Conductive grease with enhanced thermal or electrical conductivity and reduced amount of carbon particle loading
Disclosed herein is a conductive grease composition that includes a functionalized carbon nanomaterial and/or boron nanomaterial and a base oil. The nanomaterial and base oil forms hydrogen bond network in the disclosed composition. Because of the formed hydrogen bonds, the disclosed grease exhibits enhanced thermal or electrical conductivity. Also disclosed is a method to improve thermal or electrical conductivity of an existing grease composition.
1. A stable conductive grease composition comprising:
from about 25 wt-% to about 99 wt-% of a fluid;
from about 0.1 wt-% to about 5 wt-% of a nanomaterial;
wherein the nanomaterial is a carbon nanomaterial having one or more of a first functional group capable of forming a hydrogen bond or a boron nanomaterial;
wherein the fluid comprises one or more of a second functional group capable of forming a hydrogen bond, wherein the second functional group is an —OH, —NH, —COOH, —F, —BH, —O—, —N—, or combination thereof;
wherein the stable conductive grease composition is free of surfactant; and
wherein the stable conductive grease has a resistance which is improved over the fluid alone by at least about 20%.
2. The composition of claim 1 , wherein the first functional group is a hydrophilic functional group.
3. The composition of claim 2 , wherein the first functional group is an —OH, —NH, —COOH, —F, —BH, —O—, —N—, or combination thereof.
4. The composition of claim 2 , wherein the nanomaterial is the carbon nanomaterial.
5. The composition of claim 4 , wherein the carbon nanomaterial is carbon nanotube, carbon nanofiber, graphite particle, graphene particle, or combination thereof having at least one dimension that is less than 10,000 nanometers.
6. The composition of claim 1 , wherein the nanomaterial is an OH functionalized carbon nanomaterial, a fluorine functionalized carbon nanomaterial, or a combination thereof.
7. The composition of claim 1 , wherein the nanomaterial is the boron nanomaterial.
8. The composition of claim 7 , wherein the nanomaterial comprises single-walled boron nanotube, multiple-walled boron nanotube, or a combination thereof.
9. The composition of claim 1 , wherein the fluid comprises a base oil, and wherein the base oil is an API Group I oil, API Group II oil, API Group III oil, API Group IV oil, API Group V oil, or a mixture thereof.
10. The composition of claim 9 , wherein the base oil comprises an alkyl alcohol, alkylene glycols, polyol ester, or a combination thereof.
11. The composition of claim 1 , wherein the nanomaterial and the fluid are hydrogen bonded.
12. The stable conductive grease composition of claim 1 , wherein the composition further comprises a grease additive.
13. A method of preparing the stable conductive grease composition of claim 1 comprising:
(a) combining the fluid and the nanomaterial;
(b) mixing the fluid and the nanomaterial to form a grease composition; and
(c) passing the grease composition through a roller mill, an extruder, a manual stirrer, and/or a mechanical stirrer to form the stable conductive grease composition.
14. The method of claim 13 , wherein the fluid is heated prior to, during, and/or after step (a).
15. The method of claim 13 , wherein the fluid is not heated before or during mixing.
16. The method of claim 13 , wherein the grease composition is heated during and/or after step (b).