Spherical particles containing carbon nanomaterial-grafted polyurethane, as well as methods for producing and using the same.

Abstract

To provide highly spherical particles that comprise carbon nanomaterial-graft-polyurethane (CNM-g-polyurethane), and compositions, synthesis methods, and applications of such particles.SOLUTION: A method of selective laser sintering comprises: depositing carbon CNM-g-polyurethane particles optionally in combination with other thermoplastic polymer particles onto a surface, wherein the CNM-g-polyurethane particles comprise a polyurethane grafted to a carbon nanomaterial (CNM); and once deposited, exposing at least a portion of the CNM-g-polyurethane particles to a laser to fuse the polymer particles thereof and form a consolidated body by selective laser sintering.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to highly spheric particles, including carbon nanomaterial-graft-polyurethane (CNM-g-polyurethane). This disclosure further relates to compositions, synthesis methods, and applications of such particles (also referred to herein as CNM-g-polyurethane particles). [Background technology]

[0002] Thermoplastic polymers are often used to produce extruded objects such as films, bags, particles, and filaments. An example of a thermoplastic polymer is polyurethane. Polyurethane has the ability to withstand high or low temperatures without compromising its physical properties. Polyurethane is a high-performance elastomer material that combines the flexibility of rubber with toughness and durability. They have multiple applications in automobiles (e.g., seats, armrests, headrests, glaze windshields, and windows), pharmaceuticals (e.g., catheters, general-purpose tubes, hospital bedding, surgical drapes, wound dressings, injection molding machines, medical implants, medical devices), adhesives, sealants, filters, footwear components, wire sheaths, protective clothing, computer components, aerospace components, and parts. Thermoplastic elastomers are copolymers having crystalline "hard" segments and amorphous "soft" segments. Polyurethane is a thermoplastic elastomer prepared by polymerization of isocyanates, polyols, and chain extenders. The soft segment is typically a polyol with a low glass transition temperature, which gives flexibility to the polymer material. The hard segment is typically a urethane with a chain extender that provides toughness.

[0003] Thus, objects formed of thermoplastic polymers such as polyurethane can be used in demanding applications such as power tools, automotive parts, gears, and consumer electronics parts. Three-dimensional (3D) printing, also known as additive manufacturing, is increasingly being used to manufacture such objects. Selective laser sintering can directly manufacture three-dimensional objects with high resolution and dimensional accuracy from a variety of materials, including polystyrene, nylon, other plastics, and composite materials such as polymer-coated metals and ceramics.

[0004] Polyurethane is one of the most common polymers used in additive manufacturing due to its flow characteristics, lower cost than other polymers, and desirable sintering window. However, the physical properties required for objects manufactured by additive manufacturing may exceed the properties of polyurethane. Expanding the ways in which polyurethane-carbon nanomaterial composites can be manufactured into objects will further expand the polymer composite industry. SUMMARY OF THE INVENTION

[0005] The present disclosure relates to highly spherical particles comprising CNM-g-polyurethane. The present disclosure further relates to compositions, synthesis methods, and uses of such CNM-g-polyurethane particles.

[0006] Disclosed herein is depositing CNM-g-polyurethane particles, optionally in combination with other thermoplastic polymer particles, on a surface, wherein the CNM-g-polyurethane particles comprise polyurethane grafted to a carbon nanomaterial (CNM), and upon deposition, exposing at least a portion of the CNM-g-polyurethane particles to a laser by selective laser sintering to fuse the polymer particles and form a consolidated body, a method of selective laser sintering.

[0007] Disclosed herein is a method comprising: (a) carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane), wherein the CNM-g-polyurethane particles are obtained by mixing a mixture comprising (b) a dispersion medium immiscible with the polyurethane of CNM-g-polyurethane, optionally (c) a thermoplastic polymer not grafted onto the CNM, and optionally (d) an emulsifying stabilizer, at a temperature higher than the melting or softening temperature of the polyurethane and thermoplastic polymer (if present) of CNM-g-polyurethane, and at a shear rate high enough to disperse the CNM-g-polyurethane in the dispersion medium; cooling the mixture to below the melting or softening temperature to form CNM-g-polyurethane particles; and separating the CNM-g-polyurethane particles from the dispersion medium. [Brief explanation of the drawing]

[0008] The following figures are included to illustrate specific aspects of the embodiments and should not be viewed as representing exclusive embodiments. The disclosed subject matter can be substantially modified, altered, combined, and equivalent in form and function as can be conceived by those skilled in the art who are interested in this disclosure.

[0009] [Figure 1] This is a flowchart illustrating a non-exclusive, illustrative method of the present disclosure.

[0010] [Figure 2] This is a scanning electron microscope (SEM) cross-sectional image of carbon nanomaterial-grafted polyurethane. [Modes for carrying out the invention]

[0011] This disclosure relates to highly spheric particles containing carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane). This disclosure further relates to compositions, synthesis methods, and applications of such CNM-g-polyurethane particles.

[0012] Three-dimensional (3D) printing, also known as additive manufacturing, is a rapidly growing field of technology. While 3D printing has traditionally been used for rapid prototyping, this technology is increasingly being adopted for the manufacture of commercial and industrial objects that require structural and mechanical tolerances entirely different from those of rapid prototypes.

[0013] 3D printing works by depositing either (a) small droplets or flows of a molten or solidifiable material, or (b) fine powder particles, into precise locations, and then solidifying them into a larger object (which may have any number of complex shapes). Such deposition and solidification processes are typically performed under computer control, stacking the larger object layer by layer. In certain examples, the solidification of fine powder particles may be performed in a 3D printing system that uses a laser to facilitate selective laser sintering (SLS).

[0014] Powder particles usable in 3D printing include thermoplastic polymers, including thermoplastic elastomers, metals, and other solidifiable materials. When using composites in 3D printing, the particles (e.g., carbon nanomaterials in polyurethane-carbon nanomaterial composites) should be uniformly dispersed throughout the small molten droplets or powder particles; otherwise, the distribution of particles in the final object will be uneven. Consequently, the properties of the object (e.g., strength and / or conductivity) may also be irregular, which can lead to points of failure in the object.

[0015] This disclosure relates to highly spheric particles comprising carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane). Advantageously, the compositions and methods of this disclosure utilize in-situ polymerization of polyurethane. Thus, the desirable melting and flowing properties of polyurethane can be utilized in additive manufacturing methods. CNM-g-polyurethane particles may be useful, among other things, as a starting material for additive manufacturing, particularly SLS 3D printing (e.g., automotive parts, aerospace / aircraft parts, shoe soles, etc.).

[0016] The selective laser sintering method described herein comprises depositing carbon nanomaterial-grafted-polyurethane (CNM-g-polyurethane) particles on a surface in combination with other thermoplastic polymer particles of choice, wherein the CNM-g-polyurethane comprises polyurethane grafted onto carbon nanomaterial (CNM), and, after deposition, exposing at least a portion of the CNM-g-polyurethane particles to a laser by selective laser sintering to fuse the polymer particles and form a solid. Carbon nanomaterial (CNM) can improve physical properties and / or impart new physical properties to objects manufactured by additive manufacturing. Furthermore, by using CNM-g-polyurethane, the CNM can be sufficiently dispersed and / or spread throughout the polymer particles. Thus, the carbon nanomaterial can be sufficiently dispersed and / or dispersed throughout the object (or a portion thereof) manufactured by additive manufacturing.

[0017] Furthermore, this disclosure relates to polyurethane thermoplastic polymer composites covalently bonded to carbon nanotubes (CNMs), such as carbon nanotubes (CNTs), and to methods for preparing high-sphericity CNM-g-polyurethane particles from said polyurethane thermoplastic polymer composites. Non-limiting examples of CNTs include single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and double-walled carbon nanotubes (DWCNTs). In some cases, the CNM may be hydroxyl, carboxyl, or amide-functionalized CNM (e.g., MWCNTs). That is, hydroxyl-functionalized CNMs can be produced by acid treatment of the surface of the CNM to generate hydroxyl groups on the surface. Furthermore, carboxyl-functionalized CNMs can be produced by microwave radiation of the CNM using concentrated acid.

[0018] By further reacting the covalent modification of CNTs using functional groups (e.g., hydroxyl groups, amino groups, or carboxylic acids) with monomer units, oligomers, or longer polymer chains of polyurethane, the dispersion ability of CNTs within the polymer matrix can be improved, allowing for easy integration into the polymer and the formation of corresponding polyurethane thermoplastic polymer nanocomposites.

[0019] For example, CNM-g-polyurethanes can be produced by reacting amide-functionalized CNM (e.g., MWCNT) with a polyurethane, and the amide group can be inserted into the hard segment of the polyurethane via a glycol (e.g., polyoxytetramethylene glycol, PTMO) and a diisocyanate (e.g., toluene diisocyanate, TDI).

[0020] Alternatively, CNM-g-polyurethane can be produced by reacting CNM (e.g., MWCNT) with polyurethane using a sol-gel method with a silsesquioxane-like structure, and polyurethane urea and CNM can be combined.

[0021] In another example, CNM-g-polyurethanes can be produced by reacting a polyurethane with both -OH and -COOH functionalized CNMs via an in-situ coupling reaction, using a hydroxyl-terminated linear polymer diol (e.g., poly(butadiene-co-acrylonitrile) oligomer (HTBN)) as the soft segment and 1,6-hexamethylene diisocyanate (HDI) and different chain extenders as the hard segments.

[0022] In yet another example, CNM-g-polyurethanes can be produced by CNM bonded to hyperbranched polyurethanes, which can be prepared by reacting a polyol (e.g., poly(ε-caprolactone)diol) used as a soft segment, a diisocyanate (e.g., 4,4'-methylenebis(phenylisocyanate)), an oil (e.g., castor oil), and a chain extender as a hard segment. A polyurethane composite can be obtained by dispersing chemically modified CNM (e.g., functionalized MWCNTs) in DMF and adding it to a reaction mixture containing a polyol, diisocyanate, oil, and a chain exchanger.

[0023] In yet another example, CNM-g-polyurethane can be produced by acid treatment of the surface of CNM to generate hydroxyl groups on the surface, which are then reacted with a halogenated acryloyl (e.g., poly(acryloyl chloride (PACl))) to obtain encapsulation. The outer layer may have many halogenated acryloyl groups (e.g., acryloyl chloride groups) which can be esterified with an appropriate amount of ethylene glycol (EG). Then, a thermoplastic polyurethane (e.g., 4,4'-methylenebis(phenyl isocyanate) (MDI)) and a diol (e.g., 1,4-butanediol (BDO)) can be introduced into the system to form a polyurethane (PU) layer in situ. The tensile strength and modulus of the resulting CNM-g-polyurethane composite may be advantageously higher than those of a typical undiluted polyurethane composite with the same processing parameters.

[0024] In yet another example, CNM-g-polyurethane can be produced by grafting polyol-functionalized CNM (e.g., polyol-functionalized CNTs) onto TPU via in-situ polymerization, as described in more detail below.

[0025] In some cases, CNMs such as SWCNTs can be used in conjunction with soluble crosslinked polyurethanes to produce microwave-absorbing composites. A thermoplastic polyurethane (e.g., MDI) can be mixed with a hydroxyl-terminated polyol (e.g., hydroxyl-terminated polybutadiene (HTPB) polyol), followed by the addition of a chain extender that enables crosslinking (e.g., a butanediol (BD) chain extender) to form CNMs dispersed throughout the polyurethane matrix.

[0026] In some other cases, CNM-g-polyurethane can be produced via microwave-assisted solid-state grafting, where the surface of CNM (e.g., CNTs) can be modified via microwave radiation (e.g., carboxylated CNM). Once sufficiently dispersed, the functionalized CNM (e.g., carboxylated CNTs) can be added to a polyurethane solution to produce a polyurethane-CNM mixture, which can then be treated under microwave radiation to obtain CNM-g-polyurethane.

[0027] Alternatively, a grafting approach can be used to make CMN (e.g., MWCNT) functional with segmented polyurethane containing hydroxyl groups along its backbone. Esterification reactions can be used between acidified CMN and polyurethane segments to covalently bond the polyurethane to the sidewalls of the CMN.

[0028] Furthermore, groups such as carboxyl, lactone, or phenol can be bonded to CMN (e.g., MWCNT) via either covalent bonds or van der Waals forces and then introduced into the polyurethane matrix during the synthesis of the polyurethane described above. Covalently bonded CMN to polyurethane can advantageously possess superior mechanical properties compared to van der Waals bonded CMN.

[0029] CNM-g-polyurethane composites can also be synthesized by prepolymers of polyurethanes functionalized with isocyanate-N=C=O groups that can react with carboxylic acid-treated CNM (e.g., carboxylic acid-treated MWCNTs). Functionalized CNM can be used as a crosslinking agent in prepolymers prepared from the reaction of polyurethanes (e.g., 4,4'-methylenebis(phenylisocyanate) (MDI)) and diols (e.g., poly(ε-caprolactone)-diol (PCL)).

[0030] Advantageously, high sphericity CNM-g-polyurethane particles / powder can be produced from the polyurethane thermoplastic polymer composite (i.e., CNM-g-polyurethane composite) of the present disclosure, for example, by melt emulsification, freeze-grinding, and / or precipitation. The above high sphericity CNM-g-polyurethane particles can be sintered for 3D printing applications using an SLS printer.

[0031] As a result, advantageously, parts or objects printed using SLS from the highly spherical CNM-g-polyurethane particles of this disclosure may have improved mechanical properties compared to polyurethane-based microparticles that either do not contain carbon nanomaterials or simply contain blended polyurethane and carbon nanomaterials. Definitions and Test Methods

[0032] As used herein, the term “catalyst” refers to a compound that, when used in a reaction medium at very low concentrations, allows for an increase in the rate of a reaction (e.g., polymerization) through interaction with a reagent, without undergoing any chemical change at the end of the reaction.

[0033] As used herein, the term "co-catalyst" refers to a compound that can act synergistically with a catalyst to increase the rate of a reaction (e.g., polymerization).

[0034] As used herein, the term “immiscible” refers to a mixture of two or more components that, when combined, form phases with a solubility of less than 5% by weight of each other at ambient pressure and room temperature, or, if solid at room temperature, at the melting point of the components. For example, polyethylene oxide with a molecular weight of 10,000 g / mol is solid at room temperature and has a melting point of 65°C. Therefore, if a material is liquid at room temperature and the polyethylene oxide has a solubility of less than 5% by weight at 65°C, the polyethylene oxide is immiscible with the material.

[0035] As used herein, the term "polyurethane monomer" refers to the monomer that forms polyurethane.

[0036] As used herein, the term "polyacid" refers to a compound having two or more carboxylic acid moieties. In this specification, an anhydride moiety is considered a carboxylic acid moiety because the anhydride undergoes ring-opening to a carboxylic acid during synthesis.

[0037] As used herein, the term "polyamine" when referring to a compound refers to a compound having two or more amine moieties.

[0038] As used herein, the term "amino acid," when referring to a compound, means a compound having one or more carboxylic acid moieties and one or more amine moieties. Here again, the anhydride moiety is considered a carboxylic acid moiety because the anhydride undergoes ring-opening to the carboxylic acid during synthesis.

[0039] When polymers are referred to in terms of -mer units (e.g., polyurethane monomers), those skilled in the art will understand that the -mer units are polymerized within the polymer.

[0040] As used herein, the term "thermoplastic polymer" refers to a plastic polymer material that reversibly softens and hardens upon heating and cooling. Thermoplastic polymers include thermoplastic elastomers.

[0041] As used herein, the term “elastomer” refers to a copolymer comprising a crystalline “rigid” portion and an amorphous “soft” portion. In the case of polyurethane, the crystalline portion may include a portion of polyurethane containing urethane functionality and optionally selected chain-extending groups, and the soft portion may include, for example, a polyol.

[0042] As used herein, the term "polyurethane" refers to the polymer reaction product between a diisocyanate, a polyol, and an optional chain extender.

[0043] As used herein, the term "oxide" refers to both metallic oxides and non-metallic oxides. For the purposes of this disclosure, silicon is considered a metal.

[0044] As used herein, the terms “carbon nanomaterial-grafted-polyurethane” and “CNM-g-polyurethane” refer to carbon nanomaterials having polyurethane extending from a central or skeletal structure. These terms describe the structure itself, rather than the method of fabricating it.

[0045] As used herein, the term "carbon nanomaterial" refers to a molecule or particle whose core structure consists of at least 50 atomic percent carbon and whose at least one dimension is 50 nm or less. Examples of carbon nanomaterials include, but are not limited to, fullerenes, carbon nanotubes, graphite, graphene, and any combination thereof.

[0046] As used herein, the term "fullerene" refers to a particle or molecule having a cage as its core structure, wherein the cage structure has an aspect ratio of 10 or less.

[0047] As used herein, the term "carbon nanotube" refers to a particle or molecule having an elongated cylindrical structure as its core structure, wherein the elongated cylindrical structure has an aspect ratio greater than 10. As used herein, the term "carbon nanotube" encompasses single-walled carbon nanotubes (i.e., having one wall), double-walled carbon nanotubes (i.e., having two walls), and multi-walled carbon nanotubes (i.e., having two or more walls).

[0048] As used herein, the term "graphene" refers to particles or molecules having a planar graphite structure, encompassing monolayer graphene to trilayer graphene.

[0049] As used herein, the term "graphite" refers to a particle or molecule having four or more planar graphite particles.

[0050] The terms "carbon nanomaterials," "fullerenes," "carbon nanotubes," "graphite," and "graphene" encompass their functionalized versions.

