Composite materials with magnetically aligned carbon nanoparticles and methods of preparation

Patent metadata

Field	Value
Publication number	US-9892835-B2
Application number	US-201414178948-A
Country	US
Kind code	B2
Filing date	Feb 12, 2014
Priority date	Sep 16, 2010
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

The present invention relates to magnetically aligned carbon nanoparticle composites and methods of preparing the same. The composites comprise carbon nanoparticles, host material, magnetically sensitive nanoparticles and surfactant. The composites may have enhanced mechanical, thermal, and/or electrical properties.

First claim

What is claimed is:

1. A method for preparing magnetically aligned carbon nanoparticle composite compositions comprising:
preparing a host material in a liquid state;
adding carbon nanoparticles, magnetically sensitive nanoparticles, and surfactant to a solvent and physically agitating the carbon nanoparticles, magnetically sensitive nanoparticles, and surfactant in the solvent, and evaporating said solvent to form a mixture, wherein said surfactant attaches to the carbon nanoparticles thereby connecting the carbon nanoparticles with the magnetically sensitive nanoparticles by electrostatic attraction, wherein the magnetically sensitive nanoparticles are added in an amount between about 0.01 wt. % and about 10 wt. %; wherein the surfactant is added in an amount between about 0.01 wt. % and about 60 wt. %; and wherein said carbon nanoparticles are not surface functionalized;
adding the mixture of carbon nanoparticles, magnetically sensitive nanoparticles, and surfactant to the liquid host material to form a liquid composite;
applying a magnetic field to the liquid composite, wherein the magnetic field has a strength of between about 0.01 kG and about 1 TG; and
solidifying the liquid composite to form a solid composite; wherein the solid composite has increased tensile strength of at least about 10% relative to a composite having the same composition without magnetic alignment when the compositions are tested according to ASTM D 882-97.

2. The method of claim 1 , further comprising optionally, physically agitating the liquid composite, wherein the physical agitation comprises mixing, stirring, milling, ultrasonication, or a combination thereof; wherein the surfactant has a net negative charge and the pH value is more than the pHpzc of magnetically sensitive nanoparticles, or the surfactant has a net positive charge and the pH value is less than the pHpzc of magnetically sensitive nanoparticles; and wherein the composite has increased tensile strength of at least about 15% when tested according to ASTM D 882-97 and/or increased electrical conductivity of at least about 1 order of magnitude relative to a composite having the same composition without magnetic alignment.

3. The method of claim 1 , wherein the host material is selected from the group consisting of thermoset polymers, thermoplastic polymers, ceramics, metalloids, alloys, and combinations thereof, and is added in an amount to constitute between about 30 wt. % and about 99.9 wt. %; wherein the carbon nanoparticles are added in an amount between about 0.01 wt. % and about 10 wt. %; and wherein the ratio of nanoparticles to surfactant is between about 1:1 and about 1:20.

4. The method of claim 1 , wherein the carbon nanoparticles comprises at least one of the following graphene, fullerene, carbon nanotube, carbon nanotube fiber, or carbon fiber.

5. The method of claim 1 , wherein the magnetically sensitive nanoparticles comprise at least one of the following cobalt, vanadium, manganese, niobium, iron, nickel, copper, silicon, titanium, germanium, zirconium, tin, magnetically sensitive rare earth metals, oxides of the aforementioned metals, or combinations and alloys of the aforementioned metals and/or metal oxides.

6. The method of claim 1 , wherein the magnetically sensitive nanoparticles are selected from the group consisting of NdFeB, Fe Fe 2 O 3 , Fe 3 O 4 , Ni, NiO, Ni 2 O 3 , Co, CoO, Co 2 O 3 , and Co 3 O 4 , and combinations thereof.

7. The method of claim 1 , wherein the surfactant has a net negative charge and the pH value is more than the pHpzc of magnetically sensitive nanoparticles, or the surfactant has a net positive charge and the pH value is less than the pHpzc of magnetically sensitive nanoparticles.

8. The method of claim 1 , wherein the surfactant has a net negative charge and comprises sodium dodecylbenzene sulfonate or sodium dodecyl sulfate, or has a net positive charge and comprises cetyl trimethylammonium bromide.

9. The method of claim 1 , wherein the ratio of nanoparticles to surfactant is between about 1:3 and about 1:15.

10. The method of claim 1 , wherein the liquid composite has increased tensile strength of at least about 15% when tested according to ASTM D 882-97 and/or increased electrical conductivity of at least about 1 order of magnitude relative to a composite having the same composition without magnetic alignment.

11. The method of claim 1 , wherein the host material is selected from the group consisting of a thermoplastic, a thermoset, an elastomer, a polymer fiber, a silicone, and combinations thereof.

12. The method of claim 1 , wherein the magnetic field is applied during or prior to the solidifying step.

13. The method of claim 12 , wherein the liquid state of the host material is a resin that can be solidified by curing, or a polymer solution that can be solidified by solvent evaporation, or a molten polymer that can be solidified by cooling, or a monomer or oligomer that can be solidified by in-situ polymerization, and combinations thereof.

14. The method of claim 1 , wherein the steps are performed sequentially.

15. The method of claim 1 , wherein the ratio of nanoparticles to surfactant is between about 1:1 and about 1:20.

Assignees

• South Dakota Board Of Regents
• Georgia Tech Res Inst

Inventors

• Hong Haiping
• Peterson G P Bud
• Salem David R

Classifications

• C08K2201/01

  Magnetic additives · CPC title

• C08K2201/011

  Nanostructured additives · CPC title

• C08K2003/2272

  Ferric oxide (Fe2O3) · CPC title

• Y10S977/742

  Carbon nanotubes, CNTs · CPC title

• C08K2003/2275

  Ferroso-ferric oxide (Fe3O4) · CPC title