TW202334028A - Dispersion of carbon nanostructures - Google Patents

Abstract

A composition contains 5-15 wt% CNS-derived species and a polymer resin having a hydroxyl content of at least 1.5 wt% and a melt viscosity of at least 8 Pa.s at a shear rate of 0.1 s1 at a temperature 60 DEG C greater than the highest temperature at which the resin undergoes a thermal transition. The polymer resin further has either a solubility in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate of at least 5 wt%, an acid number of at least 100, or both.

Description

Carbon nanostructure dispersion

The present invention relates to the use of soluble polymers to assist in the dispersion of carbon nanostructures in liquid carriers.

One of the most notable features of carbon nanotubes is their high electrical conductivity due to their graphene structure and large aspect ratio. Due to their branched tree-like structure, carbon nanostructures (CNS) can form networks more efficiently than carbon nanotubes with much higher aspect ratios. That is, the carbon nanostructures provide higher conductivity at a given load than typical multi-walled carbon nanotubes. However, these branched structures also make it difficult to disperse carbon nanostructures, especially in organic solvent-based coatings. Until now, adequate dispersion in many coating formulations required long grinding times and low concentrations. Insufficient grinding time may not completely peel off the carbon nanostructure, and complete peeling may also fracture the CNS to the extent that its conductive efficiency is impaired. Therefore, it is desirable to have a method of dispersing CNS in liquids (especially organic solvents) to optimize dispersion and conductive efficiency.

In one embodiment, a composition includes 5 to 15 wt% CNS derivative species and a polymer resin having a) a hydroxyl content of at least 1.5 wt%; b) at a shear rate of 0.1 s ^-1 and a melt viscosity of at least 8 Pa.s at a temperature 60°C higher than the maximum temperature at which the resin undergoes thermal transfer; and c) at least one of the following: i) 1 between butyl acetate and propylene glycol methyl ether acetate: 1 (w/w) solubility in the mixture of at least 5 wt%, and ii) an acid number of at least 100. The heat transfer can be the glass transition temperature, melting temperature or softening point. The polymer resin may have a hydroxyl content from 1.5 wt% to 5 wt%. Melt viscosity can range from 8 Pa.s to 1000 Pa.s. The polymer resin may have a solubility of 5 to 10 wt% and/or a molecular weight Mn of 15,000 to 80,000 in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate. The polymer resin may have an acid value of 100 to 300. When at least 50% of the acid groups on the polymer resin are non-ionized and/or the molecular weight (Mn) is 8000 to 40000, the solubility of the polymer resin in water can be at least 5 wt%. The composition may further comprise a dispersant, which may be present in an amount of 20 to 60 wt% relative to the amount of dispersant and CNS derivative species.

A coating composition may include a composition and a coating resin, such as an acrylic, polyurethane, polyester and/or epoxy resin, such as an acrylic or polyester resin. The coating composition may comprise 0.05 to 1 wt% (dry basis), such as 0.1 to 0.5 wt% or 0.05 to 0.2 wt% CNS derivative species. The coating composition may have a Hegman grind value of 10 to 30 microns, such as 15 to 20 microns.

In another embodiment, a method for preparing a composition includes combining carbon nanostructures with a polymer resin having a hydroxyl content of at least 1.5 wt%; at a shear rate of 0.1 s ^-1 and A melt viscosity of at least 8 Pa.s at a temperature 60°C higher than the maximum temperature at which the resin undergoes thermal transfer; and at least one of the following: a) in a 1:1 ratio of butyl acetate and propylene glycol methyl ether acetate (w /w) a solubility in the mixture of at least 5 wt%, and b) an acid number of at least 100 to form a composition having 5 to 15 wt% CNS derivative species. The carbon nanostructures may be coated with a dispersant, which may be present in an amount of 20 to 60 wt% relative to the amount of coated carbon nanostructures.

The dispersant may be selected from the group consisting of poly(vinylpyrrolidone), poly(vinylpyrrolidone-co-vinyl acetate), poly(vinyl butyral), poly(vinyl alcohol), polyalkylene oxides, including amines Functional polyalkylene oxide or acrylic polymer, poly(propylene carbonate), cellulose dispersant, poly(carboxylic acid), polyacrylate, poly(methacrylate), poly(acrylamide) , amide wax, styrene maleic anhydride resin, amine functional or amine terminated compounds, alkylphenol ethoxylates or alkyl ethoxylates, AMP™ dispersants, containing 2-amino-2- Methyl-1-propanol dispersant, polyester, polyamide block copolymer with both hydrophobic and hydrophilic groups, sodium dodecyl sulfate (SDS), dodecyl benzyl sulfonic acid Sodium, an amine functional derivative of any of these, an acid functional derivative of any of these, or a mixture of two or more of these.

In another embodiment, the composition can be used to form a coating composition by allowing the polymer resin to dissolve in the solvent by combining it with a solvent and optionally a dispersant to produce a dispersion of CNS derivative species in the solvent. liquid and combine the dispersion with coating resin and optional additives. The coating resin may include acrylic, polyurethane, polyester or epoxy resin. The coating resin may be acrylic resin or polyester resin. The optional additives can be at least one of the following: co-solvents, surfactants, fillers, adhesion promoters, flow regulators, leveling aids, bactericides, and colorants. The coating composition may comprise 0.05 to 1 wt% (dry basis), such as 0.1 to 0.5 wt% or 0.05 to 0.2 wt% CNS derivative species. The coating composition may have a Hegmann fineness value of 10 to 30 microns, such as 15 to 20 microns.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and disclosing only and are intended to provide further disclosure of the invention, as claimed.

In one embodiment, the composition contains 5 to 15 wt% CNS derivative species and a polymer resin having a hydroxyl content of at least 1.5 wt%; and at a shear rate of 0.1 s ⁻¹ and at a temperature higher than the resin experienced heat The maximum transfer temperature is 60°C and the melt viscosity is at least 8 Pa.s. The polymer resin additionally has a solubility of at least 5 wt% in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate, or an acid number of at least 100, or both.

The compositions provided herein can be prepared with water-soluble polymer resins or organic solvent-soluble polymer resins. In either case, the polymer resin has a hydroxyl content of at least 1.5 wt%, such as at least 1.6 wt%, at least 1.7 wt%, at least 1.8 wt%, or from 1.5 to 2 wt%. In addition, the polymer resin has a melt viscosity of at least 8 Pa.s at a shear rate of 0.1 s ^-1 and a temperature 60°C higher than the maximum temperature at which the resin undergoes thermal transfer. For example, at a shear rate of 0.1 s ^-1 , the melt viscosity can be at least 10 Pa.s, or, for example, from 8 Pa.s to 1000 Pa.s, from 10 Pa.s to 800 Pa.s, from 12 Pa.s to 500 Pa.s, or from 14 Pa.s to 200 Pa.s. The relevant heat transfer is preferably the highest temperature transfer of the glass transition temperature (Tg), softening point or melting point (Tm). However, those skilled in the art will recognize that not all polymer resins will exhibit all three transfers. For example, not all polymer resins have melting points. More specifically, melt viscosity is measured at a temperature that is 60°C higher than the highest temperature thermal transfer (eg, Tg, Tm, or softening point) actually exhibited by the polymer resin. Differential scanning calorimetry is better used to measure Tg and Tm. The softening point is preferably measured using the ring and ball method, for example according to DIN 53180. If the softening point measurement yields a range of temperatures, the highest temperature in the range is used. Melt viscosity can be measured using any commercially available rheometer. In this example, viscosity is measured in a Discovery HR-2 Hybrid Rheometer–2 using 25 mm side-by-side disposable aluminum pans. The test sample was equilibrated at the test temperature for two minutes, pre-sheared at 0.5 1/s for 30 s, and equilibrated for another 5 minutes. Flow scans were performed from 0.1 1/s to 1000 1/s at this test temperature.

