Carbon-matrix composites, compositions and methods related thereto

• US 6,638,883 B2
• Filed: 07/26/2001
• Issued: 10/28/2003
• Est. Priority Date: 07/26/2000
• Status: Expired due to Term

• Current Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Original Assignee: Ballard Material Products, Inc.
• Inventors: Gaffney, John J., Loszewski, Raymond C.
• Primary Examiner(s): Morris, Terrel
• Assistant Examiner(s): Salvatore, Lynda
• Application Number:
  US09/916,823
• Publication Number:
  US 20030100239A1
• Time in Patent Office: 824 Days
• Field of Search: 428/299.1, 428/299.7, 428/300.4, 442/181, 442/197, 442/212, 442/213
• US Class Current: 442/181
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 35/83 Carbon fibres in a carbon matrix
• CPC Class Codes: D01F 9/22 from polyacrylonitriles
• CPC Class Codes: D10B 2331/021 aromatic polyamides, e.g. aramides
• CPC Class Codes: F16D 69/023 Composite materials containing carbon and carbon fibres or fibres made of carbonizable material
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 2300/0091 in the form of mixtures
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/0239 Organic resins; Organic polymers
• CPC Class Codes: H01M 8/0243 in the form of mixtures
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10T 428/249945 Carbon or carbonaceous fiber
• CPC Class Codes: Y10T 428/249947 Polymeric fiber
• CPC Class Codes: Y10T 428/249949 Two or more chemically different fibers
• CPC Class Codes: Y10T 428/31583 Nitrile monomer type [polyacrylonitrile, etc.]
• CPC Class Codes: Y10T 442/30 Woven fabric [i.e., woven strand or strip material]
• CPC Class Codes: Y10T 442/313 Strand material formed of individual filaments having different chemical compositions
• CPC Class Codes: Y10T 442/3252 Including synthetic polymeric strand material
• CPC Class Codes: Y10T 442/326 Including synthetic polymeric strand material
• CPC Class Codes: Y10T 442/3309 Woven fabric contains inorganic strand material
• CPC Class Codes: Y10T 442/3317 : Woven fabric contains synthetic polymeric strand material
• CPC Class Codes: Y10T 442/60 : Nonwoven fabric [i.e., nonwoven strand or fiber material]
• CPC Class Codes: Y10T 442/605 : Strand or fiber material is inorganic
• CPC Class Codes: Y10T 442/607 : Strand or fiber material is synthetic polymer
• CPC Class Codes: Y10T 442/619 : Including other strand or fiber material in the same layer not specified as having microdimensions
• CPC Class Codes: Y10T 442/63 : Carbon or carbonaceous strand or fiber material
• CPC Class Codes: Y10T 442/632 : A single nonwoven layer comprising non-linear synthetic polymeric strand or fiber material and strand or fiber material not specified as non-linear
• CPC Class Codes: Y10T 442/633 : Synthetic polymeric strand or fiber material is of staple length
• CPC Class Codes: Y10T 442/635 : Synthetic polymeric strand or fiber material
• CPC Class Codes: Y10T 442/636 : Synthetic polymeric strand or fiber material is of staple length

Abstract

The present invention relates to carbon-matrix composites, such as carbon—carbon composites, and a method for forming them by forming a fabric of fusible and infusible fibers which can be processed and carbonized to form a composite. The methods disclosed herein permit preparation of composites which are particularly thin, uniform, and highly pure. The invention also relates to preprocessed fabrics and precarbonized composites, such as those comprising carbon or oxidized polyacrylonitrile fibers and fusible polyacrylonitrile fibers.

Claims

1. A composite comprising thermoplastic fibers and stabilized carbon precursor reinforcing fibers, wherein the thermoplastic fibers are fused to the reinforcing fibers and wherein the thermoplastic fibers and the reinforcing fibers are carbonized to yield the composite.

2. The composite of claim 1, wherein the reinforcing fibers comprise oxidized polyacrylonitrile fibers.

3. The composite of claim 1, wherein the thermoplastic fibers are high char yield fibers.

4. The composite of claim 1, wherein the thermoplastic fibers comprise phenolic resin, pitch, epoxy resin, phthalonitrile resin, aromatic acetylene-derived polymer, or unoxidized polyacrylonitrile fibers.

5. The composite of claim 1, wherein the thermoplastic fibers comprise unoxidized polyacrylonitrile.

6. The composite of claim 1, wherein the composite comprises at least 30% by weight reinforcing fibers.

7. The composite of claim 1, wherein the composite comprises at least 60% by weight reinforcing fibers.

8. The composite of claim 1, wherein the composite comprises at least 90% by weight reinforcing fibers.

9. The composite of claim 1, wherein the fibers have lengths which differ by at least about 50%.

10. The composite of claim 1, wherein the fibers have lengths which differ by at least about 300%.

11. The composite of claim 1, wherein the fibers have lengths which differ by at least about 1000%.

12. The composite of claim 1, wherein the fibers have substantially identical lengths.

13. The composite of claim 1, wherein the composite has an air permeability of more than 6 Gurley seconds.

14. The composite of claim 1, wherein the composite has an air permeability of more than 9 Gurley seconds.

15. The composite of claim 1, wherein the thermoplastic fibers are interwoven with the reinforcing fibers to form a woven fabric.

16. The composite of claim 1, wherein the thermoplastic fibers and the reinforcing fibers are intermingled in a generally non-ordered arrangement to form a nonwoven fabric.

