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WO2022183049A1 - Dispersions comprenant des nanotubes à grande surface et des nanotubes de carbone discrets - Google Patents

Dispersions comprenant des nanotubes à grande surface et des nanotubes de carbone discrets Download PDF

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Publication number
WO2022183049A1
WO2022183049A1 PCT/US2022/017992 US2022017992W WO2022183049A1 WO 2022183049 A1 WO2022183049 A1 WO 2022183049A1 US 2022017992 W US2022017992 W US 2022017992W WO 2022183049 A1 WO2022183049 A1 WO 2022183049A1
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Prior art keywords
carbon nanotubes
dispersion
surface area
oxidized
nanotubes
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Inventor
Kurt W. Swogger
Clive P. Bosnyak
Malcolm Francis FINLAYSON
Jerry Gazda
Vinay BHAT
Nancy Henderson
Emily Barton Cole
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Molecular Rebar Design LLC
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Molecular Rebar Design LLC
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Priority claimed from US17/187,658 external-priority patent/US12234368B2/en
Application filed by Molecular Rebar Design LLC filed Critical Molecular Rebar Design LLC
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites

Definitions

  • the present invention is directed to novel compositions and methods for producing dispersions of high surface area nanotubes and discrete carbon nanotubes.
  • Carbon nanotubes can be classified by the number of walls in the tube, singlewall, double wall and multiwall. Each wall of a carbon nanotube can be further classified into chiral or non-chiral forms. Carbon nanotubes are currently manufactured as agglomerated nanotube balls or bundles. Use of carbon nanotubes as a reinforcing agent in polymer composites is an area in which carbon nanotubes are predicted to have significant utility. However, utilization of carbon nanotubes in these applications has been hampered due to the general inability to reliably produce individualized carbon nanotubes. To reach the full potential of performance enhancement of carbon nanotubes as composites in polymers the aspect ratio, that is length to diameter ratio, should be substantially greater than 40. The maximum aspect ratio for a given tube length is reached when each tube is fully separated from another. A bundle of carbon nanotubes, for example, has an effective aspect ratio in composites of the average length of the bundle divided by the bundle diameter.
  • carbon nanotubes may be shortened extensively by aggressive oxidative means and then dispersed as individual nanotubes in dilute solution. These tubes have low aspect ratios not suitable for high strength composite materials.
  • Carbon nanotubes may also be dispersed in very dilute solution as individuals by sonication in the presence of a surfactant.
  • Illustrative surfactants used for dispersing carbon nanotubes in aqueous solution include, for example, sodium dodecyl sulfate, or cetyltrimethyl ammonium bromide.
  • solutions of individualized carbon nanotubes may be prepared from polymer-wrapped carbon nanotubes.
  • Individualized single-wall carbon nanotube solutions have also been prepared in very dilute solutions using polysaccharides, polypeptides, water-soluble polymers, nucleic acids, DNA, polynucleotides, polyimides, and polyvinylpyrrolidone.
  • the dilution ranges are often in the mg/liter ranges and not suitable for commercial usage.
  • Coatings comprising dispersed carbon nanotubes and epoxy are highly desirable, especially in weather exposure conditions. Such conditions include salt water contact and/or high ultraviolet (UV) exposure.
  • weather exposure conditions include salt water contact and/or high ultraviolet (UV) exposure.
  • a prerequisite for the good contact and adhesion of the coatings is a fine dispersion of the epoxy particles in the formulations used for the coating in each case.
  • the present invention relates to an epoxy dispersion suitable for coatings.
  • the dispersion comprises at least one epoxy resin and a plurality of oxidized, discrete carbon nanotubes, wherein the discrete carbon nanotubes comprise an interior and exterior surface, each surface comprising an interior surface oxidized species content and an exterior surface oxidized species content, wherein the interior surface oxidized species content differs from the exterior surface oxidized species content by at least 20%, and as high as 100% and are present in the range of from about 0.1 to about 30% by weight based on the total weight of the dispersion.
  • the dispersion comprises an interior surface oxidized species content less than the exterior surface oxidized species content.
  • the dispersion can comprise an interior surface oxidized species content up to 3 weight percent relative to carbon nanotube weight, preferably from about 0.01 to about 3 weight percent relative to carbon nanotube weight, more preferably from about 0.01 to about 2, most preferably from about 0.01 to about 1.
  • the discrete carbon nanotubes of the dispersions preferably have an aspect ratio that is bimodal.
  • the dispersion can further comprise at least one epoxy resin diluent, preferably wherein the epoxy resin diluent is selected from the group consisting of a diglycidyl ether of cis-l,3-cyclohexanedimethanol, a diglycidyl ether of trans-1,3- cyclohexanedimethanol, a diglyddyl ether of cis-l,4-cyclohexanedimethanol, a diglycidyl ether of trans- 1,4-cyclohexanedimethanol, a monoglycidyl ether of cis-1,3- cyclohexanedimethanol, a monoglycidyl ether of trans-l,3-cyclohexanedimethanol, a monoglycidyl ether of cis- 1,4-cyclohexanedimethanol, a monoglycidyl ether of trans-1,4- cyclohexanedimethanol
  • the dispersions can further comprise a compound comprising zinc, phosphate, chromate, phosphosilicate, borosilicate, borate, nitrate, or mixtures thereof, especially wherein the compound comprising zinc is selected from the group consisting of zinc, zincoxide, zinc-hydroxide, zinc-sulfide, zinc-selenide, zinc-telluride, zinc-salts, and mixtures thereof.
  • the compound conyrising zinc is present in the range from about 0.1% to about 30% by weight based on the total weight of the dispersion.
  • the discrete carbon nanotubes in the dispersion can have an aspect ratio of 25 to 500.
  • At least 70 percent by weight of the carbon nanotubes in the dispersions are discrete.
  • the dispersions can further comprise at least one dispersant, preferably wherein the dispersant is selected from the group consisting of hydrophobic polymers, anionic polymers, non-ionic polymers, cationic polymers, ethylene oxide containing polymers, propylene oxide containing polymers, amphiphilic polymers, fatty adds, and mixtures thereof.
  • the dispersions can further comprise an additive selected from the group consisting of an epoxy resin diluent, a compound comprising zinc, a dispersant, and mixtures thereof.
  • the oxidized, discrete carbon nanotubes of the dispersions comprise an oxidation species selected from carboxylic acid or a derivative carbonyl containing species wherein the derivative carbonyl species is selected from ketones, quaternary amines, amides, esters, acyl halogens, and metal salt, preferably wherein the oxidized, discrete carbon nanotubes comprise an oxidation species selected from hydroxyl or derived from hydroxyl containing species.
  • the dispersions can further comprise an acrylic polymer, a silicone polymer, or a mixture thereof.
  • the plurality of oxidized, discrete carbon nanotubes of the dispersions preferably comprise multiwall carbon nanotubes.
  • the dispersions can further comprise at least one organic inhibitor selected from the group consisting of azoles, calcium alky 1-ary 1 sulfonates, diamines, and metal salts of dinonylnapathalene sulphonates.
  • Another embodiment of the invention comprises a catheter comprising the dispersions, wherein the epoxy has been at least partially cured.
  • Another embodiment of the inventions comprises a coating comprising the dispersions, wherein the epoxy has been at least partially cured.
  • Yet another embodiment of the invention is a composition
  • a composition comprising a plurality of discrete carbon nanotube fibers having an aspect ratio of from about 25 to about 500, and at least one natural or synthetic elastomer, and optionally at least one filler.
  • the composition can have carbon nanotube fibers with an oxidation level of from about 3 weight percent to about 15 weight percent, or from about 0.5 weight percent up to about 4, or up to about 3, or up to 2 weight percent based on the total weight of discrete carbon nanotubes.
  • the carbon nanotube fibers comprise preferably of about 1 weight percent to about 30 weight percent of the composition and the composition is in the form of free flowing particles or a bale.
  • the composition is further comprising of at least one surfactant or dispersing aid.
  • the composition can comprise the natural or synthetic elastomer selected from the group consisting of, but not limited to, natural rubbers, polyisobutylene, polybutadiene and styrenebutadiene rubber, butyl rubber, polyisoprene, styrene-isoprene rubbers, styrene-isoprene rubbers, ethylene propylene diene rubbers, silicones, polyurethanes, polyester-polyethers, hydrogenated and non-hydrogenated nitrile rubbers, halogen modified elastomers, flouro- elastomers, and combinations thereof.
  • the composition contains fibers that are not entangled as a mass and are uniformly dispersed in the elastomer.
  • the invention is a process to form a carbon nanotube fiber/elastomer composite comprising the steps of: (a) selecting discrete carbon nanotube fibers having an aspect ratio of from 25 to 500, (b) blending the fibers with a liquid to form a liquid/fiber mixture, (c) optionally adjusting the pH to a desired level, (d) agitating the mixture to a degree sufficient to disperse the fibers to form a dispersed fiber mixture, (e) optionally combining the dispersed fiber mixture with at least one surfactant, (f) combining the dispersed fiber mixture with at least one elastomer at a temperature sufficient to incorporate the dispersed fiber mixture to form a carbon nanotube fiber/elastomer composite/liquid mixture, (g) isolating the resulting carbon nanotube fiber/elastomer composite from the liquid.
  • the carbon nanotube fibers comprise from about 1 to about 30 weight percent of the fiber/elastomer composite of (g).
  • the liquid is aqueous based.
  • the agitating step (d) comprises sonication.
  • the elastomer is selected from, but not limited to, the natural or synthetic elastomer selected from the group consisting of, but not limited to, natural rubbers, polyisobutylene, polybutadiene and styrene-butadiene rubber, butyl rubber, polyisoprene, styrene-isoprene rubbers, styrene-isoprene rubbers, ethylene propylene diene rubbers, silicones, polyurethanes, polyester-polyethers, hydrogenated and non-hydrogenated nitrile rubbers, halogen modified elastomers, fluoroelastomers, and combinations thereof.
  • the composition is further comprising sufficient natural or synthetic elastomer to form a formulation compris
  • the invention is a formulation in the form of a molded or fabricated article, such as a tire, a hose, a belt, a seal and a tank track pad, wheel, bushings or backer plate components.
  • the invention is a nanotubes/elastomer composite further comprising of filler or fillers such as carbon black and/or silica, and wherein a molded film comprising the composition has a tensile modulus at 5 percent strain of at least about 12 MPa.
  • the composition comprising of carbon black, and wherein a molded film comprising the composition has a tear property of at least about 0.8 MPa.
  • a carbon nanotube/elastomer composition further comprising of filler, and where in a molded film comprising the composition has a tensile modulus at 5% strain of at least 8 MPa.
  • carbon nanotube fiber/elastomer composite wherein the carbon nanotube fibers are discrete fibers and comprise from about 10 to about 20 weight percent fibers and wherein the elastomer comprises a styrene copolymer rubber.
  • in still another embodiment of the invention is a method for obtaining individually dispersed carbon nanotubes in rubbers and/or elastomers comprising (a) forming a solution of exfoliated carbon nanotubes at pH greater than or equal to about 7, (b) adding the solution to a rubber or elastomer latex to form a mixture at pH greater than or equal to about 7, (c) coagulating the mixture to form a concentrate, (d) optionally incorporating other fillers into the concentrate, and (e) melt-mixing said concentrate into rubbers and/or elastomers to form elastomeric composites.
  • the carbon nanotubes comprise less than or equal to about 2 percent by weight of the solution.
  • the coagulation step comprises mixing with acetone.
  • the coagulation step comprises drying the mixture.
  • the coagulation step comprises adding at least one acid to the mixture at pH less than or equal to about 4.5 together with at least one monovalent inorganic salt.
