Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
  • C08K3/042—Graphene or derivatives, e.g. graphene oxides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/20—Compounding polymers with additives, e.g. colouring
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/011—Nanostructured additives

Definitions

• Polymer nanocomposites comprising a nanomaterial dispersed in a polymer matrix have attracted interest because they have many desirable performance attributes related to mechanical properties, electrical conductivity, thermal conductivity, gas/vapor barrier properties, etc.
• graphene nanoplatelets enhance a variety of important functional properties of commercially important polymers. Accordingly, polymer- graphene nanocomposites comprising a graphene dispersed in a polymer matrix have been the subject of much research and development activity in recent years.
• Some current solutions for producing graphene -polymer composites include intermediate steps of producing graphene by liquid phase exfoliation of graphite in organic solvents, exfoliation of graphite in aqueous surfactant solutions, and mechanical exfoliation of graphite.
• liquid phase exfoliation of graphite can produce single-layer and few-layer graphene nanoplatelets.
• a solution having a significant concentration of soluble graphene can be produced by selecting a solvent having a surface free energy to match the surface free energy of graphite.
• surfactants can be used in water to reduce the interfacial free energy between graphene platelets to the point where significant concentrations of soluble graphene can be dissolved from graphite.
• graphene dispersion intermediates can be used to produce a polymer nanocomposite.
• solutions and dispersions of graphene nanoplatelets prepared from graphite by liquid phase exfoliation have been effectively used to prepare thermoset polymer composites by mixing the graphene solutions or dispersions with liquid thermoset resins, followed by removal of the solvents and curing the resins.
• thermoset resins having an improved storage modulus.
• the improved composite resin materials have a storage modulus that is much improved relative to the storage modulus of resins comprising graphite in the absence of high shear mixing.
• the improved composite resin materials produced by the methods described herein do not have deleterious brittleness
• embodiments of the technology relate to methods for the preparation of a composite resin material by exfoliating graphite in a polymer (e.g., liquid thermoset resin) by high shear mixing.
• a polymer e.g., liquid thermoset resin
• bulk graphite is exfoliated by high shear mixing in a neat liquid thermoset resin without the use of an exfoliating solvent to produce an exfoliated graphene intermediate.
• the composite resin materials are exfoliation solvent-free. Further, the incompletely exfoliated and unexfoliated graphite are not removed from the composite resin materials.
• the composite resin materials comprise graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• the technology is useful for producing polymer- graphene composite materials at a lower cost and reduced process complexity.
• the technology provides a method of producing a graphene suspension in a resin, the method comprising high shear mixing a mixture of resin and graphite to produce a graphene suspension in a resin.
• the mixture of resin and graphite comprises at least 1% graphite (w/w), e.g., at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w).
• the graphene suspension in the resin comprises at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the resin is a liquid thermoset resin. In some embodiments, the resin is a liquid thermoset resin.
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 1,000 to 50,000 centipoise (cP) (e.g.,
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 5,000 to 30,000 cP (e.g., approximately 5,000; 7,500; 10,000; 12,500; 15,000; 17,500; 20,000; 22,500; 25,000; 27,500; or 30,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 10,000 to 20,000 cP (e.g., approximately 10,000; 10,500;
• the graphene suspension in the resin comprises unexfoliated graphite particles having a size that minimizes and/or
• graphene is not produced by exfoliation of graphite in an exfoliation solvent, e.g., in an intermediate step for producing graphene by solvent exfoliation of graphite (e.g., mixing graphite in an exfoliation solvent). Accordingly, in some embodiments the graphene suspension in the resin is exfoliation solvent-free.
• the mixture of resin and graphite is high shear mixed for at least 30 minutes, e.g., for at least 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 or more hours.
• the mixture of resin and graphite is high shear mixed, e.g., mixed using a stator-rotor mixer wherein the shear gap is between 50 ⁇ and 150 ⁇ and the tip speed of the rotor is at least 400 feet/second.
• Additional embodiments provide a method of producing a polymer- graphene composite material, the method comprising high shear mixing a mixture of resin and graphite to produce a graphene suspension in a resin! and curing the graphene suspension in the resin to produce a polymer-graphene composite material.
• the mixture of resin and graphite comprises at least 1% graphite (w/w), e.g., at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w).
• w/w graphite
• the graphene suspension in the resin comprises at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the resin is a liquid thermoset resin.
• the curing is effected by use of a chemical curing agent (e.g., a hardener), by use of incubating at increased temperature, and/or by exposure to electromagnetic radiation.
• the graphene suspension in the resin comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics of the polymer- graphene composite material.
• the graphene suspension in the resin is exfoliation solvent-free.
• the mixture of resin and graphite is high shear mixed for at least 30 minutes, e.g., for at least 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 or more hours.
• the mixture of resin and graphite is high shear mixed, e.g., mixed using a stator-rotor mixer wherein the shear gap is between 50 ⁇ and 150 ⁇ and the tip speed of the rotor is at least 400 feet/second.
• the polymer- grap he ne composite material comprises at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%,
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 1,000 to 50,000 centipoise (cP) (e.g., approximately 1,000; 5,000; 10,000; 15,000; 20,000; 25,000; 30,000; 35,000; 40,000; 45,000; or 50,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 5,000 to 30,000 cP (e.g., approximately 5,000; 7,500; 10,000; 12,500; 15,000; 17,500; 20,000; 22,500; 25,000; 27,500; or 30,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 10,000 to 20,000 cP (e.g., approximately 10,000; 10,500;
• the polymer- graphene composite material comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics of the polymer- graphene composite material. In some embodiments, the polymer -graphene composite material is exfoliation solvent-free.
