Expanded graphite and products produced therefrom
AssigneeBoard of Trustees operating Michigan State University
InventorsLawrence Drzal, Hiroyuki Fukushima
Life of this patent
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Abstract
Graphite nanoplatelets of expanded graphite and composites and products produced therefrom are described. The preferred method of expanding the graphite is by microwaves or other radiofrequency wave treatment of intercalated graphite. The expanded graphite is preferably then crushed to nanometer (substantially all 200 microns or less). The expanded graphite is used in polymer composites. The expanded graphite is particularly useful for batteries, anodes and fuel cells.
Claims18
1- A composite material which comprises:
- (a) an expanded graphite wherein a graphite precursor which is acid intercalated has been heated with a first polymer to produce the expanded graphite and to remove the acid;
- and
- (b) a second polymer having the first polymer expanded graphite dispersed therein.
2- A composite material which comprises:
- (a) an expanded graphite wherein a graphite precursor which is acid intercalated has been heated with a first polymer to produce the expanded graphite and to remove the acid;
- and
- (b) a second polymer having the first polymer expanded graphite particles dispersed therein, wherein the composite material contains up to about 50% by volume of the graphite.
3- The composite material of claim 2 wherein the expanded graphite platelets is present in an amount that composite material is conductive.
4- The composite material of any one of claims 1, 2 or 3 wherein the polymers are a thermoplastic or thermoset polymer.
5-7. (canceled)
8- The composite material of any one of claims 1, 2, or 3 wherein the polymers are an epoxy resin.
9- The composite material of any one of claims 1, 2 or wherein the precursor graphite has been treated with fuming oxy acid and then heated with the first polymer form the expanded graphite and to remove the acid.
10- The composite material of any one of claims 1, 2 or 3 wherein the polymers are thermoplastic and is selected from the group consisting of polyamides, proteins, polyesters, polyethers, polyurethanes, polysiloxanes, phenol-formaldehydes, urea-formaldehydes, melamine-formaldehydes, celluloses, polysulfides, polyacetals, polyethylene oxides, polycaprolactams, polycaprolactons, polylactides, polyimides, and polyolefins.
11- The composite material of any one of claims 1, 2 or 3 which contains less than about 8% by weight of the expanded graphite.
12- A method for preparing a shaped composite material which comprises:
- (a) providing a mixture of a finely divided expanded graphite wherein a graphite precursor which is acid intercalated has been heated with a first polymer to produce the expanded graphite and to remove the acid and a second polymer with the first polymer expanded graphite dispersed therein;
- and
- (b) forming the shaped composite material from the mixture.
13- A method for preparing a shaped composite material which comprises:
- (a) providing a mixture of an expanded graphite having single platelets wherein a graphite precursor which is acid intercalated has been heated with a first polymer to produce a first polymer expanded graphite and to release the acid wherein the graphite precursor has a length less than about 200 microns and a thickness of less than about 0.1 microns and a second polymer with the first polymer expanded graphite dispersed therein, wherein the composite material contains up to about 50% by volume of the first polymer expanded graphite platelets;
- (b) forming the shaped composite material from the mixture.
14- The method of claims 12 or 13 wherein the first polymer expanded graphite is provided in the second polymer in an amount sufficient to render the shaped composite conductive.
15- The method of claims 12 or 13 wherein the polymers are a thermoplastic or thermoset polymer.
16-17. (canceled)
18- The method of claims 12 or 13 wherein an graphite precursor has been treated with a fuming oxy acid and heated with the first polymer material to provide the first polymer expanded graphite and to remove at least a portion of the acid.
19- The method of any one of claims 12 or 13 wherein the second polymer is a curable thermoset resin which is mixed with the first polymer expanded graphite and cured.
20- The method of claims 12 or 13 wherein the shaped composite material contains less than 8% by weight of the expanded graphite.
21-28. (canceled)