Solvent-resistant membranes from solvent-inert polyimides and polyketones
View Patent ↗A solvent-resistant polymeric membrane comprising a solvent-inert polymer having a solubility parameter greater than 18 (J/cm 3 ) 0.5 , such as a polyketone, a polyether ketone, polyarylene ether ketone ketone, a polyimide, a polyetherimide, or a polyphenylene sulfide, is described. The solvent-resistant polymeric membrane can be prepared by methods in which solvent-inert polymers form a solution at room temperature.
1. A composition comprising a solution of a polymer in a eutectic solvent system comprising at least two solvents having a melting point greater than about 20° C., the eutectic solvent system having a melting point less than about 20° C., and the polymer having a solubility parameter greater than 18 (J/cm 3 ) 0.5 .
2. A composition according to claim 1 , wherein the polymer is at least partially crystalline.
3. A composition according to claim 1 , wherein the polymer comprises a polyketone, a polyether ketone, polyarylene ether ketone ketone, a polyimide, a polyetherimide, or a polyphenylene sulfide.
4. A composition according to claim 3 , wherein the polyketone comprises a polyarylene ether ketone ketone.
5. A composition according to claim 1 , wherein the polymer comprises a polyimide.
6. A composition according to claim 5 , wherein the polyimide comprises structural units derived from benzophenone-3,3′,4,4′-tetracarboxylic dianhydride and at least one diamine selected from 1,4-diaminobenzene, m-phenylenediamine, p-phenylenediamine and combinations thereof.
7. A composition according to claim 1 , wherein the polymer comprises a polyetherimide.
8. A composition according to claim 7 , wherein the polyetherimide comprises structural units derived from at least one anhydride selected from oxydiphthalic anhydride, bisphenol-A diphthalic anhydride and combinations thereof and at least one diamine selected from 1,4-diaminobenzene, m-phenylenediamine, p-phenylenediamine and combinations thereof.
9. A composition according to claim 7 , wherein the polyetherimide comprises structural units derived from oxydiphthalic anhydride, bisphenol-A diphthalic anhydride, 1,4-diaminobenzene, m-phenylenediamine and p-phenylenediamine.
10. A composition according to claim 1 , wherein the solvent system comprises a phenolic solvent.
11. A composition according to claim 10 , wherein the phenolic solvent is halogenated.
12. A composition according to claim 10 , wherein the solvent system comprises 4-chloro-3-methyl-phenol, 4-chloro-2-methyl-phenol, 2,4-dichloro-6-methyl-phenol, 2,4-dichioro-phenol, 2,6-dichloro-phenol, 4-chloro-phenol, 2-chloro-phenol, o-cresol, m-cresol, p-cresol, 4-methoxy-phenol, catechol, benzoquinone, 2,3-xylenol, 2,6-xylenol, resorcinol or a combination thereof.
13. A composition according to claim 10 , wherein the solvent system comprises a first solvent and a second solvent, the first solvent being selected from 4-chloro-3-methyl-phenol, 4-chloro-2-methyl-phenol, 2,4-dichloro-6-methyl-phenol, 2,4-dichloro-phenol, 2,6-dichloro-phenol, 4-chloro-phenol, 2-chloro-phenol, and combinations thereof and the second solvent being selected from o-cresol, m-cresol, p-cresol, 4-methoxy-phenol, catechol, benzoquinone, 2,3-xylenol, 2,6-xylenol, resorcinol and combinations thereof.
14. A composition according to claim 10 , wherein the solvent system comprises 4-chloro-2-methyl-phenol.
15. A composition according to claim 10 , wherein the solvent system comprises o-cresol, m-cresol, p-cresol or a combination thereof.
16. A composition according to claim 10 , wherein the solvent system comprises p-cresol.
17. A composition according to claim 10 , wherein the solvent system comprises 4-chloro-2-methyl-phenol and p-cresol.
18. A composition according to claim 10 , wherein the solvent system comprises about 50 parts by weight 4-chloro-2-methyl-phenol and about 50 parts by weight p-cresol.
19. A process for preparing a polymer membrane, said process comprising:
providing a pourable solution comprising a polymer having a solubility parameter greater than 18 (J/cm 3 ) 0.5 and a eutectic solvent system having a melting point less than about 20° C., the solvent system comprising at least two solvents, each having a melting point greater than about 20° C.; and
forming a membrane from the polymer solution.
20. A process according to claim 19 , wherein forming a membrane from the polymer solution comprises casting a thin film from the polymer solution.
21. A process according to claim 19 , wherein forming a membrane from the polymer solution comprises contacting the polymer solution with a coagulating bath comprising a non-solvent for the polymer.
22. A process according to claim 19 , wherein forming a membrane from the polymer solution comprises removing solvents of the solvent system from the polymer solution.
23. An ultrafiltration, microfiltration, asymmetric, hollow fiber or thin film composite membrane comprising a membrane prepared according to the process of claim 19 .
24. A process according to claim 19 , wherein the polymer comprises a polyketone.
25. A process according to claim 24 , wherein the polyketone comprises a polyarylene ether ketone ketone.
26. A process according to claim 19 , wherein the polymer comprises apolyimide.
27. A process according to claim 26 , wherein the polyimide comprises structural units derived from benzophenone-3,3′,4,4′-tetracarboxylic dianhydride and at least one diamine selected from 1,4-diaminobenzene, m-phenylene diamine, p-phenylene diamine and combinations thereof.
28. A process according to claim 19 , wherein the polymer comprises a polyetherimide.
29. A process according to claim 28 , wherein the polyetherimide comprises structural units derived from at least one anhydride selected from oxydiphthalic anhydride, bisphenol-A diphthalic anhydride and combinations thereof and at least one diamine selected from 1,4-diaminobenzene, m-phenylene diamine, p-phenylene diamine and combinations thereof.
30. A process according to claim 19 , wherein the polyetherimide comprises structural units derived from oxydiphthalic anhydride, bisphenol-A diphthalic anhydride, 1,4-diaminobenzene, m-phenylene diamine and p-phenylene diamme.
31. A process according to claim 19 , wherein the solvent system comprises a solvent having a melting point greater than 20° C. and a co-solvent.
32. A process according to claim 31 , wherein the solvent having a melting point greater than 20° C. is selected from the group consisting of 4-chloro-3-methyl-phenol, 4-chloro-2-methyl-phenol, 2,4-dichloro-6-methyl-phenol, 2,4-dichloro-phenol, 2,6-dichloro-phenol, 4-chloro-phenol, 2-chloro-phenol and combinations thereof.
33. A process according to claim 31 , wherein the solvent having a melting point greater than 20° C. comprises 4-chloro-2-methyl-phenol.
34. A process according to claim 31 , wherein the cosolvent is selected from o-cresol, m-cresol, p-cresol, 4-methoxy-phenol, catechol, benzoquinone, 2,3-xylenol, 2,6-xylenol, resorcinol and combinations thereof.
35. A process according to claim 31 , wherein the cosolvent is a cresol.
36. A process according to claim 31 , wherein the co-solvent is p-cresol.
37. A process according to claim 19 , wherein the solvent system comprises about 50 parts by weight 4-chloro-2-methyl-phenol and about 50 parts by weight p-cresol.