Claims
- 1. A gas separation membrane formed from an aromatic polyimide of the following general formula: ##STR7## wherein Ar.sub.1 and Ar.sub.2 are organic radicals with at least 80% of the Ar.sub.1 and Ar.sub.2 radicals comprising aromatic radicals, and wherein a portion of said Ar.sub.2 radicals is a sulfonic acid radical selected from the group consisting of 4,4'-diaministilbene-2,2'-disulfonic acid, 4,4'-diamino-2,2'-biphenyldisulfonic acid, one of their respective salts, or mixtures thereof.
- 2. The gas separation membrane of claim 1 wherein the concentration of said sulfonic acid radical is from 0.15 to 3 meq/q of dry polymer in H.sup.+ form.
- 3. The gas separation membrane of claim 2 wherein said sulfonic acid radical is the salt of 4,4'-diaministilbene-2,2'-disulfonic acid or the salt of 4,4'-diamino-2,2'-biphenyldisulfonic acid, and wherein said salt contains an alkali cation or an organic base.
- 4. The gas separation membrane of claim 3, wherein said alkali cation is lithium.
- 5. The gas separation membrane of claim 1 wherein said aromatic polyimide is a product of 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and at least one aromatic diamine that contains said Ar.sub.2 radicals.
- 6. A gas separation membrane formed from an aromatic polyimide of the following general formula: ##STR8## wherein Ar.sub.1 and Ar.sub.2 are organic radicals with at least 80% of the Ar.sub.1 and Ar.sub.2 radicals comprising aromatic radicals, and wherein a portion of each of said Ar.sub.1 and Ar.sub.2 aromatic radicals contain sulfonic acid radicals.
Parent Case Info
This application is a continuation of prior U.S. application Ser. No. 08/730,266 filing date Oct. 15, 1996, now abandoned which is a continuation of application Ser. No. 08/497,655 filing date Jun. 30, 1995, now U.S. Pat. No. 5,618,334.
US Referenced Citations (31)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0179474 |
Apr 1986 |
EPX |
2050251 |
Apr 1971 |
FRX |
57-159505 |
Oct 1982 |
JPX |
58-037024 |
Mar 1983 |
JPX |
Non-Patent Literature Citations (4)
Entry |
Yu E. Kirsh et al., Journal of Membrane Science, 103 (1995), 95-103. |
E. Gilbert, Sulfonation and Related Reactions, 1977, pp. 1-121. |
H. Cerfontain, Mechanistic Aspects in Aromatic Sulfonation and Desulfonation, 1968, Ch. 1-4, 6, 7 and 9. |
Vasil, eva et al., "Synthesis and Properties of Sulfonated Polypytro Mellitimides", Polymer Science, USSR, pp. 160-168, Jun. 26, 1970. |
Continuations (2)
|
Number |
Date |
Country |
Parent |
730266 |
Oct 1996 |
|
Parent |
497655 |
Jun 1995 |
|