• Still further embodiments provide a method of producing a polymer-graphene composite material, the method comprising high shear mixing a mixture of resin, graphite, and multiwall carbon nanotubes to produce a suspension of graphene and exfoliated multiwall carbon nanotubes in a resin! and curing the suspension of graphene and exfoliated multiwall carbon nanotubes in a resin to produce a polymer-graphene composite material.
• the mixture of resin, graphite, and multiwall carbon nanotubes comprises at least 1% graphite (w/w) and at least 0.1% multiwall carbon nanotubes (w/w), e.g., at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.
• the technology provides a method of producing a polymer -grap he ne composite material, the method comprising high shear mixing a mixture of resin and graphite to produce a suspension of graphene in a resin! adding multiwall carbon nanotubes to the suspension of graphene in a resin to produce a suspension of graphene and multiwall carbon nanotubes in a resin! high shear mixing the suspension of graphene and multiwall carbon nanotubes in a resin to produce a suspension of graphene and exfoliated multiwall carbon nanotubes! and curing the suspension of graphene and exfoliated multiwall carbon nanotubes in a resin to produce a polymer- graphene composite material.
• the mixture of resin and graphite comprises at least 1% graphite (w/w) and the suspension of graphene and exfoliated multiwall carbon nanotubes comprises at least 0.1% multiwall carbon nanotubes (w/w), e.g., the mixture of resin and graphite comprises at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w) and the suspension of graphene and exfoliated multiwall carbon nanotubes comprises at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%
• compositions produced according to embodiments of the methods described herein provide compositions produced according to embodiments of the methods described herein.
• the technology provides a polymer- graphene composite material produced by a method comprising high shear mixing a mixture of resin and graphite to produce a graphene suspension in a resin.
• the polymer -graphene composite material is an exfoliation solvent-free polymer- graphene composite material.
• compositions comprising a resin and graphene produced by a method comprising high shear mixing a mixture of resin and graphite to produce a graphene suspension in a resin.
• the composition comprising a resin and graphene is an exfoliation-free composition comprising a resin and gra hene. That is, in some embodiments the composition comprising a resin and graphene is completely free of any added exfoliation solvents.
• compositions For example, some embodiments provide an exfoliation solvent-free composition comprising a resin and at least 1% graphene (w/w). Some embodiments provide an exfoliation solvent-free composition comprising a resin, at least 1% graphene (w/w), and at least 0.1% exfoliated multiwall carbon nanotubes (w/w). In some embodiments, the composition is an exfoliation solvent-free polymer- graphene composite material.
• the technology provides embodiments of systems for producing a polymer- graphene composite material.
• the system comprises a resin, graphite, a high shear mixer, and a curing agent.
• the resin is a liquid thermoset resin.
• the curing agent is a chemical curing agent.
• the system further comprises multiwall carbon nanotubes.
• Fig. 1 is a bar plot showing the storage modulus of unsaturated polyester polymer composite materials prepared according to the technology described by high shear mixing resin and 10% (w/w) graphite for 0 to 3 hours.
• Fig. 2 is a bar plot showing the storage modulus of unsaturated polyester polymer composite materials prepared according to the technology described by high shear mixing resin and 20% (w/w) graphite for 0 to 4 hours.
• Fig. 3 is a bar plot showing the storage modulus of unsaturated polyester polymer composite materials prepared according to the technology described by high shear mixing resin and 25% (w/w) graphite for 0 to 6 hours in a large batch format.
• Fig. 4 is a bar plot showing the storage modulus of epoxy polymer composite materials prepared according to the technology described by high shear mixing resin and 30% (w/w) graphite for from 0 to 4 hours.
• graphene refers to an allotrope of carbon having a structure that is a single planar sheet (an "atomic layer") of sp2-bonded carbon atoms arranged in a honeycomb crystal lattice.
• the term graphene includes but is not limited to graphene in the form of a one -atom -thick (monolayer) sheet, e.g., a graphene sheet that is one atomic layer thick.
• graphene also refers to the form of graphene in which many graphene sheets are stacked together, e.g., as present in the crystalline or "flake” form of graphite.
• graphene refers to monolayer (single layer) and/or multilayer graphene with a nanoscale thickness (e.g., graphene having fewer than 20 atomic layers and preferably fewer than 10 atomic layers).
• pristine means not functionalized, modified, or chemically reacted with other elements such as oxygen.
• nanomaterial is a material having one or more external dimensions in the size range of 1 nm to 100 nm.
• the "morphology" of a nanomaterial refers to the shape of the discrete nanomaterial particles.
• a nanomaterial is described as "intercalated” when the sheets of the nanomaterial are substantially organized in parallel and a nanomaterial is described as “exfoliated” when this arrangement has been lost.
• the term “resin” refers to liquid materials that are capable of hardening permanently, e.g., by polymerization.
• some "resins” are thermosetting plastics and the term “resin” may refer to the reactant or product, or both.
• the term “resin” may refer to one of two monomers in a copolymer (the other being called a "hardener”, e.g., as in an epoxy resin).
• the monomer compound is the "resin”.
• a "polymerizer” is a chemical reagent that effects the
• polymerizers as described herein are also widely referred to as "curing agents" or “hardeners”.
