Microporous peek membranes and the preparation thereof

• US 4,992,485 A
• Filed: 10/11/1988
• Issued: 02/12/1991
• Est. Priority Date: 10/11/1988
• Status: Expired due to Fees

• Current Assignee: The Dow Chemical Company (Dow, Inc.), FilmTec Corporation (DuPont de Nemours, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.), FilmTec Corporation (DuPont de Nemours, Inc.)
• Inventors: Koo, Ja-Young, Racchini, Joel R., Chau, Chieh-Chun, Wessling, Ritchie A., Bishop, Matthew T.
• Primary Examiner(s): Hoke, Veronica P.
• Application Number:
  US07/255,220
• Time in Patent Office: 854 Days
• Field of Search: 528/126, 528/128, 528/125, 521/64, 521/79, 521/180, 524/157, 524/417, 524/165, 264/209.1, 264/209.2, 264/45.9, 264/46.1, 428/158, 428/315.5, 428/315.7, 428/318.6, 428/319.7, 428/308.4, 210/500.21, 210/500.23, 210/500.27, 210/500.33
• US Class Current: 521/180
• CPC Class Codes: B01D 71/52 Polyethers
• CPC Class Codes: B01D 71/5222 Polyetherketone, polyetheretherketone, or polyaryletherketone
• CPC Class Codes: C08J 2371/00 Characterised by the use of polyethers obtained by reactions forming an ether link in the main chain of polyacetals C08J2359/00; of epoxy resins C08J2363/00; of polythioether-ethers C08J2381/02; of polyethersulfones C08J2381/06; Derivatives of such polymers
• CPC Class Codes: C08J 9/28 by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
• CPC Class Codes: D01D 5/24 with a hollow structure; Spinnerette packs therefor D01D5/38 takes precedence; producing tubes of plastic material B29D; addition of agents forming hollow filaments D01F1/08
• CPC Class Codes: Y10T 428/24504 Component comprises a polymer [e.g., rubber, etc.]

Abstract

A microporous polyetheretherketone (PEEK) membrane in the form of films and hollow fibers formed without sulfonating the PEEK polymer. Solid fibers and articles are also claimed. A method of making membranes, fibers and articles from solutions of PEEK in non-sulfonating acid solvents in claimed. Solvents include methane sulfonic acid and trifluoromethane sulfonic acid. Sulfuric acid may be used as a diluent in non-sulfonating amounts. PEEK membranes are used as supports for composite ultrafiltration and reverse osmosis membranes. A method of making membranes, fibers, and articles is also described.

Claims

1. A method of forming an article of a PEEK polymer whereby a PEEK polymer is dissolved in a non-sulfonating acid solvent, the PEEK polymer solution is cast into the shape of the article, the article is coagulated in a coagulation bath which is a non-solvent for a PEEK polymer, but which is miscible with the non-sulfonating acid solvent, thereby leaching the non-sulfonating acid solvent from the membrane.

21. An article of a PEEK polymer prepared by the method of claim 1.

2. The method of forming a semi-permeable microporous membrane of a PEEK polymer comprising dissolving a PEEK polymer in a non-sulfonating acid, or a non-sulfonating mixture of acids, and casting the solution of a PEEK polymer to form a microporous membrane of a PEEK polymer, coagulating the cast solution of a PEEK polymer in a coagulation bath which is a non-solvent for a PEEK polymer, but which is miscible with the non-sulfonating acid solvent, thereby leaching the non-sulfonating acid solvent from the membrane.

3. The method as in claim 2 wherein the non-sulfonating acid solvent contains methane sulfonic acid or trifluoromethane sulfonic acid, or a mixture thereof.

4. The method as in claim 2 wherein the solution of dissolved PEEK polymer is cast upon a supporting substrate.

5. The method as in claim 4 wherein the supporting substrate is formed from woven or non-woven fibers of glass, polyester, natural fiber, or polyethersulfone.

6. The method as in claim 2 wherein the non-sulfonating acid solvent contains an effective amount of a halogenated hydrocarbon having three or less carbon atoms to enhance the flux of the resulting membrane.

7. The method as in claim 2 wherein the non-sulfonating acid solvent contains up to 60 percent sulfuric acid.

8. The method as in claim 2 wherein the coagulation bath has a high relative rate of diffusion into the polymer phase.

9. The method as in claim 2 wherein the coagulation bath has a low relative rate of diffusion into the polymer phase.

10. The method as in claim 2 wherein the non-sulfonating acid solvent contains at least one acid selected from the group consisting of trichloromethane sulfonic acid, hydrofluoric acid, and phosphoric acid.

20. The method as in claim 9 wherein the coagulation bath contains a non-sulfonating acid, or a non-sulfonating amount of a sulfonating acid.

11. A method of forming a fiber of a PEEK polymer comprising dissolving a PEEK polymer in a non-sulfonating acid, extruding the solution of a PEEK polymer through an orifice to form a fiber, and immersing the fiber in a coagulation bath.

25. A fiber of PEEK polymer prepared by the method of claim 11.

12. A method of forming a hollow fiber of a PEEK polymer comprising dissolving a PEEK polymer in a non-sulfonating acid, extruding the PEEK polymer solution through an annular shaped orifice, injecting at the orifice a core fluid in the lumen of the fiber thus formed, and immersing the fiber in a coagulation bath.

13. The method of forming a hollow fiber of a PEEK polymer as in claim 12 wherein the solvent is a mixture of a non-sulfonating acid and up to 60 percent H₂ SO₄.

14. The method as in claim 12 wherein the non-sulfonating acid or mixture of acids contains methane sulfonic acid, or trifluoromethane sulfonic acid, or a mixture thereof.

15. The method as in claim 12 wherein the core fluid has a high affinity for the non-sulfonating acid PEEK solvent.

16. The method as in claim 12 wherein the core fluid has a low affinity for the non-sulfonating acid solvent.

17. The method as in claim 12 wherein the coagulation bath has a high affinity for the non-sulfonating acid PEEK polymer solvent.

18. The method as in claim 12 wherein the coagulation bath has a low affinity for the non-sulfonating acid PEEK polymer solvent.

19. The method as in claim 12 wherein the non-sulfonating acid contains a halogenated hydrocarbon having three or less carbon atoms effective to enhance the flux of the resulting hollow fiber membrane.

24. A hollow fiber of a PEEK polymer prepared by the method of claim 12.

22. A microporous membrane comprising PEEK having a pore size from about 1.0 μ

m to 3 μ

m.

30. The microporous PEEK polymer membrane as in any one of claims 22, 23, and 27 wherein the membrane is used as a support substrate for interfacial condensation of coacervate forming compounds which compounds are subsequently chemically crosslinked.

23. A microporous membrane of a PEEK polymer comprising an asymmetric structure of PEEK between membrane surfaces.

26. A hollow fiber comprising a PEEK polymer.

27. A microporous membrane comprising a hollow fiber of PEEK polymer having an asymmetric structure of PEEK between the lumen surface and the outer fiber wall.

31. The microporous membrane as in claim 27 having a pore size from about 0.1 μ

m to about 3 μ

m.

28. A composite membrane comprising a substrate layer of a porous PEEK polymer and a selective layer of an interfacial condensation of permselective polymer.

29. A composite membrane comprising a substrate layer of a porous PEEK polymer and a selective layer of coacervate forming compounds.

32. A microporous hollow fiber membrane comprising PEEK having a pore size from 1.0 μ

m to 3.0 μ

m.