  • the mixture has divalent or multivalent metal ion content of less than about 20,000 parts per million, preferably less than about 10,000 parts per million and most preferably less than about 1,000 parts per million.
  • Another aspect of this invention are coagulating methods/agents are those that enable the carbon nanotube to be non-ordered on the surface of the elastomer latex particle and together are substantially removable from the liquid mixture.
  • a further aspect of this invention is a method to reduce or remove surfactants in the latex/carbon nanotube fiber composite system organic molecules of high water solubility such as acetone, denatured alcohol, ethyl alcohol, methanol, acetic acid, tetrahydrofuran.
  • Another aspect of this invention is to select coagulating methods that retain surfactant in the latex/carbon nanotube fiber material which includes coagulating methods such as sulfuric acid and inorganic monovalent element salt mixtures, acetic acid and monovalent element salt mixtures, formic acid and inorganic monovalent element salt mixtures, air drying, air spraying, steam stripping and high speed mechanical agitation.
  • coagulating methods such as sulfuric acid and inorganic monovalent element salt mixtures, acetic acid and monovalent element salt mixtures, formic acid and inorganic monovalent element salt mixtures, air drying, air spraying, steam stripping and high speed mechanical agitation.
  • Lithium ion batteries are used extensively for portable electronic equipment and batteries such as lithium ion and lead-acid are increasingly being used to provide electrical back-up for wind and solar energy.
  • the salts for the cathode materials in lithium ion batteries are generally known to have poor electrical conductivity and poor electrochemical stability which results in poor cycling (charge/discharge) ability.
  • Both cathode and anode materials in many battery types such as lithium ion based batteries exhibit swelling and deswelling as the battery is charged and discharged. This spatial movement leads to further separation of some of the particles and increased electrical resistance.
  • the high internal resistance of the batteries, particularly in large arrays of lithium ion batteries such as used in electric vehicles, can result in excessive heat generation leading to runaway chemical reactions and fires due to the organic liquid electrolyte.
  • Lithium primary batteries consist, for example, of lithium, poly(carbon monofluoride) and lithium tetrafluoroborate together with a solvent such as gammabutyrolactone as an electrolyte. These lithium primary batteries have excellent storage lifetimes, but suffer from only being able to provide low current and the capacity is about one tenth of what is theoretically possible. This is ascribed to the poor electrical conductivity of the poly(carbon monofluoride). In some cases a portion manganese dioxide is added to aid in the electrical conductivity and power of the lithium battery.
  • Binders such as polyacrylic acid (PAA), for cathodes, polystyrene butadiene), carboxymethylcellulose (CMC), styrene-butadiene (SBR), for anodes, and particularly poly vinylidene fluoride (PVDF) for cathodes and anodes, are used in lithium based batteries to hold the active material particles together and to maintain contact with the current collectors i.e., the aluminum (Al) or the copper (Cu) foil.
  • PAA and SBR are used as aqueous suspensions or solutions and are considered more environmentally benign than organic solvent based systems such as n-methyl 2 pyrrolidone (NMP) with PVDF.
  • a cathode electrode of a lithium ion battery is typically made by mixing active material powder, such as lithium iron phosphate, binder powder, i.e., high molecular weight PVDF, solvent such as NMP if using PVDF, and additives such as carbon black, into a slurry (paste) and pumping this slurry to a coating machine.
  • active material powder such as lithium iron phosphate, binder powder, i.e., high molecular weight PVDF, solvent such as NMP if using PVDF, and additives such as carbon black
  • An anode electrode for a lithium ion battery is made similarly by typically mixing griphite, or other materials such as silicon, as die active material, together with the binder, solvent and additives.
  • the coating machines spread the mixed slurry (paste) on both sides of the Al foil for the cathode and Cu foil for the anode.
  • the coated foil is subsequently calendared to make the electrode thickness more uniform, followed by a slitting operation for
  • the positive electrode can consist of a wet powder mix of manganese dioxide, a powdered carbon black and electrolyte such as ammonium chloride and water.
  • the carbon black can add electrical conductivity to the manganese dioxide particles, but is needed at high weight percentages in tire range about 10 to 50% by weight of manganese dioxide.
  • anode can be made from carbon particles together with a binder to provide higher specific capacity (capacity per unit weight).
  • the anode of a zinc-carbon battery is often a carbon rod typically made of compressed carbon particles, griphite and a binder such as pitch.
  • the carbon particle anodes tend to have poor mechanical strength leading to fracture under conditions of vibration and mechanical shock.
  • the characteristics of the cathode, anode, or binder material are important for both manufacturing and performance of the battery. Some of these characteristics of relevance are electrical and ionic conductivity, tensile strength and extensibility, adhesion to particles as well as the foils, and swelling of electrolyte. Improvement of electrical and ionic conductivity is needed for improved battery capacity and power. Materials such as lithium manganese oxide for cathodes and silicon particles for anodes exhibit much lower practical specific capacity than theoretically available. A higher electrical and ionic conductivity binder material would be most beneficial to achieve specific capacities closer to their theoretical values. It is desirable to improve the tensile and adhesive strength of binders so that less binder material can be employed and also improve the battery cycling lifetime.
  • the layer thickness of the binder can be as thin as 50 to 100 nanometers. This layer thickness precludes uniform distributions of carbon particles of sizes larger than the binder layer thickness.
  • multiwall carbon nanotubes as usually made in a gas phase reactor consist of bundles with diameters ranging from about 50 to 500 microns in diameter and would therefor reside only at the interstitial spaces between the particles.
  • Impurities such as non-lithium salts, iron, and manganese to name a few
  • the binder can also be highly deleterious to battery performance.
  • high purity of the binder material, and other additives comprising the binder material is an important factor to minimize unwanted side reactions in the electrochemical process.
  • the total iron in the manganese dioxide is less than 100 ppm to prevent hydrogen gassing at the anode.
  • the impurity residue of the nanotubes employed herein may be less than about 5 weight percent, or less than about 2 weight percent, or less than about 1 weight percent
  • lines of conductive paste ink are screen-printed onto solar panel modules.
  • the binders are usually polymer based for improved printability, such as ETHOCELTM (Dow Chemical Company). During the burning off of the polymer and cooling the lines can crack due to shrinkage forces and so increase impedance. It is highly desirable to have a more robust conductive paste ink to prevent cracking during heating and cooling.
  • ionic liquids for example, ethyl-methyl-imidazolium bis- (trifhioromethanesulfonyl)-imide (EMI-TFSI), and solid polymer, sometimes with additional additives, for example, polyethylene oxide with titanium dioxide nanoparticles, or inorganic solid electrolytes such aass a ceramic or glass of the type glass ceramics, (LTAP).
  • ionic liquids for example, ethyl-methyl-imidazolium bis- (trifhioromethanesulfonyl)-imide (EMI-TFSI)
  • solid polymer sometimes with additional additives, for example, polyethylene oxide with titanium dioxide nanoparticles, or inorganic solid electrolytes such aass a ceramic or glass of the type glass ceramics, (LTAP).
  • the electrical conductivity values of organic liquid electrolytes are in the general range of 10 -2 to 10 -1 S/cm
  • Polymer electrolytes have electrical conductivity values in the range of about 10 -7 to 10 -4 S/cm, dependent on temperature, whereas inorganic solid electrolytes generally have values in the range 10 -8 to 10 -5 S/cm At room temperature most polymer electrolytes have electrical conductivity values around 10 -5 S/cm
  • the low ionic conductivities of polymer and inorganic solid electrolytes are presently a limitation to their general use in energy storage and collection devices. It is thus highly desirable to improve the conductivity of electrolytes, and particularly with polymer and inorganic electrolytes because of their improved flammability characteristics relative to organic liquids. Also, it is desirable to improve the mechanical strength of solid electrolytes in battery applications requiring durability in high vibration or mechanical shock environments, as well as in their ease of device fabrication.
  • the electrolyte is typically potassium hydroxide.
  • Alkaline batteries are known to have significantly poorer capacity on high current discharge than low current discharge. Electrolyte ion transport limitations as well as polarization of the zinc anode are known reasons for this. An increase in the electrolyte ion transport is highly desirable.
  • DSSCs dye sensitized solar cells
  • One of the most serious drawbacks of the present DSSCs technology is the use of liquid and corrosive electrolytes which strongly limit their commercial development.
  • An example of an electrolyte currently used for DSSCs is potassium iodide/iodine. Replacement of the presently used electrolytes is desirable, but candidate electrolytes have poor ion transport.
  • Typical electrolytic capacitors are made of tantalum, aluminum, or ceramic with electrolyte systems such as boric add, sulfuric acid or solid electrolytes such as polypyrrole. Improvements desired include higher rates of charge and discharge which is limited by ion transport of the electrolyte.
  • a separator film is often added in batteries or capacitors with liquid electrolytes to perform the function of electrical insulation between the electrodes yet allowing ion transport.
  • the separator film is a porous polymer film, the polymer being, for example a polyethylene, polypropylene, or polyvinylidene fluoride. Porosity can be introduced, for example, by using a matt of spun fibers or by solvent and/or film stretching techniques.
  • the separator film is conventionally a glass fiber matt.
  • the polymer separator film comprising high-surface area carbon nanotubes of this invention can improve ion transport yet still provide the necessary electrical insulation between the electrodes.
  • Carbon nanotubes can be classified by die number of walls in the tube, singlewall, double wall and multiwall. Carbon nanotubes are currently manufactured as agglomerated nanotube balls, bundles or forests attached to substrates. Once removed from the substrate, manufactured nanotubes often form tightly bound “tree-trunk” like arrangements, particularly with single wall and double wall carbon nanotubes.
  • the use of carbon nanotubes as a reinforcing agent in composites is an area in which carbon nanotubes are predicted to have significant utility.
  • utilization of carbon nanotubes in these applications has been hampered due to the general inability to reliably produce higher-surface area carbon nanotubes and the ability to disperse carbon nanotubes in a matrix.
  • the present invention comprises improved cathodes, anodes, binders, electrolytes separator films, and composites for energy storage and collection devices like batteries, capacitors and photovoltaics comprising high-surface area carbon nanotubes, methods for their production and products obtained therefrom.
  • High-surface area carbon nanotubes are formed by fibrillation of manufactured nanotubes. This fibrillation of nanotube is caused by a combination of targeted oxidation, and/or high energy forces such as shear forces, such as generated by sonication. Fibrillation of the tree-truck agglomerates causes the nanotubes to loosen, exposing the surface or a greater number of nanotubes and/or a greater portion of the surface the nanotubes to the surrounding environment. This allows for increased interaction between the surrounding materials and the exposed surface of the nanotubes.
  • Figure 1 is optical microscopy showing progression from a wet cake to rotor shearing.
  • Figure 2 shows the effect of oxidation and processing on capacity vs. cycle.
  • Figure 3 shows optical micrographs of various compositions.
  • Figures 4A and 4B are micrographs showing the effect of shear.
  • Figure 5 shows micrographs of dry powder vs. a specific dispersion.
  • Figure 6 shows a micrograph of defibrillated ribbons.
  • Figure 7 shows a micrograph of a mixture.
  • Figure 8 shows Example 6 nanotubes before shearing.
  • Figure 9 shows Example 6 nanotubes after shearing.
  • Figure 10 shows Example 8 nanotubes before shearing.
  • Figure 11 shows Example 8 nanotubes after shearing.
  • Figure 12 shows Example 9 nanotubes before shearing.
  • Figure 13 shows Example 9 nanotubes after shearing.
  • Figure 14 shows Example 10 nanotubes before shearing.
  • Figure 15 shows Example 10 nanotubes after shearing.
  • Figure 16 shows Example 11 nanotubes before shearing.
  • Figure 17 shows Example 11 nanotubes after shearing.