The composition may be prepared with a polymer resin having a solubility in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate of at least 5 wt%, for example at least 5.5 wt%, at least 6 wt%, at least 6.5 wt%, at least 7 wt%, at least 7.5 wt%, at least 8 wt%, at least 8.5 wt% or up to 10 wt%. The solvent-soluble polymer resin may also have a glass transition temperature of at least 80°C, such as at least 85°C, at least 90°C, at least 95°C, at least 100°C, or from 80°C to 140°C. Alternatively or additionally, the solvent-soluble polymer resin may have a molecular weight (Mn) from 15,000 to 80,000.

Alternatively or additionally, the polymer resin may have an acid number of at least 100, for example from 100 to 300 or from 150 to 250. A high acid value promotes the dissolution of polymer resins, especially in aqueous solvents. For example, when at least 50% of the acid groups on the polymer resin are non-ionized, the solubility of the polymer resin in water can be at least 5 wt%, such as at least 10%, from 5% to 80%, from 15% to 65%, or from 20% to 50%. Solubility is evaluated when at least 50% of the acid groups on the polymer resin are in the -OH form and have no ionic groups that require counterions to remain neutral. Alternatively or additionally, the water-soluble polymer resin may have a molecular weight (Mn) of at least 8000, for example from 8000 to 40000.

These compositions serve as a vehicle to predisperse the CNS before complete formulation. The use of polymeric resins to provide higher viscosity may improve CNS bundle exfoliation. In order to formulate the composition into a coating composition, the polymeric resin used in the predispersion should be compatible with the polymeric binder system used in the coating, such as acrylic, polyester, polyurethane and epoxy systems. Preferred polymer systems for primer coating systems are acrylic and polyester. The hydroxyl groups on the polymer resin used to predisperse CNS can cross-link with these common binders used in coatings. The molecular weight of the polymer resin, measured directly or using glass transition temperature as a surrogate, should be high enough to cause friction during mixing with the CNS, but low enough that the polymer resin remains soluble in the liquid vehicle of the coating composition middle. Polymer resins suitable for pre-dispersed organic solvent-based systems CNS include but are not limited to cellulose acetate butyrate, cellulose acetate propionate, polyester-based solid resins, such as Evonik’s Tego AddBond LP1600 and LP1611 (1.85% hydroxyl); and Acrylic or polyester resins, which are available as liquids but can have the solvent removed and used in solid form, for example, Allnex's Setalux XCS 1518 and Paraloid AU-830 (3.45% hydroxyl). Suitable water-soluble polymer resins include Gellner Industrial LLC's Ottopol 25-30 and BASF's Joncryl resin, Kururay's ISOBAM resin, Cray Valley's SMA resin and Polyscope Polymers' XiRan resin. .

As is known in the art, carbon nanotubes (CNT or CNT plural) are carbonaceous materials that contain at least one layer of sp ² hybridized carbon atoms bonded to each other to form a honeycomb lattice that forms a cylindrical shape. or tubular structures. Carbon nanotubes can be single-walled carbon nanotubes (SWCNT) or multi-walled carbon nanotubes (MWCNT). SWCNTs can be thought of as allotropes of sp ^hybridized carbon similar to fullerenes. The structure is a cylindrical tube containing six-membered carbon rings. MWCNTs, on the other hand, have several tubes in concentric cylinders. The number of such isocentric walls may vary, for example, from 2 to 25 or more. Generally speaking, the diameter of MWNTs can be 10 nm or larger compared to the 0.7 to 2.0 nm diameter of typical SWNTs.

Among the many CNS used in various embodiments, the CNTs are MWCNTs, having, for example, at least two coaxial carbon nanotubes. The number of walls present may range from about 2 to 30, for example: 4 to 30, 6 to 30, 8 to 30, 10 to 30, 12 to 30, 14 to 30, 16 to 30, 18 to 30, 20 to 30, 22 to 30, 24 to 30, 26 to 30, 28 to 30 or 2 to 28, 4 to 28 , 6 to 28, 8 to 28, 10 to 28, 12 to 28, 14 to 28, 16 to 28, 18 to 28, 20 to 28, 22 to 28, 24 to 28, 26 to 28 or 2 to 26, 4 to 26, 6 to 26, 8 to 26, 10 to 26, 12 to 26, 14 to 26, 16 to 26, 18 to 26, 20 to 26, 22 to 26, 24 to 26 or 2 to 24, 4 to 24 , 6 to 24, 8 to 24, 10 to 24, 12 to 24, 14 to 24, 16 to 24, 18 to 24, 20 to 24, 22 to 24 or 2 to 22, 4 to 22, 6 to 22, 8 to 22, 10 to 22, 12 to 22, 14 to 22, 16 to 22, 18 to 22, 20 to 22 or 2 to 20, 4 to 20, 6 to 20, 8 to 20, 10 to 20, 12 to 20 , 14 to 20, 16 to 20, 18 to 20 or 2 to 18, 4 to 18, 6 to 18, 8 to 18, 10 to 18, 12 to 18, 14 to 18, 16 to 18 or 2 to 16, 4 to 16, 6 to 16, 8 to 16, 10 to 16, 12 to 16, 14 to 16 or 2 to 14, 4 to 14, 6 to 14, 8 to 14, 10 to 14, 12 to 14 or 2 to 12 , 4 to 12, 6 to 12, 8 to 12, 10 to 12 or 2 to 10, 4 to 10, 6 to 10, 8 to 10 or 2 to 8, 4 to 8, 6 to 8 or 2 to 6, 4 to 6 or 2 to 4.

Because CNS is a polymerized, highly branched, and cross-linked network of CNTs, at least some of the chemical reactions observed with individualized CNTs can also occur on CNS. Furthermore, some of the attractive properties typically associated with the use of CNTs are also exhibited in materials containing CNS. Such properties include, for example, electrical conductivity; attractive physical properties including maintaining or achieving good tensile strength when incorporated into polysiloxy-based compositions; thermal stability (sometimes with diamond crystals or coplanar graphite flakes) and/or chemical stability, to name a few.

However, as used herein, the term "CNS" does not refer to individual, unentangled structures such as "monomeric" fullerenes (the term "fullerene" broadly refers to allotropes of carbon that are synonyms for hollow spheres, ellipsoids, tubes, such as carbon nanotubes and other shapes). In fact, many embodiments of the present invention highlight the observed or expected differences in using CNS compared to using its CNT building blocks and Advantages. Without wishing to be bound to a particular explanation, it is believed that the combination of branching, cross-linking and co-walling between carbon nanotubes in CNS will reduce or minimize van der Waals forces when used in a similar manner Van der Waals forces often create problems when working with individual carbon nanotubes, especially when agglomeration needs to be prevented.

In addition to, or alternatively to, performance attributes, CNTs that are part of or derived from CNS can be characterized by a number of characteristics, at least some of which can distinguish CNTs from other nanomaterials, such as ordinary CNTs ( i.e. not derived from CNS and can be used as individualized, primary or replacement CNTs).

In many cases, CNTs present in or derived from CNS have typical diameters of 100 nanometers (nm) or less, such as, for example, in the range from about 5 to about 100 nm, for example, in the range from about 10 to about 100 nm. In the range of about 75, in the range from about 10 to about 50, in the range from about 10 to about 30, from about 10 to about 20 nm.

In specific embodiments, at least one CNT has a length equal to or greater than 2 microns as determined by SEM. For example, the length of at least one CNT will be in the range of 2 to 2.25 microns, from 2 to 2.5 microns, from 2 to 2.75 microns, from 2 to 3.0 microns, from 2 to 3.5 microns, from 2 to 4.0 microns, or from 2.25 to 2.5 microns. microns, from 2.25 to 2.75 microns, from 2.25 to 3 microns, from 2.25 to 3.5 microns, from 2.25 to 4 microns, or from 2.5 to 2.75 microns, from 2.5 to 3 microns, from 2.5 to 3.5 microns, from 2.5 to 4 microns, or From 3 to 3.5 microns, or from 3 to 4 microns, or from 3.5 to 4 microns or longer. In some embodiments, at least more than one (e.g., such as at least about 0.1%, at least about 1%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, as determined by SEM) At least about 35%, at least about 40, at least about 45%, at least about 50%, or even more than half) of the CNTs may have a length greater than 2 microns (eg, within the range specified above, for example).

