Modified membranes

• US 20050032982A1
• Filed: 07/29/2004
• Published: 02/10/2005
• Est. Priority Date: 11/13/2000
• Status: Abandoned Application

• Current Assignee: Heinz-Joachim Muller
• Original Assignee: Heinz-Joachim Muller
• Inventors: Muller, Heinz-Joachim
• Application Number:
  US10/903,516
• Publication Number:
  US 20050032982A1
• Time in Patent Office: Days
• US Class Current: 525/191
• 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 blend of a membrane forming polymer and a compatible second polymer, said second polymer being capable of chemical modification after membrane formation.

2. The blend according to claim 1, wherein said compatible second polymer is compatible with polyvinylidene fluoride.

3. The blend according to claim 1, wherein said compatible second polymer is compatible with polysulfone.

4. The blend according to claim 1, wherein said compatible second polymer is compatible with polyvinylidene fluoride and polysulfone.

5. The blend according to claim 1, wherein said membrane forming polymer is of low reactivity.

6. The blend according to claim 1, wherein said membrane forming polymer is inert.

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

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

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

10. The blend according to claim 9, wherein the polysulfone comprises a material selected from the group consisting of polysulfone, polyether sulfone, polyaryl sulfone, polyalkyl sulfone, and polyaralkyl sulfone.

11. The blend according to claim 9, wherein the polysulfone comprises polyphenyl sulfone.

12. The blend according to claim 1, further comprising a reactivity modifying agent adapted to modify at least one surface active property of the polymeric membrane forming material.

13. The blend according to claim 1, wherein the reactivity modifying agent comprises an anhydride.

14. The blend according to claim 12, wherein the reactivity modifying agent modifies a reactivity of a membrane surface to a chemical species.

15. The blend according to claim 12, wherein the reactivity modifying agent modifies a hydrophilicity/hydrophobicity balance of the porous polymeric membrane.

16. The blend according to claim 12, wherein the reactivity modifying agent modifies a surface charge of the porous polymeric membrane.

17. The blend according to claim 12, wherein the reactivity modifying agent comprises a linear polymeric anhydride.

18. The blend according to claim 12, wherein the reactivity modifying agent comprises a maleic anhydride copolymer.

19. The blend according to claim 12, wherein the reactivity modifying agent comprises a poly(alkyl vinyl ether/maleic anhydride).

20. The blend according to claim 12, wherein the reactivity modifying agent comprises a monomer of formula:

21. The blend according to claim 12, wherein the reactivity modifying agent comprises poly(methyl vinyl ether/maleic anhydride) having a molecular weight of from 5×

10⁴ to 5×

10⁷.

22. The blend according to claim 12, 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.

23. The blend according to claim 12, 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.

24. The blend according to claim 13, wherein said anhydride is reacted with an amine to form an amide linkage.

25. The blend according to claim 13, wherein said anhydride is reacted with a polyamine to form a crosslinked polyamide layer.

26. The blend according to claim 25, wherein said amine is selected from the group consisting of tetraethylenepentamine and tris-(hydroxymethyl) aminomethane.

27. The blend according to claim 13, wherein said anhydride is reacted with with an alcohol to form an ester linkage.

28. The blend according to claim 27, wherein said surface active anhydride sites are reacted with butanol.

29. The blend according to claim 13, wherein said anhydride is reacted with a polyol to form a crosslinked polyester layer.

30. The blend according to claim 29, wherein said polyol comprises polyethylene glycol.

31. The blend according to claim 12, wherein said anhydride is reacted with sulfuric acid.

32. The blend according to claim 13, wherein said anhydride is reacted with calcium carbonate.