• Exemplary polymerizers may comprise, but are not limited to, organic peroxides (e.g., benzoyl peroxide), amines (e.g., ethylene diamine), sulfides, anhydrides, and many other compounds that can effect
• high shear mixing refers to mixing that produces a shear rate of greater than 1.0 x 10 5 sec -1 .
• the technology is related to polymer-graphene composite materials and methods for the production of polymer- graphene composite materials.
• methods are provided for producing a polymer-graphene composite material by exfoliating graphite in a polymer (e.g., resin) by high shear mixing.
• the technology produces an exfoliation solvent-free polymer-graphene composite material.
• the technology produces a polymer-graphene composite material from a mixture comprising graphite at greater than 1% (w/w), e.g., greater than 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or more, in a resin.
• the technology is related to resins comprising graphene (e.g., suspensions of graphene in a resin) and polymer-graphene composite materials (e.g., polymer-graphene composite materials cured from suspensions of graphene in a resin).
• the technology is further related to methods of producing suspensions of graphene in a resin and producing polymer-graphene composite materials.
• Some current methods for producing polymer-graphene composites typically involve a step of producing solvent exfoliated graphene by mixing graphite in an exfoliation solvent to produce a slurry intermediate comprising graphene in exfoliation solvent. Then, the graphene is concentrated by removing some portion of the solvent, e.g., by evaporation, filtration, etc., to produce a graphene intermediate. Then, the graphene intermediate (e.g., comprising the graphene in some remainder of the exfoliation solvent) is used to prepare a resin comprising graphene and, subsequently, to produce a polymer -graphene composite material.
• solvent exfoliated graphene by mixing graphite in an exfoliation solvent to produce a slurry intermediate comprising graphene in exfoliation solvent. Then, the graphene is concentrated by removing some portion of the solvent, e.g., by evaporation, filtration, etc., to produce a graphene intermediate. Then, the graphene
• an exfoliation solvent is added with graphite to a resin and mixed to produce a suspension of graphene in a resin.
• Using such a method produces a suspension of graphene in a resin that also comprises added exfoliation solvent.
• removing the solvent from the slurry, from the suspension of graphene in the resin, and/or from the polymer- graphene composite material is difficult, costly, and time consuming! further, the small amounts of added exfoliation solvent that remain in the polymer-graphene composite materials can compromise the desirable characteristics (e.g., physical, chemical, optical, electrical, etc. characteristics) of the polymer-graphene composite materials.
• the technology provided herein provides an unexpected and important improvement over extant methods and compositions.
• the technology provides compositions that do not comprise added exfoliation solvents and provides related methods for producing such compositions that do not involve producing any of the aforementioned intermediate compositions of exfoliated graphene in an exfoliation solvent and without adding an exfoliation solvent or any other solvents to the resin or suspension of graphene in the resin.
• compositions comprising a suspension of graphene in a resin and embodiments of compositions comprising a polymer-graphene composite as described herein do not comprise any solvents other than, or any solvent in addition to, solvents that were present in the resin composition used to make the suspensions of graphene in the resin and that were subsequently carried forward into the suspensions of graphene in the resin and/or the polymer-graphene composites.
• exfoliation solvent refers to a solvent that is used to exfoliate graphite (e.g., by solvent exfoliation methods) to produce graphene in an intermediate step prior to mixing the graphite or graphene with a polymer or a resin.
• a composition that is "exfoliation solvent-free” may comprise a solvent that was originally present in the resin composition used to prepare the suspension of graphene in the resin, but a composition that is "exfoliation solvent-free” does not comprise any additional type (e.g., any additional chemical species) or any additional amount of solvent, e.g., from an independent, intermediate solvent exfoliation step wherein graphite and exfoliation solvent are mixed to produce solvent-exfoliated graphene.
• exfoliation solvents include, but are not limited to, a pyrrolidone, e.g., an N-alkyl-pyrrolidone, e.g., N-methyl pyrrolidone! or an N-alkenyl pyrrolidone, e.g., N-vinyl pyrrolidone.
• a pyrrolidone e.g., an N-alkyl-pyrrolidone, e.g., N-methyl pyrrolidone! or an N-alkenyl pyrrolidone, e.g., N-vinyl pyrrolidone.
• exfoliation solvents used to produce graphene from graphite are described in U.S. Pat. Appl. Pub. No. 2011/0117361.
• a polymer or a resin is not an "exfoliation solvent”.
• exfoliation solvent-free means that a material (e.g., such as a suspension of graphene in a resin or a polymer- graphene composite material as described herein) does not comprise any added exfoliation solvent (e.g., such as exfoliation solvents used in extant methods to produce exfoliated graphene).
• the term "exfoliation solvent-free" means that a material (e.g., such as a suspension of graphene in a resin or a polymer- graphene composite material as described herein) may comprise a solvent that is or was present in the resin composition that was mixed with graphite to prepare a suspension of graphene in the resin in an amount less than the amount in the resin composition, but does not comprise additional solvent or other solvents.
• a material e.g., such as a suspension of graphene in a resin or a polymer- graphene composite material as described herein
• a solvent that is or was present in the resin composition that was mixed with graphite to prepare a suspension of graphene in the resin in an amount less than the amount in the resin composition, but does not comprise additional solvent or other solvents.
