Electrically conductive, optically transparent polymer/carbon nanotube composites and process for preparation thereof

• US 20030158323A1
• Filed: 11/01/2002
• Published: 08/21/2003
• Est. Priority Date: 11/02/2001
• Status: Active Grant

• Current Assignee: National Aeronautics and Space Administration (Government of the United States of America)
• Original Assignee: National Aeronautics and Space Administration (Government of the United States of America)
• Inventors: Connell, John W., Harrison, Joycelyn S., Ounaies, Zoubeida, Smith, Joseph G., Watson, Kent A., Park, Cheol
• Granted Patent: US 7,588,699 B2
• Time in Patent Office: Days
• US Class Current: 524/495
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C08F 2/44 Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
• CPC Class Codes: C08G 73/10 Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
• CPC Class Codes: C08G 73/1039 comprising halogen-containing substituents
• CPC Class Codes: C08G 73/1071 Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain
• CPC Class Codes: C08K 2201/011 Nanostructured additives
• CPC Class Codes: C08K 5/00 Use of organic ingredients
• CPC Class Codes: C08K 7/24 inorganic
• CPC Class Codes: C08L 71/12 Polyphenylene oxides
• CPC Class Codes: C08L 71/123 not modified by chemical after-treatment
• CPC Class Codes: C09J 11/04 inorganic
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2904 Staple length fiber
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/2975 Tubular or cellular

Abstract

The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T_g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

Claims

1. A method for dispersing carbon nanotubes in a polymer matrix to prepare a polymer/carbon nanotube nanocomposite, comprising:

(a) dispersing carbon nanotubes in an organic solvent;

(b) adding one or more monomers of the polymer of interest to the dispersed nanotubes; and

(c) polymerizing the monomers in the presence of the dispersed nanotubes under mechanical stirring.

2. The method of claim 1, wherein the nanotubes are selected from the group consisting of single wall and multi-wall.

3. The method of claim 1, wherein the polymer is a condensation polymer.

4. The method of claim 1, wherein the polymer is an addition polymer.

5. The method of claim 1, wherein the polymer is a copolymer.

6. The method of claim 1, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(amide acid), and copoly(amide acid).

7. The method of claim 1, wherein the polymer is selected from the group consisting of poly(arylene ether) and copoly(arylene ether).

8. The method of claim 4, wherein the polymer is selected from the group consisting of poly(vinyl polymer) and poly(methyl methacrylate).

9. The method of claim 1, wherein the organic solvent is a polar aprotic solvent.

10. The method of claim 1, wherein the nanocomposite is electrically conductive and optically transparent.

11. The method of claim 6, wherein the monomers comprise at least one diamine and at least one dianhydride.

12. The method of claim 7, wherein the monomers comprise at least one activated halide and at least one bisphenol.

13. The method of claim 11, wherein a diamine is 1,3-bis(3-aminophenoxy) benzene and a dianhydride is 4,4′

-perfluoroisopropylidiene dianhydride.

14. The method of claim 11, wherein a diamine is 2,6-bis(3-aminophenoxy) benzonitrile and a dianhydride is 3,3′

,4,4′

-oxydiphthalic dianhydride.

15. The method of claim 11, wherein a diamine is [2,4-bis(3-aminophenoxy)phenyl]diphenylphosphine oxide and a dianhydride is 3,3′

,4,4′

-oxydiphthalic dianhydride.

16. The method of claim 12, wherein an activated halide is 1,3-bis(4-fluorobenzoyl)benzene and a bisphenol is 4,4′

-isopropylieienediphenol.

17. The method of claim 1, wherein the organic solvent is selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidinone .

18. The method of claim 1, wherein steps (a) through (c) occur under simultaneous sonication.

19. The method of claim 1, further comprising the step of filtering following polymerization.

67. A nanocomposite product prepared from the nanocomposite of claim 1, wherein said product is in the form selected from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

20. A method for producing a polymer/carbon nanotube nanocomposite, comprising synthesis of the polymer in the presence of pre-dispersed nanotubes.

21. The method of claim 20, wherein the nanocomposite is electrically conductive and optically transparent.

22. The method of claim 20, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(arylene ether), copoly(arylene ether), poly(amide acid), copoly(amide acid), poly(vinyl polymer), and poly(methyl methacrylate).

