Modified membranes

• US 7,404,896 B2
• Filed: 07/29/2004
• Issued: 07/29/2008
• Est. Priority Date: 11/13/2000
• Status: Expired due to Fees

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: Siemen Water Technologies Corporation (Siemens AG)
• Inventors: Muller, Heinz-Joachim
• Primary Examiner(s): Fortuna; Ana M
• Application Number:
  US10/903,809
• Publication Number:
  US 20050029186A1
• Time in Patent Office: 1,461 Days
• Field of Search: 210/500.37, 210/500.38, 210/500.42, 210/500.35, 210/490, 210/500.41, 210/500.36, 210/500.27, 264/41, 264/48, 264/49, 96/4, 96/6
• US Class Current: 210/500.38
• 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 microporous polymeric membrane comprising a blend of a polymeric anhydride ad a polymeric material comprising a polysulfone, said microporous membrane comprises surface anhydride sites reacted with amines forming amide in linkages by crosslinking.

2. The microporous polymeric membrane according to claim 1, wherein the polysulfone comprises a material selected from the group consisting of polysulfone, polyether sulfone, polyaryl sulfone, polyalkyl sulfone, and polyaralkyl sulfone.

3. The microporous polymeric membrane according to claim 1, wherein the polysulfone comprises polyphenyl sulfone.

4. The microporous polymeric membrane according to claim 1, wherein the polymeric anhydride modifies a reactivity of a membrane surface to a chemical species.

5. The microporous polymeric membrane according to claim 1, wherein the polymeric anhydride modifies a hydrophilicity/hydrophobicity balance of the microporous polymeric membrane.

6. The microporous polymeric membrane according to claim 1, wherein the polymeric anhydride modifies a surface charge of the microporous polymeric membrane.

7. The microporous polymeric membrane according to claim 1, wherein the polymeric anhydride comprises a linear polymeric anhydride.

8. The microporous polymeric membrane according to claim 1, wherein the polymeric anhydride comprises a maleic anhydride copolymer.

9. The microporous polymeric membrane according to claim 1, wherein the polymeric anhydride comprises a poly(alkyl vinyl ether/maleic anhydride).

10. The microporous polymeric membrane according to claim 1, wherein the polymeric anyhydride has a formula:

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

10⁴ to 5×

10⁷.

12. The microporous polymeric membrane according to claim 11, wherein the polymeric anhydride comprises poly(methyl vinyl ether/maleic anhydride) having a molecular weight of from 2.13×

10⁵ to 1.89×

10⁶.

13. The microporous polymeric membrane according to claim 12, wherein the polymeric anhydride comprises poly(methyl vinyl ether/maleic anhydride) having a molecular weight of from 8.72×

10⁵ to 1.25×

10⁶.

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

15. The microporous polymeric membrane according to claim 1, wherein the membrane is a shape selected from the group consisting of a hollow fibre and a flat sheet.

16. The microporous polymeric membrane according to claim 1, wherein the membrane has a uniform wall thickness.