• solvents present in the resin composition are:
• the polymer-graphene composite materials are free of unpolymerized solvents (e.g., free of monomer solvents) or comprise unpolymerized solvents (e.g., monomer solvents) in a low (e.g., trace) amount that does not compromise the improved characteristics of the suspensions of graphene in the resin and, in particular, does not compromise the improved characteristics of the polymer-graphene composites provided herein.
• solvents present in the resin composition are non-polymerizable solvents.
• the polymer-graphene composite materials are free of non-polymerizable solvents or comprise non- polymerizable solvents in a low (e.g., trace) amount that does not compromise the improved characteristics of the suspensions of graphene in the resin and, in particular, does not compromise the improved characteristics of the polymer-graphene composites provided herein.
• Some particular embodiments provide an exfoliation solvent-free polymer- graphene composite material that does not comprise a non-polymerizable solvent or that does not comprise an unpolymerized solvent (e.g., a monomer solvent). Some particular embodiments provide an exfoliation solvent-free polymer-graphene composite material that comprises a non-polymerizable solvent or that comprises an unpolymerized solvent (e.g., monomer solvent) in a low (e.g., trace) amount that does not compromise the improved characteristics of the polymer- graphene composites provided herein.
• an exfoliation solvent-free polymer- graphene composite material comprising an amount of a non-polymerizable solvent or comprising an amount of an unpolymerized solvent (e.g., monomer solvent) that is less than 0.1% of the composition, e.g., less than 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, or 0.001% (w/w) of the composition.
• an unpolymerized solvent e.g., monomer solvent
• Some particular embodiments provide an exfoliation solvent-free polymer-graphene composite material comprising an amount of a non- polymerizable solvent or comprising an amount of an unpolymerized solvent (e.g., monomer solvent) that does not effectively, substantially, and/or significantly negatively affect the desirable characteristics of the polymer-graphene composite material.
• an unpolymerized solvent e.g., monomer solvent
• Some particular embodiments provide an exfoliation solvent-free suspension of graphene in a resin that does not comprise a solvent in an amount greater that the amount of said solvent in the resin composition that was used to prepare the suspension of graphene in the resin. Some particular embodiments provide an exfoliation solvent- free suspension of graphene in a resin that does not comprise any specific chemical species of solvent that was not present in the resin composition that was used to prepare the suspension of graphene in the resin.
• Some particular embodiments provide a suspension of graphene in a solution of thermoplastic resin in a volatile solvent (i.e., not a typical exfoliation solvent as defined herein) that can be easily removed by evaporation to provide a solid graphene/polymer resin composite that is essentially free of solvent or contains such a low level of solvent as to not negatively impact the polymer composite properties.
• a volatile solvent i.e., not a typical exfoliation solvent as defined herein
• Preferred thermoplastic resins/polymers are described above.
• Preferred volatile solvents are solvents with a boiling point of less than 100 degrees Celsius at atmospheric pressure and include, but are not limited to, diethyl ether, tetrahydrofuran (THF), methanol hexane, pentane and acetone.
• Some embodiments provide methods for producing a polymer-graphene composite material. For example, some embodiments are related to a method comprising mixing a resin (e.g., a liquid polymerizable resin) and graphite (e.g., graphite powder) to produce a suspension of graphite in the resin. Further, embodiments of methods comprise high shear mixing the suspension of graphite in the resin for at least 15 minutes or more to produce a suspension of graphene in a resin. Some embodiments comprise high shear mixing the suspension of graphite in the resin for at least 30 minutes, or for 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 or more hours.
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• embodiments of methods comprise high shear mixing the suspension of graphite in the resin for at least 15 minutes or more to produce a suspension of graphene in a resin.
• Some embodiments comprise high shear mixing
• Some embodiments comprise high shear mixing the suspension of graphite in the resin at a shear rate of at least 1 x 10 5 sec -1 . Some embodiments comprise high shear mixing the suspension of graphite in the resin using a stator-rotor mixer wherein the shear gap is between 50 ⁇ and 150 ⁇ and the tip speed of the rotor is at least 400 feet/second. For example, the tip speed of the rotor is at least 500 feet/second, 600 feet/second, 700 feet/second, 800 feet/second, or more.
• the suspension of graphite in the resin is cooled prior to high shear mixing, e.g., cooled to a temperature of less than 20°C, less than 15°C, less than 10°C, less than 9°C, less than 8°C, less than 7°C, less than 6°C, less than 5°C, less than 4°C, less than 3°C, less than 2°C, or less than 1°C.
• the suspension of graphite in the resin is continuously cooled during the mixing period to limit the maximum temperature during mixing to, e.g., 25°C, 30°C, 35°C, 40°C, 50°C, 60°C, 70°C, or 80°C.
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 1,000 to 50,000 centipoise (cP) (e.g., approximately 1,000; 5,000; 10,000; 15,000; 20,000; 25,000; 30,000; 35,000; 40,000; 45,000; or 50,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 5,000 to 30,000 cP (e.g., approximately 5,000; 7,500; 10,000; 12,500; 15,000; 17,500; 20,000; 22,500; 25,000; 27,500; or 30,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 10,000 to 20,000 cP (e.g., approximately 10,000; 10,500;
• Embodiments of methods comprise mixing a resin (e.g., a liquid polymerizable resin) and graphite (e.g., graphite powder) to produce a suspension of graphite in the resin comprising at least 1% graphite (w/w).