  • Functionalized carbon nanotubes of the present disclosure generally refer to the chemical modification of any of the carbon nanotube types described hereinabove. Such modifications can involve the nanotube ends, sidewalls, or both. Chemical modifications may include, but are not limited to covalent bonding, ionic bonding, chemisorption, intercalation, surfactant interactions, polymer wrapping, cutting, solvation, and combinations thereof. In some embodiments, the carbon nanotubes may be functionalized before, during and after being exfoliated.
  • a plurality of carbon nanotubes comprising single wall, double wall or multi wall carbon nanotube fibers having an aspect ratio of from about 25 to about 500, preferably from about 60 to about 200, and a oxidation level of from about 3 weight percent to about 15 weight percent, preferably from about 5 weight percent to about 10 weight percent.
  • the oxidation level is defined as the amount by weight of oxygenated species covalently bound to the carbon nanotube.
  • the thermogravimetric method for the determination of the percent weight of oxygenated species on the carbon nanotube involves taking about 5 mg of the dried oxidized carbon nanotube and heating at 5 °C/minute from room temperature to 1000 degrees centigrade in a dry nitrogen atmosphere.
  • the percentage weight loss from 200 to 600 degrees centigrade is taken as the percent weight loss of oxygenated species.
  • the oxygenated species can also be quantified using Fourier transform infra-red spectroscopy, FTIR, particularly in the wavelength range 1730-1680 cm’ 1 .
  • the carbon nanotube fibers can have oxidation species comprising of carboxylic acid or derivative carbonyl containing species and are essentially discrete individual fibers, not entangled as a mass.
  • the derivative carbonyl species can include ketones, quaternary amines, amides, esters, acyl halogens, monovalent metal salts and the like.
  • the carbon nanotubes may comprise an oxidation species selected from hydroxyl or derived from hydroxyl containing species.
  • As-made carbon nanotubes using metal catalysts such as iron, aluminum or cobalt can retain a significant amount of the catalyst associated or entrapped within the carbon nanotube, as much as five weight percent or more. These residual metals can be deleterious in such applications as electronic devices because of enhanced corrosion or can interfere with the vulcanization process in curing elastomer composites. Furthermore, these divalent or multivalent metal ions can associate with carboxylic acid groups on the carbon nanotube and interfere with the discretization of the carbon nanotubes in subsequent dispersion processes.
  • the oxidized fibers comprise a residual metal concentration of less than about 10000 parts per million, ppm, and preferably less than about 1000 parts per million. The metals can be conveniently determined using energy dispersive X-ray, EDX.
  • a mixture of master batdies using different rubbers added to blends of different rubbers used in the rubber compound such that each rubber has a master batch that is compatible so that the individually dispersed nanotubes are distributed whether uniformly or non-uniformly in each rubber domain. This is sometimes necessary so that blends of rubbers used in the rubber compound will have carbon nanotubes in each rubber component.
  • An illustrative process for producing discrete oxidized carbon nanotubes follows: 3 liters of sulfuric acid, 97 percent sulfuric acid and 3 percent water, and 1 liter of concentrated nitric acid containing 70 percent nitric acid and 3 percent water, are added into a 10 liter temperature controlled reaction vessel fitted with a sonicator and stirrer. 40 grams of non-discrete carbon nanotubes, grade Flowtube 9000 from CNano corporation, are loaded into the reactor vessel while stirring the acid mixture and the temperature maintained at 30°C. The sonicator power is set at 130-150 watts and the reaction is continued for three hours.
  • the viscous solution is transferred to a filter with a 5 micron filter mesh and much of the acid mixture removed by filtering using a lOOpsi pressure.
  • the filter cake is washed one times with four liters of deionized water followed by one wash of four liters of an ammonium hydroxide solution at pH greater than 9 and then two more washes with four liters of deionized water.
  • the resultant pH of the final wash is 4.5.
  • a small sample of the filter cake is dried in vacuum at 100°C for four hours and a thermogravimetric analysis taken as described previously.
  • the amount of oxidized species on the fiber is 8 percent weight and the average aspect ratio as determined by scanning electron microscopy to be 60.
  • the discrete oxidized carbon nanotubes (CNT) in wet form are added to water to form a concentration by weight of 1 percent and the pH is adjusted to 9 using ammonium hydroxide.
  • Sodium dodecylbenzene sulfonic acid and is added at a concentration 1.25 times the mass of oxidized carbon nanotubes.
  • the solution is sonicated while stirring until the CNT are fully dispersed in the solution.
  • Full dispersion of individual tubes is defined when the UV absorption at 500 run is above 1.2 absorption units for a concentration of 2.5 xlO" 5 g CNT /ml.
  • Latex SBR LPF 5356 Goodyear Rubber Company
  • a solids SBR concentration of 70.2% was added to the CNT solution such that the solids ratio is 10 parts CNT for 90 parts SBR by weight.
  • the discrete carbon nanotubes may be present in the dispersion according to the invention in treated or untreated form. If they are treated, they have preferably been previously treated with an oxidizing agent.
  • the oxidizing agent is preferably nitric acid and/or sulfuric acid.
  • the discrete carbon nanotubes, especially multiwall carbon nanotubes, used preferably have an average external diameter in this case of 3 to 100 nm, particularly preferably of 5 to 80 nm, most particularly preferably of 6 to 20 nm
  • a small proportion of the smallest possible agglomerates is advantageous, because as a result of this, the physical properties of viscosity and conductivity of the dispersion, as well as its processability when used according to the invention, are improved. Coarse and numerous agglomerates may in certain circumstances lead to clogging of the coating equipment during application. In addition, coarse and numerous agglomerates may lead to areas of the coating that may be thinner or thicker in depth.
  • a smaller proportion of carbon nanotubes leads to the resulting epoxy coating being too low-viscosity and thus possibly no longer suitable for high throughput processes.
  • a higher proportion of carbon nanotubes also increases the viscosity beyond the level that would still appear meaningful for the coating to be used.
  • the at least one polymeric dispersing agent is generally at least one agent selected from the series of: water-soluble homopolymers, water-soluble random copolymers, water-soluble block copolymers, water-soluble graft polymers, particularly polyvinyl alcohols, copolymers of polyvinyl alcohols and polyvinyl acetates, polyvinyl pyrrolidones, cellulose derivatives such as e.g.
  • carboxymethyl cellulose carboxypropyl cellulose, carboxymethyl propyl cellulose, hydroxyethyl cellulose, starch, gelatine, gelatine derivatives, amino acid polymers, polylysine, polyaspartic acid, polyacrylates, polyethylene sulfonates, polystyrene sulfonates, polymethacrylates, polysulfonic acids, condensation products of aromatic sulfonic acids with formaldehyde, naphthalene sulfonates, lignin sulfonates, copolymers of acrylic monomers, polyethyleneimines, polyvinylamines, polyallylamines, poly(2-vinylpyridines), block copolyethers, block copolyethers with polystyrene blocks and polydiallyldimethylammonium chloride.
  • the at least one polymeric dispersing agent can be at least one agent selected from the series of: polyvinyl pyrrolidone, block copolyethers and block copolyethers with polystyrene blocks, carboxymethyl cellulose, carboxypropyl cellulose, carboxymethyl propyl cellulose, gelatine, gelatine derivatives and polysulfonic acids.
  • polyvinyl pyrrolidone and/or block copolyethers with polystyrene blocks are used as polymeric dispersing agents.
  • Particularly suitable polyvinyl pyrrolidone has a molecular weight Mn in the range of 5000 to 400,000.
  • Suitable examples are PVP KI 5 from Fluka (molecular weight about 10000 amu) or PVP K90 from Fluka (molecular weight of about 360000 amu) or block copolyethers with polystyrene blocks, with 62 wt. % C2 poly ether, 23 wt. % C3 poly ether and 15 wt.
  • % polystyrene based on the dried dispersing agent, with a ratio of the block lengths of C2 polyether to C3 polyether of 7:2 units (e.g. Disperbyk 190 from BYK-Chemie, Wesel).
  • the at least one polymeric dispersing agent is preferably present in a proportion of 0.01 wt. % to 10 wt. %, preferably in a proportion of 0.1 wt. % to 7 wt. %, particularly preferably in a proportion of 0.5 wt. % to 5 wt. %.
  • the generally used and preferred polymeric dispersing agents are advantageous particularly in the proportions stated since, in addition to supporting a suitable dispersing of the carbon nanotubes, they also allow an adjustment of the viscosity of the coating according to the invention as well as an adjustment of surface tension and film formation and adhesion of the coating to the respective substrate.
  • the at least one conductive salt in this case is preferably selected from the list of salts with the cations: tetraalkylammonium, pyridinium, imidazolium, tetraalkylphosphonium, and as anions various ions from simple halide via more complex inorganic ions such aass tetrafluoroborates to large organic ions such as trifluoromethanesulfonimide are employed.
  • the adding of at least one conductive salt to the coatings according to the invention is advantageous because these salts possess a negligible vapour pressure.
  • the salt is available as a film-forming agent and a conductive agent even at elevated temperatures and under reduced pressure. Particularly in the context of the coating process taking place, it may therefore be possible to prevent the coating from running.
  • the coating may additionally comprise a proportion of carbon black together with the proportions of carbon nanotubes and polymeric dispersing agent.
  • carbon black refers to fine particles of elemental carbon in griphite or amorphous form Fine particles in this context are particles with an average diameter of less than or equal to 1 pm.
  • this is preferably carbon black as obtainable from EVONIC under the name Printex®PE.
  • the addition of a proportion of carbon black to the coating can be advantageous because with only a slight further increase in viscosity, the conductivity of the coating to be obtained can be increased further in that potential voids between the carbon nanotubes are filled with carbon black, as a result of which the conductive connection between the carbon nanotubes is established and thus the conductive cross section of the coating is increased.
  • the present invention also provides a process for the preparation of a composition for the production of conductive coatings based on discrete carbon nanotubes, epoxy, and at least one polymeric dispersing agent in an aqueous formulation, particularly of a printable composition according to the invention, characterized in that it comprises at least the following steps: a) optional oxidative pretreatment of the discrete carbon nanotubes, b) preparation of an aqueous pre-dispersion by dissolving the polymeric dispersing agent in an aqueous solvent, and the input and distribution of carbon nanotubes in the resulting solution, c) input of a volume-based energy density, preferably in the form of shear energy, of at least 10 4 J/m 3 , preferably of at least 10 5 J/m 3 , particularly preferably 10 7 to 10 9 J/m 3 into the predispersion until the agglomerate diameter of the carbon nanotube agglomerates is substantially ⁇ 5 pm, preferably ⁇ 3 pm, particularly preferably ⁇ 2 pm.
  • step a) of the process according to the invention the pretreatment generally takes place by treating with an oxidizing agent.
  • the pretreatment with an oxidizing agent advantageously takes place preferably in that the carbon nanotubes are dispersed in a 5 to 10 wt. % aqueous solution of the oxidizing agent, and then the carbon nanotubes are separated out of the oxidizing agent and subsequently dried.
  • the dispersing in an oxidizing agent generally takes place for a period of one to 12 h.
  • the carbon nanotubes are preferably dispersed in the oxidizing agent for a period of 2 h to 6 h, particularly for about 4 h.
  • the separation of discrete carbon nanotubes from the oxidizing agent generally takes place by sedimentation.
  • the separation preferably takes place by sedimentation under the earth's gravity or by sedimentation in a centrifuge.
  • the drying of the carbon nanotubes generally takes place in ambient air and at temperature of 60°C to 140°C, preferably at temperatures of 80°C to 100°C.
  • the oxidizing agent is generally nitric acid and/or sulfuric acid; the oxidizing agent is preferably nitric acid.
  • the oxidizer can also be hydrogen peroxide.