17. A composite prepared by a method comprising

combining thermoplastic fibers and stabilized carbon precursor reinforcing fibers,

fusing the thermoplastic fibers to the reinforcing fibers, and

carbonizing the thermoplastic and reinforcing fibers to produce a composite.

18. The composite of claim 17, wherein the method further comprises stabilizing and/or oxidizing the thermoplastic fibers.

19. The composite of claim 18, wherein the stabilizing and/or oxidizing step occurs prior to the carbonizing step.

20. The composite of claim 17, wherein the reinforcing fibers are oxidized polyacrylonitrile fibers.

21. The composite of claim 20, wherein the thermoplastic fibers comprise polyacrylonitrile fibers.

22. The composite of claim 17, wherein the thermoplastic fibers are high char yield fibers.

23. The composite of claim 17, wherein the thermoplastic fibers comprise phenolic resin, pitch, epoxy resin, phthalonitrile resin, aromatic acetylene-derived polymer, or polyacrylonitrile fibers.

24. The composite of claim 17, wherein the combining step comprises blending the thermoplastic fibers with the reinforcing fibers to form a non-woven fabric.

25. The composite of claim 17, wherein the combining step comprises weaving the thermoplastic fibers with the reinforcing fibers to form a woven fabric.

26. A composite prepared by a method comprising

forming a precursor substrate comprising polyacrylonitrile fibers and oxidized polyacrylonitrile reinforcing fibers,

fusing the polyacrylonitrile fibers to the oxidized polyacrylonitrile reinforcing fibers, and

carbonizing the polyacrylonitrile fibers and the oxidized polyacrylonitrile reinforcing fibers to produce a composite.

27. The composite of claim 26, wherein the method further comprises stabilizing and/or oxidizing the polyacrylonitrile fibers prior to the carbonizing step.

28. The composite of claim 27, wherein the forming step comprises blending the thermoplastic fibers with the reinforcing fibers to form a non-woven fabric.

29. The composite of claim 27, wherein the forming step comprises weaving the thermoplastic fibers with the reinforcing fibers to form a woven fabric.

30. A method for forming a composite, comprising

combining thermoplastic fibers and stabilized carbon precursor reinforcing fibers,

fusing the thermoplastic fibers to the reinforcing fibers, and

carbonizing the thermoplastic and reinforcing fibers to produce a composite.

31. The method of claim 30, wherein the reinforcing fibers are oxidized polyacrylonitrile fibers.

32. The method of claim 30, further comprising stabilizing and/or oxidizing the thermoplastic fibers.

33. The method of claim 32, wherein the stabilizing and/or oxidizing step occurs prior to the carbonizing step.

34. The method of claim 30, wherein the thermoplastic fibers are high char yield fibers.

35. The method of claim 30, wherein the thermoplastic fibers comprise phenolic resin, pitch, epoxy resin, phthalonitrile resin, aromatic acetylene-derived polymer, or polyacrylonitrile fibers.

36. The method of claim 30, wherein the thermoplastic fibers comprise polyacrylonitrile fibers.

37. The method of claim 30, wherein the combining step comprises blending the thermoplastic fibers with the reinforcing fibers to form a non-woven fabric.

38. The method of claim 30, wherein the combining step comprises weaving the thermoplastic fibers with the reinforcing fibers to form a woven fabric.

39. A conductive catalyst support for a proton exchange membrane fuel cell, the catalyst support comprising

thermoplastic fibers and stabilized carbon precursor reinforcing fibers, wherein the thermoplastic fibers are fused to the reinforcing fibers and wherein the thermoplastic fibers are carbonized to yield the composite.

40. A frictional member comprising

thermoplastic fibers and stabilized carbon precursor reinforcing fibers, wherein the thermoplastic fibers are fused to the reinforcing fibers and wherein the thermoplastic fibers are carbonized to yield the composite.

41. A method of forming a composite comprising:

stabilizing a plurality of carbon precursor fibers,

combining the stabilized carbon precursor fibers with a plurality of thermoplastic fibers,

fusing the thermoplastic fibers to the carbon precursor fibers, and

carbonizing the thermoplastic and reinforcing fibers to produce a composite.

42. The method of claim 41, wherein the method further comprises stabilizing and/or oxidizing the thermoplastic fibers.

43. The method of claim 41, wherein the plurality of carbon precursor fibers comprises polyacrylonitrile fibers.

44. The method of claim 43, wherein the thermoplastic fibers comprise polyacrylonitrile fibers.

45. The method of claim 41, wherein the thermoplastic fibers comprise phenolic resin, pitch, epoxy resin, phthalonitrile resin, aromatic acetylene-derived polymer, or polyacrylonitrile fibers.

46. The method of claim 41, wherein the combining step comprises blending the thermoplastic fibers with the carbon precursor fibers to form a non-woven fabric.

47. The method of claim 46, wherein the combining step further includes consolidating the thermoplastic fibers with the carbon precursor fibers.

48. The method of claim 47, wherein the consolidating step comprises hydroentangling the thermoplastic fibers with the carbon based fibers.

49. The method of claim 47, wherein the consolidating step comprises needle-punching blended thermoplastic fibers and the carbon precursor fibers.

50. The method of claim 41, wherein the combining step comprises weaving the thermoplastic fibers with the carbon precursor fibers to form a woven fabric.