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• Some embodiments of methods comprise mixing a resin (e.g., a liquid polymerizable resin) and graphite (e.g., graphite powder) to produce a suspension of graphite in the resin comprising at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w).
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• High shear mixing of the suspension of graphite in the resin produces a suspension of graphene in the resin comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the suspension of graphene in the resin comprises unexfoliated graphite.
• the suspension of graphene in the resin comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• an added exfoliation solvent is not used to exfoliate graphite to produce graphene. Accordingly, in some embodiments the suspension of graphene in the resin is exfoliation solvent-free. That is, in some embodiments the suspension of graphene in the resin is completely free of added exfoliation solvents.
• Some embodiments relate to polymer- graphene composite materials that further comprise other materials (e.g., other nanomate rials). For example, some embodiments are related to polymer- graphene composite materials that further comprise multiwall carbon nanotubes. For example, some embodiments are related to a method comprising mixing a resin (e.g., a liquid polymerizable resin), graphite (e.g., graphite powder), and multiwall carbon nanotubes to produce a suspension of graphite and multiwall carbon nanotubes in the resin.
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• Some embodiments of methods comprise high shear mixing the suspension of graphite and multiwall carbon nanotubes in the resin for at least 15 minutes or more. Some embodiments comprise high shear mixing the suspension of graphite and multiwall carbon nanotubes in the resin for at least 30 minutes, or for 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 or more hours. Some embodiments comprise high shear mixing the suspension of graphite and multiwall carbon nanotubes in the resin using a stator-rotor mixer wherein the shear gap is between 50 ⁇ and 150 ⁇ and the tip speed of the rotor is at least 400 feet/second. For example, the tip speed of the rotor is at least 500 feet/second, 600 feet/second, 700 feet/second, 800 feet/second, or more.
• the suspension of graphite and multiwall carbon nanotubes in the resin is cooled prior to high shear mixing, e.g., cooled to a temperature of less than 20°C, less than 15°C, less than 10°C, less than 9°C, less than 8°C, less than 7°C, less than 6°C, less than 5°C, less than 4°C, less than 3°C, less than 2°C, or less than 1°C.
• the suspension of graphite in the resin is continuously cooled during the mixing period to limit the maximum temperature during mixing to, e.g., 25°C, 30°C, 35°C, 40°C, 50°C, 60°C, 70°C, or 80°C.
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 1,000 to 50,000 centipoise (cP) (e.g., approximately 1,000; 5,000; 10,000; 15,000; 20,000; 25,000; 30,000; 35,000; 40,000; 45,000; or 50,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 5,000 to 30,000 cP (e.g., approximately 5,000; 7,500; 10,000; 12,500; 15,000; 17,500; 20,000; 22,500; 25,000; 27,500; or 30,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 10,000 to 20,000 cP (e.g., approximately 10,000; 10,500;
• Embodiments of methods comprise mixing a resin (e.g., a liquid polymerizable resin), graphite (e.g., graphite powder), and multiwall carbon nanotubes to produce a suspension of graphite and carbon nanotubes in the resin comprising at least 1% graphite (w/w) and at least 0.1% multiwall carbon nanotubes.
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• multiwall carbon nanotubes e.g., a suspension of graphite and carbon nanotubes in the resin comprising at least 1% graphite (w/w) and at least 0.1% multiwall carbon nanotubes.
• Some embodiments of methods comprise mixing a resin (e.g., a liquid polymerizable resin), graphite (e.g., graphite powder), and multiwall carbon nanotubes to produce a suspension of graphite and multiwall carbon nanotubes in the resin comprising at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.
• high shear mixing of the suspension of graphite and multiwall carbon nanotubes in the resin produces a suspension of graphene in the resin comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• high shear mixing of the suspension of graphite and multiwall carbon nanotubes in the resin produces a suspension of graphene and exfoliated multiwall carbon nanotubes in the resin comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%,
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the suspension of graphene in the resin comprises unexfoliated graphite and/or unexfoliated multiwall carbon nanotubes.
• the suspension of graphene in the resin comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• an exfoliation solvent is not added to exfoliate graphite to produce graphene. Accordingly, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the resin is exfoliation solvent-free. That is, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the resin is completely free of added exfoliation solvents.
• Some embodiments are related to a method comprising mixing a resin (e.g., a liquid polymerizable resin) and graphite (e.g., graphite powder) to produce a suspension of graphite in the resin, high shear mixing the suspension of graphite in the resin to produce a suspension of graphene in the resin, adding multiwall carbon nanotubes to the suspension of graphene in the resin to produce a suspension of graphene and multiwall carbon nanotubes in the resin, and then high shear mixing the suspension of graphene and multiwall carbon nanotubes in the resin to produce a suspension of graphene and exfoliated multiwall carbon nanotubes in the resin.
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• some embodiments of methods comprise mixing a resin (e.g., a liquid polymerizable resin) and graphite (e.g., graphite powder) to produce a suspension of graphite in the resin comprising at least 1% graphite (w/w).
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• Some embodiments of methods comprise mixing a resin (e.g., a liquid polymerizable resin) and graphite (e.g., graphite powder) to produce a suspension of graphite in the resin comprising at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w).