68. A nanocomposite product prepared from the nanocomposite of claim 20, wherein said product is in the form selected from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

23. A method for producing a polymer/carbon nanotube nanocomposite, comprising synthesis of the polymer in the presence of pre-dispersed nanotubes with simultaneous sonication throughout the synthesis.

24. The method of claim 23, wherein the nanocomposite is electrically conductive and optically transparent.

25. The method of claim 23, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(arylene ether), copoly(arylene ether), poly(amide acid), copoly(amide acid), poly(vinyl polymer) and poly(methyl methacrylate).

69. A nanocomposite product prepared from the nanocomposite of claim 23, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

26. A method for preparing a polymer/carbon nanotube nanocomposite, comprising:

(a) placing carbon nanotubes into an organic solvent at a concentration ranging from approximately 0.01% to approximately 1.0% weight per volume, forming a nanotube suspension;

(b) treating the nanotube suspension with an ultrasonic bath for a period of time sufficient to disperse the nanotubes in the solvent;

(c) placing at least one first monomer solution into a reaction vessel;

(d) adding the treated nanotube suspension to the reaction vessel;

(e) stirring sufficiently to form a homogeneous suspension;

(f) adding at least one second monomer to the reaction vessel;

(g) stirring sufficiently to form a homogeneous suspension;

(h) achieving condensation of the polymer; and

(i) isolating the nanocomposite by removal of the solvent.

27. The method of claim 26, wherein the nanocomposite is electrically conductive and optically transparent.

28. The method of claim 26, wherein the step (h) condensation is achieved thermally.

29. The method of claim 26, wherein the step (h) condensation is achieved chemically.

30. The method of claim 26, comprising the further step of heating between step (g) and step (h).

31. The method of claim 26, wherein steps (a) through (h) occur under sonication.

32. The method of claim 26, wherein step (b) comprises the further treatment with a homogenizer.

33. The method of claim 26, comprising the further step of filtering following between step (h) and step (i).

54. The nanocomposite of claim 26, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(arylene ether), copoly(arylene ether), poly(amide acid), and copoly(amide acid).

63. The nanocomposite of claim 26 wherein the concentration of the carbon nanotube relative to the host matrix polymer is between approximately 0.1% to approximately 3.0% by weight.

70. A nanocomposite product prepared from the nanocomposite of claim 26, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

34. A method for preparing a polymer/carbon nanotube nanocomposite, comprising:

(a) placing carbon nanotubes into an organic solvent at a concentration ranging from approximately 0.01% to approximately 1.0% weight per volume, forming a nanotube suspension;

(b) treating the nanotube suspension with an ultrasonic bath for a period of time sufficient to disperse the nanotubes in the solvent;

(c) placing the treated nanotube suspension into a reaction vessel;

(d) adding at least one first monomer to the reaction vessel;

(e) stirring sufficiently to form a homogeneous suspension;

(f) adding at least one second monomer to the reaction vessel;

(g) stirring sufficiently to form a homogeneous suspension;

(h) achieving condensation of the polymer; and

(i) isolating the nanocomposite by removal of the solvent.

35. The method of claim 34, wherein the step (h) condensation is achieved thermally.

36. The method of claim 34, wherein the step (h) condensation is achieved chemically.

37. The method of claim 34, comprising the further step of heating between step (g) and step (h).

38. The method of claim 34, wherein steps (a) through (h) occur under sonication.

39. The method of claim 34, wherein step (b) comprises the further treatment with a homogenizer.

40. The method of claim 34, comprising the further step of filtering between step (h) and step (i).

41. The method of claim 34, wherein the nanocomposite is electrically conductive and optically transparent.

55. The nanocomposite of claim 34, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(arylene ether), copoly(arylene ether), poly(amide acid), and copoly(amide acid).

64. The nanocomposite of claim 34 wherein the concentration of the carbon nanotube relative to the host matrix polymer is between approximately 0.1% to approximately 3.0% by weight.

71. A nanocomposite product prepared from the nanocomposite of claim 34, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

42. A method for preparing a polymer/carbon nanotube nanocomposite, comprising:

(a) placing carbon nanotubes into an organic solvent at a concentration ranging from approximately 0.01% to approximately 1.0% weight per volume, forming a nanotube suspension;

(b) treating the nanotube suspension with an ultrasonic bath for a period of time sufficient to disperse the nanotubes in the solvent;

(c) placing at least one monomer into a reaction vessel;

(d) adding the treated nanotube suspension to the reaction vessel;

(e) stirring sufficiently to form a homogeneous suspension;

(f) adding at least one second monomer;

(g) stirring sufficiently to form a homogeneous suspension;

(h) achieving condensation of the polymer; and

(i) isolating the nanocomposite by removal of the solvent.