For many CNTs in CNS, at least a portion of the CNT sidewall is shared with another CNT. Although it is generally understood that not necessarily every carbon nanotube in a CNS is branched, cross-linked, or shares a wall with other CNTs, at least a portion of the CNTs in the carbon nanostructure may be interleaved with each other and/or with the carbon The remainder of the nanostructure is interlaced with branched, cross-linked or co-walled carbon nanotubes.

The morphology of CNTs present in CNS, CNS fragments, or fractured CNTs derived from CNS is often characterized by a high aspect ratio, with a length often exceeding 100 times its diameter, and in some cases even higher. For example, in CNS (or CNS fragments), the CNT length to diameter aspect ratio can range from about 200 to about 1000, such as, for example, from 200 to 300, from 200 to 400, from 200 to 500, from 200 to 600, from 200 to 700, from 200 to 800, from 200 to 900 or from 300 to 400, from 300 to 500, from 300 to 600, from 300 to 700, from 300 to 800, from 300 to 900, from 300 to 1000 or from 400 to 500, from 400 to 600, from 400 to 700, from 400 to 800, from 400 to 900, from 400 to 1000 or from 500 to 600, from 500 to 700, from 500 to 800, from 500 to 900, from 500 to 1000 or from 600 to 700, from 600 to 800, from 600 to 900, from 600 to 1000, from 700 to 800, from 700 to 900, from 700 to 1000 or from 800 to 900, from 800 to 1000 or from 900 to 1000.

It has been found that in CNS and structures derived from CNS (CNS derivatives, such as CNS fragments or fractured CNTs), at least one CNT is characterized by a certain "branching density". As used herein, the term "branch" refers to a feature in which a single carbon nanotube connected to a multi-walled carbon nanotube diverges into multiples (two or more). One embodiment has a branching density according to which at least two branches are present along a two micron length of the carbon nanostructure as determined by SEM. Three or more branches may also appear.

Additionally, or alternatively, the number of walls observed on one side of a branch (e.g., before the branch point) of a branch region (point) in CNS, CNS fragments, or fractured CNTs is the same as on the other side of this region (e.g., the branch point). Different numbers of walls are observed (behind or after the branch point). This wall number variation, also referred to herein as wall number "asymmetry," is not observed in ordinary Y-shaped CNTs (where the same number of walls is observed in the region before and after the branch point).

Figures illustrating these features are provided in Figures 1A and 1B. An exemplary Y-shaped CNT 11 not derived from CNS is shown in Figure 1A. The Y-shaped CNT 11 includes catalyst particles 13 located at or near the branch point 15 . Areas 17 and 19 are located before and after branch point 15 respectively. In the case of Y-shaped CNTs such as Y-shaped CNT 11, regions 17 and 19 are both characterized by the same number of walls, ie two walls in the figure.

In contrast, in CNS (FIG. 1B), CNT building block 111 branches at branch point 115 and does not contain catalyst particles at or near this point, as seen at catalyst-deficient region 113. Furthermore, the number of walls present in region 117 before front branch point 115 (or on the first side thereof) is different from the number of walls present in region 119 (which is behind, behind, or on the other side relative to branch point 115 ). . In more detail, the three-wall feature found in region 117 does not continue into region 119 (which has only two walls in the diagram of FIG. 1B ), creating the asymmetry described above.

These features are highlighted in the TEM images of Figures 2A and 2B.

In more detail, the CNS branching in TEM region 40 of Figure 2A shows the absence of any catalyst particles. In the TEM of Figure 2B, first channel 50 and second channel 52 illustrate the asymmetry in wall number that plays a major role in the branched CNS, while arrow 54 points to a region showing wall sharing.

One, more, or all of these attributes may be present in the coating compositions described herein.

In some embodiments, the CNS exists as part of a tangled and/or interconnected CNS network. This interconnection network may include bridges between CNSs.

Suitable techniques for preparing CNS are described, for example, in U.S. Patent Application Publication No. 2014/0093728 A1, published April 3, 2014, U.S. Patent Nos. 8,784,937B2, 9,005,755B2, 9,107,292B2, and 9,447,259 No. B2. The entire contents of these documents are incorporated herein by reference.

As described in these documents, CNS can be grown on a suitable substrate, such as a catalyst-treated fibrous material. The product can be fiber-containing CNS material. In some cases, the CNS is separated from the substrate to form flakes.

As can be seen in US 2014/0093728A1, carbon nanostructures obtained as flake materials (ie discrete particles of finite size) exist as three-dimensional microstructures due to the entanglement and cross-linking of their highly aligned carbon nanotubes. The aligned morphology reflects the formation of carbon nanotubes on the growth substrate under rapid carbon nanotube growth conditions (e.g., a few microns per second, such as about 2 microns per second to about 10 microns per second), thereby inducing substantially Vertical carbon nanotubes are grown from a growth substrate. Without being bound by any theory or mechanism, it is believed that the rapid growth rate of carbon nanotubes on the growth substrate may contribute, at least in part, to the complex structural morphology of the carbon nanostructures. In addition, the packing density of CNS can be adjusted to a certain extent by adjusting the growth conditions of carbon nanostructures, including, for example, by changing the transition metal nanoparticle catalyst disposed on the growth substrate for initiating the growth of carbon nanotubes. The concentration of particles.

The flakes may be further processed, for example, by cutting or fluffing (operations that may involve mechanical milling, grinding, mixing, etc.), chemical processes, or any combination thereof.

In some embodiments, the CNS employed is "coated," also referred to herein as "encapsulated" CNS. In a typical coating process, a coating is applied to the CNTs that form the CNS. This coating process can form a partial or complete coating that is non-covalently bonded to the CNT and, in some cases, can act as a binder. Additionally, or alternatively, the coating may be applied to the formed CNS in a post-coating (or encapsulation) process. For example, using coatings with adhesive properties, CNS can be formed into larger structures, granules or pellets. In other embodiments, the particles or pellets are formed independently of the coating function.

For example, sheet material can be harvested and sprayed with an aqueous solution containing a binder (eg, polyethylene glycol or polyurethane) to form a wet sheet. The weight ratio of aqueous binder solution to sheet material can range from 8:1 to 15:1, for example, from 10:1 to 15:1, from 10:1 to 13:1, or from 10:1 to 12:1 . The moistened flakes can then be extruded to form a moistened extrudate. The wet extrudates are dried (eg, by air drying, drying in an oven) to form CNS pellets. Alternatively, the wet flakes are dried to form CNS particles.

Various types of coatings are available. In many cases, glues commonly used to coat carbon fiber or glass fiber can also be used as coatings for CNS. In such embodiments, the coating may range from about 0.1 wt% to about 10 wt% relative to the total weight of the coated CNS material (e.g., from about 0.1 wt% to about 0.5 wt%, From about 0.5% by weight to about 1% by weight, from about 1% by weight to about 1.5% by weight, from about 1.5% by weight to about 2% by weight, from about 2% by weight to about 2.5% by weight, from about 2.5% by weight to About 3% by weight, from about 3% by weight to about 3.5% by weight, from about 3.5% by weight to about 4% by weight, from about 4% by weight to about 4.5% by weight, from about 4.5% by weight to about 5% by weight, from About 5% by weight to about 5.5% by weight, from about 5.5% by weight to about 6% by weight, from about 6% by weight to about 6.5% by weight, from about 6.5% by weight to about 7% by weight, from about 7% by weight to about 7.5% by weight, from about 7.5% by weight to about 8% by weight, from about 8% by weight to about 8.5% by weight, from about 8.5% by weight to about 9% by weight, from about 9% by weight to about 9.5% by weight, or from about ranging from 9.5% to about 10% by weight). Specific examples of sizing materials include, but are not limited to, fluorinated polymers such as: poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(tetrafluoroethylene) Fluoride) (PTFE), polyimide, and water-soluble adhesives such as poly(ethylene oxide), polyvinyl alcohol (PVA), cellulose, carboxymethyl cellulose (CMC), starch, hydroxypropyl Cellulose, regenerated cellulose, polyvinylpyrrolidone (PVP) and copolymers and their mixtures. In many examples, the CNS used is treated with polyurethane (PU), thermoplastic polyurethane (TPU) or polyethylene glycol (PEG). Polymers such as, for example, epoxy, polyester, vinylester, polyetherimide, polyetherketoneketone, polyphthalamide, polyetherketone, polyetheretherketone, polyimide, phenol- Formaldehyde, bismaleimide, acrylonitrile-butadiene-styrene (ABS), polycarbonate, polyethyleneimine, polyurethane, polyvinyl chloride, polystyrene, polyolefin, polypropylene, polyethylene, Polytetrafluoroethylene, elastomers such as, for example, polyisoprene, polybutadiene, butyl rubber, nitrile rubber, ethylene vinyl acetate polymers, silicone polymers and fluorosilicone polymers, Compositions or other polymers or polymeric mixtures may also be used as sizing materials in some cases. To increase the conductivity, conductive polymers such as, for example, polyaniline, polypyrrole and polythiophene can also be used.