• a resin e.g., a liquid polymerizable resin
• graphite e.g., graphite powder
• the suspension of graphite in the resin produces a suspension of graphene in the resin comprising at 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• nanotubes are added to the suspension of graphene in the resin to produce a suspension of graphene and multiwall carbon nanotubes in the resin comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%
• the suspension of graphene in the resin comprises unexfoliated graphite and/or unexfoliated multiwall carbon nanotubes. In some embodiments, the suspension of graphene in the resin comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness. In particular embodiments, an exfoliation solvent is not added to exfoliate graphite to produce graphene. Accordingly, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the resin is exfoliation solvent-free. That is, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the resin is completely free of added exfoliation solvents.
• Some embodiments further provide polymerizing (or, alternatively, "curing") a suspension of graphene in a resin, e.g., a suspension of graphene in a resin comprising multiwall carbon nanotubes).
• polymerizing comprises adding a polymerizer to a suspension of graphene in a resin and mixing the polymerizer and the suspension of graphene in the resin.
• polymerizing comprises incubating a suspension of graphene in a resin at a temperature of greater than 50°C, e.g., greater than 55°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or more for more than 1 hour, e.g., more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more hours.
• polymerizing comprises incubating a suspension of graphene in a resin at a plurality of temperatures of greater than 50°C, e.g., greater than 55°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or more for more than 1 hour, e.g., more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more hours.
• some embodiments comprise incubating a suspension of graphene in a resin at a first temperature greater than 50°C, e.g., greater than 55°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or more for more than 1 hour, e.g., more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more hours and then incubating the suspension of graphene in the resin at a second temperature greater than 50°C, e.g., greater than 55°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C or more for more than 1 hour, e.g.,
• polymerizing comprises exposing the suspension of graphene in a resin to electromagnetic radiation, e.g., ultraviolet radiation.
• a solid thermoplastic polymer is dissolved in a volatile solvent to produce a viscous polymer/solvent solution or resin which is mixed with graphite powder to form a suspension of graphite in the polymer/solvent solution.
• the suspension is then high-shear mixed for at least 15 minutes or more to produce a suspension of graphene in the polymer/solvent solution after which the volatile solvent is removed by evaporation to provide a solid thermoplastic graphene/polymer composite.
• Preferred thermoplastic resins/polymers are described above.
• Preferred volatile solvents are solvents with a boiling point of less than 100 degrees Celsius at atmospheric pressure and include, but are not limited to, diethyl ether, tetrahydrofuran (THF), methanol hexane, pentane and acetone.
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 1,000 to 50,000 centipoise (cP) (e.g., approximately 1,000; 5,000; 10,000; 15,000; 20,000; 25,000; 30,000; 35,000; 40,000; 45,000; or 50,000 cP).
• cP centipoise
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 5,000 to 30,000 cP (e.g., approximately 5,000; 7,500; 10,000; 12,500; 15,000; 17,500; 20,000; 22,500; 25,000; 27,500; or 30,000 cP).
• the viscosity of the resin and/or a composition comprising the resin prior to adding the graphite is approximately 10,000 to 20,000 cP (e.g., approximately 10,000; 10,500; 11,000; ⁇ ,5 ⁇ ; 12,000; 12,500; 13,000; 13,500; 14,000; 14,500; 15,000; 15,500; 16,000; 16,500; 17,000; 17,500; 18,000; 18,500; 19,000; 19,500; or 20,000 cP).
• the graphite used to produce graphene may be natural or synthetic.
• the graphite may be in the alpha (hexagonal) and/or beta (rhombohedral) forms, and may be either flat or buckled.
• the alpha form is convertible to the beta form through mechanical treatment; the beta form is convertible to the alpha form by heating above 1300°C.
• Natural graphite e.g., obtained by mining and purification of graphite -containing rock
• Synthetic graphite may be, e.g., high-quality (e.g., highly ordered pyrolytic graphite or highly oriented pyrolytic graphite) graphite, e.g., having an angular spread between the graphite sheets of less than 1°.
• Synthetic graphite may be produced by heating carborundum, e.g., to temperatures above 4000°C.
• the graphite is produced by recycling graphite -containing manufactures (e.g., electrodes).
• Commercial sources of graphite include, e.g., Technical Grade Graphite from Sargent Chemical Company! a common, commercial 350 Mesh Mr. Zip Graphite Powder from AGS Corporation of Michigan! Asbury Carbons A-625 synthetic graphite, and/or synthetic graphite powder from, e.g., Sigma-Aldrich.
• the resin is a thermoplastic resin, a thermoset resin, and/or an elastomer resin.
• the resin is a liquid thermoset resin.
• the resin is an unsaturated polyester resin.
• the resin is an epoxy resin.
• the resin is a vinyl ester resin.
• the resin is a thermoset polyurethane resin.
• the resin is an alkyl cyanoacrylate resin.
• the resin is a propylene resin.
