Modification of nanotubes oxidation with peroxygen compounds
AssigneeHyperion Catalysis International, Inc.
InventorsChunming Niu, David Moy, Jun Ma, Asif Chishti
Life of this patent
Estimating the term…
Abstract
A method of chemically modifying carbon nanotubes having a diameter less than one micron comprising: contacting the nanotubes with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids and organic hydroperoxides, or a salt thereof, under oxidation conditions and thereby producing modified carbon nanotubes. Oxidation of the nanotubes increases the degree of dispersion of aggregates of nanotubes and aids in the disassembling of such aggregates. The dispersed nanotubes are used to prepare rigid structures and can be used in electrodes and capacitors.
Claims38
A method of chemically modifying carbon nanotubes having a diameter less than one micron comprising:
- contacting the nanotubes with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids and organic hydroperoxides, or a salt thereof, at a temperature range between 5° C. to about 150° C. under oxidation conditions and thereby producing modified carbon nanotubes.
A method of chemically modifying carbon nanotubes having a diameter of from 3.5 to 75 nanometers, said nanotubes being substantially cylindrical, having a plurality of graphitic layers that are substantially paralleled to the axis of the nanotubes, a length to diameter ratio greater than 5 and substantially free of a continuous pyrolitically deposited carbon overcoat, said method comprising:
- suspending said nanotubes in a liquid medium and contacting the nanotubes, under oxidizing conditions, with a peroxygen compound selected from the group consisting of:
- (a) an inorganic peroxoacid;
- (b) a peroxycarboxylic acid of the formula Q(C(O)OOH)n;
- (c) a hydroperoxide of the formula Q(OOH)n;
- (d) salts of (a), (b) or (c) and (e) combinations of any of (a), (b), (c) or (d), wherein Q is an alkyl, aralkyl, cycloalkyl, aryl or heterocyclic group, said group having from 1 to 12 carbon atoms, and n is 1 or 2.
A method of partially disassembling an aggregate of carbon nanotubes comprising the steps of:
- contacting an aggregate of nanotubes, in a liquid medium, with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids, organic hydroperoxides and hydrogen peroxide, or a salt thereof, under conditions adapted to partially disassemble said aggregate.
A method of at least partially dispersing carbon nanotubes contained in an aggregate thereof comprising the steps of:
- contacting the nanotubes with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids, organic hydroperoxides and hydrogen peroxide, or a salt thereof, under oxidation conditions at a temperature range between 5 degrees C. to about 150 degrees C. and thereby achieving a measurable increase in the degree of dispersion of said nanotubes as evidenced by one or more physical properties thereof.
A method of decreasing the degree of aggregation of an aggregate of carbon nanotubes comprising the steps of:
- contacting the nanotubes with a peroxygen compound selected from the group consisting of organic peroxyacids, inorganic peroxoacids and organic hydroperoxides, or a salt thereof in a liquid medium, under oxidation conditions and thereby at least partially dispersing said aggregates in said liquid medium, said dispersion being evidenced by (a) an increase in the size of said aggregate or decrease in the density thereof, or (b) an unwinding of nanotubes on the exterior of said aggregate from the main body of said aggregate, or (c) separation of one or more individual nanotubes from the body of said aggregate.
A method of making a mat of carbon nanotubes comprising the steps of:
- (a) suspending an aggregate of carbon nanotubes in a liquid medium;
- (b) chemically modifying the aggregate by subjecting it to oxidation in the presence of a peroxygen compound selected from the group consisting of:
- (a) an inorganic peroxoacid;
- (b) a peroxycarboxylic acid of the formula Q(C(O)OOH)n;
- (c) a hydroperoxide of the formula Q(OOH)n;
- (d) salts of (a), (b) or (c) and (e) combinations of any of (a), (b), (c) or (d), wherein Q is an alkyl, aralkyl, cycloalkyl, aryl or heterocyclic group having from 1 to 12 carbon atoms, and n is 1 or 2, and thereby increasing the dispersion thereof;
- and
- filtering and drying said dispersed nanotubes to form a mat.
A method for producing a network of treated carbon nanotubes comprising:
- (a) contacting said carbon nanotubes with a peroxygen compound selected from the group consisting of:
- (a) an inorganic peroxoacid;
- (b) a peroxycarboxylic acid of the formula Q(C(O)OOH)n;
- (c) a hydroperoxide of the formula Q(OOH)n;
- (d) salts of (a), (b) or (c) and (e) combinations of any of (a), (b), (c) or (d), wherein Q is an alkyl, aralkyl, cycloalkyl, aryl or heterocyclic group having from 1 to 12 carbon atoms, and n is 1 or 2, under oxidation conditions sufficient to introduce oxygen containing functional groups onto the surface of said carbon nanotubes;
- (b) contacting said treated nanotubes with a reactant suitable for adding a secondary functional group to the surface thereof;
- and
- (c) further contacting said secondarily functionalized nanotubes with an effective amount of crosslinking agent.
A method for preparing a rigid porous structure comprising oxygen-containing functionalized nanotubes comprising:
- (a) oxidizing a plurality of carbon nanotubes with a peroxygen compound selected from the group consisting of:
- (a) an inorganic peroxoacid;
- (b) a peroxycarboxylic acid of the formula Q(C(O)OOH)n;
- (c) a hydroperoxide of the formula Q(OOH)n;
- (d) salts of (a), (b) or (c), and (e) combinations of any of (a), (b), (c) or (d), wherein Q is an alkyl, aralkyl, cycloalkyl, aryl or heterocyclic group having from 1 to 12 carbon atoms, and n is 1 or 2,;
- (b) dispersing said oxidized nanotubes in a medium to form a suspension;
- (c) separating said medium from said suspension to form a rigid porous structure of intertwined oxygen-containing nanotubes.
A method of making an electrode comprising carbon nanotubes comprising the steps of:
- (a) suspending carbon nanotubes in a liquid medium;
- (b) chemically modifying the nanotubes by subjecting them to oxidation in the presence of a peroxygen compound selected from the group consisting of:
- (a) an inorganic peroxoacid;
- (b) a peroxycarboxylic acid of the formula Q(C(O)OOH)n;
- (c) a hydroperoxide of the formula Q(OOH)n;
- (d) salts of (a), (b) or (c), and (e) combinations of any of (a), (b), (c) or (d), wherein Q is an alkyl, aralkyl, cycloalkyl, aryl or heterocyclic group having from 1 to 12 carbon atoms, and n is 1 or 2, and thereby increasing the dispersion thereof;
- (c) filtering said dispersion to form a mat of modified carbon nanotubes;
- and
- (d) forming an electrode from said mat.
Dependencies are inferred from the claim text.