[0051] As used herein, the term “embedding” with respect to particles (e.g., nanoparticles) and the surface of polymer particles means that the particles extend at least partially onto the surface of the polymer particles such that the polymer is in contact with the nanoparticles to a greater extent than would be possible if the nanoparticles were simply placed on the surface of the polymer particles.

[0052] Hereafter in this specification, D10, D50, D90, and particle size span are primarily used to describe particle size. As used herein, the term "D10" refers to the particle size at which 10% of the particle population (relative to the volume-based distribution unless otherwise specified) falls below it. As used herein, the terms "D50," "average particle diameter," and "average particle size" refer to the particle size at which 50% of the particle population (relative to the volume-based median mean unless otherwise specified) falls below it. As used herein, the term "D90" refers to the particle size at which 90% of the particle population (relative to the volume-based distribution unless otherwise specified) falls below it. As used herein, the terms "particle size span," "span," and "span size" when referring to particle size provide an indicator of the extent of the particle size distribution and are calculated as (D90-D10) / D50.

[0053] Particle size and particle size distribution were determined by light scattering techniques using the Malvern MASTERSIZER® 3000. For the light scattering techniques, the control sample consisted of glass beads with particle sizes ranging from 15 μm to 150 μm, obtained from Malvern Analytical Ltd. under the trademarked Quality Audit Standards QAS4002®. Unless otherwise specified, samples were analyzed as dry powders. The analyzed particles were dispersed in air and analyzed using the MASTERSIZER® 3000 with the AERO S® dry powder dispersion module. Particle size was derived using instrument software from a plot of volume density as a function of size.

[0054] When used herein, if sieving is mentioned, the pore / screen size is as described by the USA Standard Sieve (ASTM E11-17).

[0055] As used herein, the term “roundness” in relation to particles refers to how close a particle is to being a perfect sphere. To determine roundness, optical microscope images of the particles are taken using flow particle imaging. The perimeter (P) and area (A) of the particle in the plane of the microscope image are calculated (for example, using a SYSMEX FPIA 3000 particle shape and particle size analyzer available from Malvern Instruments). The roundness of the particle is C EA / P is and in the formula, C EA This is the circumference of a circle having an area equivalent to the actual particle area (A). In this specification, roundness is based on three runs using a SYSMEX FPIA 3000 particle shape and particle size analyzer, with 6,000 to 10,000 particles analyzed per run. The reported roundness is the median mean roundness based on the number of particles. In the analysis, a threshold for distinguishing the grayscale level between background pixels and particle pixels (e.g., to compensate for uneven lighting conditions) was set to 90% of the background modal value.

[0056] As used herein, the term “shear force” refers to agitation or similar processes that induce mechanical agitation in a fluid.

[0057] As used herein, the term "aspect ratio" refers to the length divided by the width, where the length is greater than the width.

[0058] Unless otherwise specified, the melting point of the polymer shall be determined according to ASTM E794-06 (2018) with a heating rate and a cooling rate of 10°C / min.

[0059] Unless otherwise specified, the softening temperature or softening point of a polymer is determined according to ASTM D6090-17. The softening temperature can be measured using a 0.50 g sample at a heating rate of 1 °C / min using a cup-and-ball apparatus available from Mettler-Toledo.

[0060] The angle of repose is a measure of the fluidity of a powder. The angle of repose was determined using Hosokawa Micron's Powder Characteristics Tester PT-R, following ASTM D6393-14 "Standard Test Method for Bulk Solids Characterized by Carr Indices".

[0061] Looseness density (ρ aer ) is measured according to ASTM D6393-14.

[0062] Bulk density (ρ bulk ) is measured according to ASTM D6393-14.

[0063] Tap density (ρ tap ) is measured according to ASTM D6393-14.

[0064] Hausner ratio (H r ) is a measure of the fluidity of powders, H r =ρtap / ρ bulk is calculated by, where ρ bulk is the bulk density according to ASTM D6393-14, and ρ tap is the tap density according to ASTM D6393-14.

[0065] When used in this specification, the viscosity of the dispersion medium is the kinematic viscosity at 25°C, measured according to ASTM D445-19, unless otherwise specified. For commercially procured dispersion media (e.g., polydimethylsiloxane oil (PDMS)), the kinematic viscosity data cited in this specification are provided by the manufacturer, regardless of whether they are measured according to the aforementioned ASTM or another standard measurement technique.

[0066] <> The crystallization temperature is the temperature at which the polymer crystallizes (i.e., solidifies) into a structured form in a naturally or artificially initiated process, and the atoms or molecules are highly organized in the crystal. The crystallization temperature can be measured by differential scanning calorimetry (DSC). DSC provides a rapid method for determining the degree of polymer crystallinity based on the heat required to melt the polymer. The crystallization temperature (°C) can be determined, for example, by the ISO11357 test method or ASTM D3417.

[0067] Unless otherwise specified, the degree of crystallinity (%) of the polymer is determined by the ASTM D3417 method by quantifying the heat associated with the melting (fusion) of the polymer.

[0068] The melt flow index (MFI) is a measure of the resistance to flow of a polymer melt under a defined set of conditions (unit: g / 10 min). When it is a measure under low shear rate conditions, the MFI is inversely proportional to the molecular weight of the polymer.

[0069] The dimensional accuracy (%) of the SLS part is a quantitative measure of the accuracy of the 3D printed sintered part of SLS.

[0070] As used herein, the "tensile modulus" (MPa) of a solid material is a mechanical property that measures its stiffness. It is defined as the ratio of its tensile stress (force per unit area) to its strain (relative deformation) when subjected to elastic deformation. It can be expressed in Pascals or pounds (psi) per square inch. The tensile modulus of a polymer can be determined using ASTM D638-14. CNM-g-polyurethane composite

[0071] The CNM-g-polyurethane of this disclosure may be used to produce spherical microparticles, pellets, or filaments. Spherical microparticles (or powder) containing the CNM-g-polyurethane of this disclosure may be used in three-dimensional (3D) printing technologies by selective laser sintering (SLS), while filaments or pellets containing the CNM-g-polyurethane of this disclosure may be used in three-dimensional (3D) printing technologies by fused filament fabrication (FFF).

[0072] The polyurethanes described herein may be thermoplastic polyurethanes (TPUs). The polyurethanes may be produced from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component.

[0073] The polyisocyanate component may include aromatic diisocyanates. The polyisocyanate component may be selected from the group consisting of 4,4'-methylenebis(phenylisocyanate), toluene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or any combination thereof.

[0074] The polyol component may be selected from the group consisting of polyether polyols, polyester polyols, copolymers of polyether and polyester polyol, or any combination thereof. Furthermore, the polyol component may include poly(tetramethylene ether glycol), polycaprolactone, adipic acid polyester, copolymers thereof, or any combination thereof.

[0075] Examples of polyurethanes include, but are not limited to, polyether polyurethanes, polyester polyurethanes, mixed polyethers and polyester polyurethanes, and any combination thereof. Examples of thermoplastic polyurethanes include, but are not limited to, poly[4,4'-methylenebis(phenylisocyanate)-alt-1,4-butanediol / di(propylene glycol) / polycaprolactone], ELASTOLLAN® 1190A (polyether polyurethane elastomer, available from BASF), ELASTOLLAN® 1190A10 (polyether polyurethane elastomer, available from BASF), and any combination thereof.

[0076] The chain extender component may include a linear alkylenediol selected from the group consisting of 1,4-butanediol, 1,12-dodecanediol, dipropylene glycol, or any combination thereof.

[0077] Examples of CNMs that may have grafted polyurethane include, but are not limited to, fullerenes, carbon nanotubes (e.g., single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), carbon nanoplatelets, carbon nanosheets, carbon nanohorns, graphite (e.g., graphite particles, highly oxidized graphite particles, etc.), graphene (e.g., graphene particles, graphene ribbons, graphene sheets, etc., and highly oxidized derivatives thereof), and any combination thereof.

[0078] CNM-g-polyurethane may contain approximately 50% to approximately 99.95% by weight (or approximately 55% to approximately 95% by weight, or approximately 60% to approximately 90% by weight, or approximately 65% ​​to approximately 85% by weight, or approximately 70% to approximately 80%) of polyurethane and approximately 0.05% to approximately 50% by weight (or approximately 5% to approximately 45% by weight, or approximately 10% to approximately 40% by weight, or approximately 15% to approximately 35% by weight, or approximately 20% to approximately 30% by weight, or approximately 25% to approximately 50%) of CNM.

[0079] In some cases, polyurethane may be grafted onto the surface of CNM by in-situ polymerization or microwave-assisted solid-state grafting, as described in more detail herein, to produce CNM-g-polyurethane. In-situ polymerization can advantageously provide improved properties (e.g., conductivity, tensile strength) of CNM-g-polyurethane compared to melt blending or solvent blending processes, and in-situ polymerization allows for highly dispersed CNM (e.g., in-situ polymerization using rGO), thus forming a strongly crosslinked network throughout the TPU matrix.

[0080] CNM is a C1-C amine containing one or more primary amines (e.g., CMN-NH2) and / or one or more secondary amines (e.g., C1-C amines such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and their isomers). 20 Alkyl alkyl group, C1-C 20 Cycloalkyl groups, C1-C 20The functionalized CNM may include arylalkyl groups (CMN-NRH), carboxylic acid-functionalized CNM (e.g., CMN-COOH), amino acid-functionalized CNM (e.g., NH2-CMN-COOH), acid chloride-functionalized CNM (e.g., CMN-COCl), hydroxyl-functionalized CNM (e.g., CMN-OH), and any combination thereof. In some cases, the functionalization of CMN (e.g., CNT) with a carboxylic acid moiety may be carried out in the presence of sulfuric acid, nitric acid, chlorate, or ammonium persulfate oxidation. Alternatively, the functionalization of CMN (e.g., CNT) may be carried out by direct sulfonation, metallization, or electrophilic addition to the deoxygenated surface of the CNT.

[0081] Grafting of polyurethane onto the surface of CNM can be carried out via in-situ polymerization under an inert atmosphere (e.g., N2 or Ar). Polyurethanes can be synthesized by polyaddition of diisocyanates and diols in the presence of an organic molecular catalyst (e.g., organotin catalysts, organotertiary amines combined with organotin catalysts, or N-heterocyclic carbenes (NHCs)). Herein, diisocyanates, polyols, and chain extenders may be used in molar ratios ranging from about 5:0.1:0.1 to about 1:1:1, for example, 1:0.5:0.5 (the molar ratio may be modified to obtain different properties), and prepolymers may be prepared by reacting a diisocyanate (e.g., 4,4'-methylenebis(phenylisocyanate) (MDI)) with a polyol (e.g., polyether polyol) at a temperature ranging from about 50°C to about 120°C (preferably 80°C). Solvents such as organic reactants (e.g., dimethylformamide, DMF) and miscible organic solvents may be used herein. The conversion of the -OH group can be monitored / analyzed by titration of the NCO group. A diol (e.g., 1,4-butanediol) and a catalyst (e.g., an organotin catalyst such as dibutyltin dilaurate) can be added to the reaction vessel to allow chain extension, and then CNM (preferably functionalized CNM) can be added to the reaction vessel. The resulting slurry mixture can then be poured into a mold and the solvent can be evaporated. Any residual solvent can be removed by placing the polymer product in a vacuum oven at a temperature in the range of about 25°C to about 100°C (preferably 50°C). However, CNM may be added before the addition of the polyol, before the addition of the chain extender, or after the completion of polymerization.

[0082] In this specification, CNM may be graphene oxide prepared from natural graphite via the modified Hummers process and further functionalized to, for example, carboxylic acid-modified graphite oxide (GO-COOH) or amino-modified graphite oxide (GO-NH2). Carboxylic acid-functionalized CNM (e.g., carboxylic acid-modified graphite oxide (GO-COOH)) may be conjugated with diamine monomers and / or dicarboxylic acid monomers via condensation reactions. CNM-g-polyurethanes may be formed by condensation reactions between diamine-functionalized graphene oxide and dicarboxylic acid monomers. Suitable examples of diamines include, but are not limited to, ethylenediamine, 1,6-diaminohexane, p-phenylenediamine, propylamine, or butylamine. CNM may be thermally reduced GO (rGO) obtained by thermal reduction of GO after preparation from natural graphite via the modified Hummers process.

[0083] CNM-g-polyurethanes may be polyurethanes containing GO produced by a covalent bonding reaction between polyurethane (e.g., TPU) and GO, or polyurethanes synthesized in the presence of GO.

[0084] For example, a CNM-g-polyurethane in which CNM is GO can be formed as follows: The diisocyanate, polyol, and chain extender can be combined in various molar ratios, such as in the range of about 5:0.1:0.1 to about 1:1:1 (preferably 1:0.5:0.5). Poly(tetrahydrofuran), 4,4'-methylenediphenyl diisocyanate (MDI) can be mixed, and the resulting mixture can be heated at a temperature in the range of about 50°C to about 120°C (preferably 80°C) to form a prepolymer. In a separate reaction vessel, GO can be mixed in an organic solvent that may be miscible with water (e.g., dimethylformamide (DMF)), and then sonicated to obtain a stable dispersion of GO. Next, a diol (e.g., 1,4-butanediol) and a catalyst (e.g., dibutyltin laurate catalyst) are added to the reaction vessel under an inert atmosphere (e.g., argon) at a temperature in the range of about 50°C to about 120°C (preferably 80°C) to allow for chain extension. The reactants are vigorously stirred for about 30 minutes to 5 hours, and then the viscous mixture is poured into a Teflon-coated mold and / or under vacuum, and any remaining solvent is evaporated to obtain graphene oxide-grafted polyurethane.

[0085] CNM-g-polyurethanes can be produced from isocyanate-functionalized CNM (e.g., isocyanate-functionalized GO), which can be grafted with polyurethane (e.g., TPU) via in-situ polymerization. This grafting process can be carried out under an inert atmosphere (e.g., N2 or Ar). Isocyanate-functionalized CNM can be prepared as follows: CNM (e.g., GO) is first dispersed in water via sonication for 5 minutes to 10 hours (or 30 minutes to 5 hours, or 1 hour to 3 hours), and then centrifuged at 500 rpm to 10,000 rpm (or 1,000 rpm to 5,000 rpm, or 2,000 rpm to 4,000 rpm). The CNM suspension (e.g., GO suspension) can then be subjected to a solvent exchange process to obtain a dispersion of CNM (e.g., GO) in an organic solvent such as DMF. The solvent exchange process can be carried out by adding an organic solvent (e.g., DMF) to aqueous CNM (e.g., GO), followed by sonication, centrifugation, and then removal of the supernatant. This process can be repeated several times. The CNM (e.g., GO) can then be resuspended in an organic solvent (e.g., DMF) and reacted with a polyisocyanate (PI) such as an aliphatic polyisocyanate (e.g., DESMODUR® N75) to produce isocyanate-functionalized CNM (e.g., isocyanate-functionalized GO). The polyisocyanate-functionalized CNM product (e.g., polyisocyanate-functionalized graphene oxide (PI-GO)) can then be coagulated (using an organic solvent such as dichloromethane), filtered, washed, and dried.

[0086] A method for grafting a polyisocyanate-functionalized CNM product (e.g., PI-GO) onto a polyurethane (e.g., TPU, or polyurethane prepolymer) via in-situ polymerization involves dispersing the polyisocyanate-functionalized CNM product (e.g., PI-GO) in an organic solvent (e.g., DMF) to produce a homogeneous solution, transferring the homogeneous solution to a separate container, and adding diisocyanate (e.g., 4,4'-methylenebis(phenylisocyanate (MDI)) and polyglycol (e.g., poly(tetrahydrofuran)) to an organic solvent (e.g., dry DM). This may include adding F) in a molar ratio in the range of 1:0.1 to 1:1 (preferably 1:0.5). The reaction mixture may be heated at a temperature in the range of about 50°C to about 120°C (preferably 80°C) for 30 minutes or more (or 1 hour or more, or 2 hours or more, or 3 hours or more, or 4 hours or more, or 5 hours or more). A diol (e.g., 1,4-butanediol) and catalyst suitable for polymerizing polyurethane (e.g., dibutyltin laurate catalyst) may be added to the reaction vessel. Upon completion, the reaction vessel may be degassed under vacuum, and the resulting slurry (viscous polymer solution) may be poured into an aluminum pan and the solvent may be evaporated.

[0087] CNM-g-polyurethanes may be polyurethanes containing CNTs (e.g., single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), or double-walled carbon nanotubes (DWCNTs)) produced by a covalent bonding reaction between polyurethane (e.g., TPU) and CNTs, or polyurethanes synthesized in the presence of CNTs. Other non-limiting examples of preferred methods for evaporating the solvent may include polymer precipitation, spray drying, thin-film evaporation, and rotational evaporation.