  • step b) of the novel process advantageously takes place by dissolving the at least one polymeric dispersing agent in an initial charge of water, and then adding carbon nanotubes.
  • organic solvents preferably selected from the series of: Ci to Cs alcohol, particularly Ci to Cs alcohol, ethers, particularly dioxalane, and ketones, particularly acetone, may also be added to the water.
  • the addition of discrete carbon nanotubes can take place together with the at least one polymeric dispersing agent or consecutively.
  • the at least one polymeric dispersing agent is added first and then the carbon nanotubes are added in batches.
  • the addition of the at least one dispersing agent and then the addition of the carbon nanotubes in batches take place with stirring and/or with ultrasound treatment.
  • this dispersive coating comprises conductive salts and/or carbon black
  • the carbon black is preferably added together with the carbon nanotubes in the same way and/or the conductive salts are added together with the at least one polymeric dispersing agent in the same way.
  • step b) of the process according to the invention after the addition of at least one polymeric dispersing agent and the addition of carbon nanotubes, at least one conductive salt is also added.
  • a slurry of oxidized carbon nanotubes with concentrations from 0.5% to 3% is acidified with a strong acid to an acid concentration from 1% to 100%.
  • Typical pH of the water wash is less than 4, preferably less than 1 and especially about 0.5.
  • Acids can include, nitric, hydrochloric, sulfuric, and mixtures thereof.
  • the liquid phase of the slurry is removed by filtration, Gentrification or other conventional solid/liquid separation technology. The subsequent filter cake is then washed with an acid at a concentration from 1% to 100.
  • Adds can include, nitric, hydrochloric, sulfuric, and mixtures thereof, This is followed by a water washing until the acid is removed and liquid phase removal by conventional solid/liquid separation technology.
  • a slurry of oxidized carbon nanotubes with concentrations from 0.5% to 3% is acidified with a strong acid to an add concentration from 1% to 100%.
  • Typical iron content starts at about 8000 ppm and is reduced by at least 70%, preferably 85%, more preferably 95% and especially 99%.
  • the input of die volume-based energy density, e.g. in the form of shear energy, into the pre-dispersion according to step c) of the novel process particularly preferably takes place by passing the pre-dispersion at least once through a homogenizer.
  • the volume-based energy density can be introduced into the pre-dispersion e.g. in the area of the nozzle orifice.
  • All embodiments known to the person skilled in the art such as e.g. high pressure homogenizers, are suitable as homogenizers.
  • Particularly suitable high- pressure homogenizers are known in principle e.g. from the document Chemie Ingenieurtechnik, Volume 77, Issue 3 (pp. 258-262).
  • Particularly preferred homogenizers are high- pressure homogenizers; most particularly preferred high-pressure homogenizers are jet dispersers, gap homogenizers and high-pressure homogenizers of the Microfluidizer® type.
  • the pre-dispersion is preferably passed at least twice through a homogenizer, preferably a high-pressure homogenizer.
  • a homogenizer preferably a high-pressure homogenizer.
  • the pre- dispersion is passed at least three times through a homogenizer, preferably a high-pressure homogenizer.
  • the multiple passes through a homogenizer are advantageous because any coarse agglomerates of the carbon nanotubes remaining are comminuted by this process, as a result of which the dispersion is improved in its physical properties, such as e.g. viscosity and conductivity.
  • a homogenizer preferably a high-pressure homogenizer
  • the homogenizer preferably the high-pressure homogenizer, is generally a jet disperser or a gap homogenizer, which is operated with an input pressure of at least 50 bar and an automatically adjusted gap width.
  • the homogenizer preferably the high-pressure homogenizer, is preferably operated with an input pressure of 1000 bar and an automatically adjusted gap width. Most particularly preferred are high-pressure homogenizers of the Micronlab type.
  • steps b) and c) of the novel process provides die treatment of the pre-dispersion in a triple roll mill.
  • the preferred process is characterized in that the preparation of the pre-dispersion b) and the input of shear energy c) take place by a treatment of the predispersion in a triple roll mill with rotating rolls, the process comprising at least die following steps: bl) introduction of the solution of the polymeric dispersing agent in the aqueous solvent together with the carbon nanotubes into a first gap between a first and a second roll with different rates of rotation, wherein the carbon nanotubes are pre-dispersed in the solution and coarse agglomerates are comminuted; b2) transport of the pre-dispersion from step bl) to a second gap between the second roll and a third roll with a different rate of rotation, the pre-dispersion at least partly adhering to the roll surface during transport; cl) introduction of the pre-dispersion into the second gap, wherein the agglomerates of the carbon nanotubes in the dispersion are comminuted to a diameter of substantially ⁇ 5 pm,
  • the alternative embodiment of the process according to the invention is preferably operated in such a way that the ratio of the rate of rotation of the first roll and the second roll and the ratio of the rate of rotation of the second roll and the third roll are, independently of one another, at least 1:2, preferably at least 1:3.
  • the width of the gap between the first and second roll and between the second and third roll may be the same or different.
  • the gap width is preferably the same.
  • the gap width is particularly preferably the same and less than 10 pm, preferably less than 5 pm, particularly preferably less than 3 pm.
  • step c) it is particularly advantageous to cany out the alternative steps b) and c) of the novel process because, as a result of the different rates of rotation of the rolls of the same diameter, high shear rates are achieved in the first and second gaps, which permit good dispersion of the carbon nanotubes. Particularly in combination with the prefened equal, small gap widths, the result is very advantageous.
  • step c) it is possible to obtain dispersions with small proportions of agglomerates and small agglomerate sizes.
  • the adjustment of the gap in the homogenizer preferably the high-pressure homogenizer
  • the adjustment of the input pressure is regulated by the adjustment of the input pressure such that this is comparable to the adjustment of the gap between the rolls in the triple roll mill.
  • the passage through the two gaps in the triple roll mill can approximately correspond to two passes in the homogenizer, preferably the high- pressure homogenizer.
  • dispersions according to the invention obtained according to the process according to the invention and its preferred and alternative embodiments are particularly suitable for use e.g. in screen printing, offset printing or similar, generally known, high throughput processes for the production of conductive printed images.
  • the invention also provides an electrically conductive coating obtainable by printing, particularly by means of screen printing or offset printing of the composition according to the invention on to a surface and removal of the solvent or solvents.
  • the invention also provides an object with surfaces of non-conductive or poorly conductive material (surface resistance of less than 104 Ohmm) exhibiting a coating obtainable from the composition according to the invention.
  • the conductive printed image of the dispersion can optionally be thermally posttreated.
  • the thermal post-treatment of the printed dispersion takes place in the context of its use preferably by drying at a temperature from room temperature (23°C) to 150°C, preferably 30°C to 140°C, particularly preferably 40°C to 80°C.
  • a thermal post-treatment is advantageous if the adhesion of the dispersion according to the invention to the substrate can be improved thereby and the printed dispersion can thereby be secured against slurring.
  • the novel dispersions also possess other properties which may be advantageous for other applications.
  • the group of substances of the carbon nanotubes and also the special carbon nanotubes used according to the invention have particularly high strength. It is therefore conceivable using the dispersion according to the invention, by applying the same on to a surface, to transfer the positive mechanical properties of the special carbon nanotubes on to the surface, at least in part.
  • Discrete oxidized carbon nanotubes are obtained from as-made bundled carbon nanotubes by methods such as oxidation using a combination of concentrated sulfuric and nitric acids.
  • the techniques disclosed in PCT/US09/68781, the disclosure of which is incorporated herein by reference, are particularly usefill in producing the discrete carbon nanotubes used in this invention.
  • the bundled carbon nanotubes can be made from any known means such as, for example, chemical vapor deposition, laser ablation, and high pressure carbon monoxide synthesis.
  • the bundled carbon nanotubes can be present in a variety of forms including, for example, soot, powder, fibers, and bucky paper.
  • the bundled carbon nanotubes may be of any lengtii, diameter, or chirality.
  • Carbon nanotubes may be metallic, semi-metallic, semiconducting, or non-metallic based on their chirality and number of walls.
  • the discrete oxidized carbon nanotubes may include, for example, single-wall, double-wall carbon nanotubes, or multi-wall carbon nanotubes and combinations thereof.
  • the nanotubes are cut into segments, preferably with at least one open end, and residual catalyst particles that are interior to the carbon nanotubes as received from the manufacturer are removed at least partially.
  • This cutting of the tubes helps with exfoliation.
  • the cutting of die tubes reduces the length of the tubes into carbon nanotube segments that are defined here as Molecular Rebar.
  • Proper selection of the carbon nanotube feed stock related to catalyst particle type and distribution in the carbon nanotubes allows more control over the resulting individual tube lengths and overall tube length distribution. A preferred selection is where the internal catalyst sites are evenly spaced and where the catalyst is most efficient.
  • the preferred aspect ratio is greater than about 25 and less than about 200 for a balance of viscosity and mechanical performance.
  • substantially all of the discrete carbon nanotubes tube ends are open ended after the MR conversion process. The selection can be evaluated using electron microscopy and determination of the discrete tube distribution.
  • Oxidized moieties include, but are not limited to, carboxylates, hydroxyls, ketones and lactones.
  • the oxidized species can react advantageously with species such as, but not limiting in scope to, an acyl halide, epoxy, isocyanate, hydroxyl, carboxylic add, or amine group. This reaction may increase the stability of the dispersion of MR in the fluid.
  • the weight fraction of oxidized moieties is determined from the weight loss in the temperature range 200 to 600°C using a theromogravimetric analyzer in nitrogen run at 5°C /minute.
  • the residual catalyst in the Molecular Rebar is determined by heating the Molecular Rebar to 800°C in air for 30 minutes using a thermogravimetric analyzer.
  • Condition 1 is an example of a narrow distribution with low mean length.
  • Condition 2 is an example of broad distribution with low mean length.
  • Condition 3 is an example of high mean length and broad distribution.
  • Additives can be included and can further react or be completely inert with other components of the formulation. Fibrous additives can be surface active to react with surroundings.
  • a sample of tubes is diluted in isopropyl alcohol and sonicated for 30 minutes. It is then deposited onto a silica wafer and images are taken at 15 kV and 20,000 x magnification by SEM. Three images are taken at different locations. Utilizing the JEOL software (included with the SEM) a minimum of 2 lines are drawn across on each image and measure the length of tubes that intersect this line.
  • Skewness is a measure of the asymmetry of a probability distribution.
  • a positive value means the tail on the right side of the distribution histogram is longer than tire left side and vice versa.
  • Positive skewness is preferred for the nanotubes of the present invention, which indicates more tubes of long lengths.
  • a value of zero means a relatively even distribution on both sides of the mean value.
  • Kurtosis is the measure of the shape of the distribution curve and is generally relative to a normal distribution. Both skewness and kurtosis are unitless.
  • Functionalized carbon nanotubes of the present disclosure generally refer to the chemical modification of any of the carbon nanotube types described hereinabove. Such modifications can involve the nanotube ends, sidewalls, or both. Chemical modifications may include, but are not limited to covalent bonding, ionic bonding, chemisorption, intercalation, surfactant interactions, polymer wrapping, cutting, solvation, and combinations thereof.
  • Materials comprising DCNT can have other additives such as other fibers (carbon, griphite, graphene, polymeric (polypropylene, polyethylene to name just a couple), and particulates (such as powders (carbon black), sand, diatomaceous earth, cellulose, colloids, agglomerates, antimicrobials and inorganic salts).
  • other additives such as other fibers (carbon, griphite, graphene, polymeric (polypropylene, polyethylene to name just a couple), and particulates (such as powders (carbon black), sand, diatomaceous earth, cellulose, colloids, agglomerates, antimicrobials and inorganic salts).
