Thiation of carbon nanotubes and composite formation

• US 20060079626A1
• Filed: 03/21/2005
• Published: 04/13/2006
• Est. Priority Date: 03/19/2004
• Status: Active Grant

• Current Assignee: Arrowhead Center, Inc.
• Original Assignee: Arrowhead Center, Inc.
• Inventors: Curran, Seamus A., Ellis, Amanda V.
• Granted Patent: US 7,713,508 B2
• Time in Patent Office: Days
• US Class Current: 524/496
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C07C 327/36 Esters of dithiocarboxylic acids
• CPC Class Codes: C08K 2201/011 Nanostructured additives
• CPC Class Codes: C08K 2201/014 Additives containing two or more different additives of the same subgroup in C08K
• CPC Class Codes: C08K 7/24 inorganic
• CPC Class Codes: Y10S 977/847 Surface modifications, e.g. functionalization, coating

Abstract

The present invention comprises nanotube structures comprising nanotubes covalently bonded via chemically reactive groups on the outer walls of the nanotubes and methods for forming the covalently bonded nanotube structures. The present invention also comprises materials comprising the functionalized nanotubes covalently bonded to organic based monomers and/or polymers, and methods for their formation.

Claims

1. A nanotube structure comprising at least two covalently bonded nanotubes.

2. The structure of claim 1 wherein said structure comprises a dithioester.

3. The structure of claim 1 wherein said dithioester comprises a reactive group of the formula S═

C—

Ch₂—

S covalently bonded to said nanotubes.

4. The structure of claim 2 wherein said dithioester comprises a thiocarboxylic O-ester.

5. The structure of claim 1 wherein said nanotubes comprise multi-walled carbon nanotubes.

6. The structure of claim 1 wherein said nanotubes are covalently bonded to at least one polymer or monomer.

7. A method of functionalizing at least one carbon nanotube comprising thiolating at least one surface of the at least one nanotube.

8. The method of claim 7 comprising reacting the at least one nanotube with phosphorus pentasulfide to thiolate the at least one nanotube.

9. The method of claim 7 further comprising carboxylizing the at least one nanotube prior to reacting the at least one nanotube with phosphorus pentasulfide in solution to prepare a dithiocarboxylic ester of the formula

10. The method of claim 9 comprising reacting the at least one carbon nanotube and the phosphorus pentasulfide in a solution comprising anhydrous toluene.

11. The method of claim 10 further comprising the step of refluxing the solution.

12. The method of claim 11 comprising refluxing the solution for between approximately 10 and 50 hours at from between approximately 0 and 150°

C.

13. The method of claim 8 further comprising covalently bonding a first of the at least one nanotube to a second of the at least one nanotube and polymerizing the nanotubes.

14. The method of claim 13 wherein the covalently bonded nanotubes comprise nanotube dithioesters utilized as chain transfer agents for living free-radical polymerization of polymer monomers.

15. The method of claim 14 wherein the polymerization comprises Reversible Addition-Fragmentation Chain Transfer Polymerization.

16. The method of claim 15 comprising:

sonicating the nanotube dithioesters; and

reacting the nanotube dithioesters with a polymer.

17. The method of claim 16 further comprising sonicating the nanotube dithioesters in a solution comprising anhydrous toluene.

18. The method of claim 16 wherein said polymer comprises styrene.

19. The method of claim 15 further comprising heating a reaction mixture comprising the nanotube dithioesters and the polymer.

20. The method of claim 19 further comprising:

cooling the reaction mixture; and

adding tetrahydrofuran to the reaction mixture.

21. The method of claim 19 further comprising adding the reaction mixture to methanol and precipitating a polymerized nanocomposite material.