Modified membranes

• US 20050029186A1
• Filed: 07/29/2004
• Published: 02/10/2005
• Est. Priority Date: 11/13/2000
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: Siemen Water Technologies Corporation (Siemens AG)
• Inventors: Muller, Heinz-Joachim
• Granted Patent: US 7,404,896 B2
• Time in Patent Office: Days
• US Class Current: 210/500.270
• CPC Class Codes: B01D 2323/02 Hydrophilization
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2323/36 Introduction of specific chemical groups
• CPC Class Codes: B01D 2325/24 Mechanical properties, e.g. strength
• CPC Class Codes: B01D 67/0018 Thermally induced processes [TIPS]
• CPC Class Codes: B01D 67/0093 Chemical modification
• CPC Class Codes: B01D 67/00933 by addition of a layer chemically bonded to the membrane
• CPC Class Codes: B01D 69/125 In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
• CPC Class Codes: B01D 71/34 Polyvinylidene fluoride
• CPC Class Codes: B01D 71/40 Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
• CPC Class Codes: B01D 71/403 Polymers based on the polymerisation of maleic acid or derivatives thereof
• CPC Class Codes: B01D 71/48 Polyesters
• CPC Class Codes: B01D 71/56 Polyamides, e.g. polyester-amides
• CPC Class Codes: B01D 71/68 Polysulfones; Polyethersulfones

Abstract

A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Claims

1. A porous polymeric membrane formed from a blend of a polymeric membrane forming material and an anhydride as a reactivity modifying agent adapted to modify at least one surface active property of the porous polymeric membrane relative to a porous polymeric membrane formed from the polymeric membrane forming material without said anhydride.

2. The porous polymeric membrane according to claim 1, wherein the polymeric membrane forming material comprises polyvinylidene fluoride.

3. The porous polymeric membrane according to claim 1, wherein the polymeric membrane forming material comprises hydrophobic polyvinylidene fluoride.

4. The porous polymeric membrane according to claim 1, wherein the polymeric membrane forming material comprises a polysulfone.

5. The porous polymeric membrane according to claim 4, wherein the polysulfone comprises a material selected from the group consisting of polysulfone, polyether sulfone, polyaryl sulfone, polyalkyl sulfone, and polyaralkyl sulfone.

6. The porous polymeric membrane according to claim 4, wherein the polysulfone comprises polyphenyl sulfone.

7. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent modifies a reactivity of a membrane surface to a chemical species.

8. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent modifies a hydrophilicity/hydrophobicity balance of the porous polymeric membrane.

9. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent modifies a surface charge of the porous polymeric membrane.

10. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent comprises a linear polymeric anhydride.

11. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent comprises a maleic anhydride copolymer.

12. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent comprises a poly(alkyl vinyl ether/maleic anhydride).

13. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent comprises a monomer of formula:

14. The porous polymeric membrane according to claim 1, wherein the reactivity modifying agent comprises poly(methyl vinyl ether/maleic anhydride) having a molecular weight of from 5×

10⁴ to 5×

10⁷.

15. The porous polymeric membrane according to claim 14, wherein the reactivity modifying agent comprises poly(methyl vinyl ether/maleic anhydride) having a molecular weight of from 2.13×

10⁵ to 1.89×

10⁶.

16. The porous polymeric membrane according to claim 15, wherein the reactivity modifying agent comprises poly(methyl vinyl ether/maleic anhydride) having a molecular weight of from 8.72×

10⁵ to 1.25×

10⁶.

17. The porous polymeric membrane according to claim 1, comprising surface anhydride sites.

18. The porous polymeric membrane according to claim 17, wherein said surface anhydride sites are in a reacted form.

19. The porous polymeric membrane according to claim 18, wherein said surface anhydride sites are reacted with an amine to form an amide linkage.

20. The porous polymeric membrane according to claim 19, wherein said surface anhydride sites are reacted with a polyamine to form a crosslinked polyamide layer.

21. The porous polymeric membrane according to claim 1, wherein there is a negative charge on a surface of the porous polymeric membrane.

22. The porous polymeric membrane according to claim 1, wherein the porous polymeric membrane has a high permeability.

23. The porous polymeric membrane according to claim 1, wherein the porous polymeric membrane has a substantial macroscopic integrity.

24. The porous polymeric membrane according to claim 1, wherein the membrane comprises a hollow fibre.

25. The porous polymeric membrane according to claim 1, wherein the membrane comprises a flat sheet.

26. The porous polymeric membrane according to claim 1, wherein the membrane comprises a uniform wall thickness.

27. The porous polymeric membrane according to claim 1, wherein the membrane has a high mechanical strength.