43. The method of claim 42, wherein the nanocomposite is electrically conductive and optically transparent.

44. The method of claim 42, wherein the step (h) condensation is achieved thermally.

45. The method of claim 42, wherein the step (h) condensation is achieved chemically.

46. The method of claim 42, comprising the further step of heating between step (g) and step (h).

47. The method of claim 42, wherein steps (a) through (h) occur under sonication.

48. The method of claim 42, wherein step (b) comprises the further treatment with a homogenizer.

49. The method of claim 42, comprising the further step of filtering between step (h) and step (i).

56. The nanocomposite of claim 42, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(arylene ether), copoly(arylene ether), poly(amide acid), and copoly(amide acid).

65. The nanocomposite of claim 42 wherein the concentration of the carbon nanotube relative to the host matrix polymer is between approximately 0.1% to approximately 3.0% by weight.

72. A nanocomposite product prepared from the nanocomposite of claim 42, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

50. A method for preparing a polymer/carbon nanotube nanocomposite, comprising:

a. placing carbon nanotubes into an organic solvent at a concentration ranging from approximately 0.01% to approximately 1.0% weight per volume, forming a nanotube suspension;

b. treating the nanotube suspension with an ultrasonic bath for a period of time sufficient to disperse the nanotubes in the solvent;

c. placing at least one monomer into a reaction vessel;

d. adding the treated nanotube suspension to the reaction vessel;

e. stirring sufficiently to form a homogeneous suspension;

f. adding an initiator;

g. stirring sufficiently to form a homogeneous suspension; and

h. achieving a polymer by addition polymerization.

51. The method of claim 50, wherein the nanocomposite is electrically conductive and optically transparent.

52. The method of claim 50, wherein steps (a) through (h) occur under sonication.

53. The method of claim 50, wherein step (b) comprises the further treatment with a homogenizer.

57. The nanocomposite of claim 50, wherein the polymer is selected from the group consisting of poly(vinyl polymer) and poly(methyl methacrylate).

66. The nanocomposite of claim 50 wherein the concentration of the carbon nanotube relative to the host matrix polymer is between approximately 0.1% to approximately 3.0% by weight.

73. A nanocomposite product prepared from the nanocomposite of claim 50, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

58. An electrically conductive, optically transparent polymer/carbon nanotube nanocomposite, having an electrically conductivity between approximately 10⁻

12 S/cm and 10<sup>−

5</sup> S/cm and a greater than 50% optical transparency relative retention at a wavelength of 500 nm.

59. The nanocomposite of claim 58, wherein the polymer is selected from the group consisting of polyimide, copolyimide, poly(arylene ether), copoly(arylene ether), poly(amide acid), copoly(amide acid), poly(vinyl polymer) and poly(methyl methacrylate).

60. An electrically conductive, optically transparent poly (amide acid)/carbon nanotube nanocomposite, comprising a carbon nanotube and a poly(amide acid), wherein the poly(amide acid) is

74. A nanocomposite product prepared from the nanocomposite of claim 60, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

61. An electrically conductive, optically transparent polyimide/carbon nanotube nanocomposite comprising a carbon nanotube and a polyimide, wherein the polyimide is

75. A nanocomposite product prepared from the nanocomposite of claim 61, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

62. An electrically conductive, optically transparent poly(arylene ether)/carbon nanotube nanocomposite comprising a carbon nanotube and a poly(arylene ether), wherein the poly(arylene ether) is

76. A nanocomposite product prepared from the nanocomposite of claim 62, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.

77. An electrically conductive, optically transparent poly(methyl methacrylate)/ carbon nanotube nanocomposite, comprising a carbon nanotube and a poly(methyl methacrylate), wherein the poly(methyl methacrylate) is

78. An electrically conductive, optically transparent poly(vinyl polymer)/carbon nanotube nanocomposite, comprising a carbon nanotube and a poly(vinyl polymer), wherein the poly(vinyl polymer) is

79. A nanocomposite product prepared from the nanocomposite of claim 78, wherein said product is in the form from the group consisting of a film, fiber, foam, coating, adhesive, molding and paste.