Claims
- 1. A microfiltration or ultrafiltration membrane comprising a terpolymer derived from a tetrafluoroethylene monomer, a polyvinylidene fluoride monomer, and a hexafluoropropylene monomer.
- 2. The membrane according to claim 1, wherein the terpolymer comprises from about 35 wt. % to about 40 wt. % of repeating units derived from the polyvinylidene fluoride monomer, from about 17 wt. % to about 20 wt. % of repeating units derived from the hexafluoropropylene monomer, and from about 40 wt. % to about 48 wt. % of repeating units derived from the tetrafluoroethylene monomer.
- 3. The membrane according to claim 1, wherein the terpolymer comprises about 36.5 wt. % of repeating units derived from the polyvinylidene fluoride monomer, about 18.9 wt. % of repeating units derived from the hexafluoropropylene monomer, and about 44.6 wt. % of repeating units derived from the tetrafluoroethylene monomer.
- 4. The membrane according to claim 1, the filtration membrane having an asymmetric cross section defining a large-pore face and a small-pore face, the membrane having a higher flux at a predetermined pressure from the large-pore face to the small-pore face than from the small-pore face to the large-pore face.
- 5. The membrane according to claim 1, wherein the filtration membrane comprises a hollow fiber.
- 6. The membrane according to claim 1, further comprising a hydrophobicity modifying agent.
- 7. The membrane according to claim 6, wherein the hydrophobicity modifying agent comprises a polyvinylethylether.
- 8. The membrane according to claim 6, wherein the membrane comprises about 2 wt. % of the hydrophobicity modifying agent.
- 9. A method of casting a polymeric membrane, the method comprising:
preparing a membrane dope, wherein the membrane dope is resistant to a leachant, and wherein the membrane dope comprises a leachable pore forming agent; casting a filtration membrane from the membrane dope; and leaching the leachable pore forming agent from the membrane with the leachant.
- 10. The method according to claim 9, wherein the membrane dope comprises a terpolymer derived from tetrafluoroethylene monomer, polyvinylidene fluoride monomer, and hexafluoropropylene monomer.
- 11. The method according to claim 10, wherein the terpolymer comprises from about 35 wt. % to about 40 wt. % of repeating units derived from the polyvinylidene fluoride monomer, from about 17 wt. % to about 20 wt. % of repeating units derived from the hexafluoropropylene monomer, and from about 40 wt. % to about 48 wt. % of repeating units derived from the tetrafluoroethylene monomer.
- 12. The method according to claim 10, wherein the terpolymer comprises about 36.5 wt. % of repeating units derived from the polyvinylidene fluoride monomer, about 18.9 wt. % of repeating units derived from the hexafluoropropylene monomer, and about 44.6 wt. % of repeating units derived from the tetrafluoroethylene monomer.
- 13. The method according to claim 9, further comprising the step of adding a polyvinylethylether to the membrane dope as a hydrophobicity modifying agent.
- 14. The method according to claim 9, wherein the leachable pore forming agent comprises an inorganic solid having an average particle size of less than about 1 micron.
- 15. The method of claim 9, wherein the leachable pore forming agent comprises leachable silica, and wherein the leachant comprises a caustic solution.
- 16. A method of casting a polymeric membrane, the method comprising:
preparing a membrane dope comprising a polymer and a catalytic amount of a nucleating agent; and casting a filtration membrane from the membrane dope.
- 17. The method according to claim 16, wherein the nucleating agent comprises an insoluble inorganic solid or an inert inorganic solid.
- 18. A method according to claim 16, wherein the nucleating agent has an average particle size of less than about 1 micron.
- 19. A method according to claim 16, wherein the nucleating agent comprises TiO2.
- 20. The method according to claim 16, wherein the polymer comprises from about 35 wt. % to about 40 wt. % of repeating units derived from the polyvinylidene fluoride monomer, from about 17 wt. % to about 20 wt. % of repeating units derived from the hexafluoropropylene monomer, and from about 40 wt. % to about 48 wt. % of repeating units derived from the tetrafluoroethylene monomer.
Priority Claims (1)
Number |
Date |
Country |
Kind |
PR 5843 |
Jun 2001 |
AU |
|
RELATED APPLICATION
[0001] This application is a continuation, under 35 U.S.C. § 120, of International Patent Application No. PCT/AU02/00784, filed on Jun. 14, 2002 under the Patent Cooperation Treaty (PCT), which was published by the International Bureau in English on Dec. 27, 2002, which designates the U.S. and claims the benefit of Australian Provisional Patent Application No. PR 5843, filed Jun. 20, 2001.
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/AU02/00784 |
Jun 2002 |
US |
Child |
10738628 |
Dec 2003 |
US |