• the resin is an ester resin, an amide resin, a styrene resin, a vinyl resin (e.g., a vinyl chloride resin), an imide resin, a dimethylsiloxane resin, an olefin resin, a carbonate resin, a nitrile rubber resin, a styrene -co -acrylic acid resin, a urethane resin, a silicone resin, an ethylene -co -vinyl acetate resin, a methylmethacrylate resin, a butyl rubber resin, an acrylic rubber resin, an N-vinyl pyrrolidone resin, an ethylene oxide resin, an ethylene -propylene -diene monomer resin, a styrene butadiene rubber resin, an ethylene-co-octene resin, a halobutyl rubber resin, a silylated-sulfonated ether ether ketone resin, a benzimidi
• the technology produces a polymer
• the polymer comprising graphene is an
• the polymer comprising graphene is an epoxy polymer. In some embodiments, the polymer comprising graphene is a polypropylene. In some embodiments, the polymer comprising graphene is a polyester, a polyamide, a polystyrene, a polyvinyl (e.g., a polyvinyl chloride), a polyimide, a polydimethylsiloxane, a polyolefin, a polycarbonate, a nitrile rubber, a poly(styrene-co- acrylic acid), a polyurethane, a silicone, a poly(ethylene -co -vinyl acetate), a
• Some embodiments are related to a composition comprising a resin and graphite. Some embodiments are related to a composition comprising a resin and graphene, e.g., a suspension of graphene in a resin produced by a method comprising high shear mixing graphite and a resin as described herein (e.g., without an intermediate step of exfoliating graphite in an exfoliation solvent to produce graphene).
• Some embodiments provide a suspension of graphite in a resin comprising at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w).
• Some embodiments provide a suspension of graphene in a resin comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the suspension of graphene in the resin comprises unexfoliated graphite.
• the suspension of graphene in the resin comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• the suspension of graphene in the resin is exfoliation solvent-free. That is, in some embodiments the suspension of graphene in the resin is completely free of added exfoliation solvents.
• Some embodiments relate to polymer- graphene composite materials that further comprise other materials (e.g., other nanomaterials). For example, some embodiments are related to polymer- graphene composite materials that further comprise multiwall carbon nanotubes.
• some embodiments provide a suspension of graphite and carbon nanotubes in a resin comprising at least 1% graphite (w/w) and at least 0.1% multiwall carbon nanotubes.
• Some embodiments provide a suspension of graphite and multiwall carbon nanotubes in the resin comprising at least 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% or more graphite (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%
• Some embodiments provide a suspension of graphene and exfoliated multiwall carbon nanotubes in a resin comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the suspension of graphene in the resin comprises unexfoliated graphite and/or unexfoliated multiwall carbon nanotubes.
• the suspension of graphene in the resin comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• an exfoliation solvent is not added to exfoliate graphite to produce graphene. Accordingly, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the resin is exfoliation solvent-free. That is, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the resin is completely free of added exfoliation solvents.
• Some embodiments are related to a composition comprising a polymer and graphene, e.g., a suspension of graphene in a polymer produced by a method comprising high shear mixing graphite and a resin as described herein (e.g., without exfoliating graphite in an exfoliation solvent) to produce a suspension of graphene in the resin and, in some embodiments, curing the suspension of graphene in the resin to produce a suspension of graphene in a polymer.
• a composition comprising a polymer and graphene, e.g., a suspension of graphene in a polymer produced by a method comprising high shear mixing graphite and a resin as described herein (e.g., without exfoliating graphite in an exfoliation solvent) to produce a suspension of graphene in the resin and, in some embodiments, curing the suspension of graphene in the resin to produce a suspension of graphene in a polymer.
• Some embodiments provide a suspension of graphene in a polymer comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w).
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the suspension of graphene in the polymer comprises unexfoliated graphite.
• the suspension of graphene in the polymer comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• the suspension of graphene in the polymer is exfoliation solvent-free. That is, in some embodiments the suspension of graphene in the polymer is completely free of added exfoliation solvents.
• Some embodiments relate to polymer- graphene composite materials that further comprise other materials (e.g., other nanomaterials). For example, some embodiments are related to polymer-graphene composite materials that further comprise exfoliated multiwall carbon nanotubes.
• Some embodiments provide a suspension of graphene and exfoliated multiwall carbon nanotubes in a polymer comprising at least 0.1% graphene (w/w), e.g., at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, or 4.0% or more graphene (w/w) and at least 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.
• the graphene particles have fewer than 20 atomic layers, preferably fewer than 10 atomic layers.
• the suspension of graphene in the polymer comprises unexfoliated graphite and/or unexfoliated multiwall carbon nanotubes.
• the suspension of graphene in the polymer comprises unexfoliated graphite particles having a size that minimizes and/or eliminates undesirable mechanical characteristics such as brittleness.
• an exfoliation solvent is not added to exfoliate graphite to produce graphene.
• the suspension of graphene and multiwall carbon nanotubes in the polymer is exfoliation solvent-free. That is, in some embodiments the suspension of graphene and multiwall carbon nanotubes in the polymer is completely free of added exfoliation solvents.
• the polymer-graphene composite materials described herein have an improved storage modulus. In some embodiments, the polymer-graphene composite materials have an improved impact strength. In some embodiments, the polymer-graphene composite materials comprising exfoliated multiwall carbon nanotubes have characteristics related to improved electrostatic dissipation.
• the polymer-graphene composite materials described herein have a storage modulus that is increased at least 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% or more relative to the storage modulus of materials comprising the same polymer without comprising graphene (e.g., a graphene-free polymer).
• a storage modulus that is increased at least 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% or more relative to the storage modulus of materials comprising the same polymer without comprising graphene (e.g., a graphene-free polymer
• the polymer-graphene composite materials described herein have a storage modulus that is increased at least 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% or more relative to the storage modulus of materials comprising graphite and the same polymer, but that have not been high shear mixed.
• the polymer-graphene composite materials have an impact strength that is similar or within 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25% of the impact strength of materials comprising the same polymer without comprising graphene (e.g., a graphene- free polymer).