[0088] CNM-g-polyurethanes can be produced from functionalized CNM (e.g., COOH-functionalized CNTs), and functionalized CNM can be grafted onto polyurethane (e.g., TPU) via microwave-assisted solid-state grafting. Methods for grafting COOH-functionalized CNM products (e.g., COOH-CNTs) onto polyurethane via microwave-assisted solid-state grafting may include (a) and (b) below: (a) Before synthesizing the CNM-g-polyurethane polymer composite, CNTs in a mixture of concentrated acids (e.g., a mixture of sulfuric acid and nitric acid in a ratio of 3:1 to 1:1) are acid-treated via microwave radiation for 1 minute or more (or 5 minutes or more, or 10 minutes or more, or 15 minutes or more, or 20 minutes or more, or 25 minutes or more, or 30 minutes or more) at a temperature in the range of about 100°C to about 200°C (preferably about 120°C to about 150°C, such as 140°C). After acid treatment, the CNTs may be transferred to a separate container, followed by the addition of deionized (DI) water, and the mixture may be cooled to room temperature. The oxidation product may be filtered using a Teflon membrane, and the resulting carboxylated CNT product may be washed with DI water until a neutral pH is reached, and then dried in a vacuum oven. (b) Grafting of carboxylated CNTs via microwave radiation by dispersing the carboxylated CNTs in an organic solvent (e.g., THF) via sonication (0.5 wt% CNTs or more, 1 wt% CNTs or more, 5 wt% CNTs or more, 10 wt% or more). In a separate container, the polyurethane may be dissolved in the same organic solvent (e.g., THF), and the well-dispersed carboxylated CNTs may be added dropwise to the polyurethane solution while stirring until a homogeneous mixture is obtained. The mixture may then be poured into a mold and the solvent may be evaporated. Next, the mixture of polyurethane and carboxylated CNTs can be treated under microwave irradiation for 1 minute or more (or 5 minutes or more, or 10 minutes or more, or 15 minutes or more, or 20 minutes or more, or 25 minutes or more, or 30 minutes or more) at a total power output of approximately 10% or more of 500W to 1,000W (or 20% or more, or 30% or more, or 40% or more, or 50% or more), preferably 50% of 800W.

[0089] In some cases, a method for producing CNM-g-polyurethane may include (a) oxidizing CNM (e.g., CNT) to produce carboxyl-functionalized CNM (e.g., COOH-CNT); (b) acid chloride functionalization of the carboxyl-functionalized CNM surface (e.g., COOH-CNT surface) in the presence of thionyl chloride (SOCl2) by sonication to produce acyl chloride-functionalized CMN (e.g., ClCO-CNT); (c) grafting the acid chloride-functionalized CMN onto a polyol (e.g., poly(ε-caprolactone)(PCL)-diol) to produce polyol-functionalized CMN; and (d) grafting the polyol-functionalized CMN onto polyurethane via in-situ polymerization to produce CNM-g-polyurethane (additional material may also be used to end-cap the polymer if isocyanate groups are present in excess, after the completion of polymerization).

[0090] In some other cases, methods for producing CNM-g-polyurethanes may involve in-situ polymerization with amine-functionalized CNM (e.g., amine-modified carbon sources such as H2N-CNTs). Preparation of amino-functionalized CNM (e.g., amino-functionalized CNTs such as H2N-MWCNTs) may involve oxidizing CNM by acid treatment with a mixture of concentrated acids (e.g., a mixture of sulfuric acid and nitric acid in a ratio of 3:1 to 1:1). Acidification may be carried out by sonication of CNM in an acid solution at a temperature in the range of about 30°C to about 100°C (preferably 50°C). The CNM / acid mixture can then be poured into deionized water, filtered, and washed repeatedly until the pH of the filtered solution reaches about 7 (neutral pH). The acidified CNM product can then be dried in a vacuum oven. The resulting CNM-COOH can be dispersed in an organic solvent (e.g., THF) under sonication for at least 1 hour. To this dispersion, ethylenediamine (EDA), 4-(dimethylamino)pyridine (DMAP), and N,N'-dicyclohexylcarbodiimide (DCC) can be added while stirring at ambient temperature. The dispersion / solution can be heated with stirring at a temperature in the range of about 30°C to about 100°C (preferably 60°C) and maintained for 12 to 24 hours. The product may be a black solid that can be easily collected and washed with an organic solvent (e.g., THF). The product can be dried in a vacuum oven to obtain amine-functionalized CNM. Grafting the amine-functionalized CNM onto TPU via in-situ polymerization may involve dispersing the amine-functionalized CNM in dry DMF via sonication to produce a homogeneous solution, and transferring the homogeneous solution to a separate container and dispersing the amine-functionalized CNM in dry DMF via sonication. MDI and poly(tetrahydrofuran) may be added, and the reaction may be carried out at a temperature in the range of about 30°C to about 100°C (preferably 80°C) for 1 hour or more (or 2 hours or more, or 3 hours or more, or 5 hours or more, or 10 hours or more).Next, a catalyst suitable for polymerization of a diol (e.g., 1,4-butanediol) and TPU (e.g., dibutyltin laurate catalyst) may be added. Then, the solvent of the resulting slurry can be evaporated.

[0091] CNM-g-polyurethanes can be fullerene-containing polyurethanes that can be produced by a covalent bonding reaction between a functional polymer and a fullerene, or by synthesizing a polymer in the presence of a fullerene. Polymeric fullerenes can be prepared by side-chain polymers, main-chain polymers, dendritic fullerenes, star-shaped polymers, fullerene end-cap polymers, and the like. In this specification, functionalized CNMs are, for example, amino-functionalized CNMs. 60 Fullerene system, carboxyamide functionalized C 60 It may be a fullerene system. Fullerene-g-polyurethane is C 60 - Aminofunctionalized C to form amide bonds between primary and / or secondary amines 60 This can be formed at room temperature under mild conditions by reacting a fullerene system with an acid chloride-functionalized polyurethane.

[0092] In another non-limiting example, CNM-g-polyurethanes can use soluble amino polymers (e.g., monomers containing NH2 groups or branched amino groups from the terminal groups of the polyurethane) that can be added to the fullerene double bond to form a polymer bond C 60 It may be a polyurethane containing fullerene manufactured from CNM-g-polyurethane (e.g., C 60 -g-polyurethane) is an amino polymer that can be converted to C under mild conditions at room temperature. 60 It can be obtained by reacting with it.

[0093] In another non-limiting example, CNM-g polyurethane is used to produce (a) hydroxyl-functionalized fullerenes by acid-mediated oxidation of fullerenes (e.g., treating fresh fullerenes with concentrated HNO3). 60(b) Surface modification of fullerene C60, wherein the hydroxyl-functionalized fullerene is washed with distilled water until a neutral pH is reached, dried under vacuum to remove any residual solvent, thereby obtaining a hydroxyl-functionalized fullerene powder that can be used in polymerization reactions; (b) Grafting of hydroxyl-functionalized fullerene onto TPU via in-situ polymerization, which may result in a polyurethane containing hydroxyl-functionalized fullerene. Depending on when the hydroxyl-functionalized fullerene can be added to polymerization, the material may be used to graft onto the polymer backbone or to end-cap polymer chains. CNM-g-polyurethane and method of production

[0094] The methods and compositions described herein relate to highly spheric polymer particles containing CNM-g-polyurethane. As described above, this disclosure relates to polyurethanes (e.g., TPU), thermoplastic elastomers (TPEs), and other thermoplastic rubbers that combine crystalline (hard segment) polymers with amorphous (soft segment) polymers that can be covalently bonded, grafted, or bonded with carbon nanofillers (e.g., CNTs), graphene oxides (GO), carbon nanofibers, fullerenes, etc. The compositions herein may include carbon nanofillers (e.g., CNTs), hard segments (e.g., diisocyanates and diols, or diamines), and soft segments (polyesters or polyether macrodiols) and may undergo composite melt emulsification into highly spheric microparticles. Although not limited to theory, having polyurethane grafted onto CNM is thought to help a more homogeneous distribution of CNM in the polymer particles, thereby resulting in a more homogeneous distribution in objects (or parts thereof) produced by additive manufacturing methods using such polymer particles.

[0095] The disclosure also relates to a method comprising: (a) CNM-g-polyurethane particles, wherein the CNM-g-polyurethane particles include polyurethane grafted onto carbon nanomaterials; (b) a dispersion medium immiscible with the polyurethane of the CNM-g-polyurethane; optionally (c) a thermoplastic polymer not grafted onto CNM (which may be the same as or different from the polyurethane of the CNM-g-polyurethane); and optionally (d) an emulsifying stabilizer; mixing a mixture at a temperature higher than the melting or softening temperature of the polyurethane and at a shear rate high enough to disperse the CNM-g-polyurethane in the dispersion medium; cooling the mixture to below the melting or softening temperature of the polyurethane to form spherical polymer particles; and separating the spherical polymer particles from the dispersion medium.

[0096] Figure 1 is a flowchart of a non-limiting exemplary method 100 of the present disclosure. A mixture 112 is produced by combining CNM-g-polyurethane 102, a dispersion medium 104, an optional emulsifying stabilizer 106, and optionally a thermoplastic polymer 108 not grafted onto CNM (e.g., the polyurethane of CNM-g-polyurethane 102, a polyurethane not of CNM-g-polyurethane 102, another thermoplastic polymer, or any combination thereof) 110. Note that reference no. 108 refers to “thermoplastic polymer not grafted onto CNM”.

[0097] Components 102, 104, 106, and 108 may be added individually or in any order to a blend of components, and the process of combining components 102, 104, 106, and 108 includes mixing and / or heating during the process 110. For example, CNM-g-polyurethane 102, and, if included, thermoplastic polymer 108 that is not grafted onto CNM, may be pre-mixed before the combination 110. In this specification, polyurethane in CNM-g-polyurethane refers to polyurethane if it is not grafted onto CNM.

[0098] Next, the mixture 112 is treated 114 by applying a sufficiently high shear force to the mixture 112 at a temperature higher than the higher of the melting point or softening temperature of (a) the polyurethane of CNM-g-polyurethane 102 or (b) the thermoplastic polymer 108 that is not grafted onto CNM, to form a molten emulsion 116. Since the temperature exceeds the melting point or softening temperature of the polymer portion of the mixture 112 (i.e., the polyurethane of CNM-g-polyurethane 102, and, if present, the thermoplastic polymer 108 that is not grafted onto CNM), a polymer melt containing CNM-g-polyurethane 102 and, if present, the thermoplastic polymer 108 that is not grafted onto CNM is produced. The shear rate should be sufficient to disperse the polymer melt (e.g., containing CNM-g-polyurethane) as droplets (i.e., polymer emulsion 116) in the dispersion medium 104. While not bound by theory, it is reasonable to assume that, all other factors being equal, increasing the shear force should decrease the size of the polymer molten droplets in the dispersion medium 104. However, at some point, increasing the shear force and decreasing the droplet size may result in reduced return, or the contents of the droplets may collapse, leading to a decrease in the quality of the particles produced from them.

[0099] Next, the molten emulsion 116 inside and / or outside the mixing vessel is cooled 118 to solidify the polymer droplets into CNM-g-polyurethane particles 124. The term "CNM-g-polyurethane particles" refers to polymer particles containing CNM-g-polyurethane 102, which may include other components in the polymer particles (e.g., thermoplastic polymer 108 not grafted onto CNM).

[0100] Next, the cooled mixture 120 can be processed 122 to isolate the CNM-g-polyurethane particles 124 from other components 126 (e.g., dispersion medium 104, excess emulsifying stabilizer 106, etc.), and the CNM-g-polyurethane particles 124 can be washed or otherwise purified. The CNM-g-polyurethane particles 124 comprise CNM-g-polyurethane 102, and, if present, a thermoplastic polymer 108 not grafted onto CNM, and, if present, at least a portion of the emulsifying stabilizer 106, which coats the outer surface of the CNM-g-polyurethane particles 124. The emulsifying stabilizer 106 or a portion thereof may be deposited on the CNM-g-polyurethane particles 124 as a coating, possibly as a uniform coating. In some cases, depending on non-limiting factors such as temperature (including cooling rate), type of CNM-g-polyurethane 102, and type and size of emulsifying stabilizer 106, the nanoparticles of the emulsifying stabilizer 106 may be at least partially embedded within the outer surface of the CNM-g-polyurethane particles 124. Even without embedding, at least a portion of the nanoparticles in the emulsifying stabilizer 106 may remain firmly associated with the CNM-g-polyurethane particles 124, facilitating further use. In contrast, a dry blend of already formed polymer microparticles (e.g., formed by a cryogenic grinding or precipitation process) with a flow aid such as silica nanoparticles does not result in a firm and uniform coating of the flow aid on the polymer microparticles.

[0101] The CNM-g-polyurethane particles 124 may be optionally further purified 128 (as described in more detail below) to obtain purified CNM-g-polyurethane particles 130.

[0102] The dispersion medium 104 should be selected such that the CNM-g-polyurethane 102 and the dispersion medium 104 are immiscible at various processing temperatures (e.g., from room temperature to the process temperature). An additional factor that may be considered is the difference in viscosity (e.g., difference or ratio) between the CNM-g-polyurethane 102 and the dispersion medium 104 at the process temperature. The difference in viscosity can affect droplet breakdown and particle size distribution. Although not bound by theory, if the viscosities of the CNM-g-polyurethane 102 and the dispersion medium 104 are too similar, the overall roundness of the product may be reduced, and particles may become more oval and elongated.

[0103] CNM-g-polyurethane 102 may be present in the mixture 112 in an amount of about 5% to about 60% by weight (or about 5% to about 25% by weight, or about 10% to about 30% by weight, or about 20% to about 45% by weight, or about 25% to about 50% by weight, or about 40% to about 60% by weight) of the combined CNM-g-polyurethane 102, the thermoplastic polymer 108 not grafted onto CNM, and the dispersion medium 104. If the CNM contains an ungrafted thermoplastic polymer 108, the combined CNM-g-polyurethane 102 and the ungrafted thermoplastic polymer 108 may be present in the mixture 112 in amounts of about 5% to about 60% by weight (or about 5% to about 25% by weight, or about 10% to about 30% by weight, or about 20% to about 45% by weight, or about 25% to about 50% by weight, or about 40% to about 60% by weight) of the combined CNM-g-polyurethane 102, the ungrafted thermoplastic polymer 108, and the dispersion medium 104. If included, the weight ratio of CNM-g-polyurethane 102 to thermoplastic polymer 108 not grafted onto CNM may be approximately 10:90 to approximately 99:1 (or approximately 10:90 to approximately 50:50, or approximately 25:75 to approximately 75:25, or approximately 50:50 to approximately 99:1, or approximately 80:20 to approximately 99:1).

[0104] Examples of thermoplastic polymers 108 that are not grafted onto CNM include polyamides, polyurethanes, polyethylene (preferably functionalized polyethylene), polypropylene (preferably functionalized polypropylene), polyacetals, polycarbonates, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), ethylene vinyl acetate copolymer (EVA), ethylene propylene diene rubber (EPDM), ethylene-propylene elastomer (EPR), poly(4-methyl-1-pentene), polyhexamethylene terephthalate, polystyrene, polyvinyl chloride, polytetrafluoroethene, polyester (e.g., polylactic acid), polyethers, and polyethersulfones. Sulfones (PESU), polysulfones (PSU), polyether ether ketone, polyacrylate, polymethacrylate, polyimide, acrylonitrile butadiene styreneCopolymers containing styrene (ABS), polyphenylene sulfide, vinyl polymer, polyarylene ether, polyarylene sulfide, polysulfone, polyether ketone, polyamide-imide, polyetherimide, polyether ester, polyether block and polyamide block (PEBA or polyether block amide), grafted or ungrafted thermoplastic polyamide, functionalized or unfunctionalized ethylene / vinyl monomer polymer, functionalized or unfunctionalized ethylene / alkyl (meth)acrylate, functionalized or unfunctionalized (meth)acrylic acid polymer, functionalized or unfunctionalized ethylene / vinyl monomer / alkyl (meth)acrylate terpolymer, ethylene / vinyl monomer / carbonyl terpolymer, ethylene / alkyl (meth)acrylate / carbonyl terpolymer, methyl methacrylate-butadiene-styrene (MBS) type core-shell polymer, polystyrene-block-polybutadiene-block-poly(methyl methacrylate) Examples of such materials include, but are not limited to, methacrylate, SBM, block polymers, chlorinated or chlorosulfonated polyethylene, polyvinylidene fluoride (PVDF), phenolic resins, poly(ethylene / vinyl acetate), polybutadiene, polyisoprene, styrene-based block copolymers, polyacrylonitrile, silicones, and any combination thereof. Furthermore, copolymers comprising one or more of the aforementioned materials may be used in the methods and systems of this disclosure.

[0105] Non-polar polymer blends (e.g., polymer blends of TPU with various thermoplastic polymers such as polyacetal, polyamide 6, poly(vinyl chloride), poly(vinyl butyral), polycarbonate, polypropylene, and polyethylene) may be achievable by using compatibilizers. TPU itself may be modified via soft and hard segments to increase its compatibility or miscibility with other polymers (e.g., poly(styrene-b-4-vinylpyridine) diblock copolymer as a compatibilizer).

[0106] Examples of polyamides include polycaproamide (nylon 6, polyamide 6, or PA6), poly(hexamethylene succinamide) (nylon 4,6, polyamide 4,6, or PA4,6), polyhexamethylene adipamide (nylon 6,6, polyamide 6,6, or PA6,6), polypentamethylene adipamide (nylon 5,6, polyamide 5,6, or PA5,6), polyhexamethylene sevacamide (nylon 6,10, polyamide 6,10, or PA6,10), polyundecaamide (nylon 11, polyamide 11, or PA11), polydodecaamide (nylon 12, polyamide 12, or PA12), and polyhexamethylene terephthalamide (na Examples include, but are not limited to, nylon 6T, polyamide 6T, or PA6T), nylon 10,10 (polyamide 10,10 or PA10,10), nylon 10,12 (polyamide 10,12 or PA10,12), nylon 10,14 (polyamide 10,14 or PA10,14), nylon 10,18 (polyamide 10,18 or PA10,18), nylon 6,18 (polyamide 6,18 or PA6,18), nylon 6,12 (polyamide 6,12 or PA6,12), nylon 6,14 (polyamide 6,14 or PA6,14), nylon 12,12 (polyamide 12,12 or PA12,12), and any combination thereof. Copolyamides may also be used. Examples of copolyamides include, but are not limited to, PA11 / 10,10, PA6 / 11, PA6,6 / 6, PA11 / 12, PA10,10 / 10,12, PA10,10 / 10,14, PA11 / 10,36, PA11 / 6,36, PA10,10 / 10,36, PA6T / 6,6, and any combination thereof. Polyamides where the first number is followed by a second number are polyamides with a first number of main-chain carbons between nitrogen=O in the non-pendant portion, and the second number of main-chain carbons are between two nitrogens in the pendant=O portion. As a non-limiting example, nylon 6,10 is [NH-(CH2)6-NH-CO-(CH2)8-CO] nWhen polyamide is followed by a number (or multiple numbers) or a backslash (or multiple numbers), it is a copolymer of polyamides, as indicated by the number before and after the backslash.

