Carbon nanoparticle-containing lubricant and grease

• US 20070158609A1
• Filed: 01/12/2006
• Published: 07/12/2007
• Est. Priority Date: 01/12/2006
• Status: Abandoned Application

• Current Assignee: South Dakota School of Mines and Technology
• Original Assignee: South Dakota School of Mines and Technology
• Inventors: Marquis, Fernand D.S., Hong, Haiping, Waynick, John Andrew
• Application Number:
  US11/332,679
• Publication Number:
  US 20070158609A1
• Time in Patent Office: Days
• US Class Current: 252/71
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C09K 5/10 Liquid materials
• CPC Class Codes: C10M 169/04 Mixtures of base-materials and additives
• CPC Class Codes: C10M 177/00 Special methods of preparation of lubricating compositions; Chemical modification by after-treatment of components or of the whole of a lubricating composition, not covered by other classes
• CPC Class Codes: C10M 2201/041 Carbon; Graphite; Carbon black
• CPC Class Codes: C10M 2205/0285 used as base material
• CPC Class Codes: C10M 2207/2835 used as base material
• CPC Class Codes: C10M 2219/044 Sulfonic acids, Derivatives thereof, e.g. neutral salts
• CPC Class Codes: C10N 2020/06 Particles of special shape or size
• CPC Class Codes: C10N 2030/00 Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
• CPC Class Codes: C10N 2050/10 Semi-solids; greasy
• CPC Class Codes: C10N 2070/00 Specific manufacturing methods for lubricant compositions

Abstract

The present invention relates to processes for preparing a stable suspension of carbon nanoparticles in a thermal transfer fluid to enhance thermal conductive properties, viscosity, and lubricity. One process is to disperse carbon nanoparticles directly into a thermal transfer fluid and other additives in the present of surfactants with intermittent ultrasonication. The second process is carried out in three stages. First, carbon nanoparticles are dispersed into a volatile solvent. Then, a thermal transfer fluid, surfactants, and other additives are added into this intermediate dispersion and mixed thoroughly. At last, the volatile solvent is removed to produce a uniformly dispersed nanofluid. The third process is to disperse carbon nanoparticles at an elevated temperature into a homogeneous mixture of surfactants and other additives in a thermal transfer fluid with help of a physical agitation. The present invention also relates to compositions of carbon nanoparticle nanofluids, such as nanolubricants and nanogreases. The nanofluid of the present invention is a dispersion of carbon nanoparticles, particularly carbon nanotubes, in a thermal transfer fluid in the present of surfactants. Addition of surfactants significantly increases the stability of nanoparticle dispersion. For nanogreases, carbon nanoparticles function both as a thickener to modulate viscosity and as a solid heat transfer medium to enhance thermal conductivity and high temperature resistance.

Claims

1. A method for producing a nanofluid with enhanced thermal properties comprising a step of dispersing carbon nanoparticles into a mixture comprising a thermal transfer fluid and at least one surfactant with intermittent ultrasonication.

2. The method of claim 1, wherein the nanoparticle is selected from the group consisting of diamond nanoparticles, graphite nanoparticles, fullerenes, carbon nanotubes, and combinations thereof.

3. The method of claim 1, wherein the nanoparticle is a carbon nanotube.

4. The method of claim 3, wherein the nanotube has an diameter of from about 0.2 to about 100 nm.

5. The method of claim 3, wherein the nanotube has an aspect ratio of no greater than 1,000,000.

6. The method of claim 3, wherein the nanotube has a thermal conductivity of no less than 10 W/m·

K.

7. The method of claim 1, wherein the surfactant is an anionic surfactant.

8. The method of claim 7, wherein the anionic surfactant is a sulfonate surfactant.

9. The method of claim 7, wherein the anionic surfactant is a sulfosuccinate, a sulfosuccinamate, or a combination thereof.

10. The method of claim 9, wherein the sulfosuccinate is dioctyl sulfosuccinate, bistridecyl sulfosuccinate, or di(1,3-di-methylbutyl)sulfosuccinate.

11. The method of claim 1, wherein the thermal transfer fluid is selected from the group consisting of petroleum distillates, synthetic petroleum oils, greases, gels, oil-soluble polymer composition, vegetable oils, and combinations thereof.

12. The method of claim 1, wherein the organic oil is a synthetic petroleum oil.

13. The method of claim 12, wherein the synthetic petroleum oil is selected from the group consisting of polyalphaolefins, polyol esters, and combinations thereof.

14. The method of claim 13, wherein the polyol ester is pentaerythritol ester, trimethylolpropane ester, or neopentyl glycol ester.

15. A method for producing a nanofluid with enhanced thermal properties comprising the steps of:

dispersing carbon nanoparticles in a volatile solvent with a first physical mixing method to form an intermediate dispersion;

adding a mixture comprising a thermal transfer fluid and at least one surfactant to the intermediate dispersion;

mixing thoroughly with a second physical mixing method; and

removing the volatile solvent.

16. The method of claim 15, wherein the nanoparticle is selected from the group consisting of diamond nanoparticles, graphite nanoparticles, fullerenes, carbon nanotubes, and combinations thereof.

17. The method of claim 15, wherein the thermal transfer fluid is selected from the group consisting of petroleum distillates, synthetic petroleum oils, greases, gels, oil-soluble polymer composition, vegetable oils, and combinations thereof.

18. The method of claim 15, wherein the thermal transfer fluid is a synthetic petroleum oil.

19. The method of claim 18, wherein the synthetic petroleum oil is selected from the group consisting of polyalphaolefins, polyol esters, and combinations thereof.

