Polyvinylidene fluoride composites and methods for preparing same
View Patent ↗An electrically conductive composite comprising a polyvinylidene fluoride polymer or copolymer and carbon nanotubes is provided. Preferably, carbon nanotubes may be present in the range of about 0.5-20% by weight of the composite. The composites are prepared by dissolving the polymer in a first solvent to form a polymer solution and then adding the carbon nanotubes into the solution. The solution is mixed using an energy source such as a sonicator or a Waring blender. A precipitating component is added to precipitate out a composite comprising the polymer and the nanotubes. The composite is isolated by filtering the solution and drying the composite.
1. A method for preparing an electrically conductive composite comprising the step of mixing a copolymer or terpolymer of vinylidene fluoride and another monomer selected from the group consisting of hexafluoropropylene, styrene, propylene, chlorotrifluoroethylene, tetrafluoroethylene, and olefins with carbon nanotubes at temperatures greater than 200° C. to form an electrically conductive composite, wherein the electrically conductive composite has a bulk resistivity of less than about 10 ohm-cm.
2. The method of claim 1 , further comprising the step of molding said electrically conductive composite.
3. The method of claim 1 , wherein the mixing occurs in the mixing head of a mixer.
4. The method of claim 1 , wherein the electrically conductive composite comprises about 0.01-30 weight % carbon nanotubes.
5. The method of claim 1 , wherein the electrically conductive composite comprises about 0.5-20 weight% carbon nanotubes.
6. The method of claim 1 , wherein the electrically conductive composite comprises about 13 to 20 weight% carbon nanotubes.
7. The method of claim 1 , wherein the electrically conductive composite comprises about 1-15 weight% carbon nanotubes.
8. The method of claim 1 , wherein the electrically conductive composite has a bulk resistivity of less than about 1 ohm-cm.
9. The method of claim 1 , wherein the electrically conductive composite has a bulk resistivity of between about 0.02 and 0.08 ohm-cm.
10. The method of claim 1 , wherein the electrically conductive composite further comprises a filler.
11. The method of claim 10 , wherein the filler comprises graphite.
12. The method of claim 1 , wherein the monomer is present in an amount less than about 90% by weight of the copolymer.
13. The method of claim 1 , wherein the monomer is present in an amount between about 1 to 70% by weight of the copolymer.
14. The method of claim 1 , wherein the monomer is present in an amount between about 10 to 50% by weight of the copolymer.