  • the DCNT molecular rebar (MR) can comprise 0.01 to 90% by weight of the formulation, preferably 0.1 to 50, more preferably 0.25 to 25 % by weight of the formulation.
  • 10% by weight or less of the discrete carbon nanotubes MR of the formulation can comprise L/D of about 100 to 200 and about 30% or more of the discrete carbon nanotubes MR of the formulation can comprise L/D of 40 to 80.
  • the L/D of the discrete carbon nanotubes can be a unimodal distribution, or a multimodal distribution (such as a bimodal distribution).
  • the multimodal distributions can have evenly distributed ranges of aspect ratios (such as 50% of one L/D range and about 50% of another L/D range).
  • the distributions can also be asymmetrical - meaning that a relatively small percent of discrete nanotubes can have a specific L/D while a greater amount can comprise another aspect ratio distribution.
  • deforming stress e.g. by thermoforming, if die surface consists of a polymer material
  • a dispersion composition comprising a plurality of oxidized, discrete carbon nanotube fibers having an aspect ratio of from about 25 to about 500, and at least one natural or synthetic elastomer, and optionally at least one filler.
  • composition of embodiment 1 wherein at least 70 percent, preferably at least 80 percent, by weight of the nanotube fibers are fully exfoliated.
  • composition of embodiment 1 wherein the nanotube fibers are further functionalized.
  • composition of embodiment 1 wherein the carbon nanotube fibers comprise an oxidation level from about 3 weight percent to about 15 weight percent.
  • composition of embodiment 1 wherein the carbon nanotube fibers comprise from about 1 weight percent to about 30 weight percent of the composition.
  • composition of embodiment 1 further comprising at least one surfactant or dispersing aid.
  • composition of embodiment 1 wherein the natural or synthetic elastomer is selected from the group consisting of natural rubbers, poly isobutylene, poly butadiene and styrene-butadiene, butyl rubber, polyisoprene, ethylene propylene diene rubbers and hydrogenated and non-hydrogenated nitrile rubbers, polyurethanes, polyethers, silicones, halogen modified elastomers, especially chloroprene and fluoroelastomers and combinations thereof.
  • composition of embodiment 1 wherein the fibers are not entangled as a mass 9. The composition of embodiment 1 wherein the fibers are not entangled as a mass.
  • a process to form a carbon nanotube fiber/elastomer composite comprising the steps of:
  • elastomer is selected from the group consisting of natural rubbers, poly isobutylene, poly butadiene and styrene-butadiene rubber, ethylene propylene diene rubbers, butyl rubber, polyisoprene and hydrogenated and non-hydrogenated nitrile rubbers, polyurethanes, polyethers, halogen containing elastomers and fluoroelastomers and combinations thereof.
  • composition of embodiment 1 further conyrising sufficient natural or synthetic elastomer to form a formulation comprising from about 0.1 to about 25 weight percent carbon nanotube fibers.
  • composition of embodiment 1 in the form of a molded or fabricated article, such as a tire, a hose, a belt, a seal and a tank track.
  • composition of embodiment 1 further comprising carbon black and/or silica and wherein a molded film comprising the composition has a tensile modulus at 5% strain and 25 degrees C of at least about 12 MPa.
  • composition of embodiment 1 further comprising carbon black and/or silica, and wherein a molded film comprising the composition has a tear property at 25 degrees C of at least about 0.8 MPa.
  • composition of embodiment 1 further cony rising filler, and wherein a molded film comprising the composition has a tensile modulus at 5% strain and 25 degrees C of at least about 8 MPa.
  • a carbon nanotube fiber/elastomer composite wherein the carbon nanotube fibers are discrete fibers and comprise from about 10 to about 20 weight percent fibers and wherein the elastomer comprises a styrene copolymer rubber.
  • a method for obtaining individually dispersed carbon nanotubes in rubbers and/or elastomers comprising (a) forming a solution of exfoliated carbon nanotubes at pH greater than or equal to about 7, (b) adding the solution to a rubber or elastomer latex to form a mixture at pH greater than or equal to about 7, (c) coagulating the mixture to form a concentrate, (d) optionally incorporating other fillers into the concentrate, and (e) meltmixing said concentrate into rubbers and/or elastomers to form elastomeric composites.
  • the method of embodiment 21 wherein the coagulation step (c) comprises mixing with organic molecules of high water solubility such as acetone, denatured alcohol, ethyl alcohol, methanol, acetic acid, tetrahydrofuran that partially or wholly removes surfactants form the latex/carbon nanotube fiber concentrate.
  • organic molecules of high water solubility such as acetone, denatured alcohol, ethyl alcohol, methanol, acetic acid, tetrahydrofuran that partially or wholly removes surfactants form the latex/carbon nanotube fiber concentrate.
  • An individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles wherein the concentrate contains a concentration of less than 20,000 parts per million divalent or multivalent metal salt.
  • An individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate comprising free flowing particles wherein the concentrate contains agglomerations of carbon nanotubes that comprise less than Ipercent by weight of the concentrate and wherein the carbon nanotube agglomerates comprise more than 10 micrometers in diameter.
  • a composite comprising the concentrate of embodiments 31 or 32.
  • a method of dispersing the individually dispersed carbon nanotube/rubber or carbon nanotube/elastomer concentrate into an elastomer by first melt mixing the elastomer and concentrate to a uniform consistency before addition of other fillers and oils.
  • composition of embodiment 5 comprising a mixture of natural and synthetic elastomers such that each elastomer is compatible with at least one of the elastomers such that the nanotubes are individually dispersed in the mixture of elastomer(s).
  • composition of embodiment 35 wherein at least one of the elastomers does not comprise nanotubes.
  • a composition comprising one first elastomer and nanotubes, another different second elastomer and nanotubes, and yet another third elastomer which does not comprise nanotubes.
  • a process to increase cure rate of a composition comprising at least one natural or synthetic elastomer and carbon nanotubes, comprising selecting discrete carbon nanotubes to form the cured composition, wherein the cured composition has at least a 25 percent curing rate increase over the curing rate obtained for a cured elastomer not comprising carbon nanotubes.
  • composition of (A) elastomers, fillers and discrete carbon nanotubes wherein to maintain or increase stiffness or hardness as compared to (B) a composition not containing discrete carbon nanotubes, wherein composition (A) has less filler content than (B).
  • a method of mixing carbon nanotubes and at least one first elastomer wherein a master batch of carbon nanotubes is first melt mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200* C, subsequently then additional elastomers, fillers, and additives are added and melt mixed further, to produce a composition suitable for vulcanization.
  • a method of mixing carbon nanotubes and at least one first elastomer wherein a master batch of carbon nanotubes is first mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200* C and in the presence of at least one solvent, then the at least one solvent is removed, subsequently and optionally additional elastomers, fillers and additives are added and mixed further to produce a composition suitable for vulcanization.
  • a method of mixing carbon nanotubes and at least one first elastomer wherein a master batch of carbon nanotubes is first mixed with the elastomer, either the same or different from the first elastomer, at a temperature from about 20 to about 200* C and in the presence of at least one solvent, subsequently and optionally additional elastomers, fillers and additives are added and mixed further, followed by solvent removal to produce a composition suitable for vulcanization.
  • a dispersion comprising at least one epoxy resin and a plurality of oxidized, discrete carbon nanotubes, wherein the discrete carbon nanotubes comprise an interior and exterior surface, each surface comprising an interior surface oxidized species content and an exterior surface oxidized species content, wherein the interior surface oxidized species content differs from the exterior surface oxidized species content by at least 20%, and as high as 100% and are present in the range of from about 0.1 to about 30% by weight based on the total weight of the dispersion.
  • dispersant is selected from the group consisting of hydrophobic polymers, anionic polymers, non-ionic polymers, cationic polymers, ethylene oxide containing polymers, propylene oxide containing polymers, amphiphilic polymers, fatty acids, and mixtures thereof.
  • composition of embodiment 1 wherein at least a portion of the oxidized, discrete carbon nanotubes comprise an oxidation species selected from carboxylic acid or a derivative carbonyl containing species wherein the derivative carbonyl species is selected from ketones, quaternary amines, amides, esters, acyl halogens, and metal salts.
  • composition of embodiment 1 wherein the oxidized, discrete carbon nanotubes comprise an oxidation species selected from hydroxyl or derived from hydroxyl containing species.
  • composition of embodiment 1 further comprising an acrylic polymer, a silicone polymer, or a mixture thereof.
  • composition of embodiment 1 further comprising at least one organic inhibitor selected from the group consisting of azoles, calcium alky 1-ary 1 sulfonates, diamines, and metal salts of dinonylnapathalene sulphonates.
  • a catheter comprising the dispersion of embodiment 1, wherein the epoxy has been at least partially cured.
  • a coating comprising the dispersion of embodiment 1, wherein the epoxy has been at least partially cured.
  • Functionalized carbon nanotubes of the present disclosure generally refer to the chemical modification of any of die carbon nanotube types described hereinabove. Such modifications can involve the nanotube ends, sidewalls, or both. Chemical modifications may include, but are not limited to covalent bonding, ionic bonding, chemisorption, intercalation, surfactant interactions, polymer wrapping, cutting, solvation, and combinations thereof. In some embodiments, the carbon nanotubes may be functionalized before, during and after being exfoliated partially or fully.
  • a plurality of carbon nanotubes comprising single wall, double wall or multi wall carbon nanotubes having an aspect ratio of at least about 50, or at least about 100, or at least about 250, or at least about 500, or at least about 700, or at least about 1,000, or at least about 1,500, or at least or about 2,000, or at least about 3000 up to about 6000, or up to about 5000.
  • the carbon nanotubes comprise an overall (total) oxidation level of from about 0.01 weight percent to about 60 weight percent, preferably from about 0.1 weight percent to about 50 weight percent, more preferably from about 0.5 weight percent to 25 weight percent, more preferably from about 1 weight percent to 20 weight percent, or from about 0.1 weight percent to 5 weight percent.
  • the oxidation level is defined as the amount by weight of oxygenated species covalently bound to the carbon nanotube determined by thermogravimetrically. In some embodiments the oxidation level may be 0, or at least about
  • thermogravimetric method for the determination of the percent weight of oxygenated species on the carbon nanotube involves taking about 7-15 mg of the dried oxidized carbon nanotube and heating at 5 °C/minute from 100 degrees centigrade to 700 degrees centigrade in a dry nitrogen atmosphere. The percentage weight loss from 175-575 degrees centrigade or 200 to
  • the range is typically selected based on the onset of weight loss of the oxygenated species. For example, with polyethers attached to the carbon nanotubes the range is set from 175-575 degrees centigrade.
  • the oxygenated species can also be quantified using Fourier transform infra-red spectroscopy, FTIR, particularly in the wavelength range 1730-1680 cm -1 or alternatively
  • the oxidation level may be 0%.
  • the carbon nanotubes can have oxidation species comprising carboxylic acid or derivative carbonyl containing species.
  • the derivative carbonyl species can include phenols, ketones, quaternary amines, amides, esters, acyl halogens, monovalent, divalent, or multivalent metal salts and the like, and can vary between the inner and outer surfaces of the tubes.
  • Other oxygenated species can comprise, although not limited to, ether groups, ketones, and lactones, alcohols and oxiranes without limit of molecular weight.
  • one or more types of acid can be used to oxidize the tubes exterior surfaces, followed by water washing and the induced shear, thereby breaking and/or partially separating the tubes.
  • the formed nanotubes or high-surface area bundles, having essentially no (or zero) interior tube wall oxidation can be further oxidized with a different oxidizing agent, or even the same oxidizing agent as that used for the tubes’ exterior wall surfaces at a different concentration, resulting in differing amounts - and/or differing types - of interior and surface oxidation.
