Crosslinkable sulfonated copolymer and fuel cell including polymeric composition of the same

Abstract

A sulfonated copolymer including a crosslinking functional group and a fuel cell including a polymeric composition of the same are provided. The sulfonated copolymer including a crosslinking functional group can remarkably reduce methanol crossover and maintain superior dimensional stability and ionic conductivity by reducing swelling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other embodiments of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawing in which:

FIG. 1 is a schematic drawing of a membrane electrode assembly according to an embodiment of the invention.

Claims

1. A crosslinkable sulfonated copolymer, comprising a polymerizable unsaturated functional group at one end or both ends thereof, the crosslinkable sulfonated copolymer further comprising: at least one aromatic ether repeating unit; andan aromatic ether repeating unit comprising a sulfonic acid group or a sulfonate group.

2. The crosslinkable sulfonated copolymer of claim 1, wherein the aromatic ether repeating unit including a sulfonic acid group or a sulfonate group is at least one selected from the group consisting of repeating units represented by Formulas 1 to 3 below, and the degree of polymerization is in the range of 3 to 1,000:

3. The crosslinkable sulfonated copolymer of claim 2, wherein the repeating unit of Formula 1 has a structure represented by Formula 11 or 12:

4. The crosslinkable sulfonated copolymer of claim 2, wherein the repeating unit of Formula 2 has a structure represented by Formula 21:

5. The crosslinkable sulfonated copolymer of claim 2, wherein the repeating unit of Formula 3 has a structure represented by Formula 31:

6. The crosslinkable sulfonated copolymer of claim 1, wherein the polymerizable unsaturated functional group is selected from the group consisting of (meth)acrylate, styryl, cinnamate, furfuryl, vinyl, acetylene, epoxy, and cyanate based functional groups.

7. The crosslinkable sulfonated copolymer of claim 1, wherein the at least one aromatic ether repeating unit is at least one repeating unit selected from the group consisting of repeating units represented by Formulas (a) to (w) below:

8. The crosslinkable sulfonated copolymer of claim 1, wherein the at least one aromatic ether repeating unit is represented by Formula 4 below:

9. The crosslinkable sulfonated copolymer of claim 1, wherein the at least one aromatic ether repeating unit is selected from the group consisting of repeating units represented by Formulas 41 to 43 below:

10. The crosslinkable sulfonated copolymer of claim 1, wherein the mole ratio of the at least one aromatic ether repeating unit and the aromatic ether repeating unit containing a sulfonic acid group or a sulfonate group is in the range of 99:1 to 5:95.

11. The crosslinkable sulfonated copolymer of claim 1 having a structure represented by Formula 10 below:

12. A cured product of the crosslinkable sulfonated copolymer of claim 1.

13. A method of preparing a crosslinkable sulfonated copolymer comprising: condensation polymerization of at least one aromatic diol-, dinitro-, or dihalide-based monomer with an aromatic diol-, dinitro-, or dihalide-based monomer containing a sulfonic acid group or a sulfonate group;preparing sulfonated polyarylene ether having a hydroxyl group at ends thereof by adding the hydroxyl group at both ends of the result of the condensation polymerization;covalently bonding the hydroxyl group at the ends of the sulfonated polyarylene ether with a crosslinking derivative.

14. The method of claim 13, wherein the mole ratio between a hydroxyl group of the aromatic diol-based monomer and a hydroxyl group, a nitro group, or a halogen group of the aromatic diol-, dinitro-, or dihalide-based monomer containing a sulfonic acid group or a sulfonate group is in the range of 4.0:6.0 to 6.0:4.0 in the condensation polymerization.

15. The method of claim 13, wherein the mole ratio between the aromatic diol-, dinitro-, or dihalide-based monomer and the aromatic diol-, dinitro-, or dihalide-based monomer containing a sulfonic acid group or a sulfonate group is in the range of 99:1 to 5:95.

16. A method of preparing a sulfonated copolymer cured product, the method comprising forming a curing reaction product by curing a crosslinkable sulfonated copolymer obtained by using the method of claim 13 with a polymerization initiator.

17. The method of claim 16 comprising forming a curing reaction product with a polymerization initiator.

18. The method of claim 17, wherein the polymerization initiator is selected from the group consisting of benzoin ethyl ether, benzyldimethylketal, diethoxyacetophenone, AIBN, and combinations thereof.

19. The method of claim 17, wherein the amount of the polymerization initiator is in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the crosslinkable sulfonated copolymer.

20. A polymer electrolyte membrane comprising the cured product of the crosslinkable sulfonated copolymer of claim 12.

21. A membrane electrode assembly comprising: a cathode comprising a catalyst layer and a diffusion layer;an anode comprising a catalyst layer and a diffusion layer; anda polymer electrolyte membrane interposed between the cathode and the anode, wherein the polymer electrolyte membrane comprises a cured product of the crosslinkable sulfonated copolymer of claim 12.

22. A fuel cell comprising: a cathode comprising a catalyst layer and a diffusion layer;an anode comprising a catalyst layer and a diffusion layer; anda polymer electrolyte membrane interposed between the cathode and the anode, wherein the polymer electrolyte membrane comprises a cured product of the crosslinkable sulfonated copolymer of claim 12.