20. The method of claim 19, wherein the polyol ester is pentaerythritol ester, trimethylolpropane ester, or neopentyl glycol ester.

21. The method of claim 15, wherein the volatile solvent has a boiling point of below 150°

C.

22. The method of claim 15, wherein the volatile solvent is an organic solvent.

23. The method of claim 22, wherein the organic solvent is selected from the group consisting of halogenated solvents, ethers, carboxylic esters, carbonyl solvents, nitriles, and amides, and combinations thereof.

24. A method for producing a nanofluid with enhanced thermal properties comprising the steps of:

preparing a mixture comprising a thermal transfer fluid and at least one surfactant;

heating the mixture to a predetermined temperature; and

dispersing carbon nanoparticles into the heated mixture with a physical agitation;

25. The method of claim 24, wherein the nanoparticle is selected from the group consisting of diamond nanoparticles, graphite nanoparticles, fullerenes, carbon nanotubes, and combinations thereof.

26. The method of claim 24, wherein the nanoparticle is a carbon nanotube.

27. The method of claim 24, wherein the surfactant is an anionic surfactant, a nonionic surfactant, or a combination thereof.

28. A nanolubricant with enhanced thermal conductivities comprising a thermal transfer fluid, carbon nanoparticles, and at least one surfactant.

29. The nanolubricant of claim 28, wherein the thermal transfer fluid is selected from the group consisting of petroleum distillates, synthetic petroleum oils, greases, gels, oil-soluble polymer composition, vegetable oils, and combinations thereof.

30. The nanolubricant of claim 28, wherein the thermal transfer fluid is a synthetic petroleum oil.

31. The nanolubricant of claim 30, wherein the synthetic petroleum oil is selected from the group consisting of polyalphaolefins, polyol esters, and combinations thereof.

32. The nanolubricant of claim 31, wherein the polyol ester is pentaerythritol ester, trimethylolpropane ester, and neopentyl glycol ester.

33. The nanolubricant of claim 28, wherein the amount by weight of the carbon nanoparticles is no greater than about 30%.

34. The nanolubricant of claim 28, wherein the nanoparticle is selected from the group consisting of diamond nanoparticles, graphite nanoparticles, fullerenes, carbon nanotubes, and combinations thereof.

35. The nanolubricant of claim 28, wherein the nanoparticle is a carbon nanotube.

36. The nanolubricant of claim 35, wherein the nanotube has a diameter of from about 0.2 to about 100 nm.

37. The nanolubricant of claim 35, wherein the nanotube has an aspect ratio of no greater than 1,000,000.

38. The nanolubricant of claim 35, wherein the nanotube has a thermal conductivity of no less than 10 W/m K.

39. The nanolubricant of claim 28, wherein the surfactant is an anionic surfactant.

40. The nanolubricant of claim 39, wherein the anionic surfactant is a sulfonate surfactant.

41. The nanolubricant of claim 40, wherein the anionic surfactant is a sulfosuccinate, a sulfosuccinamate, or a combination thereof.

42. The nanolubricant of claim 41, wherein the sulfosuccinate is selected from the group consisting of dioctyl sulfosuccinate, bistridecyl sulfosuccinate, di(1,3-di-methylbutyl)sulfosuccinate, and combinations thereof.

43. The nanolubricant of claim 28, wherein the amount of the surfactant is about from 0.1 to about 30% by weight.

44. A nanogrease with enhanced thermal conductivities comprising a thermal transfer fluid, carbon nanoparticles, and at least one surfactant.

45. The nanogrease of claim 44, wherein the thermal transfer fluid is selected from the group consisting of petroleum distillates, synthetic petroleum oils, greases, gels, oil-soluble polymer composition, vegetable oils, and combinations thereof.

46. The nanogrease of claim 44, wherein the thermal transfer fluid has a viscosity of from about 2 to about 800 centistokes.

47. The nanogrease of claim 44, wherein the thermal transfer fluid is a synthetic petroleum oil.

48. The nanogrease of claim 47, wherein the synthetic petroleum oil is selected from the group consisting of polyalphaolefins, polyol esters, and combinations thereof.

49. The nanogrease of claim 48, wherein the polyol ester is pentaerythritol ester, trimethylolpropane ester, or neopentyl glycol ester.

50. The nanogrease of claim 44, wherein the amount by weight of the carbon nanoparticles is no greater than about 30%.

51. The nanogrease of claim 44, wherein the nanoparticle is selected from the group consisting of diamond nanoparticles, graphite nanoparticles, fullerenes, carbon nanotubes, and combinations thereof.

52. The nanogrease of claim 44, wherein the nanoparticle is a carbon nanotube.

53. The nanogrease of claim 52, wherein the nanotube has a diameter of from about 0.2 to about 100 nm.

54. The nanogrease of claim 52, wherein the nanotube has an aspect ratio of on greater than 1,000,000.

55. The nanogrease of claim 52, wherein the nanotube has a thermal conductivity of no less than 10 W/m K.

56. The nanogrease of claim 44, wherein the surfactant is an anionic surfactant or a mixture of an anionic and nonionic surfactant.

57. The nanogrease of claim 56, wherein the anionic surfactant is a sulfonate surfactant.

58. The nanogrease of claim 56, wherein the anionic surfactant is a sulfosuccinate, a sulfosuccinamate, or a combination thereof.

59. The nanogrease of claim 58, wherein the sulfosuccinate is dioctyl sulfosuccinate, bistridecyl sulfosuccinate, or di(1,3-di-methylbutyl)sulfosuccinate.

60. The nanogrease of claim 44, wherein the amount of surfactant is about from 0.1 to about 30% by weight.