Electrically conductive composite

Abstract

The invention provides an electrically conductive composite having high conductivity, hermeticity, high mechanical strength, low surface roughness, lightweight, and thin profile. The composite comprises a rubber modified with vinyl ester resin. After curing in mold, the composite may serve as a bipolar plate in a fuel cell. For example, the bipolar plate is combined with a membrane electrode assembly (MEA) to form a proton exchange membrane fuel cell (PEMFC).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is cross section of a conventional proton exchange membrane fuel cell.

Claims

1. An electrically conductive composite, comprising: 20-40 weight percent of a block copolymer; and60-80 weight percent of a conductive filler;wherein the block copolymer is a copolymer of a rubber and a vinyl ester resin, and the rubber has greater weight ratio than the vinyl ester.

2. The electrically conductive composite as claimed in claim 1, wherein the conductive filler comprises graphite powder, carbon fiber, carbon black, coke, carbon nanotubes, or combinations thereof.

3. The electrically conductive composite as claimed in claim 1, wherein the block copolymer is copolymerized in the presence of a radical initiator, and comprises 1 to 50 weight percent of a rubber;to 60 weight percent of a vinyl ester resin; andto 40 weight percent of a crosslinking agent.

4. The electrically conductive composite as claimed in claim 3, wherein the radical initiator comprises tert-butylperoxybenzoate or peroxybenzoate.

5. The electrically conductive composite as claimed in claim 3, wherein the rubber comprises poly butadiene, nature rubber, polyisoprene, styrene-butadiene rubber, butadiene nitrile rubber, ethylene-propylene, polychloroprene, chlorinated polyethylene, silicone, fluorocarbon, or combinations thereof.

6. The electrically conductive composite as claimed in claim 3, wherein the rubber is poly acrynitrile butadiene copolymer.

7. The electrically conductive composite as claimed in claim 5, wherein the rubber has a molecular weight of about 1000 to 10000.

8. The electrically conductive composite as claimed in claim 7, wherein the rubber has a molecular weight of about 4500 to 5500.

9. The electrically conductive composite as claimed in claim 3, wherein the vinyl ester resin has functional groups comprising bisphenol A epoxy-based methacrylate, bisphenol A epoxy-based acrylate, tetrabromo bisphenol A epoxy-based methacrylate, or phenol-novalac epoxy-based acrylate.

10. The electrically conductive composite as claimed in claim 3, wherein the crosslinking agent is a vinyl monomer which comprises α-methyl styrene monomer, chlorostyrene monomer, divinyl benzene, vinyl toluene, divinyl toluene, diallylphthalate monomer, methylmethacrylate, or acrylic nitrile monomer, or combinations thereof.

11. The electrically conductive composite as claimed in claim 1, further comprising a rheologymodifier or a demolding agent.

12. The electrically conductive composite as claimed in claim 11, wherein the rheologymodifier comprises magnesium oxide.

13. The electrically conductive composite as claimed in claim 11, wherein the demolding agent comprises fluorine wax, metal soap, hydrocarbon wax, polyethylene, amide wax, fatty acid, fatty alcohol, or fatty ester.

14. The electrically conductive composite as claimed in claim 1, wherein the electrically conductive composite has flexural strength of about 4000 to 7000 psi.

15. The electrically conductive composite as claimed in claim 1, wherein the electrically conductive composite has tensile strength of about 3000 to 5000 psi.

16. The electrically conductive composite as claimed in claim 1, wherein the electrically conductive composite has conductivity of about 150 to 200 S/cm.

17. The electrically conductive composite as claimed in claim 1, wherein the electrically conductive composite is an electrode.

18. The electrically conductive composite as claimed in claim 1, wherein the electrode is a bipolar plate of a proton exchange membrane fuel cell.