• the polymer-graphene composite materials comprising exfoliated multiwall carbon nanotubes have characteristics related to electrostatic dissipation, e.g., a volume resistivity of less than 10 8 Ohm-cm.
• Unsaturated polyester resin (PCCR 741-6510 isophthalic base pultrusion resin, 4502 g) was added to a 12-liter capacity stainless steel mixing vessel equipped with an overhead open blade paddle stirrer with 4-inch diameter blade and a Silverson L5M overhead high shear mixer fitted with a 1.25-inch diameter mixing assembly and general purpose disintegrating mixing head.
• the mixing vessel was immersed in a water cooling batch containing a stainless steel cooling coil held at 0°C using a recirculating chiller.
• Bis phenol A epoxy resin (Epon 828, 185.32 g) was added to an 8 ounce glass jar.
• Graphite powder (Asbury A625 synthetic graphite, 79.42 g) was mixed into the liquid resin by manual mixing until a uniformly mixed suspension was obtained.
• the glass jar was placed in a cooling batch at 5 °C, and the suspension was then mixed using a Silverson L5M overhead high shear lab mixer fitted with a 1 inch tubular mixing assembly and low flow, high shear, mixing head. The mixing was carried out at 8,000 rpm for four hours. Throughout the mixing period, the jar was continuously moved in relation to the mixing head to ensure mixing of the entire sample volume (i.e. no "dead zones"). Samples of the mixture were removed before the high shear mixing was started (graphite control) and after each hour of high shear mixing.
• Graphite powder (Asbury A625 synthetic graphite, 5.40 g) was mixed into the viscous resin solution by manual mixing until a uniformly mixed suspension was obtained.
• the glass jar was placed in a cooling batch at 10 °C, and the suspension was then mixed using a Silverson L5M overhead high shear lab mixer fitted with a 1 inch tubular mixing assembly and low flow, high shear mixing head.
• the mixing was carried out at 8,000 rpm for two hours, moving the sample in relation to the mixing head every 20 minutes to ensure mixing of the entire sample volume (i.e. no "dead zones") resulting in a uniform, physically stable, dispersion which was poured into open cavity molds where the solvent was allowed to slowly evaporate at room temperature overnight followed by heating at 60 °C in a convection oven for one hour to produce test bars.
• DMA dynamic mechanical analysis
• Epoxy resin samples were mixed with epoxy hardener (Dow DEH 20) in a weight ratio of 5 parts resin to 1 part hardener, poured into silicone cavity molds (Ladd Research Industries, 12.5 cm by 1.2 cm cavities) to a depth of about 2 mm, and cured in a vacuum oven at 60 °C for two hours to produce cured epoxy test bars for DMA.
• epoxy hardener Dow DEH 20
• silicone cavity molds Ladd Research Industries, 12.5 cm by 1.2 cm cavities
• Cured sample polymer bars prepared as describe above from the 10% and 20% graphite loading examples described above, were analyzed by dynamic mechanical analysis (DMA) using a constant temperature strain sweep at room temperature and a 3 -point bending mode.
• DMA dynamic mechanical analysis
• the storage modulus values as a function of mixing time for 10% graphite loading are summarized in Figure 1.
• Storage modulus values were measured for controls.
• the first "unsheared resin” control was a cured polymer bar of the UPR resin with no added graphite and no high shear mixing treatment.
• the second "sheared resin” control was a cured polymer bar of the resin with no added graphite that was high shear mixed for a period of 24 hours.
• the storage modulus values as a function of mixing time for 20% graphite loading are summarized in Figure 2.
• the storage modulus measured for the "0 Hr" shear sample (comprising 20% graphite and not high shear mixed) was not significantly different than the storage modulus of the unsheared resin-only "Control" ( Figure 2, columns 1 and 3).
• the storage modulus of the 20% graphite samples (“1 Hr") increased by 22% relative to the unsheared resin-only "Control" ( Figure 2, columns 4 and l).
• Example 2 Izod impact testing of cured unsaturated polyester resin samples at 10% (w/w) graphite loading
• Example 3 Electrical resistivity testing of cured unsaturated polyester resin samples
• Cured sample test bars were prepared as described above from unsheared resin containing no graphite! and from resin with 10% graphite loading and 0.5% MWCNT loading as described above.
• the test bars were tested for electrical resistivity using a Static Solutions RT- 1000 Megohmmeter.
• the average resistivity value for the unsheared resin-only test bars was 6.76 x 10 10 Ohm-cm and the average resistivity value for the test bars with 10% graphite and 0.5% MWCNT was 2.46 x 10 7 Ohm-cm.
• Example 4 Dynamic mechanical analysis of cured unsaturated polyester samples from large batch mixing
• Cured epoxy test bars prepared as described in the Materials and Methods above, were analyzed by dynamic mechanical analysis (DMA) on an RSA III Dynamic Mechanical Analyzer using a constant temperature strain sweep at room temperature and 3 -point bending mode.
• the storage modulus values as a function of time for 30% graphite loading are summarized in Figure 4.
• the storage modulus measured for the "0 hr" samle (comprising 30% graphite and not high shear mixed) was 11% higher than the epoxy resin-only control. After 1 hour of high shear mixing there was an increase in storage modulus to 14% higher than the resin-only control. After 2 hours of high shear mixing there was a further increase in storage modulus to a value 27% higher than the resin- only control. After 3 and 4 hours of mixing there was a decrease in storage modulus to values that were 22% and 17% higher than the control, respectively.

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• 2015
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