  • Additional oxygen containing molecules can be reacted onto the carbon nanotubes, for example, although not limited to, by interaction of carboxylic acid groups and hydroxyl groups, carboxylic acid groups and amine groups, azide groups, and glycidyl groups.
  • As-made carbon nanotubes are treated with mechanical forces such as shear forces and/or oxidation to at least partially defibrillate tightly bundled nanotube “tree-trunks”.
  • the high-surface area nanotubes have at least about 10% greater surface area after treatment than before. In other embodiments, the high-surface area nanotubes have at least about 20%, at least about 30%, at least about 50%, at least about 75%, or at least about 100% greater surface area after treatment than before. In some embodiments, the high-surface area nanotubes have at least about 2.5x, at least about
  • BET surface area of nanotubes may be measured using N2 BET isotherms according to ASTM D6556-16.
  • the BET surface area of the nanotubes herein may vary depending upon the type of nanotubes, treatment methods, and desired applications.
  • the single and double walled nanotubes treated with shear, oxidation, or both that are described herein usually have a BET surface area of at least about 400 m 2 /g, or of at least about 500 m 2 /g, or at least about 550 m 2 /g, or at least about 600 m 2 /g, or at least about 650 m 2 /g, or at least about 700 m 2 /g, or at least about 750 m 2 /g, or at least about 800 m 2 /g, or at least about 850 m 2 /g, or at least about 900 m 2 /g, or at least about 1000 m 2 /g, or at least about
  • Nanotube surface area may be measured using known methods including but not limited to gas adsorption techniques such as, for example, BET analysis, nitrogen, argon, and/or carbon dioxide adsorption. These measurements may be conducted isothermally.
  • the high-surface area nanotubes have a measured surface after being treated about 25%, about 40%, about 55%, about 80%, or about 95% greater than the measured surface area prior to treatment.
  • the high-surface area nanotubes have a measured surface after being treated about 2x, about 3x, about 4x, about 5x, about 7x, about lOx, or about 15x greater than the measured surface area prior to treatment.
  • high-surface area carbon nanotubes have a surface area greater than about 300m 2 /g, or greater than about 500m 2 /g, or greater than about 700m 2 /g, or greater than about l,000m 2 /g, or greater than about l,500m 2 /g, or greater than about 2,000m 2 /g, or greater than about 2,500m 2 /g, or greater than about 3,000m 2 /g.
  • high-surface area carbon nanotubes have a surface area less than about 500m 2 /g, or less than about 700m 2 /g, or less than about l,000m 2 /g, or less than about l,500m 2 /g, or less than about 2,000m 2 /g, or less than about 2,500m 2 /g, or less than about 3,000m 2 /g.
  • As-made carbon nanotubes using metal catalysts such as iron, aluminum or cobalt can retain a significant amount of the catalyst associated or entrapped within the structure of the carbon nanotubes, as much as five weight percent or more. These residual metals can be deleterious in such applications as electronic devices because of enhanced corrosion or can interfere with the vulcanization process in curing elastomer composites. Furthermore, these divalent or multivalent metal ions can associate with carboxylic acid groups on the carbon nanotube and interfere with the loosening and/or dispersion processes.
  • metal catalysts such as iron, aluminum or cobalt
  • the oxidized carbon nanotubes comprise a residual metal concentration of less than about 10,000 parts per million, ppm, less than about 5,000 ppm, less than about 3,000 ppm, less than about 1,000 ppm, or be substantially free from residual metals.
  • the metals can be conveniently determined using energy dispersive X-ray spectroscopy or thermogravimetric methods.
  • Bosnyak et al. in various patent applications (e.g., US 2012-0183770 A1 and US 2011-0294013 Al), have made discrete carbon nanotubes through judicious and substantially simultaneous use of oxidation and shear forces, thereby oxidizing both the inner and outer surface of the nanotubes, typically to approximately the same oxidation level on the inner and outer surfaces, resulting in individual or discrete tubes.
  • the present inventions differ from those earlier Bosnyak et al. applications and disclosures.
  • the present inventions describe a composition of high-surface area carbon nanotubes having targeted, or selective, oxidation levels and/or content on the exterior and/or interior of the tube walls.
  • Such novel carbon nanotubes can have little to no inner tube surface oxidation, or differing amounts and/or types of oxygencontaining species, e.g., oxidation, between the tubes’ inner and outer surfaces or among the carbon nanotubes.
  • oxygencontaining species e.g., oxidation
  • the degree of fibrillation can influence the population of tubes that differ by extent or type of oxygen containing species.
  • the tubes within the core of the trunk are less likely to contain oxygenated species than the tubes on the outermost portion of the trunk.
  • These new nanotubes are useful in many implications, including cathode material, anode material, binder material, electrolyte material, separator film material, and or composites for energy storage devices for the improvement of mechanical, electrical, and thermal properties.
  • One embodiment of the present invention is a composition comprising a plurality of high-surface area carbon nanotubes, wherein the high-surface area carbon nanotubes comprise an interior and exterior surface, each surface comprising an interior surface oxidized species content (also called interior oxygen containing species content because the interior oxygen species may differ from the exterior oxygen species) and an exterior surface oxidized species content (also called exterior oxygen containing species content because the interior oxygen species may differ from the exterior oxygen species), wherein the interior surface oxidized species content differs from the exterior surface oxidized species content by at least 20%, and as high as 100%, preferably wherein the interior surface oxidized species content is less than the exterior surface oxidized species content.
  • an interior surface oxidized species content also called interior oxygen containing species content because the interior oxygen species may differ from the exterior oxygen species
  • an exterior surface oxidized species content also called exterior oxygen containing species content because the interior oxygen species may differ from the exterior oxygen species
  • the interior surface oxidized species content can be up to 3 weight percent relative to carbon nanotube weight, preferably from about 0.01 to about 3 weight percent relative to carbon nanotube weight, more preferably from about 0.01 to about 2, most preferably from about 0.01 to about 1. Especially preferred interior surface oxidized species content is from zero to about 0.01 weight percent relative to carbon nanotube weight.
  • the exterior surface oxidized species content can be from about 0.1 to about
  • weight percent relative to carbon nanotube weight preferably from about 1 to about 40, more preferably from about 1 to about 20 weight percent relative to carbon nanotube weight.
  • the interior and exterior surface oxidized species content totals can be from about 0.01 to about 65 weight percent relative to carbon nanotube weight.
  • Another embodiment of the invention is a composition comprising a plurality of high-surface area carbon nanotubes, wherein the high-surface area carbon nanotubes comprise an interior and exterior surface, each surface comprising an interior surface and an exterior surface oxidized species content, wherein the interior surface oxidized species content comprises from about 0.01 to less than about 1 percent relative to carbon nanotube weight and the exterior surface oxidized species content comprises more than about 0.1 to about 65 percent relative to carbon nanotube weight.
  • the invention is a composition comprising a plurality of high- surface area carbon nanotubes, wherein at least a portion of the high-surface area carbon nanotubes are open ended, wherein the composition comprises a cathode, an anode, a binder material, an electrolyte material a separator film, or a composite material for an energy storage or collection device.
  • the composition comprises a plurality of high-surface area carbon nanotubes in which at least a portion of the carbon nanotubes are open ended and ion conducting.
  • the composition can further comprise at least one polymer.
  • the polymer is selected from the group consisting of vinyl polymers, preferably poly(styrene-butadiene), partially or fully hydrogenated poly(styrene butadiene) containing copolymers, functionalized poly(styrene butadiene) copolymers such as carboxylated poly(styrene butadiene) and the like, poly(styrene-isoprene), poly(methacrylic acid), poly(acrylic acid), poly(vinylalcohols), and poly(vinylacetates), fluorinated polymers, preferably poly(vinylidine difluoride) and poly(vinylidene difluoride) copolymers, conductive polymers, preferably poly(acetylene), poly(phenylene
  • polymers that may be employed include, for example, carboxymethyl cellulose or a salt thereof such as an alkali metal salt or an alkaline earth metal salt and in particular the sodium salt, cellulose-based polymers, hydrophilic polymers with aqueous solubility over 1% w/v, polystyrene sulfonate or a salt thereof such as an alkali metal salt or an alkaline earth metal salt and in particular the sodium salt. Hydrophilic polymers may be preferable in some embodiments.
  • the plurality of high-surface area carbon nanotubes are further functionalized, preferably the functional group comprises a molecule of mass greater than 50g/mole, and more preferably the functional group comprises carboxylate, hydroxyl, ester, ether, or amide moieties, or mixtures thereof.
  • a further embodiment of this invention comprising a plurality of high-surface area carbon nanotubes further comprising at least one dispersion aid.
  • the plurality of carbon nanotubes further comprise additional inorganic structures comprising of elements of the groups two through fourteen of the Periodic Table of Elements.
  • additional inorganic structures can be in the form of particles, layers or as continuous media.
  • Preferred inorganic structures include electrically conducting inorganic structures such as, but not limited to, silver or copper, magnetic inorganic structures such as, but not limited to, iron oxide and low melting point inorganic structures such as, but not limited to, indium-tin alloys
  • Another embodiment of this invention comprises a plurality of carbon wherein tire composition has a flexural strength of at least about ten percent higher than a comparative composition made without the plurality of high-surface area carbon nanotubes.
  • Yet another embodiment of this invention is a cathode, an anode, a binder, electrolyte or separator film composition comprising a plurality of high-surface area carbon nanotubes having a portion of carbon nanotubes that are open ended and ion conducting.
  • the composition further comprises other carbon structures.
  • the other carbon structures may comprise components selected from the group consisting of carbon black, graphite, graphene, oxidized graphene, fullerenes and mixtures thereof.
  • the graphene or oxidized graphene have at least a portion of high-surface area carbon nanotubes interspersed between the graphene or oxidized graphene platelets.
  • a yet further embodiment of this invention is a composition comprising a plurality of high-surface area carbon nanotubes where the cathode, anode, or binder material has an impedance of less than or equal to about one billion (1 x 10 9 ) ohm-m and the electrolyte material has a charge transfer resistance of less than or equal to about 10 million
  • Another embodiment of this invention comprises an electrolyte or separator film composition comprising a plurality of high-surface area carbon nanotubes wherein the carbon nanotubes are oriented.
  • the orientation is accomplished by fabrication techniques such as in a sheet, micro-layer, micro-layer with vertical film orientation, film, molding, extrusion, or fiber spinning fabrication method.
  • the orientation may also be made via post fabrication methods, such as tentering, uniaxial orientation, biaxial orientation and thermoforming.
  • the orientation may also be introduced by 3-D printing techniques.
  • the oriented carbon nanotubes of this invention may be extracted from the oriented fiber or sheet containing the oriented carbon nanotubes by removal of the matrix material, such as, but not limited to, using a liquid solvent to dissolve a polymer matrix, add to dissolve an inorganic matrix or degradation of the matrix by chemical means.
  • a further embodiment of this invention is a composition comprising a plurality of high-surface area carbon nanotubes wherein the portion of open ended tubes comprise electrolyte.
  • the polymer is preferred to comprise a molecular weight of the polymer less than 10,000 daltons, such that die polymer can enter within the tube.
  • the electrolyte may contain liquids.
  • An additional embodiment of this invention comprises a composition including a plurality of high-surface area carbon nanotubes, and wherein at least a portion of the high-surface area carbon nanotubes are open ended.
  • the disclosed high-surface area nanotubes include increased length and diameter bundles wherein at least about 5% of the nanotubes have a portion of their outer surface exposed to the surrounding environment.
  • Such high-surface area nanotubes include defiibillated bundles.