[0107] The thermoplastic polymer 108 not grafted onto the CNM in the compositions and methods of this disclosure may be an elastomer or not. Some of the aforementioned examples of thermoplastic polymers may be elastomers or non-elastomers depending on the exact composition of the polymer. For example, polyethylene, which is a copolymer of ethylene and propylene, may be an elastomer or not, depending on the amount of propylene in the polymer.

[0108] Thermoplastic elastomers generally fall within one of six classes: styrene-based block copolymers, thermoplastic polyolefin elastomers, thermoplastic vulcanized rubber (also called elastomer alloys), thermoplastic polyurethanes, thermoplastic copolyesters, and thermoplastic polyamides (typically block copolymers containing polyamides). Examples of thermoplastic elastomers can be found in Handbook of Thermoplastic Elastomers, 2nd ed., BMWalker and CPRader, eds., Van Nostrand Reinhold, New York, 1988. Examples of thermoplastic elastomers include, but are not limited to, elastomeric polyamides, polyurethanes, copolymers containing polyether blocks and polyamide blocks (PEBA or polyether block amides), methyl methacrylate-butadiene-styrene (MBS) type core-shell polymers, polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (SBM) block copolymers, polybutadiene, polyisoprene, styrene-based block copolymers, as well as polyacrylonitrile and silicones. Elastic styrene-based block copolymers may include at least one block selected from the group consisting of isoprene, isobutylene, butylene, ethylene / butylene, ethylene-propylene, and ethylene-ethylene / propylene. More specific examples of elastic styrene-based block copolymers include, but are not limited to, poly(styrene-ethylene / butylene), poly(styrene-ethylene / butylene-styrene), poly(styrene-ethylene / propylene), poly(styrene-ethylene / propylene-styrene-ethylene-propylene), poly(styrene-butadiene-styrene), poly(styrene-butylene-butadiene-styrene), and any combination thereof.

[0109] Polyurethanes may contain aliphatic groups, aromatic groups, ether groups, ester groups, urethane groups, and urea groups, and therefore offer a wide range of polarity and hydrogen bonding potential that can promote miscibility with a wide variety of other polymers, or at least strong interfacial bonding.

[0110] Compatibilizers may be used as desired to improve the blending efficiency and effectiveness of CNM-g-polyurethane 102 with one or more thermoplastic polymers. Examples of polymer compatibilizers, though not limited to them, include: PROPOLDER® MPP2020 20 (polypropylene, available from Polygroup Inc.), PROPOLDER® MPP2040 40 (polypropylene, available from Polygroup Inc.), NOVACOM® HFS2100 (maleic anhydride-functionalized high-density polyethylene polymer, available from Polygroup Inc.), KEN-REACT® CAPS® L® 12 / L (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT® CAPOW® L® 12 / H (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT® LICA® 12 (organometallic coupling agent, available from Kenrich Petrochemicals), and KEN-REACT® CAPS® KPR® 12 / LV (organometallic coupling agent, available from Kenrich Petrochemicals). Available from Petrochemicals), KEN-REACT(trademark) CAPOW(trademark) KPR(trademark) 12 / H (organometallic coupling agent, available from Kenrich Petrochemicals), KEN-REACT(trademark) titanate & zirconate (organometallic coupling agent, KenrichAvailable from Petrochemicals), VISTAMAXX (Trademark) (Ethylene-propylene copolymer, available from ExxonMobil), SANTOPRENE (Trademark) (Thermoplastic vulcanized ethylene-propylene-diene rubber and polypropylene, available from ExxonMobil), VISTALON (Trademark) (Ethylene-propylene-diene rubber, available from ExxonMobil), EXACT (Trademark) (Plastomer, available from ExxonMobil), EXXEL OR (trademark) (polymer resin, available from ExxonMobil), FUSABOND (trademark) M603 (random ethylene copolymer, available from Dow), FUSABOND (trademark) E226 (anhydrous modified polyethylene, available from Dow), BYNEL (trademark) 41E710 (co-extrudeable adhesive resin, available from Dow), SURLYN (trademark) 1650 (ionomer resin, available from Dow), FUSABOND (trademark) P353 (chemically modified polypropylene copolymer, available from Dow) (Available from Dow), ELVALOY® PTW (ethylene terpolymer, available from Dow), ELVALOY® 3427AC (ethylene and butyl acrylate copolymer, available from Dow), LOTADER® AX8840 (ethylene acrylate terpolymer, available from Arkema), LOTADER® 3210 (ethylene acrylate terpolymer, available from Arkema), LOTADER® 3410 (ethylene acrylate terpolymer) (Available from Arkema), LOTADER(trademark) 3430 (ethylene acrylate terpolymer, available from Arkema), LOTADER(trademark) 4700 (ethylene acrylate terpolymer, available from Arkema), LOTADER(trademark) AX8900 (ethylene acrylate terpolymer, available from Arkema), LOTADER(trademark) 4720 (ethylene acrylate terpolymer, available from Arkema), BAXXODUR(trademark) EC 301 (epoxy amine available from BASF), BAXXODUR(trademark) EC 311 (epoxy amine, available from BASF), BAXXODUR(trademark) ECExamples include 303 (epoxy amine, available from BASF), BAXXODUR® EC 280 (epoxy amine, available from BASF), BAXXODUR® EC 201 (epoxy amine, available from BASF), BAXXODUR® EC 130 (epoxy amine, available from BASF), BAXXODUR® EC 110 (epoxy amine, available from BASF), styrene-based, polypropylene, polyurethane, polycarbonate, EASTMAN® G-3003 (maleic anhydride grafted polypropylene, available from Eastman), RETAIN® (polymer modifier, available from Dow), AMPLIFY TY® (maleic anhydride grafted polymer, available from Dow), INTUNE® (olefin block copolymer, available from Dow), and any combination thereof.

[0111] The CNM-g-polyurethane 102 and / or thermoplastic polymer 108 not grafted onto CNM may have a melting point or softening temperature of about 50°C to about 450°C (or about 50°C to about 125°C, or about 100°C to about 175°C, or about 150°C to about 280°C, or about 200°C to about 350°C, or about 300°C to about 450°C).

[0112] The CNM-g-polyurethane 102 and / or thermoplastic polymer 108 not grafted onto CNM may have a glass transition temperature (using a heating and cooling rate of 10°C / min as defined in ASTM E1356-08(2014)) of about -50°C to about 400°C (or about -50°C to about 0°C, or about -25°C to about 50°C, or about 0°C to about 150°C, or about 100°C to about 250°C, or about 150°C to about 300°C, or about 200°C to about 400°C).

[0113] The thermoplastic polymer 108, which is not grafted onto the CNM, may optionally contain additives. Typically, the additives are present before the thermoplastic polymer is added to the mixture. Thus, in the polymer melt droplets and the resulting CNM-g-polyurethane particles 124 / 130, the additives are dispersed throughout the thermoplastic polymer. For this reason, for clarity, these additives are referred to herein as “internal additives.” The internal additives may be blended with the thermoplastic polymer immediately before or considerably before the mixture is prepared.

[0114] When describing the amounts of components in the compositions described herein (e.g., mixture 112 and CNM-g-polyurethane particles 124), the amounts are weight percent based on the thermoplastic polymer without internal additives. For example, a composition containing 1% by weight of emulsifying stabilizer 106 per 100 g of thermoplastic polymer, which contains 10% by weight of internal additives and 90% by weight of thermoplastic polymer, is a composition containing 0.9 g of emulsifying stabilizer 106, 90 g of thermoplastic polymer, and 10 g of internal additives.

[0115] This disclosure provides compositions comprising CNM-g-polyurethane particles, which include polyurethane grafted onto carbon nanomaterials. The CNM-g-polyurethane particles may have an average particle size of about 10 μm to about 100 μm and a particle size span of about 1 to about 2. The CNM-g-polyurethane particles may contain about 0.05% to about 50% by weight of CNM, where CNM may be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerene, and any combination thereof.

[0116] The internal additive may be present in the thermoplastic polymer 108 that is not grafted onto the CNM in amounts of about 0.1% to about 60% by weight (or about 0.1% to about 5% by weight, or about 1% to about 10% by weight, or about 5% to about 20% by weight, or about 10% to about 30% by weight, or about 25% to about 50% by weight, or about 40% to about 60% by weight). For example, the thermoplastic polymer may consist of about 70% to about 85% by weight of the thermoplastic polymer and about 15% to about 30% by weight of the internal additive, such as glass fibers or carbon fibers.

[0117] Examples of internal additives include, but are not limited to, fillers, reinforcing agents, pigments, pH adjusters, and combinations thereof. Examples of fillers include, but are not limited to, glass fibers, glass particles, mineral fibers, carbon fibers, oxide particles (e.g., titanium dioxide and zirconium dioxide), metal particles (e.g., aluminum powder), and any combination thereof. Examples of pigments include, but are not limited to, organic pigments, inorganic pigments, carbon black, and any combination thereof. For example, fillers used herein may include exfoliated graphite (EG), exfoliated graphite nanoplatelet (xGnP), carbon black, carbon nanofiber (CNF), carbon nanotube (CNT), graphene, graphene oxide, graphite oxide, graphene oxide nanosheets, and fullerenes.

[0118] A suitable dispersion medium (e.g., dispersion medium 104) may have a viscosity at 25°C of approximately 1,000 cSt to approximately 150,000 cSt (or approximately 1,000 cSt to approximately 60,000 cSt, or approximately 40,000 cSt to approximately 100,000 cSt, or approximately 75,000 cSt to approximately 150,000 cSt). For example, a suitable dispersion medium (e.g., dispersion medium 104) may have a viscosity at 25°C of approximately 10,000 cSt to approximately 60,000 cSt.

[0119] Examples of dispersion media (e.g., dispersion media 104) include silicone oil, fluorinated silicone oil, perfluorinated silicone oil, polyethylene glycol, alkyl-terminated polyethylene glycol (e.g., tetraethylene glycol dimethyl ether) Examples of polysiloxanes include, but are not limited to, C1-C4 terminal alkyl groups (such as ether, TDG), paraffin, liquid petrolatum, mink oil, turtle oil, soybean oil, perhydrosqualene, sweet almond oil, calophyllum oil, palm oil, pearl reem oil, grapeseed oil, sesame oil, corn oil, rapeseed oil, sunflower oil, cottonseed oil, apricot oil, castor oil, avocado oil, jojoba oil, olive oil, cereal germ oil, lanolinic acid esters, oleic acid esters, lauric acid esters, stearic acid esters, aliphatic esters, higher fatty acids, aliphatic alcohols, fatty acid-modified polysiloxanes, aliphatic alcohol-modified polysiloxanes, polyoxyalkylene-modified polysiloxanes, and any combination thereof. Examples of silicone oils, but not limited to, include polydimethylsiloxane (PDMS), methylphenylpolysiloxane, alkyl-modified polydimethylsiloxane, alkyl-modified methylphenylpolysiloxane, amino-modified polydimethylsiloxane, amino-modified methylphenylpolysiloxane, fluorine-modified polydimethylsiloxane, fluorine-modified methylphenylpolysiloxane, polyether-modified polydimethylsiloxane, polyether-modified methylphenylpolysiloxane, and any combination thereof. If the dispersion medium 104 contains two or more of the above, the dispersion medium 104 may have one or more phases. For example, polysiloxanes modified with fatty acids and polysiloxanes modified with aliphatic alcohols (preferably having similar chain lengths to fatty acids and aliphatic alcohols) can form a single-phase dispersion medium. In another example, the dispersion medium 104 containing a silicone oil and alkyl-terminated polyethylene glycol can form a two-phase dispersion medium. In at least one embodiment, the dispersion medium 104 is polydimethylsiloxane (PDMS).

[0120] The dispersion medium 104 may be present in the mixture in an amount of about 40% to about 95% by weight (or about 75% to about 95% by weight, or about 70% to about 90% by weight, or about 55% to about 80% by weight, or about 50% to about 75% by weight, or about 40% to about 60%) of the combined CNM-g-polyurethane 102, the thermoplastic polymer 108 not grafted onto CNM, and the dispersion medium 104. The dispersion medium may be present in a weight ratio of the dispersion medium to the combination of CNM-g-polyurethane 102 and the thermoplastic polymer in the range of 50:50 to 90:10.

[0121] In some cases, the dispersion medium 104 has a density of approximately 0.6 g / cm³. 3 ~Approx. 1.5g / cm 3 Even if it is not, the thermoplastic polymer has a density of approximately 0.7 g / cm³. 3 ~Approx. 1.7g / cm 3 The thermoplastic polymer may have a density similar to, lower than, or higher than, the density of the dispersion medium 104.

[0122] CNM should be sufficiently stable so as not to decompose at processing temperatures. Examples of CNM include, but are not limited to, carbon nanotubes, graphite, graphene, fullerenes, carbon black, and any combination thereof.

[0123] The emulsifying stabilizers used in the methods and compositions of this disclosure (e.g., emulsifying stabilizer 106) may include nanoparticles (e.g., oxide nanoparticles, carbon black, polymer nanoparticles, and combinations thereof), surfactants, and any combination thereof.

[0124] Oxide nanoparticles may be metal oxide nanoparticles, nonmetal oxide nanoparticles, or mixtures thereof. Examples of oxide nanoparticles include, but are not limited to, silica, titania, zirconia, alumina, iron oxide, copper oxide, tin oxide, boron oxide, cerium oxide, thallium oxide, and tungsten oxide, as well as any combination thereof. Mixed metal oxides and / or nonmetal oxides such as aluminosilicates, borosilicates, and aluminoborosilicates are also included in the term metal oxides. Oxide nanoparticles may be hydrophilic or hydrophobic, and may be natural particles or the result of surface treatment of particles. For example, silica nanoparticles having a hydrophobic surface treatment such as dimethylsilyl or trimethylsilyl may be used in the methods and compositions of this disclosure. In addition, silica with a functional surface treatment such as methacrylate functional groups may be used in the methods and compositions of this disclosure. Non-functionalized oxide nanoparticles may also be suitable for use.

[0125] Examples of commercially available silica nanoparticles include AEROSIL® (registered trademark) available from Evonik (e.g., AEROSIL® R812S (hydrophobic modified surface and 260±30m)). 2 Silica nanoparticles with an average particle size of approximately 7 nm and a BET surface area of ​​1 / g, AEROSIL® RX50 (hydrophobic modified surface and 35±10m 2 Silica nanoparticles with an average particle size of approximately 40 nm and a BET surface area of ​​1 / g, AEROSIL® 380 (hydrophobic modified surface and 380±30m 2 Examples include, but are not limited to, silica nanoparticles having a surface area of ​​ / g, and any combination thereof.

[0126] Carbon black is another type of nanoparticle that may be present as an emulsifying stabilizer in the compositions and methods disclosed herein. Various grades of carbon black are familiar to those skilled in the art, and any of them may be used herein. Other nanoparticles capable of absorbing infrared radiation may be used similarly.

[0127] Polymer nanoparticles are another type of nanoparticle that may exist as emulsifying stabilizers (e.g., emulsifying stabilizer 106) in the disclosure herein. Suitable polymer nanoparticles may comprise one or more polymers that are thermosetting and / or crosslinked so as not to melt when treated by melt emulsification according to the disclosure herein. High molecular weight thermoplastic polymers having high melting or decomposition points may also constitute suitable polymer nanoparticle emulsifying stabilizers.

[0128] Surfactants may be anionic, cationic, nonionic, or dipolar ionic. Examples of surfactants include, but are not limited to, sodium dodecyl sulfate, sorbitan oleate, poly[dimethylsiloxane-co-[3-(2-(2-hydroxyethoxy)ethoxy)propylmethylsiloxane]], sodium docusate (sodium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate), and any combination thereof. Examples of commercially available surfactants include, but are not limited to, CALFAX® DB-45 (sodium dodecyldiphenyl oxide disulfonate, available from Pilot Chemicals), SPAN® 80 (sorbitan maleate nonionic surfactant), MERPOL® surfactant (available from Stepan Company), TERGITOL® TMN-6 (water-soluble nonionic surfactant, available from DOW), TRITON® X-100 (octylphenol ethoxylate, available from Sigma-Aldrich), IGEPAL® CA-520 (polyoxyethylene(5) isooctylphenyl ether, available from Sigma-Aldrich), BRIJ® S10 (polyethylene glycol octadecyl ether, available from Sigma-Aldrich), and any combination thereof.

[0129] Surfactants may be present in the mixture at a concentration of approximately 0.01% to 10% by weight (or approximately 0.01% to 1% by weight, or approximately 0.5% to 2% by weight, or approximately 1% to 3% by weight, or approximately 2% to 5% by weight, or approximately 5% to 10% by weight) based on the weight of CNM-g-polyurethane 102. Alternatively, the mixture may be surfactant-free (or surfactant-absent).