Alternative examples may utilize coatings that help stabilize CNS dispersions in aqueous or organic solvents. In one example, the coating is selected to promote and/or stabilize dispersed CNS in a vehicle produced by combining the desired resin for the coating with the desired solvent and optional dispersant. Any suitable combination of the resins and solvents provided above may be used. In another example, the coating is the same, similar or compatible with the dispersant or thickener used in treating CNS. For example, the CNS flake material can be coated with a suitable dispersant for use with a solvent (eg, organic or aqueous) system in which the CNS-polymer resin composition is dissolved/dispersed. To provide a suitable amount of dispersant for a liquid dispersion or other formulation, it may be desirable to increase the amount of dispersant used as a coating compared to the amount of coating of CNS pellets or granules used in the sizing materials described above. For example, the amount of dispersant may be at least 20% by weight relative to the majority of the coated CNS material, such as 25% to 60%, 30% to 55%, 40% to 50%, or 45% to 60% by weight.

Exemplary dispersants include, but are not limited to, poly(vinylpyrrolidone), poly(vinylpyrrolidone-co-vinyl acetate), poly(vinyl butyral), poly(vinyl alcohol), polyalkylene oxide ( such as polyethylene oxide or polypropylene oxide), polyalkylene oxide or acrylic polymers including amine functionality, poly(propylene carbonate), cellulosic dispersants such as methylcellulose, carboxymethyl fiber cellulose, ethylcellulose, hydroxymethylcellulose, and hydroxypropylcellulose; poly(carboxylic acids) such as poly(acrylic acid), polyacrylate, poly(methacrylate), poly(acrylamide), Amine waxes, styrene maleic anhydride resins, amine functional or amine terminated compounds such as polyamines, tertiary or quaternary ammonium functional compounds such as tetraoctylammonium bromide, ethoxylates such as alkyl Phenol ethoxylates, for example, octylphenol ethoxylates or alkyl ethoxylates, polyfunctional co-dispersants such as AMP™ dispersants, 2-amino-2-methyl-1-propanol containing Dispersants, polyesters such as polycaprolactone, polyvalerolactone, poly(hydroxystearic acid) or poly(hydroxyoleic acid), polyamides such as polycaprolactam, and having both hydrophobic and hydrophilic properties Block copolymers of functional groups. Other possible candidates include sodium dodecyl sulfate (SDS), sodium dodecyl benzyl sulfonate, derivatives of polyacrylic acid, etc. Additional examples include amine functionalized derivatization (such as polyamine, tertiary amine or quaternary ammonium functional derivatives), acid functional derivatives of these (such as carboxylic acid or phosphoric acid functional derivatives), such as amine functional groups including amine or acid functional groups or amine-terminated polyalkylene oxide or acrylic polymers. Other suitable dispersants include those known to those skilled in the art for use with carbon black, graphene or carbon nanotubes. Such combinations The composition may contain one dispersant or a mixture of two or more dispersants.

In one formulation, the dispersants are included in a class that includes styrene maleic anhydride resins and/or derivatives thereof obtained by reacting a styrene maleic anhydride resin or a prehydrolyzed styrene maleic anhydride resin with at least one Polymers prepared by the chemical reaction of small or large organic molecules with end groups (such as amine or epoxy groups). Generally, such polymeric dispersants (also referred to herein as styrene maleic anhydride groups) have a styrene maleic anhydride copolymer backbone modified with a variety of polymer brushes and/or small molecules.

In another formulation, the dispersant includes PVP (various molecular weights) or derivatives thereof, the latter generally referring to dispersants having a PVP backbone modified by small or large molecules, such as through chemical reactions. Examples of PVP-based dispersants include Ashland PVP K-12, K-15, K-30, K-60, K-90 and K-120 products, polyvinylpyrrolidone copolymers such as polyvinylpyrrolidone-co- Vinyl acetate, butylated polyvinylpyrrolidone such as Ganex ^™ P-904LC polymer.

In a further elaboration, the dispersant is a cellulose-based dispersant, which contains, for example, cellulose or a cellulose derivative having a cellulose backbone optionally modified with small or large organic molecules having at least one reactive end group. chain. In one specific example, the cellulose-based dispersant is CMC (eg, at different viscosities), a compound typically prepared by reacting cellulose with chloroacetic acid. In another example, the dispersant is hydroxyethyl cellulose.

Many of the embodiments described herein use CNS materials with CNT purity of 97% or higher. Generally speaking, the CNS used in this article does not require additional additives to offset van der Waals forces.

CNS may be provided in the form of loose particulate materials (eg, CNS flakes, granules, pellets, etc.) or formulations that also include a liquid medium (eg, dispersions, slurries, pastes) or other forms. In many embodiments, the CNS used is separated from its growth medium.

In some embodiments, the CNS removed from the growth substrate on which the carbon nanostructures were originally formed is provided in the form of a thin sheet of material. As used herein, the term "flake material" refers to discrete particles of finite size. For example, an illustrative depiction of CNS flake material after separation from the growth matrix is shown in Figure 3A. The lamellar structure 100 may have a first dimension 110 ranging from about 1 nm to about 35 microns thick, specifically about 1 nm to about 500 nm thick, including any values in between and any decimal. The lamella structure 100 may have a second dimension 120 ranging from about 1 micron to about 750 microns high, including any values in between and any decimals thereof. The lamella structure 100 may have a third dimension 130 that may range from about 1 micron to about 750 microns, including any values in between and any decimals thereof. Two or all of dimensions 110, 120 and 130 may be the same or different.

For example, in some embodiments, the second dimension 120 and the third dimension 130 may independently range from about 1 micron to about 10 microns, or from about 10 microns to about 100 microns, or from about 100 microns to about 250 microns, from about 250 microns to about 250 microns. to about 500 microns, or on the order of about 500 microns to about 750 microns.

The length of CNTs within CNS can vary from about 10 nanometers (nm) to about 750 micrometers (μm) or more. Therefore, CNTs can be from 10 nm to 100 nm, from 10 nm to 500 nm, from 10 nm to 750 nm, from 10 nm to 1 micron, from 10 nm to 1.25 micron, from 10 nm to 1.5 micron, from 10 nm to 1.75 micron, from 10 nm to 2 micron, or from 100 nm to 500 nm, from 100 nm to 750 nm, from 100 nm to 1 micron, from 100 to 1.25 micron, from 100 to 1.5 micron, from 100 to 1.75 micron , from 100 to 2 microns, from 500 nm to 750 nm, from 500 nm to 1 micron, from 500 nm to 1 micron, from 500 nm to 1.25 microns, from 500 nm to 1.5 microns, from 500 nm to 1.75 microns, from 500 nm to 2 micron, from 750 nm to 1 micron, from 750 nm to 1.25 micron, from 750 nm to 1.5 micron, from 750 nm to 1.75 micron, from 750 nm to 2 micron, from 1 micron to 1.25 micron, from 1.0 Micron to 1.5 micron, from 1 micron to 1.75 micron, from 1 micron to 2 micron, or from 1.25 micron to 1.5 micron, from 1.25 micron to 1.75 micron, from 1 micron to 2 micron, or from 1.5 to 1.75 micron, from 1.5 to 2 microns, or from 1.75 to 2 microns. In some embodiments, at least one of the CNTs has a length equal to or greater than 2 microns, such as up to 4 microns or longer, as measured by SEM.