  • the bundles may have an average length of at least about 400nm, about 800nm, about 1pm, about pm, about 10pm, about 50pm, about 100pm, about 500pm, about 1,000pm, about 1,250pm, about 1,400 pm, about 1,500pm, about 1,600pm, about 1,800pm, about 2,000pm, about 3,000pm, or about
  • the high-surface area carbon nanotubes are bundles of singled walled nanotubes with individual aspect ratios of at least about 50, at least about 100, at least about
  • a bimodal distribution is a continuous probability distribution with two different modes. These appear as distinct peaks (local maxima) in the probability density function. More generally, a multimodal distribution is a continuous probability distribution with two or more modes.
  • the high-surface area carbon nanotubes can have a unimodal, bimodal or multimodal distribution of diameters and/or lengths both for the individual nanotubes which make up a high-surface area bundle and for the high-surface area bundles themselves. These compositions are useful in cathode materials, anode materials, binder materials, separator materials, and electrolytes of the invention.
  • the invention is an electrode paste, preferably an anode paste, for a lead acid battery, the paste comprising high-surface area carbon nanotubes having an average length and/or high-surface area bundle length of at least about 1pm, about
  • the embodiment further comprising, dispersing aids such as, but not limited to, polyvinyl alcohol, water, lead oxide and/or sulfuric acid.
  • dispersing aids such as, but not limited to, polyvinyl alcohol, water, lead oxide and/or sulfuric acid.
  • the carbon nanotubes, dispersing aid, and water form a dispersion, and the dispersion is then contacted with lead oxide followed by sulfuric acid to form the electrode paste of a lead acid battery, or other cathode or anaode materials to form other types of batteries.
  • suitable solvents for aiding in the dispersion of carbon nanotubes include, for example, renewable solvents such as CYRENETM (Dihydrolevoglucosenone) or solvents such as glycols.
  • the solvents may be miscible with, for example, deionized water.
  • Another embodiment of the invention is a composition consisting of high- surface area carbon nanotubes, wherein the high-surface area carbon nanotubes are coated with water, oils, waxes, nitric acid, or sulfuric acid. This coating reduces and/or prevents the formation of Van der Waals, electrical, or electrostatic forces between the carbon nanotubes, thereby reducing and/or preventing the high-surface area carbon nanotubes from agglomerating into a tight bundle, thereby reducing the exposed surface area of the carbon nanotubes, CNT.
  • the composition may comprise as much as 99.99% composite material and as little as about 0.01% carbon nanotubes by weight, or as little as about 0.025% carbon nanotubes by weight. In other embodiments, the composition may contain as much as 2% carbon nanotubes (CNTs), or as much as 5% CNTs, or as much as
  • CNTs or as much as 20% CNTs, or as much as 10% CNTs, or as much as 20% CNTs, or as much as 35% CNTs, or as much as 50% CNTs, or as much as 80% CNTs by weight.
  • the high-surface area carbon nanotubes of any composition embodiment above preferably comprise a plurality of open ended tubes, more preferably the plurality of high-surface area carbon nanotubes comprise a plurality of open ended tubes.
  • the high- surface area carbon nanotubes of any composition embodiment above are especially preferred wherein the inner and outer surface oxidation difference is at least about 0.2 weight percent.
  • the high-surface area carbon nanotubes of any composition embodiment above preferably comprise a portion of carbon nanotubes that have a different amount of oxygen containing species than another portion.
  • the high-surface area carbon nanotubes of any composition embodiment above are especially preferred wherein a portion of the carbon nanotubes differ from another portion of carbon nanotubes by at least about 0.2 weight percent
  • compositions described herein can be used as an ion transport.
  • Various species or classes of compounds/drugs/chemicals which demonstrate this ion transport effect can be used, including ionic, some non-ionic compounds, hydrophobic or hydrophilic compounds.
  • Ethers, carbonates and polyethers in electrolytes are known to help convey lithium ion species.
  • the new carbon nanotubes disclosed herein are also useful in ground water remediation.
  • compositions comprising the novel high-surface area targeted oxidized carbon nanotubes can also be used as a component in, or as, a sensor.
  • compositions disclosed herein can also be used as a component in, or as, drug delivery or controlled release formulations.
  • compositions disclosed herein may be used as a structural scaffolding for catalysts.
  • catalysts, enzymes, proteins, peptides or other small or large molecules may be attached to the exterior of the disclosed carbon nanotubes.
  • the disclosed nanotube scaffolding may be useful for positioning the attached catalysts within a matrix, positioning multiple catalytic proteins or molecules with respect to each other.
  • Magnetic particles may be bound or attached to the carbon nanotubes disclosed herein.
  • the bound magnetic particles may be used to influence the orientation, location, or position of the carbon nanotube to which the magnetic particle is attached.
  • Magnetic fields may be generated by natural magnets or electro-magnetic devices including at least, MRI, fMRI, or pulsed electromagnetic field generator devices. Additionally, a single magnetic field generation device may be utilized or multiple magnetic field generation devices may be used. In some embodiments, an array of EMF generators may be used to move CNTs bound to magnetic particles and/or cause such CNTs to vibrate, rotate, oscillate, or to direct CNTs from one specific position to another.
  • More than one species of magnetic particle may be bound to a single carbon nanotube.
  • the distinct species of magnetic particle may behave differently in the same magnetic field, thus creating an increased variety of possibilities for impacting the behavior of carbon nanotubes attached to more than one species of magnetic particle.
  • Magnetic particles bound to carbon nanotubes may comprise approximately
  • 0.001 weight percent relative to carbon nanotube weight or may comprise approximately
  • 0.01 weight percent relative to carbon nanotube weight or may comprise approximately 0.1 weight percent relative to carbon nanotube weight, or may comprise approximately 1 weight percent relative to carbon nanotube weight, or may comprise approximately 10 weight percent relative to carbon nanotube weight, or may comprise approximately up to 50 weight percent relative to carbon nanotube weight, or may comprise up to approximately 90 weight percent relative to carbon nanotube weight.
  • Carbon nanotubes bound to magnetic particles may additionally contain a payload molecule as discussed above or have peptides, small molecules, nucleic acids, or other drugs or molecules attached to their exterior. These combinations may allow the nanotube, along with its associated payload or substantially non-magnetic attached molecule to be directed to a particular location where the payload molecule of the attached molecule may be desired. In this manner, targeted molecules could be delivered to a particular location using a controlled magnetic field.
  • magnetic fields may be used in order to flex or distort carbon nanotubes or a network, matrix, or scaffold of carbon nanotubes. If an open ended, payload carrying nanotube is flexed or distorted as described, this may increase the rate at which the interior payload molecule is emptied into the surrounding environment thereby enabling the controlled, targeted, and/or timed release of payload molecules. Similarly, the described flexing of a network of carbon nanotubes may increase the rate at which payload molecules are loaded into die interior of open ended nanotubes or allow molecules to be entrapped within die interior spaces of the nanotube network itself while remaining external to any particular nanotube.
  • Batteries comprising the compositions disclosed herein are also useful. Such batteries include lithium, nickel cadmium, or lead acid types.
  • Formulations comprising the compositions disclosed herein can further comprise molecules comprising an epoxide moiety (moiety may also be referred to as chemical group), or a urethane moiety, or an ether moiety, or an amide moiety, an alkane moiety, or a vinyl moiety.
  • the molecules may be in a rigid or elastomeric or fluid state at room temperature.
  • Such formulations can be in the form of a dispersion.
  • the formulations can also include nanoplate structures.
  • compositions can further comprise at least one hydrophobic material in contact with at least one interior surface.
  • the present invention relates to a composition
  • a composition comprising a plurality of high- surface area carbon nanotubes and a plasticizer wherein the high-surface area carbon nanotubes can be functionalized with oxygen containing species on their outermost wall surface.
  • One group of high-surface area carbon nanotubes comprise an interior and exterior surface, each surface comprising an interior surface and exterior surface oxidized species content wherein the interior surface oxidized species content comprises from about 0.01 to less than about 1 percent relative to carbon nanotube weight and the exterior surface oxidized species content comprises more than about 1 to about 3 percent relative to carbon nanotube weight.
  • the oxygen species can comprise carboxylic adds, phenols, ketones, lactones, or combinations thereof.
  • the composition can further comprise a plasticizer selected from the group consisting of dicarboxylic/tricarboxylic esters, timellitates, adipates, sebacates, maleates, glycols and polyethers, polymeric plasticizers, bio-based plasticizers and mixtures thereof.
  • a plasticizer selected from the group consisting of dicarboxylic/tricarboxylic esters, timellitates, adipates, sebacates, maleates, glycols and polyethers, polymeric plasticizers, bio-based plasticizers and mixtures thereof.
  • the composition can comprise plasticizers comprising a process oil selected from the group consisting of naphthenic oils, paraffin oils, paraben oils, aromatic oils, vegetable oils, seed oils, and mixtures thereof.
  • the composition can further comprise a plasticizer selected from the group of water immiscible solvents consisting of but not limited to xylene, pentane, methylethyl ketone, hexane, heptane, ethyl acetate, ethers, dicloromethane, dichloroethane, cyclohexane, chloroform, carbon tetrachloride, butyl acetate butanol, benzene, cresol or mixtures thereof.
  • a plasticizer selected from the group of water immiscible solvents consisting of but not limited to xylene, pentane, methylethyl ketone, hexane, heptane, ethyl acetate, ethers, dicloromethane, dichloroethane, cyclohexane, chloroform, carbon tetrachloride, butyl acetate butanol, benzene, cresol
  • composition is further comprises an inorganic filler selected from the group consisting of silica, nano-clays, carbon black, graphene, glass fibers, and mixtures thereof.
  • composition in the form of free flowing particles.
  • the composition comprises a plurality of high-surface area carbon nanotubes and a plasticizer wherein the high-surface area carbon nanotubes comprise from about 10 weight percent to about 90 weight percent, preferably 10 wdght percent to 40 weight percent, most preferably 10 to 20 weight percent.
  • Another embodiment is the composition of high-surface area carbon nanotubes in a plasticizer further mixed with a least one rubber.
  • the rubber can be natural or synthetic rubbers and is preferably selected from the from the group consisting of natural rubbers, polyisobutylene, polybutadiene and styrene-butadiene rubber, butyl rubber, polyisoprene, styrene-isoprene rubbers, styrene-isoprene rubbers, ethylene, propylene diene rubbers, silicones, polyurethanes, polyester-polyethers, hydrogenated and non-hydrogenated nitrile rubbers, halogen modified elastomers, flouro-elastomers, and combinations thereof.
  • thermoplastic can be selected from but is not limited to acrylics, polyamides, polyethylenes, polystyrenes, polycarbonates, methacrylics, phenols, polypropylene, polyolefins, such as polyolefin plastomers and elastomers, EPDM, and copolymers of ethylene, propylene and functional monomers.
  • thermoset polymers preferably an epoxy, or a polyurethane.
  • the thermoset polymers can be selected from but is not limited to epoxy, polyurethane, or unsaturated polyester resins.
  • compositions containing high-surface area carbon nanotubes for the improved performance of energy storage devices, including, but not limited to lithium ion battery technology.
  • single layer pouch cells in silicon containing anodes show tremendous cycle life improvement when carbon nanotubes such as produced by OCSiAl single wall carbon nanotubes (SWNTs) are treated according to the disclosed processes to create high-surface area single wall carbon nanotubes.
  • SWNTs OCSiAl single wall carbon nanotubes
  • Other manufacturers of carbon nanotubes that may be suitable for use in the applications described herein include, for example, Southwest Nanotechnologies, Zeonano or
  • samples may be subjected to intensely disruptive forces generated by shear (turbulent) and/or cavitation with process equipment capable of producing energy densities as high as of 10 6 to 10 8 Joules/m 3 .
  • Equipment that meets this specification includes but is not limited to ultrasonicators, cavitators, mechanical homogenizers, pressure homogenizers and microfluidizers (Table 3).