[0130] The weight ratio of nanoparticles to surfactant in the emulsifying stabilizer 106 may be approximately 1:10 to approximately 10:1 (or approximately 1:10 to approximately 1:1, or approximately 1:5 to approximately 5:1, or approximately 1:1 to approximately 10:1).

[0131] The emulsifying stabilizer 106 may be present in the mixture at a concentration of about 0.01% to about 10% by weight (or about 0.01% to about 1% by weight, or about 0.1% to about 3% by weight, or about 1% to about 5% by weight, or about 5% to about 10% by weight) based on the weight of the CNM-g-polyurethane 102 and the thermoplastic polymer 108 that is not grafted onto CNM.

[0132] With respect to combination 110 in Figure 1, in some cases, the emulsifying stabilizer 106 may be dispersed in the dispersion medium 104 while optionally heating the dispersion, first before adding the CNM-g-polyurethane 102 and / or the thermoplastic polymer 108 that is not grafted onto CNM. In another non-limiting example, the CNM-g-polyurethane 102 and / or the thermoplastic polymer 108 that is not grafted onto CNM may be heated to produce a polymer melt, to which the dispersion medium 104 and the emulsifying stabilizer 106 may be added together or in either order. In yet another non-limiting example, the CNM-g-polyurethane 102 and / or the thermoplastic polymer 108 that is not grafted onto CNM may be mixed together with the dispersion medium 104 at a temperature higher than the required melting or softening temperature described herein, and at a shear rate sufficient to disperse the polymer melt in the dispersion medium 104. The emulsifying stabilizer 106 is then added to form a mixture 112, which can be maintained under suitable process conditions for a set period of time.

[0133] Combining CNM-g-polyurethane 102, ungrafted thermoplastic polymer 108, dispersion medium 104, and optionally emulsifying stabilizer 106 in any combination may occur in the mixing apparatus and / or other suitable container used for processing. As a non-limiting example, the CNM-g-polyurethane 102 and / or ungrafted thermoplastic polymer 108 may be heated in the mixing apparatus used for processing to a temperature exceeding the required melting or softening temperature described herein, and the emulsifying stabilizer 106 may be dispersed in the dispersion medium 104 in a separate container. The dispersion can then be added to the molten material in the mixing apparatus used for processing.

[0134] The mixing apparatus used in the process 114 for producing the molten emulsion 116 should be able to maintain the molten emulsion 116 at a temperature above the required melting point or softening temperature described herein and apply a shear rate sufficient to disperse the polymer melt as droplets in the dispersion medium 104.

[0135] Examples of mixing equipment used in the process 114 for producing the molten emulsion 116 include, but are not limited to, extruders (e.g., continuous extruders, batch extruders, etc.), agitated reactors, blenders, reactors equipped with inline homogenizer systems, and equipment derived therefrom.

[0136] Processing 114 under suitable process conditions (e.g., temperature, shear rate, etc.) for a set period of time, and formation of a molten emulsion 116.

[0137] The temperature at which the treatment 114 and the formation of the molten emulsion 116 are performed should be higher than the required melting or softening temperature described herein and lower than the decomposition temperature of any component in the mixture 112 (i.e., CNM-g-polyurethane 102, thermoplastic polymer 108 not grafted onto CNM, dispersion medium 104, and emulsifying stabilizer 106). For example, the temperature at which the treatment 114 and the formation of the molten emulsion 116 are performed may be about 1°C to about 50°C (or about 1°C to about 25°C, or about 5°C to about 30°C, or about 20°C to about 50°C) higher than the melting or softening temperature described herein, provided that the temperature at which the treatment and the formation of the molten emulsion 116 are performed is lower than the decomposition temperature of any component in the mixture 112 (i.e., CNM-g-polyurethane 102, thermoplastic polymer 108 not grafted onto CNM, dispersion medium 104, and emulsifying stabilizer 106).

[0138] The shear rate of the process 114 and the formation of the molten emulsion 116 should be high enough to disperse the polymer melt as droplets in the dispersion medium 104. These droplets should include droplets with a particle size of about 1000 μm or less (or about 1 μm to about 1000 μm, or about 1 μm to about 50 μm, or about 10 μm to about 100 μm, or about 10 μm to about 250 μm, or about 50 μm to about 500 μm, or about 250 μm to about 750 μm, or about 500 μm to about 1000 μm).

[0139] The time for maintaining the temperature and shear rate for the process 114 and the formation of the molten emulsion 116 may be 10 seconds to 18 hours or more (or 10 seconds to 30 minutes, or 5 minutes to 1 hour, or 15 minutes to 2 hours, or 1 hour to 6 hours, or 3 hours to 18 hours). Although not bound by theory, it is considered that a steady state of droplet particle size will be reached at a point in time when the process can be stopped. This time may depend, in particular, on the temperature, shear rate, CNM-g-polyurethane 102, the thermoplastic polymer 108 not grafted onto CNM, the dispersion medium composition 104, and the emulsifying stabilizer composition 106.

[0140] The molten emulsion 116 may then be cooled 118. The cooling 118 can be slow (e.g., allowing the molten emulsion 116 to be cooled under ambient conditions) or fast (e.g., rapid cooling). For example, the rate of cooling 118 can range from about 10°C / hour to about 100°C / second, or even nearly instantaneous by rapid cooling (e.g., dry ice) (or about 10°C / hour to about 60°C / hour, or about 0.5°C / min to about 20°C / min, or about 1°C / min to about 5°C / min, or about 10°C / min to about 60°C / min, or about 0.5°C / second to about 10°C / second, or about 10°C / second to about 100°C / second).

[0141] During cooling, shear force may be applied little to no to the molten emulsion 116. In some cases, the shear force applied during heating may be applied during cooling 118.

[0142] The cooled mixture obtained from the cooling 118 of the molten emulsion 116 may contain solidified CNM-g-polyurethane particles 124 and other components (e.g., dispersion medium 104, excess emulsifying stabilizer 106, etc.). The CNM-g-polyurethane particles 124 may be dispersed in the dispersion medium 104 and / or settle in the dispersion medium 104.

[0143] The cooled mixture can then be treated to separate CNM-g-polyurethane particles 124 from the other components. Suitable treatments include, but are not limited to, washing, filtering, centrifugation, and decanting, as well as any combination thereof.

[0144] The solvent used to wash the CNM-g-polyurethane particles 124 should generally be (a) miscible with the dispersion medium 104 and (b) nonreactive (e.g., non-swelling and non-soluble) with the CNM-g-polyurethane 102 and / or the thermoplastic polymer 108 not grafted onto CNM. The choice of solvent will depend, in particular, on the composition of the dispersion medium 104, the CNM-g-polyurethane 102, and the thermoplastic polymer 108 not grafted onto CNM.

[0145] Examples of solvents include, but are not limited to, hydrocarbon solvents (e.g., pentane, hexane, heptane, octane, cyclohexane, cyclopentane, decane, dodecane, tridecane, and tetradecane), aromatic hydrocarbon solvents (e.g., benzene, toluene, xylene, 2-methylnaphthalene, and cresol), ether solvents (e.g., diethyl ether, tetrahydrofuran, diisopropyl ether, and dioxane), ketone solvents (e.g., acetone and methyl ethyl ketone), alcohol solvents (e.g., methanol, ethanol, isopropanol, and n-propanol), ester solvents (e.g., ethyl acetate, methyl acetate, butyl acetate, butyl propionate, and butyl butyrate), halogenated solvents (e.g., chloroform, bromoform, 1,2-dichloromethane, 1,2-dichloroethane, carbon tetrachloride, chlorobenzene, and hexafluoroisopropanol), water, and any combination thereof.

[0146] The solvent may be removed from the CNM-g-polyurethane particles 124 by drying using a suitable method such as air drying, heat drying, vacuum drying, freeze-drying, or a hybrid thereof. Heating may preferably be carried out at a temperature lower than the glass transition temperature of the polyurethane of the CNM-g-polyurethane 102 and the thermoplastic polymer 108 that is not grafted onto the CNM (e.g., about 50°C to about 150°C).

[0147] Advantageously, the dispersion medium (e.g., dispersion medium 104) and cleaning solvent of the systems and methods described herein can be recycled and reused. Those skilled in the art will recognize any necessary cleaning of the used dispersion medium 104 and solvent required for the regeneration process.

[0148] The CNM-g-polyurethane particles 124, after being separated from other components, may be optionally further purified. For example, to narrow the particle size distribution (or reduce the particle size span), the CNM-g-polyurethane particles 124 can be passed through a sieve with a pore size of approximately 10 μm to approximately 250 μm (or approximately 10 μm to approximately 100 μm, or approximately 50 μm to approximately 200 μm, or approximately 150 μm to approximately 250 μm).

[0149] In another exemplary purification technique, the CNM-g-polyurethane particles 124 may be washed with water to remove surfactants while retaining substantially all of the nanoparticles associated with the surface of the CNM-g-polyurethane particles 124. In yet another exemplary purification technique, the CNM-g-polyurethane particles 124 may be blended with additives to obtain the desired final product. For clarity, such additives are blended with the CNM-g-polyurethane particles 124 described herein after the particles have solidified, and such additives are referred to herein as “external additives.” Examples of external additives include flow aids, other polymer particles, fillers, and any combination thereof.

[0150] In some cases, the surfactants used to produce the CNM-g-polyurethane particles 124 may be undesirable in downstream applications. Therefore, yet another exemplary purification technique may include removing the surfactant from the CNM-g-polyurethane particles 124 at least substantially (e.g., by washing and / or thermal decomposition).

[0151] CNM-g-polyurethane particles 124 and / or purified CNM-g-polyurethane particles 124 may be characterized by their composition, physical structure, etc.

[0152] As described above, the emulsifying stabilizer (e.g., emulsifying stabilizer 106) is located at the interface between the polymer melt and the dispersion medium 104. As a result, when the mixture cools, the emulsifying stabilizer (e.g., emulsifying stabilizer 106) remains at or near the interface. Therefore, the structure of the CNM-g-polyurethane particles 124 generally includes, when the emulsifying stabilizer (e.g., emulsifying stabilizer 106) is used, (a) dispersed on the outer surface of the CNM-g-polyurethane particles 124 and / or (b) embedded in the outer portion of the CNM-g-polyurethane particles 124 (e.g., outer 1 vol%).

[0153] Furthermore, if voids are formed inside the polymer molten droplets, the emulsifying stabilizer (e.g., emulsifying stabilizer 106) should generally be located (and / or embedded) at the interface between the void and the CNM-g-polyurethane 124 and / or thermoplastic polymer. The voids generally do not contain CNM-g-polyurethane 124 and / or thermoplastic polymer. Rather, the voids may contain, for example, the dispersion medium 104, contain air, or be empty. The CNM-g-polyurethane particles 124 may contain the dispersion medium 104 in an amount of about 5% by weight or less (or about 0.001% to about 5% by weight, or about 0.001% to about 0.1% by weight, or about 0.01% to about 0.5% by weight, or about 0.1% to about 2% by weight, or about 1% to about 5% by weight) of the CNM-g-polyurethane particles 124.

[0154] If the CNM does not contain an ungrafted thermoplastic polymer, the combined CNM-g-polyurethane and the ungrafted thermoplastic polymer may be present in the CNM-g-polyurethane particles in an amount of approximately 90% to approximately 99.5% by weight (or approximately 90% to approximately 95% by weight, or approximately 92% to approximately 97% by weight, or approximately 95% to approximately 99.5% by weight) of the CNM-g-polyurethane particles. If the CNM contains an ungrafted thermoplastic polymer, the combined CNM-g-polyurethane and the ungrafted thermoplastic polymer may be present in the CNM-g-polyurethane particles in an amount of approximately 90% to approximately 99.5% by weight (or approximately 90% to approximately 95% by weight, or approximately 92% to approximately 97% by weight, or approximately 95% to approximately 99.5% by weight) of the CNM-g-polyurethane particles. The weight ratio of CNM-g-polyurethane to thermoplastic polymers not grafted onto CNM (if present) may be approximately 10:90 to approximately 99:1 (or approximately 10:90 to approximately 50:50, or approximately 25:75 to approximately 75:25, or approximately 50:50 to approximately 99:1, or approximately 80:20 to approximately 99:1).

[0155] If present, emulsifying stabilizers (e.g., emulsifying stabilizer 106) may be present in CNM-g-polyurethane particles 124 in amounts of about 10% by weight or less (or about 0.01% to about 10% by weight, or about 0.01% to about 1% by weight, or about 0.5% to about 5% by weight, or about 3% to about 7% by weight, or about 5% to about 10% by weight). After purification to remove at least substantially any surfactant or other emulsifying stabilizer, emulsifying stabilizers may be present in CNM-g-polyurethane particles 124 / 130 in amounts of less than 0.01% by weight (or 0% to about 0.01% by weight, or 0% to 0.001% by weight).

[0156] When forming thermoplastic microparticles according to the disclosure herein using particulate emulsifying stabilizers, at least a portion of the particulate emulsifying stabilizer, such as silica nanoparticles, may be arranged as a coating on the outer surface of the CNM-g-polyurethane particles 124 / 130. At least a portion of the surfactant, if used, may similarly associate on the outer surface. The coating may be distributed substantially uniformly on the outer surface. As used herein with respect to coatings, the term “substantially uniform” means a uniform coating thickness on the surface area covered by the coating composition (e.g., nanoparticles and / or surfactant), particularly over the entire outer surface. The emulsifying stabilizer 106 may form a coating covering at least 5% (or about 5% to about 100%, or about 5% to about 25%, or about 20% to about 50%, or about 40% to about 70%, or about 50% to about 80%, or about 60% to about 90%, or about 70% to about 100%) of the surface area of ​​the CNM-g-polyurethane particles. After purification to remove at least substantially any surfactant or other emulsifying stabilizer, the emulsifying stabilizer may be present in the CNM-g-polyurethane particles 124 / 130 in an area of ​​less than 25% of the surface area of ​​the CNM-g-polyurethane particles 124 / 130 (or 0% to about 25%, or about 0.1% to about 5%, or about 0.1% to about 1%, or about 1% to about 5%, or about 1% to about 10%, or about 5% to about 15%, or about 10% to about 25%). The coverage of the emulsifying stabilizer on the outer surface of the CNM-g-polyurethane particles 124 / 130 may be determined using analysis of scanning electron microscope images (SEM images). The emulsifying stabilizer may form a coating that covers at least 5% (or about 5% to about 100%, or about 5% to about 25%, or about 20% to about 50%, or about 40% to about 70%, or about 50% to about 80%, or about 60% to about 90%, or about 70% to about 100%) of the surface area of ​​the CNM-g-polyurethane particles 124 / 130 (and coated CNM-g-polyurethane particles if manufactured).After purification to remove at least substantially any surfactant or other emulsifying stabilizer, the emulsifying stabilizer may be present in CNM-g-polyurethane particles 124 / 130 in an area of ​​less than 25% of the surface area of ​​the CNM-g-polyurethane particles 124 / 130 (or 0% to about 25%, or about 0.1% to about 5%, or about 0.1% to about 1%, or about 1% to about 5%, or about 1% to about 10%, or about 5% to about 15%, or about 10% to about 25%). The coverage of the emulsifying stabilizer on the outer surface of the CNM-g-polyurethane particles can be determined using image analysis of SEM micrographs.

[0157] The CNM-g-polyurethane particles 124 / 130 of this disclosure may comprise about 0.01% to about 50% by weight (or about 0.01% to about 1% by weight, or about 0.1% to about 5% by weight, or about 1% to about 10% by weight, or about 5% to about 20% by weight, or about 10% to about 30% by weight, or about 25% to about 50% by weight) of carbon nanomaterial (or, if two or more are used, carbon nanomaterial in total).

[0158] The CNM-g-polyurethane particles 124 / 130 may comprise one or more carbon nanomaterials. For example, two or more different carbon nanomaterials may be grafted onto polyurethane in the same reaction and then used as CNM-g-polyurethane 102 in the methods and compositions described herein. In another example, two different CNM-g-polyurethanes may be produced and blended before (or during) the mixing process of the melt emulsification process described herein.

[0159] CNM-g-polyurethane particles 124 / 130 may have a roundness of approximately 0.90 to approximately 1.0.

[0160] CNM-g-polyurethane particles 124 / 130 have a BET surface area of ​​approximately 10 m². 2 / g~about 500m 2 / g (or approximately 10m 2 / g~about 150m 2 / g, or approximately 25m 2 / g~about 100m 2 / g, or about 100 m 2 / g to about 250 m 2 / g, or 250 m 2 / g to about 500 m 2 / g).

[0161] CNM-g-polyurethane particles 124 / 130 may have a D10 of about 0.1 μm to about 125 μm (or about 0.1 μm to about 5 μm, about 1 μm to about 10 μm, about 5 μm to about 30 μm, or about 1 μm to about 25 μm, or about 25 μm to about 75 μm, or about 50 μm to about 85 μm, or about 75 μm to about 125 μm), a D50 of about 0.5 μm to about 200 μm (or about 0.5 μm to about 10 μm, or about 5 μm to about 50 μm, or about 30 μm to about 100 μm, or about 30 μm to about 70 μm, or about 25 μm to about 50 μm, or about 50 μm to about 100 μm, or about 75 μm to about 150 μm, or about 100 μm to about 200 μm), a D90 of about 3 μm to about 300 μm (or about 3 μm to about 15 μm, or about 10 μm to about 50 μm, or about 25 μm to about 75 μm, or about 70 μm to about 200 μm, or about 60 μm to about 150 μm, or about 150 μm to about 300 μm), and D10 < D50 < D90. CNM-g-polyurethane particles 124 / 130 may also have a particle size span of about 0.2 to about 10 (or about 0.2 to about 0.5, or about 0.4 to about 0.8, or about 0.5 to about 1, or about 1 to about 3, or about 2 to about 5, or about 5 to about 10). Without limitation, a diameter span value of 1.0 or more is considered wide, and a particle size span value of 0.75 or less is considered narrow. Preferably, CNM-g-polyurethane particles 124 / 130 have a particle size span of about 0.2 to about 1.

[0162] In a first non-limiting example, CNM-g-polyurethane particles 124 / 130 may have a D10 of about 0.1 μm to about 10 μm, a D50 of about 0.5 μm to about 25 μm, a D90 of about 3 μm to about 50 μm, and D10 < D50 < D90. The CNM-g-polyurethane particles 124 / 130 may have a particle size span of about 0.2 to about 2.

[0163] In a second non-limiting example, the CNM-g-polyurethane particles 124 / 130 may have a D10 of about 5 μm to about 30 μm, a D50 of about 30 μm to about 70 μm, a D90 of about 70 μm to about 120 μm, and D10 < D50 < D90. The CNM-g-polyurethane particles 124 / 130 may have a particle size span of about 1.0 to about 2.5.

[0164] In a third non-limiting example, the CNM-g-polyurethane particles 124 / 130 may have a D10 of about 25 μm to about 60 μm, a D50 of about 60 μm to about 110 μm, a D90 of about 110 μm to about 175 μm, and D10 < D50 < D90. The CNM-g-polyurethane particles 124 / 130 may have a particle size span of about 0.6 to about 1.5.

[0165] In a fourth non-limiting example, the CNM-g-polyurethane particles 124 / 130 may have a D10 of about 75 μm to about 125 μm, a D50 of about 100 μm to about 200 μm, a D90 of about 125 μm to about 300 μm, and D10 < D50 < D90. The CNM-g-polyurethane particles 124 / 130 may have a particle size span of about 0.2 to about 1.2.

[0166] In a fifth non-limiting example, the CNM-g-polyurethane particles 124 / 130 may have a D10 of about 1 μm to about 50 μm (or about 5 μm to about 30 μm, or about 1 μm to about 25 μm, or about 25 μm to about 50 μm), a D50 of about 25 μm to about 100 μm (or about 30 μm to about 100 μm, or about 30 μm to about 70 μm, or about 25 μm to about 50 μm, or about 50 μm to about 100 μm), a D90 of about 60 μm to about 300 μm (or about 70 μm to about 200 μm, or about 60 μm to about 150 μm, or about 150 μm to about 300 μm), and D10 < D50 < D90. The CNM-g-polyurethane particles 124 / 130 may also have a particle size span of about 0.4 to about 3 (or about 0.6 to about 2, or about 0.4 to about 1.5, or about 1 to about 3).

[0167] The CNM-g-polyurethane particles 124 / 130 may have a roundness of approximately 0.9 or higher (or approximately 0.90 to approximately 1.0, or approximately 0.93 to approximately 0.99, or approximately 0.95 to approximately 0.99, or approximately 0.97 to approximately 0.99, or approximately 0.98 to approximately 1.0).

[0168] CNM-g-polyurethane particles 124 / 130 may have an angle of repose of approximately 25° to approximately 45° (or approximately 25° to approximately 35°, or approximately 30° to approximately 40°, or approximately 35° to approximately 45°).

[0169] The CNM-g-polyurethane particles 124 / 130 may have a Hausner ratio of approximately 1.0 to approximately 1.5 (or approximately 1.0 to approximately 1.2, or approximately 1.1 to approximately 1.3, or approximately 1.2 to approximately 1.35, or approximately 1.3 to approximately 1.5).

[0170] CNM-g-polyurethane particles 124 / 130 have a bulk density of approximately 0.3 g / cm³. 3 ~about 0.8g / cm 3 (or approximately 0.3 g / cm³) 3 ~about 0.6g / cm 3 , or approximately 0.4 g / cm³ 3 ~about 0.7g / cm 3 , or approximately 0.5 g / cm³ 3 ~about 0.6g / cm 3 , or approximately 0.5 g / cm³ 3 ~about 0.8g / cm 3 ) is also acceptable.

[0171] CNM-g-polyurethane particles 124 / 130 have a loosening density of approximately 0.5 g / cm³. 3 ~about 0.8g / cm 3 (or approximately 0.5 g / cm³) 3 ~about 0.7g / cm 3 , or approximately 0.55 g / cm³ 3 ~about 0.80g / cm 3 ) is also acceptable.

[0172] CNM-g-polyurethane particles 124 / 130 have a tap density of approximately 0.6 g / cm³. 3~Approx. 0.9g / cm 3 (or approximately 0.60 g / cm³) 3 ~Approx. 0.75g / cm 3 , or approximately 0.65 g / cm³ 3 ~about 0.80g / cm 3 , or approximately 0.70 g / cm³ 3 ~Approx. 0.90g / cm 3 ) is also acceptable.

[0173] Depending on the processing temperature and shear rate, as well as the composition and relative concentration of the components (e.g., CNM-g-polyurethane 102, thermoplastic polymer, dispersion medium 104, excess emulsifying stabilizer 106, etc.), different structural shapes constituting the CNM-g-polyurethane particles 124 / 130 can be produced. Typically, the CNM-g-polyurethane particles 124 / 130 include substantially spherical particles (roundness of about 0.97 or greater). However, other structures, including disc-shaped and elongated structures, may be observed in the CNM-g-polyurethane particles 124 / 130. Thus, the CNM-g-polyurethane particles 124 / 130 may include one or more of the following: (a) substantially spherical particles with roundness of 0.97 or greater, (b) disc-shaped structures with an aspect ratio of about 2 to about 10, and (c) elongated structures with an aspect ratio of 10 or greater. Each of the above structures (a), (b), and (c) has an emulsifying stabilizer dispersed on the outer surface of the structure (a), (b), and (c), and / or embedded in the outer portion of the structure (a), (b), and (c). At least some of the structures (a), (b), and (c) may aggregate. For example, the elongated structure of (c) may be located on the surface of the substantially spherical particles of (a).

[0174] CNM-g-polyurethane particles 124 / 130 may have a sintering window of 10°C, preferably 5°C, within the sintering window of CNM-g-polyurethane.

[0175] CNM-g-polyurethane particles 124 / 130 may have a melting point in the range of about 170°C to about 200°C (or about 175°C to about 195°C, or about 180°C to about 190°C, for example, about 185°C to about 190°C).

[0176] CNM-g-polyurethane particles 124 / 130 may have a crystallization temperature in the range of about 130°C to about 170°C (or about 135°C to about 165°C, or about 140°C to about 160°C, for example, about 145°C to about 155°C).

[0177] CNM-g-polyurethane particles 124 / 130 may have a degree of crystallinity ranging from approximately 20% to approximately 40% (or approximately 22% to approximately 38%, or approximately 24% to approximately 36%, or approximately 26% to approximately 34%, or approximately 28% to approximately 32%, or approximately 20% to approximately 30%, or approximately 22% to approximately 28%).

[0178] CNM-g-polyurethane particles 124 / 130 may have an MFI flow rate in the range of approximately 0.5 g / 10 min to approximately 10 g / 10 min (or approximately 1 g / 10 min to approximately 8 g / 10 min, or approximately 1.5 g / 10 min to approximately 6 g / 10 min, or approximately 2 g / 10 min to approximately 5 g / 10 min).

[0179] CNM-g-polyurethane particles 124 / 130 can provide dimensional accuracy for SLS portions in the range of 0.1% to approximately 5% (or approximately 0.5% to approximately 4.5%, or approximately 1% to approximately 4%).

[0180] CNM-g-polyurethane particles 124 / 130 may have a tensile strength in the range of approximately 50 MPa to approximately 200 MPa (or approximately 60 MPa to approximately 150 MPa, or approximately 80 MPa to approximately 100 MPa).

[0181] The tensile strength and dimensional accuracy of the SLS portion of the CNM-g polyurethane particles 124 / 130 of this disclosure may be advantageously higher than those of the SLS portion of typical polyurethane particles processed with the same parameters.

[0182] CNM-g-polyurethane particles 124 / 130 may have a tensile modulus (as a fiber) in the range of approximately 400 MPa to approximately 1000 MPa (or approximately 425 MPa to approximately 800 MPa, or approximately 450 MPa to approximately 600 MPa, or approximately 475 MPa to approximately 500 MPa, or approximately 500 MPa to approximately 600 MPa).

[0183] CNM-g-polyurethane particles 124 / 130 may have an ultimate strength in the range of approximately 50 MPa to approximately 500 MPa (or approximately 60 MPa to approximately 450 MPa, or approximately 70 MPa to approximately 400 MPa, or approximately 80 MPa to approximately 350 MPa, or approximately 90 MPa to approximately 300 MPa, or approximately 100 MPa to approximately 250 MPa, or approximately 50 MPa to approximately 150 MPa, or approximately 80 MPa to approximately 120 MPa).

[0184] CNM-g-polyurethane particles 124 / 130 may have a curvature modulus in the range of approximately 50 MPa to approximately 2000 MPa (or approximately 100 MPa to approximately 1500 MPa, or approximately 150 MPa to approximately 1000 MPa, or approximately 200 MPa to approximately 800 MPa, or approximately 500 MPa to approximately 1000 MPa).

[0185] CNM-g-polyurethane particles 124 / 130 may have an elongation at fracture of approximately 2% to approximately 200% (or approximately 4% to approximately 190%, or approximately 6% to approximately 180%, or approximately 8% to approximately 160%, or approximately 10% to approximately 140%, or approximately 15% to approximately 120%, or approximately 20% to approximately 100%, or approximately 50% to approximately 150%). Applications of CNM-g polyurethane

[0186] The disclosure also relates to a method of selective laser sintering, which may include (a) depositing (a1) CNM-g-polyurethane and optionally (a2) a thermoplastic polymer that is not grafted onto CNM but is not the polyurethane of CNM-g-polyurethane, and optionally (b) other thermoplastic polymer particles that do not contain CNM-g-polyurethane on a surface, and after deposition, exposing at least a portion of the spherical polymer particles to a laser to fuse the polymer particles and form a solid.

[0187] The CNM-g-polyurethane particles 124 / 130 described herein may be used to manufacture a variety of articles. In non-limiting examples, a 3D printing process of this disclosure may include depositing the CNM-g-polyurethane particles 124 / 130 described herein onto a surface (e.g., in layers and / or in a particular shape), and after depositing, heating at least a portion of the particles to promote solidification of the particles and form a solidified body (or object). The solidified body may have a porosity of about 5% or less after solidification (e.g., 0% to about 5%, or about 0.5% to about 2%, or about 1% to about 3%, or about 2% to about 5%). For example, heating and solidification of polymer particles (e.g., CNM-g-polyurethane particles 124 / 130 and other thermoplastic polymer particles) may be carried out in a laser-based 3D printing apparatus such that heating and solidification are performed by selective laser sintering.

[0188] Examples of articles that can be formed in whole or in part using the CNM-g-polyurethane particles 124 / 130, and that can be manufactured in such a manner, include, but are not limited to, particles, films, packaging materials, toys, household goods, automotive parts, aerospace / aircraft parts, containers (e.g., for food, beverages, cosmetics, personal care compositions, pharmaceuticals, etc.), shoe soles, furniture parts, decorative household goods, plastic gears, screws, nuts, bolts, cable ties, jewelry, works of art, statues, medical items, prosthetic devices, orthopedic implants, the manufacture of artifacts to aid learning in education, 3D anatomical models to assist in surgery, robotics supplies, biomedical devices (orthotics), household appliances, dental supplies, electronic equipment, and sporting goods. Furthermore, the particles may be useful in applications such as, but are not limited to, paints, powder coatings, inkjet materials, electrophotographic toners, and 3D printing. Exemplary Embodiments

[0189] A first non-limiting exemplary embodiment described herein is a selective laser sintering method comprising depositing carbon nanomaterial-grafted-polyurethane (CNM-g-polyurethane) particles on a surface in combination with optionally other thermoplastic polymer particles, wherein the CNM-g-polyurethane particles comprise polyurethane grafted onto carbon nanomaterial (CNM), and, after deposition, exposing at least a portion of the CNM-g-polyurethane particles to a laser by selective laser sintering to fuse the polymer particles and form a solid. The first non-limiting exemplary embodiment may further include one or more of the following: Element 1: CNM-g-polyurethane comprises, based on the total weight of the CNM-g-polyurethane, about 50% to about 99.95% by weight of polyurethane, and about 0.Element 4: Contains 0.5 wt% to approximately 50 wt% carbon nanomaterials; Element 5: Polyurethane is grafted onto CNM by in-situ polymerization or microwave-assisted solid-state grafting; Element 6: Polyurethane is thermoplastic polyurethane (TPU); Element 7: Polyurethane is manufactured from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component; Element 8: Element 4, and the polyisocyanate component includes an aromatic diisocyanate; Element 9: Element 4, and the polyisocyanate component is selected from the group consisting of 4,4'-methylenebis(phenylisocyanate), toluene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or any combination thereof; Element 10: Element 4, and the polyol component is a polyether polyol, polyester polyol, or a copolymer of a polyether and a polyester polyol. Element 8: is element 7, and the polyol component includes poly(tetramethylene ether glycol), polycaprolactone, adipic acid polyester, copolymers thereof, or any combination thereof; Element 9: is element 4, and the chain extender component includes linear alkylenediol; Element 10: is element 9, and the chain extender component is selected from the group consisting of 1,4-butanediol, 1,12-dodecanediol, dipropylene glycol, or any combination thereof; Element 11: CNM is selected from the group consisting of carbon nanotubes, graphite, graphene, fullerene, and any combination thereof; Element 12: the molar ratio of polyurethane to CNM is about 500:1 to about 1:500; Element 13: the molar ratio of polyurethane to CNM is about 20:1 to about 10:1; Element 14: the molar ratio of CNM-g-polyurethane particles is about 0.90 to about 1.Having a true roundness of 0; Element 15: The CNM-g-polyurethane particles have an emulsifying stabilizer embedded within the outer surface of the CNM-g-polyurethane particles; Element 16: Element 15, and the emulsifying stabilizer contains nanoparticles; Element 17: Element 16, and at least a part of the CNM-g-polyurethane particles has voids containing an emulsifying stabilizer at the void / polymer interface; Element 18: Element 16, and the emulsifying stabilizer contains nanoparticles, and the nanoparticles are embedded at the void / polymer interface; Element 19: The CNM-g-polyurethane particles further contain a thermoplastic polymer not grafted to the CNM; Element 20: The CNM-g-polyurethane particles further contain a dispersion medium immiscible with the polyurethane of the CNM-g-polyurethane; Element 21: The CNM-g-polyurethane particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, and D10 < D50 < D90; Element 22: The CNM-g-polyurethane particles have a particle size span of about 0.2 to about 10;; Element 23: The CNM-g-polyurethane particles have an angle of repose of about 25° to about 45°; Element 24: The CNM-g-polyurethane particles have a Hausner ratio of about 1.0 to about 1.5..

[0190] A second non-limiting exemplary embodiment of the present disclosure is a composition comprising CNM-g-polyurethane particles comprising polyurethane grafted to a carbon nanomaterial. The CNM-g-polyurethane particles may contain about 0.05 wt% to about 50 wt% of CNM, and the CNM may be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof. The second non-limiting exemplary embodiment may further include one or more of Element 1; Element 2; Element 3; Element 5; Element 6; Element 9; Element 10; Element 10; Element 11; Element 12; Element 13; Element 14; Element 15; Element 16; Element 17; Element 18; Element 19; Element 20; Element 21; Element 22; and Element 23: The polyurethane is a thermoplastic polyurethane (TPU) produced from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component.

[0191] A third non-limiting exemplary embodiment is a carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane), wherein the CNM-g-polyurethane particles include polyurethane grafted onto a carbon nanomaterial; (b) a dispersion medium immiscible with the polyurethane of the CNM-g-polyurethane; optionally (c) a thermoplastic polymer not grafted onto the CNM; and optionally (d) an emulsifying stabilizer at a temperature higher than the melting or softening temperature of the polyurethane and thermoplastic polymer of the CNM-g-polyurethane, and, if present, at a shear rate high enough to disperse the CNM-g-polyurethane in the dispersion medium; a method comprising cooling the mixture to below the melting or softening temperature to form CNM-g-polyurethane particles; and separating the CNM-g-polyurethane particles from the dispersion medium. A third non-limiting exemplary embodiment may further include one or more of the following: Element 1; Element 2; Element 3; Element 5; Element 6; Element 9; Element 10; Element 10; Element 11; Element 12; Element 13; Element 14; Element 15; Element 16; Element 17; Element 18; Element 19; Element 20; Element 21; Element 22; Element 23; Element 24: a polyisocyanate component, a polyol component, and an optional chain extender component combined in a molar ratio of 1:0.5:0.5; Element 25: a dispersion medium present in a weight ratio of the dispersion medium to a combination of CNM-g-polyurethane and thermoplastic polymer in the range of 50:50 to 90:10; Element 26: the dispersion medium is polydimethylsiloxane (PDMS). Clause

[0192] Clause 1. A method of selective laser sintering, comprising: depositing carbon nanomaterial-grafted-polyurethane (CNM-g-polyurethane) particles on a surface in combination with other thermoplastic polymer particles of any choice, wherein the CNM-g-polyurethane particles contain polyurethane grafted onto carbon nanomaterial (CNM); and, after deposition, exposing at least a portion of the CNM-g-polyurethane particles to a laser by selective laser sintering to fuse the polymer particles and form a solidified body.

[0193] Clause 2. The method according to Clause 1, wherein the CNM-g-polyurethane comprises, based on the total weight of the CNM-g-polyurethane, approximately 50% to approximately 99.95% by weight of polyurethane and approximately 0.05% to approximately 50% by weight of carbon nanomaterials.

[0194] Clause 3. The method according to Clause 1, wherein the polyurethane is grafted onto the CNM by in-situ polymerization or microwave-assisted solid-state grafting.

[0195] Clause 4. The method according to Clause 1, wherein the polyurethane is thermoplastic polyurethane (TPU).

[0196] Clause 5. The method according to Clause 1, wherein the polyurethane is manufactured from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component.

[0197] Clause 6. The method according to Clause 5, wherein the polyisocyanate component comprises an aromatic diisocyanate.

[0198] Clause 7. The method according to Clause 5, wherein the polyisocyanate component is selected from the group consisting of 4,4'-methylenebis(phenylisocyanate), toluene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or any combination thereof.

[0199] Clause 8. The method according to Clause 5, wherein the polyol component is selected from the group consisting of polyether polyols, polyester polyols, copolymers of polyether and polyester polyol, or any combination thereof.

[0200] Clause 9. The method according to Clause 8, wherein the polyol component comprises poly(tetramethylene ether glycol), polycaprolactone, polyester adipic acid, copolymers thereof, or any combination thereof.

[0201] Clause 10. The chain extender component comprises a linear alkylenediol, as described in Clause 5.

[0202] Clause 11. The method according to Clause 10, wherein the chain extender component is selected from the group consisting of 1,4-butanediol, 1,12-dodecanediol, dipropylene glycol, or any combination thereof.

[0203] Clause 12. The method according to Clause 1, wherein the CNM is selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof.

[0204] Clause 13. The method according to Clause 1, wherein the molar ratio of polyurethane to CNM is approximately 500:1 to approximately 1:500.

[0205] Clause 14. The method according to Clause 1, wherein the molar ratio of polyurethane to CNM is approximately 20:1 to approximately 10:1.

[0206] Clause 15. CNM-g-polyurethane particles having a roundness of about 0.90 to about 1.0, as described in Clause 1.

[0207] Clause 16. The method according to Clause 1, wherein the CNM-g-polyurethane particles have an emulsifying stabilizer embedded within the outer surface of the CNM-g-polyurethane particles.

[0208] Clause 17. The emulsifying stabilizer is the method according to Clause 16, comprising nanoparticles.

[0209] Clause 18. The method according to Clause 17, wherein at least a portion of the CNM-g-polyurethane particles have voids containing an emulsifying stabilizer at the void / polymer interface.

[0210] Clause 19. The emulsifying stabilizer comprises nanoparticles, the nanoparticles being embedded in the void / polymer interface, as described in Clause 17.

[0211] The method according to item 1, wherein the CNM-g-polyurethane particles further comprise a thermoplastic polymer not grafted to the CNM.

[0212] The method according to item 1, wherein the CNM-g-polyurethane particles further comprise a dispersion medium immiscible with the polyurethane of the CNM-g-polyurethane.

[0213] The method according to item 1, wherein the CNM-g-polyurethane particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, and D10 < D50 < D90.

[0214] The method according to item 1, wherein the CNM-g-polyurethane particles have a particle size span of about 0.2 to about 10.

[0215] The method according to item 1, wherein the CNM-g-polyurethane particles have an angle of repose of about 25° to about 45°.

[0216] The method according to item 1, wherein the CNM-g-polyurethane particles have a Hausner ratio of about 1.0 to about 1.5.

[0217] A composition comprising CNM-g-polyurethane particles comprising polyurethane grafted to a carbon nanomaterial. The CNM-g-polyurethane particles may comprise about 0.05 wt% to about 50 wt% of CNM of the CNM-g-polyurethane particles, and the CNM may be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof.

[0218] The composition according to item 26, wherein the polyisocyanate component, the polyol component, and an optional chain extender component are combined in a molar ratio of 1:0.5:0.5.

[0219] Clause 28. The composition according to Clause 26, wherein the CNM-g-polyurethane comprises, based on the total weight of the CNM-g-polyurethane, about 50% to about 99.95% by weight of polyurethane and about 0.05% to about 50% by weight of carbon nanomaterials.

[0220] Clause 29. The composition according to Clause 26, further comprising a dispersion medium that is immiscible with polyurethane for CNM-g-polyurethane particles.

[0221] Clause 30. The composition according to Clause 26, wherein the dispersion medium is present in a weight ratio of the dispersion medium to a combination of CNM-g-polyurethane and a thermoplastic polymer in the range of 50:50 to 90:10.

[0222] Clause 31. The composition according to Clause 26, wherein the dispersion medium is polydimethylsiloxane (PDMS).

[0223] Clause 32. The composition according to Clause 26, wherein the polyurethane is a thermoplastic polyurethane (TPU) manufactured from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component.

[0224] Clause 33. A method comprising: (a) carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane), wherein the CNM-g-polyurethane particles include polyurethane grafted onto carbon nanomaterial; (b) a dispersion medium immiscible with the polyurethane of CNM-g-polyurethane; optionally (c) a thermoplastic polymer not grafted onto CNM; and optionally (d) an emulsifying stabilizer; mixing the mixture at a temperature higher than the melting or softening temperature of the polyurethane and thermoplastic polymer (if included) and at a shear rate high enough to disperse the CNM-g-polyurethane in the dispersion medium; cooling the mixture to below the melting or softening temperature to form CNM-g-polyurethane particles; and separating the CNM-g-polyurethane particles from the dispersion medium.

[0225] Clause 34. The method according to Clause 33, wherein the polyurethane is a thermoplastic polyurethane (TPU) produced from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component.

[0226] Clause 35. The method according to Clause 34, wherein the polyisocyanate component, the polyol component, and the optional chain extender component are combined in a molar ratio of 1:0.5:0.5.

[0227] Clause 36. The method according to Clause 33, wherein the CNM-g-polyurethane contains about 50 wt% to about 99.95 wt% of polyurethane and about 0.05 wt% to about 50 wt% of carbon nanomaterials based on the total weight of the CNM-g-polyurethane.

[0228] Clause 37. The method according to Clause 33, wherein the dispersion medium is present in a weight ratio of the dispersion medium to the combination of CNM-g-polyurethane and the thermoplastic polymer in the range of 50:50 to 90:10.

[0229] Clause 38. The method according to Clause 33, wherein the dispersion medium is polydimethylsiloxane (PDMS).

[0230] Clause 39. The method according to Clause 33, wherein the CNM-g-polyurethane particles have a D10 of about 0.1 μm to about 125 μm, a D50 of about 0.5 μm to about 200 μm, and a D90 of about 3 μm to about 300 μm, and D10 < D50 < D90.

[0231] Clause 40. The method according to Clause 33, wherein the CNM-g-polyurethane particles have a particle size span of about 0.2 to about 10.

[0232] Clause 41. The method according to Clause 33, wherein the CNM-g-polyurethane particles have an angle of repose of about 25° to about 45°.

[0233] Clause 42. The method according to Clause 33, wherein the CNM-g-polyurethane particles have a Hausner ratio of about 1.0 to about 1.5.

[0234] Clause 43. CNM-g-polyurethane particles having a roundness of about 0.90 to about 1.0, as described in Clause 33.

[0235] Clause 44. The method according to Clause 33, wherein the CNM-g-polyurethane particles have an emulsifying stabilizer embedded within the outer surface of the CNM-g-polyurethane particles.

[0236] Clause 45. The emulsifying stabilizer is the method described in Clause 33, comprising nanoparticles.

[0237] Unless otherwise stated, all figures used in this specification and related claims, such as quantities of components, molecular weights and other properties, process conditions, etc., should be understood in all cases to be modified by the term "approximately." Therefore, unless otherwise indicated, the numerical parameters described in the following specification and the attached claims are approximations that may vary depending on the desired properties to be obtained by the embodiments of this disclosure. At the very least, without any attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter should be interpreted by applying the usual rounding method in light of the number of significant figures reported.

[0238] One or more exemplary embodiments incorporating the embodiments of the disclosure disclosed herein are presented herein. For clarity, not all features of physical implementations are described or represented in this application. It is understood that in developing physical implementations incorporating the embodiments of the disclosure, numerous implementation-specific decisions must be made to achieve the developer's objectives, such as compliance with system-related, business-related, government-related, and other constraints, which vary by implementation and time. While the developer's efforts may be time-consuming, such efforts are routine for those skilled in the art and will benefit them from this disclosure.

[0239] Although compositions and methods are described herein using the term “containing” various components or processes, compositions and methods may also “essentially consist of” or “consist of” various components and processes.

[0240] To facilitate a better understanding of the embodiments of this disclosure, the following examples of preferred or representative embodiments are provided. The following examples should not be interpreted in any way as limiting or defining the scope of this disclosure. [Examples]

[0241] Example 1. General, in-situ TPU polymerization without CNM. General, in-situ pure TPU polymerization (without a carbon source) is described. A molar ratio of 1.02:0.5:0.5 for diisocyanate, polyol, and chain extender can be used (the ratio can be modified to obtain different properties). Trace amounts of moisture can be removed by drying the polyether polyol and 1,4-butanediol overnight at 50°C and drying the 4,4'-methylenebis(phenylisocyanate) (MDI) in a vacuum oven at room temperature for 1 hour. The prepolymer can be prepared with a solid content of 20% by reacting the MDI with the polyol in dry DMF at 80°C for 2 hours under a nitrogen sweep while stirring in a three-necked round-bottom flask. The temperature can be maintained using an oil bath. The conversion of the -OH group can be confirmed by titration of the NCO group.

[0242] Example 2. General, in-situ TPU polymerization using CNM. The molar ratio of diisocyanate, polyol, and chain extender may be 1.02:0.5:0.5 (the ratio may be modified to obtain different properties). Trace amounts of moisture can be removed by drying the polyether polyol and 1,4-butanediol overnight at 50°C and drying the 4,4'-methylenebis(phenylisocyanate) (MDI) in a vacuum oven at room temperature for 1 hour. The prepolymer can be prepared with a solid content of 20% by reacting the MDI with the polyol in dry DMF at 80°C for 2 hours under nitrogen sweep with stirring in a three-necked round-bottom flask. The temperature can be maintained at 80°C using an oil bath. The conversion of the -OH group can be confirmed by titration of the NCO group. 1,4-butanediol and 2.3 × 10 -7 mol / cm 3 The dibutyltin laurate catalyst may be added to the reaction vessel in dry DMF at 80°C under a continuous stream of nitrogen. After 6 minutes of chain extension, a calculated amount of the modified carbon source may be added to the reaction vessel. The reactants may be stirred for a further 2 hours, and then the resulting viscous mixture may be poured into a mold and the DMF may be evaporated. After the DMF has evaporated, the residual solvent can be removed by leaving the polymer in a vacuum oven at 50°C overnight. However, CNM may be added before the addition of the polyol, before the addition of the chain extender, or after the completion of polymerization.

[0243] Example 3. Figure 2 is a non-limiting example of scanning electron microscope (SEM) cross-sectional images of 0.5% graphene oxide in synthetic TPU (MDI, p(THF), 1,4-BD), prepared as follows: the molar ratio of diisocyanate, polyol, and chain extender was 1.02:0.5:0.5 (this ratio can be modified to obtain different properties). The polyether polyol and 1,4-butanediol were dried overnight at 50°C, and the MDI was dried in a vacuum oven at room temperature for 1 hour to remove trace amounts of moisture. The graphene oxide was dried in a vacuum oven at 50°C for 3 hours. Poly(tetrahydrofuran) (10 g, 0.01 mol, 1000 kDa), methylenediphenyl diisocyanate (MDI, 5.2 g, 0.0204 mol), and 55 mL of dry DMF were added to a three-necked round-bottom flask equipped with an argon inlet. The reaction mixture was heated to 80°C and then reacted for 2 hours with vigorous stirring to obtain a prepolymer. Separately, graphene oxide (0.08 g) was mixed with 10 mL of DMF and sonicated for 1 hour to obtain a stable dispersion of GO. After 2 hours at 80°C, 1,4-butanediol (0.9 g, 0.01 mol) and one drop of dibutyltin laurate catalyst were added to the reaction vessel in dry DMF using 5 mL of dry DMF, while maintaining the reaction temperature at 80°C under continuous argon. After chain extension for 5 minutes, the GO dispersion was added to the reaction mixture. The reactants were further vigorously stirred for 2 hours, and then the viscous mixture was poured into a Teflon-lined mold to evaporate the DMF. After the DMF had evaporated, the residual solvent was removed by leaving the polymer overnight in a vacuum oven at 50°C. The (SEM) cross-sectional image in Figure 2 shows good dispersion throughout the TPU matrix.

[0244] Hypothetical example 1: Microwave-assisted solid-state grafting.

[0245] 1) Surface modification via microwave radiation is described below. Before synthesizing the polymer composite, CNTs can be carboxylated. Carboxylation of CNTs can be carried out by treating CNTs in a mixture of concentrated sulfuric acid and nitric acid via microwave radiation, which can be achieved by combining 1 g of CNTs with 100 mL of 1:1 concentrated H2SO4 and concentrated HNO3. The flask can then be subjected to microwave irradiation at 140°C for 10 minutes. After acid treatment, the CNTs can be transferred to a beaker, followed by the addition of 100 mL of deionized (DI) water, and the mixture can be cooled to room temperature. The oxidation product can be filtered using a Teflon membrane with a pore size of 0.22 μm. The resulting carboxylated CNT product can be washed with DI water until a neutral pH is reached, and then dried in a vacuum oven.

[0246] 2) Grafting of carboxylated CNTs (5 wt% CNTs) via microwave radiation is described below. 1 g of carboxylated CNTs can be dispersed in 10 mL of THF via sonication. In a separate container, 20 g of TPU can be dissolved in 100 mL of THF. Once the carboxylated CNTs are sufficiently dispersed, they can be added dropwise to the TPU solution while stirring. Stirring can be continued until a homogeneous mixture is obtained. The mixture can then be poured into a mold and the solvent can be evaporated. The mixture of TPU and carboxylated CNTs can then be treated under microwave irradiation at 50% total power output (50% of 800 W) for 5 minutes.

[0247] Hypothetical example 2: Fullerene (hydroxyl modification).

[0248] 1) Surface modification of fullerenes is described below. Fullerene soot can first be annealed at 450°C for 4 hours. Then, fresh fullerenes can be oxidized to functionalize the molecular surface. Oxidation of fullerenes can be carried out by refluxing with concentrated nitric acid. 1.5 g of fresh fullerene C 60The mixture can then be refluxed at 120°C for 48 hours using 70 mL of concentrated HNO3 solution. The mixture can then be diluted with distilled water and filtered, for example, using a Teflon membrane with a pore size of 0.45 μm. The oxidized material can then be washed with distilled water until a neutral pH is reached, and then dried under vacuum to remove residual water. The dried hydroxyl-functionalized fullerene powder may then be used in the polymerization reaction.

[0249] 2) The grafting of hydroxyl-functionalized fullerenes into TPUs via in-situ polymerization is described. Depending on when the functionalized fullerenes can be added to the polymerization, the material may be used to graft into the polymer backbone or to end-cap the polymer chains (see in-situ polymerization with a carbon source above).

[0250] Hypothetical example 3: Nanotubes (PCL-CNTs).

[0251] 1) The oxidation of CNTs is described below. Carbon nanotubes (CNTs) can be oxidized before further processing can occur. This conversion can be achieved by dispersing 1 g of raw CNTs in 100 mL of a 3:1 mixture of concentrated sulfuric acid and nitric acid using an ultrasonicator. The mixture can then be gradually heated to 90°C and stirred for 30 minutes. After the reaction is complete, the mixture can be diluted with DI water and filtered through a Teflon membrane. The product can then be washed with DI water until it reaches a neutral pH and then dried in a vacuum oven.

[0252] 2) The functionalization of the CNT surface with acid chlorides is described below. Before grafting oxidized CNTs onto polyurethane / polyol via excess hydroxyl groups, the oxidized CNTs can be further functionalized with thionyl chloride (SOCl2). 1 g of oxidized CNTs can be dispersed in 10 mL of SOCl2 by sonication. The mixture can then be slowly heated to 65°C and kept under reflux for 1 day with stirring. The mixture can then be filtered through a 0.22 μm Teflon membrane. The product can then be washed with dry acetone to obtain an acid chloride intermediate.

[0253] 3) Grafting to poly(ε-caprolactone)(PCL)-diol / common polyols. Solid acid chloride-functionalized CNTs can be immediately transferred to a solution of PCL-diol in dry THF (average Mn of 530 g / mol to 2,000 g / mol) and stirred at 60°C for 24 hours. The resulting reaction mixture can be filtered, washed, and dried to obtain polyol-grafted CNTs. This method can also be used to cap TPUs containing hydroxyl-terminated groups.

[0254] 4) Grafting of polyol-functionalized CNTs onto TPU via in-situ polymerization. Polyol-functionalized CNTs can then be used in in-situ TPU polymerization to graft nanotubes onto polymer chains (see polymerization procedure above). The material can also be used to end-cap the polymer if added after polymerization is complete and if there is an excess of isocyanate groups.

[0255] Hypothetical example 4. Graphene (isocyanate modified).

[0256] 1) The isocyanate functionalization of graphene oxide (GO) is described below. GO can first be dispersed in water via sonication for 1 hour, and then centrifuged at 4,000 rpm for 10 minutes. The GO suspension can then be subjected to a solvent exchange process to obtain a dispersion of GO in DMF. The solvent exchange process can be carried out by adding DMF to aqueous GO, followed by sonication, centrifugation, and then removal of the supernatant. This process should be repeated three times. Next, GO can be reacted with an aliphatic polyisocyanate (PI) (e.g., DESMODUR® N75) to produce isocyanate-functionalized GO. GO (1 g) can be added to a 250 mL round-bottom flask equipped with a magnetic stirring rod at a speed of 200 rpm and with a flow of nitrogen. 100 mL of anhydrous DMF may be added and the mixture stirred until a homogeneous suspension is formed. Next, 40 mmol of PI can be added to the suspension and the mixture can be stirred at 50°C under nitrogen for 72 hours. After the reaction, the mixture can be poured into dichloromethane (DCM) to allow the product, i.e., polyisocyanate-functionalized graphene oxide (PI-GO), to solidify. The PI-GO product may then be filtered and washed with additional DCM.

[0257] 2) A method for grafting polyisocyanate-functionalized graphene oxide (PI-GO) onto TPU via in-situ polymerization is described. The calculated amount of PI-GO can be dispersed in dry DMF by sonication for 30 minutes. Once a homogeneous solution is formed, the resulting mixture can be transferred to a 2-liter three-necked round-bottom flask equipped with a condenser and nitrogen purge. Methylenediphenyl diisocyanate and poly(tetrahydrofuran) (approximately 1000 g / mol Mw) (in a molar ratio of 1:0.5) and dry DMF (20 wt% solid reaction) can be added to the flask. The reaction mixture may be heated at 80°C for 2 hours. Next, 1,4-butanediol (0.5 equivalents) and 2.3 × 10⁻⁶ -7 mol / cm 3The dibutyltin laurate catalyst may be added to the reaction vessel in dry DMF at 80°C under a continuous stream of nitrogen. The mixture may be stirred for a further 2 hours at 80°C. Upon completion, the reaction vessel can be degassed under vacuum until no more bubbles are observed, and the viscous polymer solution can be poured into an aluminum pan and the solvent evaporated.

[0258] Hypothetical example 5. CNM-grafted 4,4'-methylenebis(phenylisocyanate) (MDI) and modified CNM-grafted polyurethane via polyurethane prepolymer.

[0259] GO can be reacted directly with diisocyanate monomers before polymerization. A 0.033 wt% GO composite can be prepared by dispersing 50 mg of GO in 500 g of dry DMF by sonication at room temperature for 30 minutes. The homogeneous solution can then be added to a 1 liter flask equipped with a condenser and nitrogen purge. Next, 36 g of MDI may be added to the GO dispersion and heated to 80°C. The solution may be stirred for 2 hours to allow the GO sheets to adhere to the MDI monomers. Next, 64 g of poly(tetrahydrofuran) (1000 Mw) can be added to the flask and the mixture can be stirred for a further 2 hours at 80°C to prepare a polyurethane prepolymer having grafted graphene oxide nanosheets. Next, 5.75 g of 1,4-butanediol (chain extender) and 2.3 × 10⁻⁶ -7 mol / cm 3 The dibutyltin laurate catalyst may be added to the reaction vessel in dry DMF at 80°C under a sustained nitrogen atmosphere. The mixture may be stirred for a further 2 hours at 80°C. Upon completion of the reaction, the reaction vessel may be degassed under vacuum until no more bubbles are observed, and then the viscous polymer solution can be poured into an aluminum pan and the solvent evaporated.

[0260] Hypothetical example 6. In-situ polymerization with amine-modified carbon sources.

[0261] 1) Preparation of amino-functionalized carbon nanotubes is described below. Multiwall carbon nanotubes (MWCNTs) can first be oxidized via a mixture of concentrated sulfuric acid and nitric acid in a 3:1 volume ratio. Acidification can be carried out by sonication of the MWCNTs in the acid solution in an ultrasonic bath at 50°C for 3 hours. The MWCNT / acid mixture can then be poured into deionized water, filtered, and washed repeatedly until the pH of the filtered solution is approximately 7 (neutral pH). The acidified MWCNT product can then be dried in a vacuum oven at 80°C for 6 hours. Approximately 1 g of MWCNT-COOH can be dispersed in 2 liters of THF under sonication for at least 1 hour. To this dispersion, 20 g (340 mmol) of ethylenediamine (EDA), 1 g (10 mmol) of 4-(dimethylamino)pyridine (DMAP), and 10 g (50 mmol) of N,N'-dicyclohexylcarbodiimide (DCC) may be added while stirring at ambient temperature. The dispersion / solution can be heated to 60°C and maintained at 60°C for 24 hours while stirring. The product may be a black solid that can be easily collected and washed three times with THF (1-1.5 liters / wash). The product can be dried in a vacuum oven to obtain functionalized MWCNTs.

[0262] 2) A method for grafting amine-functionalized CNTs onto TPUs via in-situ polymerization is described. 1 g of amine-functionalized CNTs can be dispersed in 50 mL of dry DMF via sonication for 30 minutes. After a homogeneous solution is obtained, the solution can be added to a 1 liter three-necked round-bottom flask equipped with a magnetic stirrer, condenser, and nitrogen purge. Then, 340 mL of dry DMF, MDI (32.5 g, 0.127 mol) and poly(tetrahydrofuran) (1000 Mw, 62.0 g, 0.062 mol) may be added. The reaction mixture can be set to 80°C for 2 hours. In a separate container, 1 g of amine-functionalized nanotubes can be dispersed in 50 mL of dry DMF via sonication. After 2 hours, 1,4-butanediol (5.6 g, 0.062 mol) and 2.3 × 10⁻¹⁶ -7 mol / cm 3Dibutyltin laurate catalyst may be added to a 1-liter flask. The reaction mixture may be stirred for a further 2 hours, and then the viscous mixture may be poured into an aluminum pan and the DMF may be evaporated. After the DMF has evaporated, the residual solvent can be removed by leaving the polymer in a vacuum oven at 50°C overnight.

[0263] Hypothetical Example 6. Preparation of CNM-g-polyurethane nanoparticles (e.g., CNT, GO, fullerene, etc.) by melt emulsification. CNM-g-polyurethane nanoparticles can be produced from CNM-g-polyurethane nanocomposites (prepared as described in Examples 1-6) by melt extrusion into a HAAKE® RHEOMIX twin-screw extruder equipped with a high-shear rotor. The extruder may be heated to a temperature near the melting point of the polymer, and the rotor may be started at a slow speed. TPU-carbon polymer pellets produced from the CNM-g-polyurethane nanocomposites (prepared as described in Examples 1-6) can be added to a heated extruder, followed by the addition of a dispersion medium. The dispersion medium may be a PDMS oil having a viscosity of 10,000-60,000 cSt at room temperature. The ratio of PDMS oil to polymer may be 70:30 or 30% polymer solid in 70% oil. An optional dispersant or flow aid may be added before the dispersion medium to aid the flow of dry particles. At 200°C, the extruder can be operated at 200 rpm (maximum speed) for 30 minutes. The mixture can then be released onto a metal tray with dry ice to provide rapid quenching. Once the dry ice has completely sublimated, the oil can be washed away from the fine particles with a 3-heptane washing solution, and the fine particles can be isolated by vacuum filtration. The fine particles can then be dried overnight in a vacuum oven at room temperature to evaporate any remaining heptane. The dried particles can then be sieved through a 150 μm or 250 μm screen. The resulting powder may have a final average particle size (D50) of about 50 micrometers and a span of about 1.000. The span is calculated as the difference between D90 and D10 divided by D50 and is a measure of the particle size distribution.

[0264] Virtual Example 7. SLS Printing and Mechanical Testing: The baseline performance of dry powder can be determined by sintering the material using a SNOWWHITE SLS printer (available from Sharebot). The laser can selectively fuse the material by scanning the cross-section of the desired object, which is generated using a computer-aided design (CAD) model. After the first layer is scanned, the powder bed can be lowered, new powder material can be rolled on top, and subsequent layers can be scanned until the part is complete. The main advantages of this powder-based system are the elimination of printing supports and the ability to reuse materials, compared to other additive manufacturing technologies.

[0265] Accordingly, this disclosure is well adapted to achieve the objectives and benefits mentioned, as well as those inherent to them. The specific examples and configurations disclosed above are merely illustrative, as this disclosure may be modified and implemented in different but equivalent ways that will be obvious to those skilled in the art who have an interest in the teachings herein. Furthermore, it is not intended to limit the details of the structures or designs shown herein to those not described in the following claims. Accordingly, it is clear that the specific exemplary examples disclosed above may be modified, combined, or altered, and all such variations are considered within the scope and spirit of this disclosure. The disclosures preferably illustrated herein may be implemented in the absence of any elements not specifically disclosed herein, and / or any optional elements disclosed herein. While compositions and methods are described using the terms “comprising,” “containing,” or “including” various components or processes, compositions and methods may also “essentially consist of” or “consist of” various components and processes. All the number and scope disclosed above may vary somewhat. Whenever a numerical range with lower and upper limits is disclosed, any number and any range included within that range are specifically disclosed. In particular, all ranges of values ​​disclosed herein (in the form of "about a to about b," or equivalently "approximately a to b," or equivalently "about a to b") should be understood to describe all numbers and ranges encompassed within a broad range of values. Furthermore, terms in the claims have plain, ordinary meanings unless explicitly and clearly defined by the patent holder. In addition, when used in claims, the indefinite article "a" or "an" is defined herein to mean one or more of the elements it introduces. Another aspect of the present invention may be as follows: [1] A method of selective laser sintering, wherein the method is: The method involves depositing carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane) particles on a surface in combination with other thermoplastic polymer particles of any choice, wherein the CNM-g-polyurethane particles contain polyurethane grafted onto carbon nanomaterial (CNM). A method comprising: depositing the CNM-g-polyurethane particles, then exposing at least a portion of the CNM-g-polyurethane particles to a laser by selective laser sintering to fuse at least a portion of the polymer particles of the CNM-g-polyurethane particles and form a solidified body. [2] The method according to [1], wherein the CNM-g-polyurethane comprises, based on the total weight of the CNM-g-polyurethane, about 50% to about 99.95% by weight of the polyurethane and about 0.05% to about 50% by weight of the carbon nanomaterial. [3] The method according to [1], wherein the polyurethane is grafted onto the CNM by in-situ polymerization or microwave-assisted solid-state grafting. [4] The method according to [1], wherein the polyurethane is thermoplastic polyurethane (TPU). [5] The method according to [1], wherein the polyurethane is produced from (a) a polyisocyanate component, (b) a polyol component, and (c) an optional chain extender component. [6] The method according to [5], wherein the polyisocyanate component comprises an aromatic diisocyanate. [7] The method according to [5], wherein the polyisocyanate component is selected from the group consisting of 4,4'-methylenebis(phenylisocyanate), toluene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, or any combination thereof. [8] The method according to [5], wherein the polyol component is selected from the group consisting of polyether polyols, polyester polyols, copolymers of polyether and polyester polyol, or any combination thereof. [9] The method according to [8], wherein the polyol component comprises poly(tetramethylene ether glycol), polycaprolactone, adipic acid polyester, copolymers thereof, or any combination thereof.

[10] The method according to [5], wherein the chain extender component comprises a linear alkylenediol.

[11] The method according to

[10] , wherein the chain extender component is selected from the group consisting of 1,4-butanediol, 1,12-dodecanediol, dipropylene glycol, or any combination thereof.

[12] The method according to [1], wherein the CNM is selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof.

[13] The method according to [1], wherein the molar ratio of polyurethane to CNM is approximately 500:1 to approximately 1:500.

[14] The method according to [1], wherein the molar ratio of polyurethane to CNM is approximately 20:1 to approximately 10:1.

[15] The method according to [1], wherein the CNM-g-polyurethane particles have a roundness of about 0.90 to about 1.0.

[16] The method according to [1], wherein the emulsifying stabilizer comprises nanoparticles, and the CNM-g-polyurethane particles have an emulsifying stabilizer embedded within the outer surface of the CNM-g-polyurethane particles.

[17] The method according to [1], wherein the CNM-g-polyurethane particles further comprise a thermoplastic polymer that is not grafted onto the CNM.

[18] The method according to [1], wherein the CNM-g-polyurethane particles have an angle of repose of about 25° to about 45°.

[19] The method according to [1], wherein the CNM-g-polyurethane particles have a Hausner ratio of about 1.0 to about 1.5.

[20] A method, (a) Carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane), wherein the CNM-g-polyurethane particles include polyurethane grafted onto carbon nanomaterials; (b) a dispersion medium immiscible with the polyurethane of the CNM-g-polyurethane; optionally (c) a thermoplastic polymer not grafted onto CNM; optionally (d) an emulsifying stabilizer; and a mixture thereof, mixed at a temperature higher than the melting point or softening temperature of the polyurethane and the thermoplastic polymer (if included) of the CNM-g-polyurethane, and at a shear rate sufficiently high to disperse the CNM-g-polyurethane in the dispersion medium. The mixture is cooled to below its melting point or softening temperature to form CNM-g-polyurethane particles. A method comprising separating the CNM-g-polyurethane particles from the dispersion medium.

Claims

1. A method of selective laser sintering, The method involves depositing carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane) particles on a surface in combination with other thermoplastic polymer particles of any choice, wherein the CNM-g-polyurethane particles contain polyurethane grafted onto carbon nanomaterial (CNM), and the CNM-g-polyurethane particles have a roundness of approximately 0.90 to approximately 1.

0. The process includes, after deposition, exposing at least a portion of the CNM-g-polyurethane particles to a laser by selective laser sintering to form a solidified body, A method comprising producing the polyurethane from (i) a polyisocyanate component, (ii) a polyol component, and (iii) a chain extender component different from the polyol component, wherein the chain extender component comprises a linear alkylenediol.

2. The method according to claim 1, wherein the CNM-g-polyurethane comprises, based on the total weight of the CNM-g-polyurethane, about 50% to about 99.95% by weight of the polyurethane and about 0.05% to about 50% by weight of the carbon nanomaterial.

3. The method according to claim 1, wherein the polyurethane is grafted onto the CNM by in-situ polymerization or microwave-assisted solid-state grafting.

4. The method according to claim 1, wherein the polyurethane is thermoplastic polyurethane (TPU).

5. The method according to claim 1, wherein the polyisocyanate component comprises an aromatic diisocyanate.

6. The method according to claim 1, wherein the polyisocyanate component is selected from the group consisting of 4,4'-methylenebis(phenylisocyanate), toluenediisocyanate, 2,4-toluenediisocyanate, 2,6-toluenediisocyanate, and any combination thereof.

7. The method according to claim 1, wherein the polyol component is selected from the group consisting of polyether polyols, polyester polyols, copolymers of polyether and polyester polyol, and any combination thereof.

8. The method according to claim 7, wherein the polyol component comprises poly(tetramethylene ether glycol), polycaprolactone, adipic acid polyester, copolymers thereof, or any combination thereof.

9. The method according to claim 1, wherein the chain extender component is selected from the group consisting of 1,4-butanediol, 1,12-dodecanediol, and any combination thereof.

10. The method according to claim 1, wherein the CNM is selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof.

11. The method according to claim 1, wherein the molar ratio of polyurethane to CNM is about 500:1 to about 1:

500.

12. The method according to claim 1, wherein the molar ratio of polyurethane to CNM is about 20:1 to about 10:

1.

13. The method according to claim 1, wherein the CNM-g-polyurethane particles further comprise an emulsifying stabilizer containing nanoparticles, the nanoparticles being embedded within the outer surface of the CNM-g-polyurethane particles.

14. The method according to claim 1, wherein the CNM-g-polyurethane particles further comprise a thermoplastic polymer that is not grafted onto the CNM.

15. The method according to claim 1, wherein the CNM-g-polyurethane particles have an angle of repose of about 25° to about 45°.

16. The method according to claim 1, wherein the CNM-g-polyurethane particles have a Hausner ratio of about 1.0 to about 1.

5.

17. It is a method, (a) Carbon nanomaterial-grafted polyurethane (CNM-g-polyurethane), wherein the CNM-g-polyurethane comprises polyurethane grafted onto carbon nanomaterial, and the polyurethane is produced from (i) a polyisocyanate component, (ii) a polyol component, and (iii) a chain extender component different from the polyol component, wherein the chain extender component comprises a linear alkylenediol, and (b) a dispersion medium immiscible with the polyurethane of the CNM-g-polyurethane, optionally (c) a thermoplastic polymer not grafted onto the CNM, and optionally (d) an emulsifying stabilizer, is sheared at a temperature higher than the melting point or softening temperature of the polyurethane and the thermoplastic polymer (if included) of the CNM-g-polyurethane, and at a shear rate sufficiently high to disperse the CNM-g-polyurethane in the dispersion medium as a polymer melt containing droplets emulsified in the dispersion medium. The mixture is cooled to below the melting point or softening temperature to form CNM-g-polyurethane particles having a roundness of about 0.90 to about 1.

0. A method comprising separating the CNM-g-polyurethane particles from the dispersion medium.

18. The method according to claim 13, wherein the nanoparticles include metal-containing oxide nanoparticles.

19. The method according to claim 1, wherein the molar ratio of the polyisocyanate component: polyol component: chain extender component is in the range of about 5.0:1.0:0.1 to about 1:1:1.

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