Figure 3B shows an illustrative SEM image of carbon nanostructures obtained as flake material. The carbon nanostructure shown in Figure 3B exists as a three-dimensional microstructure due to the entanglement and cross-linking of its highly aligned carbon nanotubes. The aligned morphology reflects the formation of carbon nanotubes on the growth substrate under rapid carbon nanotube growth conditions (e.g., a few microns per second, such as about 2 microns per second to about 10 microns per second), thereby inducing substantial Vertical carbon nanotubes are grown from the growth substrate. Without being bound by any theory or mechanism, it is believed that the rapid growth rate of carbon nanotubes on the growth substrate may contribute, at least in part, to the complex structural morphology of the carbon nanostructures. In addition, the packing density of carbon nanostructures can be adjusted to a certain extent by adjusting the growth conditions of the carbon nanostructures, including, for example, by changing the transition metal nanostructures disposed on the growth substrate used to initiate the growth of carbon nanotubes. Concentration of particle catalyst particles.

The lamellar structure may comprise a network of carbon nanotubes in the form of a carbon nanotube polymer (i.e., a "carbon nanopolymer") with a molecular weight ranging from about 15,000 g/mol to about 150,000 g/mol. , the range includes all values in between and any decimals. In some cases, the upper limit of the molecular weight range can be even higher, including about 200,000 g/mol, about 500,000 g/mol, or about 1,000,000 g/mol. Higher molecular weight can be associated with longer dimensions of the carbon nanostructures. Molecular weight can also be a function of the primary carbon nanotube diameter and the amount of carbon nanotube walls present in the carbon nanostructure. The cross-linking density of the carbon nanostructure can be between about 2 mol/cm ³ and about 80 mol/cm ³ . Generally speaking, the cross-linking density is a function of the carbon nanostructure growth density on the growth substrate surface, carbon nanostructure growth conditions, etc. It should be noted that typical CNS structures containing many CNTs arranged in an open network eliminate van der Waals forces or weaken their effects. This structure can be more easily exfoliated, making the many additional steps to separate or decompose the structure into branched structures unique and different from those for ordinary CNTs.

Having a network morphology, the carbon nanostructure may have a relatively low packing density, for example, from about 0.005 g/cm ³ to about 0.1 g/cm ³ or from about 0.01 g/cm ³ to about 0.05 g/cm ³ . The carbon nanostructures so produced can have an initial packing density ranging from about 0.003 g/ ^cm to about 0.015 g/ ^cm . Further consolidation and/or coating to create carbon nanostructured flake materials or similar morphologies can increase the packing density to a range from about 0.1 g/ ^cm to about 0.15 g/ ^cm . In some embodiments, optional further modifications can be made to the carbon nanostructures to further change the packing density and/or other properties of the carbon nanostructures. In some embodiments, the packing density of the carbon nanostructures can be further adjusted by forming a coating on the carbon nanotubes of the carbon nanostructures and/or infiltrating the interior of the carbon nanostructures with various materials. Coating carbon nanotubes and/or infiltrating the interior of the carbon nanostructure can further tailor the properties of the carbon nanostructure for various applications. Additionally, forming a coating on the carbon nanotubes may desirably facilitate processing of the carbon nanostructures. In some embodiments, further compaction can increase the packing density to an upper limit of about 1 g/ ^cm , while chemical modification of the carbon nanostructures can increase the packing density to ^an upper limit of about 1.2 g/cm.

In addition to the flakes described above, the CNS material may be provided as granules, pellets, or other forms of loose particulate material having a thickness of from about 1 mm to about 1 cm, such as from about 0.5 mm to about 1 mm, from about 1 mm to about 2 mm, from about 2 mm to about 3 mm, from about 3 mm to about 4 mm, from about 4 mm to about 5 mm, from about 5 mm to about 6 mm, from about 6 mm to about 7 mm, Typical particle sizes range from about 7 mm to about 8 mm, from about 8 mm to about 9 mm, or from about 9 mm to about 10 mm.

Examples of commercially available CNS materials are those developed by Applied Nanostructured Solutions, LLC (ANS) (Massachusetts, USA).

Techniques used to combine CNS with polymer resins can produce CNS-derived species, such as "CNS fragments" and/or "fragmented CNTs," which are distributed (e.g., uniformly) in an individualized manner throughout the masterbatch. As mentioned above, in addition to being reduced in size, CNS fragments (the term also includes partially fragmented CNS) generally have the characteristics of intact CNS and can be identified by electron microscopy and other techniques. For example, cleaved CNTs can be formed when cross-links between CNTs within a CNS break, such as under applied shear. Fractured carbon nanotubes derived (generated or prepared) from CNS are branched and share a common wall with each other.

In some cases, the initial CNS is broken down into smaller CNS units or fragments. As mentioned above, apart from their reduced size, these fragments generally have the characteristics of an intact CNS and can be identified by electron microscopy and other techniques.

Changes in the morphology of the initial nanostructure of the CNS are also possible. For example, applied shear can break the cross-links between CNTs within the CNS to form CNTs, which are typically dispersed as individual CNTs in a polymer resin. We found that many of these CNTs retained the structural features of branches and shared walls even after cross-links were removed. CNTs that are derived (prepared) from CNS and retain the structural characteristics of CNT branches and shared walls are referred to herein as "fractured" CNTs. These substances can impart improved interconnectivity (between CNT units), resulting in better conductivity at lower concentrations.

Thus, the coating compositions described herein will generally contain fractured CNTs compared to coating compositions employing ordinary, individualized CNTs, for example in their original form. Such fractured carbon nanotubes can be easily distinguished from ordinary carbon nanotubes by standard carbon nanotube analysis techniques, such as, for example, SEM. Note also that not every CNT encountered needs to be branched and share a common wall; rather, it is a plurality of fractured CNTs that as a whole will have these characteristics.

CNS, as used herein, can be identified and/or characterized by a variety of techniques. Electron microscopy (including techniques such as, for example, transmission electron microscopy (TEM) and scanning electron microscopy (SEM)) can provide information on, for example, the presence of specific wall numbers, branching, frequency of absence of catalyst particles, etc. Characteristic information. See, for example, Figures 2A-2B.

Raman spectroscopy can show bands associated with impurities. For example, the D band (about 1350 cm ^-1 ) is related to amorphous carbon; the G band (about 1580 cm ^-1 ) is related to crystalline graphite or CNT). The G' band (about 2700 cm ^-1 ) is expected to appear at about 2X the D band frequency. In some cases, CNS and CNT structures can be distinguished by thermogravimetric analysis (TGA).

The carbon nanostructures are preferably combined with a polymer resin to form a highly dispersed mixture of polymer resin and CNS derivative species. Any method known to those skilled in the art for combining particulate fillers and polymeric resins may be used. For example, devices such as planetary mixers, roller mills, Brabender mixers, Banbury mixers, and other devices known to those skilled in the art for use with the polymeric resins described herein may be used. In preferred embodiments, the mixture of polymer resin and CNS derivative species contains 5 to 15 wt% CNS derivative species. For example, the composition may contain 5 to 7 wt%, 7 to 9 wt%, 9 to 11 wt%, 11 to 13 wt%, or 13 to 15 wt% CNS derivative species.

The resulting composition may be cut or ground into chips, pellets or powder using any suitable device known to those skilled in the art, such as a cutting mill. Such powders can be in any particle size useful for the desired end use, but will typically be on the order of a few millimeters, such as 0.5 to 5 mm. The resulting particles contain polymer resin and CNS derivative species and are referred to herein as CNS resin powder regardless of particle shape. This CNS resin powder can be incorporated into coating formulations without the need for a grinding step. For example, the CNS resin powder can be incorporated into the solvent (organic or aqueous) by incubating the CNS resin powder in the solvent for an appropriate time and then treating the mixture in a high-speed mixer to dissolve the polymer resin and disperse the CNS derivative species. )middle.

Suitable liquid carriers include any liquid carrier suitable for the desired end use. For coatings, typical organic solvents include, but are not limited to, ester solvents (such as butyl acetate), glycol ether esters (such as propylene glycol methyl ether acetate), ketone solvents (such as acetone), and the combination of these solvents with aromatic A mixture of solvents such as xylene, toluene, and Aromatic 100 (sometimes referred to as A-100 or Solvent 100). Alternatively, CNS-resin powder can be dispersed in an aqueous solvent (such as water) for use with water-based coatings . For water-based coatings, it is preferred to add sufficient base to the aqueous solvent containing the CNS resin powder to neutralize at least 50% (molyl) of any acid groups in the polymer resin, such as acid groups (which may have ionic reactions). ions) into the -OH form of the acid. For example, sufficient base may be added to neutralize at least 60%, at least 70%, at least 80%, at least 90%, or at least 100% of any acid groups in the polymer resin , such as 50 to 100% acid groups in the polymer resin. Regardless of the liquid carrier composition, a dispersant is generally employed to facilitate dispersion of the CNS fragments. Suitable dispersants include any dispersant known to those skilled in the art to be suitable for use in coating formulations agent and can be cationic, anionic or nonionic.

Once dissolved in an organic or aqueous solvent, the resulting liquid solution containing CNS derivative species can be combined with other components of the desired coating to form a coating composition. These components typically include coating resins, such as acrylic, polyurethane, polyester or epoxy resins, such as acrylic or polyester resins. In addition, additives can affect other properties of the coating composition, such as viscosity, leveling and drying time. Exemplary additives include, but are not limited to, co-solvents (e.g., water-soluble organic solvents for aqueous coating compositions), surfactants, and fillers such as clays, talc, hydrophilic and hydrophobic fumed and precipitated silicas, and carbonic acids. salt. In addition, adhesion promoters, flow regulators, leveling aids and fungicides can be used. Exemplary adhesion promoters include, but are not limited to, modified polyolefins (chlorinated or non-chlorinated). The coating resin itself can also be modified with modified polyolefin adhesion promoters. Additional colorants such as titanium dioxide or colored pigments or dyes may also be used. Since the CNS derivative species are already pre-dispersed by the polymer resin, there is no need to grind the coating composition to disperse the CNS. Accordingly, coating compositions containing CNS derivative species may have a Hegmann fineness value of 10 to 20 microns, for example 15 to 20 microns.

The resulting coating compositions can be used to impart electrical conductivity to the surface of a coated substrate. The required loading of CNS derivative species in the coating (dry basis) will vary depending on the intended application, and may range, for example, from 0.05 to 1 wt%, such as 0.1 to 0.5 wt%. Due to the elongated structure of CNS derivatives, suitable conductivity can be achieved at low loadings (e.g., up to 0.2 wt%). For example, the coating composition can be used as a primer coating to facilitate electrostatic coating of other non-conductive materials, such as plastics. Electrostatic coating is used to coat grounded surfaces with charged paint particles from a specialized spray gun. Primer coatings loaded with CNS provide a conductive surface that can even be grounded to non-conductive substrates.

Alternatively or in addition, a CNS-loaded conductive primer coating may facilitate plating of non-conductive substrates. For example, plastic workpieces can be coated with a CNS-loaded primer and immersed in a suitable plating bath. Applying an electric current causes a thin metal layer to be deposited on the workpiece. Metal can be patterned by controlling where the loaded CNS primer is applied. For example, standard photolithography techniques can be used to deposit a CNS-loaded primer onto a non-conductive substrate at the desired location. In one embodiment, the workpiece is photoresist coated and patterned with appropriate radiation. Loaded CNS primer is applied to the work piece. Cleaning the workpiece with an appropriate fluid will remove those portions of the photoresist that were not exposed to radiation, thereby also washing away those portions of the primer coating. Since the substrate is not electrically conductive, only those portions of the surface coated with the loaded CNS primer can be plated. Other patterned coating methods known to those skilled in the art may also be used.

Alternatively or additionally, loading CNS coatings may aid in electromagnetic shielding. Many automotive components are manufactured to provide EMI shielding for electronic components against external radio signals. While older cars with metal bodies automatically perform this function, the trend toward lightweighting in the automotive manufacturing industry has led to the replacement of many of these metal parts with plastic. In addition, the increased use of electronic devices and power supply components in vehicles (such as keyless ignition systems, remote starters, automatic sliding doors and power seat controls and windows) generates increased amounts of electromagnetic emissions. At the same time, vehicles continue to incorporate more electronic systems, such as GPS navigation systems, entertainment systems, Bluetooth compatible devices, hands-free control devices for cabin functions from navigation to entertainment systems, and generate and are susceptible to electromagnetic interference (" Touch screen control system affected by EMI"). Loaded CNS coatings provide automotive and component designers with an additional tool that can enhance the EMI shielding capabilities of coated parts. Coatings containing CNS-derived fragments may be used as primer coatings or may contain colored pigments and be used as decorative coatings.

CNS derivative species are dispersed into the coating composition to provide additional conductive functionality to the final coating. For example, coatings are commonly used to provide primers for concrete for floors and other applications, to provide anti-corrosion primers for metals, and to provide linings for tanks, vessels and pipes. Well-dispersed CNS-derived species in these coatings can help dissipate static charges in all these and other applications.

The invention will be further demonstrated by the following examples, which are intended to be illustrative in nature only. Example Viscosity Measurement

The melt viscosity of several polymer resins was measured using 25 mm side-by-side disposable aluminum pans in a Discovery HR-2 Hybrid Rheometer–2. The test sample was equilibrated at the test temperature for two minutes, pre-sheared at 0.5 1/s for 30 s, and equilibrated for another 5 minutes. Flow scans were performed from 0.1 1/s to 1000 1/s at the test temperature. The results are shown in Table 1 below. The melting point range of CAB 551-0.2 and 551-0.01 resins (Eastman Chemical Company) is 127 to 142°C according to the manufacturer and measured at 200°C. The softening range of Laropal A81 resin (BASF) according to the manufacturer is 80 to 95°C, and the melt viscosity is measured at 155°C. Addbond LP1611 resin has a Tg of -40°C and melt viscosity measured at 20°C. Viscosity(Pas.s) Resin: CAB 551-0.2 CAB 551-0.01 Addbond LP 1611 Laropal A81 Shear rate (1/s) 0.1 121.0 13.9 15.6 5.2 1 119.2 12.4 15.9 3.4 10 115.0 11.4 15.9 1.3 Table 1 Example 1

CNS-Resin Mix: Load the Brabender mixer with the polymer resins (53.3 g) specified in Table 2 below (CAB551-0.01 and CAB551-0.2, both from Eastman Chemical Company, and BASF's Laropal A81 resin) into a 60 mL mixing chamber and mix at 60 rpm at 180°C until a homogeneous melt is obtained. Polyethylene glycol-coated CNS pellets (4.7 g, Applied Nanostructured Solutions, LLC) were then incorporated into the liquid melt at 60 rpm, then the mixing speed was increased to 100 rpm and allowed to continue for the time specified in Table 2. The mixture was removed from the mixing chamber, cooled to ambient temperature, and ground to a dry powder with 8.1 wt% CNS-derived particles using a Retsch cutting mill SM300 (bottom mesh size 4 mm). Sample ID Resin type Mixing time(min.) Appearance grade after dissolving in propylene glycol methyl ether acetate and EFKA 4310 dispersant (1 to 5, 5 is the best) Sample 1 CAB551-0.01 8 3 Sample 2 CAB551-0.2 5 4 Sample 3 CAB551-0.2 8 5 Sample 4 Laropal A81 8 1 Sample 5 Laropal A81 11 1 Table 2

Coating Formulation: A dry powder containing CNS derivative species (2 g) was soaked overnight in a mixture of propylene glycol methyl ether acetate (PGMEA, 27 g) and Efka® PX 4310 dispersant (0.486 g, 50% solids). The solid/liquid mixture was then dispersed using a Dispermat CV (blade diameter, 4 cm, volume 100 mL) at 1000 rpm for 1 h to obtain a liquid mixture with a total solid concentration of 6.78 wt% and a CNS derivative species concentration of 0.55 wt%. The mixture was evaluated using a Hegman gauge; the results are shown in Figure 4 and described in Table 2, and show that Sample 3 was the best dispersed of the five samples. The liquid mixtures containing the CAB resins of Samples 1 to 3 were used directly with the other components in the formulations of Part A of the coating formulations of Examples 2 and 4 below. Example 2

To prepare Part A, 18 g of Setalux 1753 SS-70 resin (70% solids, Allnex GmbH), 41 g of a 50/50 w/w mixture of butyl acetate and PGMEA, 0.5 g of EFKA 4310 dispersant and 26 g of Ti-Pure R-960 titanium dioxide (Chemours) were mixed at 2000 rpm for 1 hour. Then 17.5 g of the liquid mixture with CNS derivative species was added and the entire mixture was milled in a LAU DAS 200 disperser for half an hour with 150 g (1.5 times the total weight of the part A formulation) of 1 mm _ZrO2 beads. Combine part B components (11 g of butyl acetate/PGMEA solution and 8.5 g of Desmodur N3390 hardener from Covestro, 90% solids) with part A using a Speedmixer DAC600 FVZ mixer with gentle mixing at 1000 rpm for 1 minute. The resulting coating compositions were evaluated on a Hegmann mill and cast with wirewound coated rods to produce 100 μm (wet) films on Leneta Form 2C charts. The wet film was cured at 140°C for 30 minutes to form a dry coating with 0.2 wt% CNS derivative species and 2.27 wt% CAB. Tint strength (L* and b*) was measured using an X-Rite SP64 handheld spectrophotometer in a CIE L*a*b* colorimetric system, excluding specular mode. Surface resistivity was measured using a Keithley model 6517B electrometer equipped with a Keithley 8009 test fixture. A qualitative assessment of the film's appearance. All results are shown in Table 3. Although the lower MW CAB551-0.01 provided poorer film appearance, the difference in results between Sample 2 and Sample 3 confirms that increasing milling time improves coating appearance (Table 3). It is expected that increasing the milling time of the CAB-CNS mixture of Sample 1 will also improve the coating appearance. Sample ID Fineness of wet coating (µm) Tinting intensity Surface resistivity (ohm/sq) Coating appearance (1 bad, 8 best) L* b* Sample 1 15 69.57 -4.22 2.30E+06 5 Sample 2 15 67.78 -4.15 1.20E+06 6 Sample 3 15 66.88 -4.09 1.10E+07 8 Table 3 Example 3 ( Comparison )

In a comparative example, PEG-coated CNS (Advanced Nanostructure Materials, LLC, Boston MA) was mixed with resin, solvent, dispersant (BYK Chemie's BYK 163 dispersant), pigment and 140 in a LAU DAS 200 disperser. g of 1 mm zirconia beads were milled together for 8 hours to prepare Part A of the two-part coating composition shown in Table 4. After filtering out the zirconia beads, the Part A and Part B components were combined in the same manner as in Example 2 to form a coating composition that was cast and cured to form a coating with 0.2 wt% CNS derivative species , and evaluated in the same way as Example 2. The results are shown in Table 5. Although the resistivity of the coatings was less than that of all three coatings of Example 2, the Hegemann fineness value of the wet coating composition and the appearance of the dry coating were much worse. Part A Ingredients Wt/g solid Setalux 1753 SS-70 Resin 18.00 70% Butyl acetate/PGMEA (50/50) 40.00 0 BYK163 dispersant 1.00 100% Ti-Pure R-960 Titanium Dioxide 20.62 100% CNS pellets (containing PEG binder) 0.083 100% Part B Butyl acetate/PGMEA (50/50) 20.30 0 N3390 hardener 8.50 90% Table 4 Fineness of wet coating (µm) Tinting intensity Resistivity(ohm/sq) Appearance (1 bad, 8 best) L* b* 100 65.33 -4.31 5.50E+05 3 Table 5 Example 4

A polyester coating was prepared in the same manner as in Example 2 using a liquid mixture of the CNS derivative species and the CAB resin of Sample 3 (Example 1), but with the formulation shown in Table 6 below (Allnex's Setal 189xx-65 polyester resin and Cymel 325 cross-linker). The performance evaluation of the wet coating composition and dry coating (0.2% CNS derivatives and 2.27% CAB on a dry basis) is as shown in Example 2 and is listed in Table 7. Part A Ingredients Wt/g solid Setal 189xx-65 resin twenty three 65% Butyl acetate/PGMEA (50/50) 41 0 BYK163 dispersant 0.5 50% Ti-Pure R-960 Titanium Dioxide 22.3 100% Sample 3 solvent-based solution 15 6.78% Part B Butyl acetate/PGMEA (50/50) 3 0 Cymel 325 cross-linker 2.6 80% Table 6 Fineness of wet coating (µm) Tinting intensity Resistivity(ohm/sq) Appearance (1 bad, 8 best) L* b* 15 69.50 -3.54 2.00E+07 8 Table 7

The results show that the coating has a comparable appearance to the acrylic coating of Example 2 and excellent resistivity. Example 5 ( comparison )

Follow the method described in Example 3 using 0.4 g of PEG-coated CNS, 88.4 g of a 1:1 (w/w) mixture of butyl acetate and PGMEA, 1.2 g of EFKA 4310 dispersant and 10 g of Setal 189xx-65 Resin, grind matrix was prepared with 0.4 wt% CNS derivative species, but with 150 g zirconia beads (150% of the mass of the grind matrix formulation).

Prepare the white grinding matrix according to the following process and formula. Put 17.0 g of propylene glycol methyl ether acetate (PGMEA), 17.0 g of butyl acetate and 6.0 g of DISPERBYK®-161 dispersant (BYK Chemie) into a tin can, and stir with a Dispermat CV-SIP mixer at 1500 rpm for 15 min. . While maintaining stirring, add 60.0 g of Ti-Pure® R960 titanium dioxide, then increase the stirring speed to 2000 rpm and stir the mixture for a further 15 min. The titanium dioxide dispersion was filled into a paint can containing 150 g of 1 mm zirconium beads. The paint cans were milled in a Lau model DAS 200 disperser for one hour and the contents were passed through a 200 mesh filter to separate the beads and ground matrix dispersion (60 wt% _TiO2 ).

The ground base containing CNS derivative species was mixed with the other components of the coating formulation (Table 8) in a Speedmixer DAC600 FVZ mixer at 1000 rpm for 3 minutes. Coatings with 0.2 wt% CNS-derived chips were cast and evaluated as described in Example 3 (Table 9). The resulting coating composition and coating had poorer Hegemann fineness values, conductivity, and appearance than the coating prepared in Example 2. Components Quantity(g) Setal 189XX-65 resin 30.00 Cymel 325 (80% solids) cross-linker 3.00 Butyl acetate 4.65 PGMEA 4.65 BYK 346 leveling agent 0.20 TiO ₂ dispersion (60 wt%) 35.00 CNS grinding matrix 22.50 Table 8 Fineness of wet coating (µm) Tinting intensity Resistivity(ohm/sq) Appearance (1 bad, 8 best) L* b* 55 69.28 -1.11 1.10E+09 5.5 Table 9 Example 6 ( Comparison )

Follow the method described in Example 5, using 0.4 g of PEG-coated CNS, 88.4 g of a 1:1 (w/w) mixture of butyl acetate and PGMEA, 1.2 g of EFKA 4310 dispersant, and 10 g of Setalux 1753 SS70 resin. (70% active) A grinding matrix containing 0.4 wt% CNS derivative species was prepared in an acrylic system. A titanium dioxide dispersion as described in Example 5 was also prepared. Coatings with 0.2% CNS-derived fragments were prepared using the method described in Example 5 and the formulation in Table 10. The properties of the wet coating composition and dry coating are as shown in Table 11 and are not as good as those of the coating formulation and coating in Example 4. Components wt/g Setalux 1753SS70 resin 28.00 Cymel 325 (80%) cross-linker 3.00 Butyl acetate 5.65 PGMEA 5.65 BYK 346 leveling agent 0.20 TiO ₂ dispersion (60%) 35.00 CNS grinding matrix 22.50 Table 10 Fineness of wet coating (µm) Tinting intensity Resistivity(ohm/sq) Appearance (1 bad, 8 best) L* b* 60 63.14 -3.34 1.10E+11 6.5 Table 11 Example 7 ( Comparison )

According to the method described in Example 5, 0.4 g of PEG-coated CNS, 79 g of a 1:1 (w/w) mixture of butyl acetate and PGMEA, 0.6 g of EFKA 4310 dispersant and 20 g of CAB 551-0.2 were used Resin (30% active) prepared grinding matrix containing 0.4 wt% CNS derivative species, i.e. 60 wt% titanium dioxide dispersion. Prepare CAB 551-0.2 solution by slowly adding the resin powder to a 1:1 mixture of butyl acetate and PGMEA with overhead mixing until the resin dissolves. Coatings with 0.2 wt% CNS-derived fragments were prepared using the method described in Example 5 and the formulations in Table 12. The properties of the wet coating composition and dry coating are shown in Table 13. The coating compositions had lower Hegman fineness values than the coating compositions of Samples 2 and 3. Although the resistivity of the coatings was comparable, the appearance of the coatings was inferior to those of Samples 2 and 3. Components wt/% Setal 189XX65 resin 30.00 Cymel 325 (80%) cross-linker 3.00 Butyl acetate 4.65 PGMEA 4.65 BYK 346 leveling agent 0.20 TiO ₂ dispersion (60%) 35.00 CNS grinding matrix 22.50 Table 12 Fineness of wet coating (µm) Tinting intensity Resistivity(ohm/sq) Appearance (1 bad, 8 best) L* b* 60 70.35 -2.38 1.30E+07 4.5 Table 13

The foregoing descriptions of preferred embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations of the invention are possible in light of the above teachings, or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application, to enable others skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the patent claims appended hereto and their equivalents.

11:Y-shaped CNT 13:Catalyst particles 15:branch point 17:Area 19:Area 40:TEM area 50: first channel 52:Second channel 54:Arrow 100:Thin sheet structure 110:First Dimension 111:CNT building blocks 113: Catalyst missing area 115:branch point 117:Area 119:Area 120:Second Dimension 130:Third Dimension

The invention is described with reference to the several figures of the accompanying drawings, in which:

Figures 1A and 1B are diagrams illustrating the difference between Y-shaped MWCNTs that are not in or derived from carbon nanostructures (Figure 1A) and branched MWCNTs in carbon nanostructures (Figure 1B).

Figures 2A and 2B are TEM images showing characteristics characterizing multi-walled carbon nanotubes found in carbon nanostructures.

Figure 3A is an illustrative depiction of the carbon nanostructure sheet material after the carbon nanostructure is separated from the growth matrix.

Figure 3B is an SEM image of an illustrative carbon nanostructure obtained as a thin sheet material.

Figure 4 is a photograph of several dissolved CNS-CAB compositions according to embodiments of the present invention after application to the Hegemann gauge.

Claims (28)

A composition comprising: 5 to 15 wt% CNS derivative species, and a polymer resin having a hydroxyl content of at least 1.5 wt%; at a shear rate of 0.1 s ^-1 and above the maximum temperature at which the resin undergoes thermal transfer A melt viscosity of at least 8 Pa.s at a temperature of 60°C; and at least one of the following: a) at least 5 wt% in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate solubility, and b) an acid value of at least 100. The composition of claim 1, wherein the heat transfer is glass transition temperature, melting temperature or softening point. The composition of claim 1 or 2, wherein the polymer resin has a hydroxyl content from 1.5 wt% to 5 wt%. The composition of any one of claims 1 to 3, wherein the melt viscosity is from 8 Pa.s to 1000 Pa.s. The composition of any one of claims 1 to 4, wherein the polymer resin has 5 wt% to 10 wt% in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate. solubility. The composition of any one of claims 1 to 5, wherein the polymer resin has a molecular weight Mn of 15,000 to 80,000. The composition of any one of claims 1 to 6, wherein the polymer resin has an acid value of 100 to 300. The composition of any one of claims 1 to 7, wherein when at least 50% of the acid groups on the polymer resin are non-ionized, the solubility of the polymer resin in water is at least 5 wt%. The composition of any one of claims 1 to 8, wherein the polymer resin has a molecular weight (Mn) of 8,000 to 40,000. The composition of any one of claims 1 to 9, further comprising a dispersant. The composition of claim 10, wherein the dispersant is present in an amount of 20 to 60 wt% relative to the amount of dispersant and CNS derivative species. A method for preparing a composition, the method comprising: combining carbon nanostructures with a polymer resin having a hydroxyl content of at least 1.5 wt%; at a shear rate of 0.1 s ^-1 and greater than the resin experienced A melt viscosity of at least 8 Pa.s at a temperature 60°C higher than the maximum temperature of heat transfer; and at least one of the following: a) in a 1:1 (w/w) mixture of butyl acetate and propylene glycol methyl ether acetate a solubility in at least 5 wt%, and b) an acid value of at least 100 to form a composition having from 5 to 15 wt% CNS derivative species. The method of claim 12, wherein the carbon nanostructure is coated with a dispersant. The method of claim 13, wherein the dispersant is present in an amount of 20 to 60 wt% relative to the amount of coated carbon nanostructures. The method of claim 13 or 14, wherein the dispersant is selected from the group consisting of poly(vinylpyrrolidone), poly(vinylpyrrolidone-co-vinyl acetate), poly(vinyl butyral), poly(ethylene alcohol), polyalkylene oxides, polyalkylene oxides or acrylic polymers including amine functional groups, poly(propylene carbonate), cellulose dispersants, poly(carboxylic acids), polyacrylates, poly(methyl Acrylates), poly(acrylamide), amide waxes, styrene maleic anhydride resins, amine functional or amine-terminated compounds, alkylphenol ethoxylates, or alkyl ethoxylates, AMP™ Dispersant, dispersant containing 2-amino-2-methyl-1-propanol, polyester, polyamide block copolymer with both hydrophobic and hydrophilic groups, sodium lauryl sulfate ( SDS), sodium dodecyl benzyl sulfonate, an amine functional derivative of any of these, an acid functional derivative of any of these, or a mixture of two or more of these . A method of preparing a coating composition, the method comprising: Combining a composition according to any one of claims 1 to 11 with a solvent and optional dispersant; allowing the polymer resin to dissolve in the solvent to produce a dispersion of CNS derivative species in the solvent, and Combine this dispersion with a coating resin and optional additives. The method of claim 16, wherein the coating resin includes acrylic, polyurethane, polyester or epoxy resin. The method of claim 17, wherein the coating resin is acrylic resin or polyester resin. The method of any one of claims 16 to 18, wherein the coating composition includes 0.05 to 1 wt% (dry basis) CNS derivative species. The method of any one of claims 16 to 19, wherein the coating composition contains 0.1 to 0.5 wt% or 0.05 to 0.2 wt% CNS derivative species. The method of any one of claims 16 to 20, wherein the coating composition has a Hegman grind value of 10 to 20 microns, such as 15 to 20 microns. The method of any one of claims 16 to 21, wherein the optional additive is at least one of the following: co-solvent, surfactant, filler, adhesion promoter, flow regulator, leveling aid, bactericide and coloring agent. A coating composition, which includes the composition according to any one of claims 1 to 11 and a coating resin. The coating composition of claim 23, wherein the coating composition includes 0.05 to 1 wt% (dry basis) CNS derivative species. The coating composition of claim 23 or 24, wherein the coating composition contains 0.1 to 0.5 wt% or 0.05 to 0.2 wt% CNS derivative species. The coating composition of any one of claims 23 to 25, wherein the coating composition has a Hegeman fineness value of 10 to 20 microns, such as 15 to 20 microns. The coating composition of any one of claims 23 to 26, wherein the coating resin includes acrylic, polyurethane, polyester or epoxy resin. The coating composition according to any one of claims 23 to 27, wherein the coating resin is an acrylic resin or a polyester resin.