  • Additional shearing equipment includes, but is not limited to, HAAKETM mixers, Brabender mixers, Omni mixers, Silverson mixers, Gaullin homogenizers, and/or twin-screw extruders.
  • HAAKETM mixers Brabender mixers
  • Omni mixers Omni mixers
  • Silverson mixers Silverson mixers
  • Gaullin homogenizers Gaullin homogenizers
  • twin-screw extruders twin-screw extruders.
  • a plurality of high-surface area oxidized carbon nanotubes results from this process, preferably at least about 60%, more preferably at least about 75%, most preferably at least about 95% and as high as 100%, with the minority of the tubes, usually the vast minority of the tubes remaining tightly bundled and with the surface of such tightly bundled nanotubes substantially inaccessible.
  • OCSiAl Oxidizing TuballTM
  • Example 2 Shear Treatment of Non-Oxidized and Oxidized OCSiAl Tubes
  • Example 2A Shear treatment of oxidized OCSiAl tubes
  • Oxidized OCSiAl source 82-final (pH 3.61, 27.1% solids)
  • Optical Microscopy shown in Figure 1, shows a progression from wetcake to rotor shearing 8 cycles shearing with a high shear rate mixer. R/S performs the initial breakup of the bundles and this is significantly furthered by passing through a shearing device.
  • the experimental results described throughout are expected to be obtainable using multiple shearing devices including those described in Table 3 as well as HAAKETM mixers,
  • OCSiAl source TUBALLTM single wall carbon nanotubes. Batch number
  • Figure 2 shows a comparison of a control vs. OcSiAl TuballTM Batt product
  • FIG. 3 shows Optical Microscopy (all images at ⁇ same magnification).
  • the center electron micrograph shows the “as received” OCSiAl dry powder. It is a ribbon or tree trunk type structure with a very small amount of fibrillation and low surface area. In this structure the majority of the tubes surface area is not exposed as it is protected by surrounding tubes.
  • the top left image shows effect of putting a dilute (-0.15%) solution in water through a rotor/stator at 9900 rpm for 10 minutes. Clearly this process has some effect on breaking up the ribbons and causing some level of fibrillation thus increasing the surface area (SA).
  • FIG. 3 The bottom left image of Figure 3 shows effect of putting the above material through a shear treatment - further increasing the fibrillation and thus increasing the exposed surface area.
  • Top right shows oxidized OCSiAl through the shearing treatment - again increasing the fibrillation and thus surface area. Oxidation introduces functionality to the material and significantly reduces the amount of residual metal contamination.
  • Bottom right shows the effect of adding surfactant to the oxidized sheared material followed by sonication.
  • Figures 4A and 4B electron micrographs show side by side comparisons of unoxidized vs. oxidized shear treated OCSiAl.
  • Figure 4A shows 2,500X magnification while
  • Figure 4B shows 25,000X magnification. Both levels of magnification show significantly more fibrillation for the oxidized vs. non-oxidized sheared materials.
  • Figure 5 shows a comparison of dry powder OCSiAl vs. PSS (polystyrene sulfonate) dispersion of oxidized OCSiAl
  • Figure 6 shows that it is possible to get the ribbons defibrillated down to single tubes in some instances.
  • Figure 7 an electron micrograph, shows oxidized carbon nanotubes and O-
  • MR Rebar®
  • This micrograph shows a synergy in that the MR forms a coating on the silicon oxide SiOx particles and interacts intimately with the carbon black while the “tree trunk” Ox-OCSiAl MR is long enough to span the length of the SiOx particle and is long enough to span the gaps that are too large for MR to bridge.
  • Figure 7 shows the tree trunk covering the entire length of the SiOx particle. Such lengths are easily capable of spanning the gaps between SiOx and graphite.
  • MR particles may be too short to accomplish this but, as shown in Figure 7, MR particles cover the surface of the SiOx in a “cage type” structure.
  • the oxidized OCSiAl structures are capable of having electroactive material, e.g. Li attached to the functional groups.
  • Electroactive materials include, but are not limited to, griphite, lithium cobalt oxide, lithium iron phosphate, and/or lithium manganese oxide.
  • Example 6 High purity OCSiAl Tuball SWCNT through shearing device
  • Example 8 Aqueous dispersion of high purity OCSiAl Tuball SWCNT and
  • Example 9 Aqueous dispersion of oxidized Zeonano SWCNT and Sodium Carboxymethyl Cellulose
  • the first pass was sheared at 6000 psi and the subsequent passes at 8000-9000 psi.
  • the pH was adjusted to pH 7 after pass 4.
  • Walocel CRT 30 PA sodium carboxymethyl cellulose (CMC) was added in a mass ratio of 1 SWCNT to 1 CMC.
  • the mixture was then passed through the shearing device at 8000-9000 psi for an additional 11 passes while maintaining the temperature of the mixture below 40°C.
  • additional surfactant was added to give a ratio of 1 SWCNT to 2.25 CMC.
  • additional surfactant was added to give a ratio of 1 SWCNT to 2.75 CMC.
  • Figure 12 shows Oxidized Zeonano SWCNT before shearing and Figure 13 shows it after shearing device and addition of CMC (11.25X magnification).
  • Example 10 Aqueous dispersion of un-oxidized Zeonano SWCNT and
  • a composition for use as a binder material, an electrolyte material or a separator film material of an energy storage or collection device comprising: a plurality of high-surface area carbon nanotubes, wherein at least a portion of the high-surface area carbon nanotubes are open ended.
  • composition of embodiment 3, wherein the polymer is selected from the group consisting of vinyl polymers, poly(styrene-butadiene), partially or fully hydrogenated poly(styrene butadiene) containing copolymers, functionalized polystyrene butadiene) copolymers such as carboxylated polystyrene butadiene), poly(styrene-isoprene), poly(methacrylic acid), poly(methylmethacrylate), poly(acrylic acid), poly(vinylalcohols), poly(vinylacetates), fluorinated polymers, polyvinylpyrrolidone, conductive polymers, polymers derived from natural sources, polyethers, polyesters, polyurethanes, and polyamides; homopolymers, graft, block or random co- or ter-polymers, and mixtures thereof.
  • the polymer is selected from the group consisting of vinyl polymers, poly(styrene-butadiene), partially or fully
  • composition of embodiment 2 further comprising additional inorganic structures comprising elements of the groups two through fourteen of the Periodic Table of
  • the binder composition of embodiment 2 further comprising carbon structures selected from the group consisting of carbon black, griphite, graphene, oxidized graphene, fullerenes, and mixtures thereof.
  • composition of embodiment 1, wherein the binder material has an impedance of less than or equal to about one billion ohm-m.
  • composition of embodiment 1, where the electrolyte material or separator film has a charge transfer resistance of less than or equal to about 10 million ohm- m
  • An electrode paste for a lead-acid battery comprising: high-surface area carbon nanotubes having an average length from about 1 ⁇ m to about 1,500 ⁇ m; and a polymer surfactant including polyvinyl alcohol.
  • composition comprising a plurality of high-surface area carbon nanotubes, wherein the carbon nanotubes comprise an interior and exterior surface
  • the improvement comprising: the interior surface comprising an interior surface oxidized species content and the exterior surface comprising an exterior surface oxidized species content, wherein the interior surface oxidized species content differs from the exterior surface oxidized species content by at least 20%, and as high as 100%.
  • die oxygenated species is selected from the group consisting of carboxylic acids, phenols, aldehydes, ketones, ether linkages, and combinations thereof.
  • a composition for use as a binder material, an electrolyte material or a separator film material of an energy storage or collection device comprising: a plurality of high-surface area carbon nanotube bundles, wherein the high-surface area bundles comprise individual carbon nanotubes, wherein the aspect ratio of the individual nanotubes is between about 700 and about 1,500, and wherein die average length of the high-surface area carbon nanotube bundles is between about 800 microns and about 1,500 microns.
  • compositions for use as a cathode material, an anode material, a binder material, an electrolyte material or a separator film material of an energy storage or collection device comprising: a portion of carbon nanotubes that have a different amount of oxygen containing species than another portion.
  • a further embodiment is the composition of embodiment 20 further comprising a portion of the carbon nanotubes that differ from another portion of carbon nanotubes by an amount of oxygen containing species of at least about 0.2 weight percent.
  • Another embodiment of this invention is a composition for use as a cathode material, an anode material, a binder material, an electrolyte material or a separator film material of an energy storage or collection device, comprising: a portion of carbon nanotubes that have a different type of oxygen containing species than another portion.
  • a yet further embodiment of this invention is the composition of embodiment 22 further comprising a portion of the carbon nanotubes that have a different type of oxygen containing species of not more than 50% by weight of all carbon nanotubes with oxygen containing species.
  • a dispersion comprising: oxidized, discrete carbon nanotubes wherein the discrete carbon nanotubes comprise an interior and exterior surface, each surface comprising an interior surface oxidized species content and an exterior surface oxidized species content, wherein the interior surface oxidized species content differs from the exterior surface oxidized species content by at least 20%, and as high as 100%; and high-surface area carbon nanotubes, wherein the high-surface area nanotubes are single-wall nanotubes, wherein the BET surface area of the high-surface area nanotubes is from about 550 m 2 /g to about 1500 m 2 /g according to ASTM D6556-16 and wherein the aspect ratio is at least about 500 up to about 6000; wherein the sum of the weight of the oxidized, discrete carbon nanotubes and the high surface area carbon nanotubes is in the range of from about 0.1 to about 30% by weight based on the total weight of the dispersion.
  • dispersant is selected from the group consisting of hydrophobic polymers, anionic polymers, non-ionic polymers, cationic polymers, ethylene oxide containing polymers, propylene oxide containing polymers, amphiphilic polymers, fatty acids, CYRENETM (Dihydrolevoglucosenone), and mixtures thereof.
  • polymer is selected from the group consisting of vinyl polymers, poly(styrene-butadiene), partially or fully hydrogenated poly(styrene butadiene) containing copolymers, functionalized polystyrene butadiene) copolymers such as carboxylated poly(styrene butadiene), poly(styrene- isoprene), poly(methacrylic acid), poly(methylmethaciylate), poly(acrylic acid), poly(vinylalcohols), poly(vinylacetates), fluorinated polymers, polyvinylpyrrolidone, conductive polymers, polymers derived from natural sources, polyethers, polyesters, polyurethanes, and polyamides; homopolymers, graft, block or random co- or terpolymers, and copolymers and mixtures thereof.
  • vinyl polymers poly(styrene-butadiene), partially or fully hydrogenated poly(styrene butadiene

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Abstract

La présente demande concerne des dispersions comprenant des nanotubes de carbone discrets oxydés et des nanotubes de carbone à grande surface. Les nanotubes de carbone discrets oxydés comprennent une surface intérieure et une surface extérieure, chaque surface comprenant une teneur en espèces oxydées de surface intérieure et une teneur en espèces oxydées de surface extérieure. La teneur en espèces oxydées de surface intérieure diffère de la teneur en espèces oxydées de surface extérieure d'au moins 20 %, et peut aller jusqu'à 100 %. Les nanotubes à grande surface sont généralement des nanotubes à paroi unique. La surface BET des nanotubes à grande surface est d'environ 550 m2/g à environ 1 500 m2/g selon la norme ASTM D6556-16. Le facteur de forme est d'au moins environ 500 et peut aller jusqu'à environ 6 000. Les dispersions comprennent d'environ 0,1 à environ 30 % en poids de nanotubes sur la base du poids total de la dispersion.
PCT/US2022/017992 2021-02-26 2022-02-25 Dispersions comprenant des nanotubes à grande surface et des nanotubes de carbone discrets Ceased WO2022183049A1 (fr)

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