biphenyl (HAB) and 2,2'-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA)
AU - Smith, Zachary P.
AU - Sanders, David F.
AU - Ribeiro, Cláudio P.
AU - Guo, Ruilan
AU - Freeman, Benny D.
AU - Paul, Donald R.
AU - McGrath, James E.
AU - Swinnea, Steve
N1 - Funding Information:
The authors gratefully acknowledge the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy (DOE) through Grant DE-FG02-02ER15362 for funding the development of TGA-MS, FT-IR, permeation, and sorption results. This research was also supported in part by ConocoPhillips. Further support was provided by the DOE Office of Science Graduate Fellowship Program administered by the Oak Ridge Institute for Science and Education (ORISE). ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE contract number DE-AC05-06OR23100. All opinions expressed in this paper are the author's and do not necessarily reflect the policies and views of DOE, ORAU, or ORISE.
Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 2012/10/1
Y1 - 2012/10/1
N2 - The solubilities of H 2, N 2, O 2, CH 4, and CO 2 were determined over a range of pressures at 35°C in a glassy, amorphous, ortho-functional polyimide prepared from 3,3'-dihydroxy-4,4'-diamino-biphenyl (HAB) and 2,2'-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA). The HAB-6FDA polyimide was partially converted to its corresponding thermally rearranged (TR) polymer by thermal treatments at different times and temperatures. At 10atm, solubility coefficients of H 2, N 2, O 2, CH 4, and CO 2 increased by a factor of approximately two between the polyimide and the most highly converted TR polymer. Correlations between solubility and penetrant condensability were in good agreement with such correlations in other fluorinated polymers. Dual-mode sorption model parameters were determined from the sorption isotherms. The affinity constant, Henry's law solubility, and Langmuir capacity constant increased with gas condensability, and increases in the Langmuir capacity constant were observed as TR polymer conversion increased. Comparisons were made between the solubility selectivity of CO 2/CH 4, O 2/N 2, CH 4/N 2, and CO 2/N 2 with HAB-6FDA, its corresponding TR polymers, and with other polymers in the literature. Qualitatively, a decrease in solubility selectivity for gas pairs including CO 2 correlates with imide and acetate loss during conversion.
AB - The solubilities of H 2, N 2, O 2, CH 4, and CO 2 were determined over a range of pressures at 35°C in a glassy, amorphous, ortho-functional polyimide prepared from 3,3'-dihydroxy-4,4'-diamino-biphenyl (HAB) and 2,2'-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA). The HAB-6FDA polyimide was partially converted to its corresponding thermally rearranged (TR) polymer by thermal treatments at different times and temperatures. At 10atm, solubility coefficients of H 2, N 2, O 2, CH 4, and CO 2 increased by a factor of approximately two between the polyimide and the most highly converted TR polymer. Correlations between solubility and penetrant condensability were in good agreement with such correlations in other fluorinated polymers. Dual-mode sorption model parameters were determined from the sorption isotherms. The affinity constant, Henry's law solubility, and Langmuir capacity constant increased with gas condensability, and increases in the Langmuir capacity constant were observed as TR polymer conversion increased. Comparisons were made between the solubility selectivity of CO 2/CH 4, O 2/N 2, CH 4/N 2, and CO 2/N 2 with HAB-6FDA, its corresponding TR polymers, and with other polymers in the literature. Qualitatively, a decrease in solubility selectivity for gas pairs including CO 2 correlates with imide and acetate loss during conversion.
KW - Dual mode parameters
KW - Gas separations
KW - Gas solubility
KW - Polybenzoxazole
KW - Thermal rearrangement
UR - http://www.scopus.com/inward/record.url?scp=84864767496&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2012.05.050
DO - 10.1016/j.memsci.2012.05.050
M3 - Article
AN - SCOPUS:84864767496
SN - 0376-7388
VL - 415-416
SP - 558
EP - 567
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -