GRAFTED FUNCTIONAL GROUPS ON EXPANDED TETRAFLUOROETHYLENE (ePTFE) SUPPORT FOR FUEL CELL AND WATER TRANSPORT MEMBRANES

Patent metadata

Field	Value
Publication number	US-2016190626-A1
Application number	US-201414586132-A
Country	US
Kind code	A1
Filing date	Dec 30, 2014
Priority date	Dec 30, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO 2 H or SO 2 H or SO 3 H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.

First claim

What is claimed is:

1 . A method comprising:
providing a solid fluorinated polymer; contacting the solid fluorinated polymer with a sodium-naphthalenide solution to form a treated fluorinated solid polymer; and contacting the treated fluorinated solid polymer with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer.

2 . The method of claim 1 wherein the solid fluorinated polymer is a polymeric membrane.

3 . The method of claim 2 wherein the solid fluorinated polymer includes repeating CF 2 —CF 2 groups.

4 . The method of claim 2 wherein the solid fluorinated polymer is a perfluorinated polymer.

5 . The method of claim 2 wherein the solid fluorinated polymer is porous.

6 . The method of claim 5 wherein the solid fluorinated polymer has a void volume from about 10 to about 95 percent.

7 . The method of claim 5 wherein the solid fluorinated polymer is an expanded polytetrafluoroethylene.

8 . The method of claim 5 further comprising imbibing an ion-conducting polymer into the solid grafted fluorinated polymer to form a supported membrane.

9 . The method of claim 8 further comprising incorporating the supported membrane into a fuel cell or a water transfer device.

10 . The method of claim 1 wherein the sodium-naphthalenide solution includes sodium-naphthalenide in an amount from about 0.05 to about 1 moles/liter.

11 . A method for comprising:
providing an expanded polytetrafluoroethylene membrane; contacting the expanded polytetrafluoroethylene membrane with a sodium-naphthalenide solution to form a treated expanded polytetrafluoroethylene membrane; and contacting the expanded polytetrafluoroethylene membrane with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted expanded polytetrafluoroethylene membrane; and imbibing an ion-conducting polymer into the solid grafted expanded polytetrafluoroethylene membrane.

12 . The method of claim 11 wherein the solid fluorinated polymer has a void volume from about 10 to about 95 percent.

13 . The method of claim 11 wherein the sodium-naphthalenide solution includes sodium-naphthalenide in an amount from about 0.05 to about 1 moles/liter.

14 . The method of claim 11 further comprising incorporating the supported membrane into a fuel cell or a water transfer device.

Assignees

• Gm Global Tech Operations Inc

Inventors

• Fuller Timothy J
• Jiang Ruichun

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04149

  by diffusion, e.g. making use of membranes · CPC title

• C08J2327/18

  Homopolymers or copolymers of tetrafluoroethylene · CPC title

• H01M8/1039

  halogenated, e.g. sulfonated polyvinylidene fluorides · CPC title

• C08J9/224

  Surface treatment · CPC title