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 steps of:
(a) dissolving a polymer selected from the group consisting of polyvinylidene fluoride and copolymer of vinylidene fluoride and another monomer in a solvent to form a solution;
(b) dispersing nanotubes in said solution; and
(c) adding a precipitating component into said solution to precipitate a composite comprising said polymer and said nanotubes.
2. The method of claim 1 , further comprising the step of filtering said solution to isolate said composite.
3. The method of claim 1 , further comprising the step of drying said composite.
4. The method of claim 1 , wherein said dispersing step is performed with a sonicator or an ultrasonic sonifier.
5. The method of claim 1 , wherein said solvent is acetone.
6. The method of claim 1 , wherein said solvent is selected from the group consisting of tetrahydrofuran, methyl ethyl ketone, dimethyl formamide, dimethyl acetamide, tetramethyl urea, dimethyl sulfoxide, trimethyl phosphate, 2-pyrrolidone, butyrolacetone, isophorone, and carbitor acetate.
7. The method of claim 1 , wherein said precipitating component is water.
8. The method of claim 1 , wherein said monomer is selected from the group consisting of hexafluoropropylene, polystyrene, polypropylene, chiorotrifluoroethylene, tetrafluoroethylene, terpolymers or olefins.
9. A method for making bipolar plates comprising the steps of:
(a) dissolving a polymer selected from the group consisting of polyvinylidene fluoride and copolymer of vinylidene fluoride and another monomer in a solvent to form a solution;
(b) dispersing said nanotubes in said solution;
(c) adding a precipitating component into said solution to precipitate out a composite comprising said polymer and said nanotubes;
(d) isolating said composite;
(e) extruding said composite; and
(f) engraving one or more flow channels on said composite.
10. The method of claim 9 , wherein said monomer is selected from the group consisting of hexafluoropropylene, polystyrene, polypropylene, chlorotrifluoroethylene, tetrafluoroethylene, terpolymers or olefins.