Dispersions comprising discrete carbon nanotube fibers
This present invention relates to the carbon nanotubes as composites with materials such as elastomers, thermosets and thermoplastics or aqueous dispersions of open-ended carbon nanotubes with additives. A further feature of this invention relates to the development of a concentrate of carbon nanotubes with an elastomer wherein the concentrate can be further diluted with an elastomer and other polymers and fillers using conventional melt mixing equipment.
1. A dispersion comprising a plurality of oxidized, discrete carbon nanotubes and at least one additive, wherein the oxidized, discrete carbon nanotubes have an aspect ratio of 25 to 500, are multiwall, and are present in the range of greater than zero to about 30% by weight based on the total weight of the dispersion.
2. The dispersion of claim 1 wherein at least 70 percent by weight of the nanotubes are discrete.
3. The dispersion of claim 1 in the form of free flowing particles.
4. The dispersion of claim 1 wherein the oxidized, discrete carbon nanotubes comprise an oxidation species selected from carboxylic acid or a derivative carbonyl containing species wherein the derivative carbonyl species is selected from ketones, quaternary amines, amides, esters, acyl halogens, and monovalent metal salts.
5. The dispersion of claim 1 wherein the oxidized, discrete carbon nanotubes comprise an oxidation species selected from hydroxyl or derived from hydroxyl containing species.
6. The dispersion of claim 1 wherein the oxidized, discrete carbon nanotubes are present in the range of 15% to about 25% by weight based on the total weight of the dispersion.
7. The dispersion of claim 1 wherein the oxidized, discrete carbon nanotubes are present in the range of 18% to about 22% by weight based on the total weight of the dispersion.
8. The dispersion of claim 1 , wherein the additive is selected from the group consisting of dicarboxylic/tricarboxylic esters, timellitates, adipates, sebacates, maleates, glycols and polyethers, polymeric plasticizers, bio-based plasticizers, and mixtures thereof.
9. The dispersion of claim 1 , wherein the additives is a process oil.
10. The dispersion of claim 9 , where in the process oil is selected from the group consisting of naphthenic oils, paraffin oils, paraben oils, aromatic oils, vegetable oils, seed oils, silicones, and mixtures thereof.
11. The dispersion of claim 1 , wherein the additive is a solvent.
12. The dispersion of claim 11 , where in the solvent is selected from the group consisting of substituted or unsubstituted, halogenated or nonhalogenated hydrocarbons.
13. The dispersion of claim 1 , wherein the additive comprises at least one reactive species capable of creating a thermoset polymer.
14. The dispersion of claim 13 , wherein the thermoset polymer is selected from epoxy, polyurethane and silicone.
15. The dispersion of claim 1 , wherein the additive comprises natural wax, synthetic wax, or mixtures thereof.
16. The dispersion of claim 15 further comprising a fluoroelastomer.
17. The dispersion of claim 1 which further comprises at least one filler.
18. The dispersion of claim 17 , wherein the filler has at least one dimension less than about 20 microns.
19. The dispersion of claim 18 , wherein the filler is selected from silicon, lead, lead derivatives, carbon black, graphite, graphene, graphene oxides, paramagnetic particles and mixtures thereof.
20. A dispersion comprising a plurality of oxidized, discrete carbon nanotubes and at least one wax additive and at least one fluoroelastomer, wherein the discrete carbon nanotubes have an aspect ratio of 25 to 500, are multiwall, and are present in the range of greater than zero to about 30% by weight based on the total weight of the dispersion.
21. The dispersion of claim 15 which further comprises a crosslinking agent.
22. The dispersion of claim 15 wherein the additive comprises natural wax wherein the natural wax is plant derived.
23. The dispersion of claim 22 which further comprises a crosslinking agent.