Selective laser sintering method

Abstract

To provide a method of forming highly spherical carbon nanomaterial-graft-polyamide (CNM-g-polyamide) polymer particles.SOLUTION: The method may comprise: mixing a mixture comprising (a) carbon nanomaterial-graft-polyamide (CNM-g-polyamide), (b) a carrier fluid that is immiscible with the polyamide of the CNM-g-polyamide, optionally (c) a thermoplastic polymer not grafted to a CNM, and optionally (d) an emulsion stabilizer, at a temperature higher than a melting point or softening temperature of the polyamide of the CNM-g-polyamide and the thermoplastic polymer (if included) and at a shear rate sufficiently high to disperse the CNM-g-polyamide in the carrier fluid; cooling the mixture to below the melting point or softening temperature to form CNM-g-polyamide particles; and isolating the CNM-g-polyamide particles from the carrier fluid.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to extremely spherical particles comprising carbon nanomaterial-grafted-polyamide (CNM-g-polyamide). The present disclosure further relates to compositions, synthesis methods, and uses of such particles (also referred to herein as CNM-g-polyamide particles).

Background Art

[0002] Thermoplastic polymers are often used to make extruded objects such as films, bags, particles, and filaments. An example of a thermoplastic polymer is polyamide. Polyamides such as nylon are off-white polymers having the ability to withstand high or low temperatures without degrading their physical properties. Thus, objects formed of thermoplastic polymers such as polyamides 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 make objects. Selective laser sintering has enabled the direct manufacture of three-dimensional objects with high resolution and dimensional accuracy from a variety of materials such as polystyrene, nylon, other plastics, and composite materials such as polymer-coated metals and ceramics.

[0003] Polyamide is one of the most common polymers used in additive manufacturing due to its flow properties, lower cost than other polymers, and desirable sintering window. However, the physical properties required for objects produced by additive manufacturing may exceed the properties of polyamide. Expanding the ways in which polyamide-carbon nanomaterial composites can be manufactured into objects would further expand the polymer composite industry.

Summary of the Invention

[0004] The present disclosure relates to extremely spherical particles comprising CNM-g-polyamide. The present disclosure further relates to compositions, synthesis methods, and uses of such particles (also referred to herein as CNM-g-polyamide particles).

[0005] Disclosed herein is a method of selective laser sintering, comprising depositing CNM-g-polyamide particles, optionally in combination with other thermoplastic polymer particles, on a surface, wherein the CNM-g-polyamide particles comprise polyamide grafted to a carbon nanomaterial (CNM), and after deposition, exposing at least a portion of the CNM-g-polyamide particles to a laser by selective laser sintering to melt the polymer particles and form a solidified body.

[0006] Disclosed herein is a method comprising: mixing (a) CNM-g-polyamide comprising polyamide grafted to a carbon nanomaterial, (b) a dispersion medium immiscible with the polyamide of the CNM-g-polyamide, optionally (c) a thermoplastic polymer not grafted to the CNM, and optionally (d) an emulsifying stabilizer, at a temperature higher than the melting point or softening temperature of the polyamide of the CNM-g-polyamide and the thermoplastic polymer (if included) and at a shear rate high enough to disperse the CNM-g-polyamide in the dispersion medium; cooling the mixture to below the melting point or softening temperature to form CNM-g-polyamide particles; and isolating the CNM-g-polyamide particles from the dispersion medium. [[ID=IO]]

Brief Description of the Drawings

[0007] The following figures are included to illustrate specific aspects of the embodiments and should not be regarded as exclusive embodiments. The disclosed subject matter is capable of considerable modification, change, combination, and equivalents in form and function, as will occur to those skilled in the art having the benefit of this disclosure.

[0008] [Figure 1]This is a flowchart illustrating a non-exclusive, illustrative method of the present disclosure. [Modes for carrying out the invention]

[0009] This disclosure relates to extremely spherical particles comprising carbon nanomaterial-grafted polyamide (CNM-g-polyamide). This disclosure further relates to compositions, synthesis methods, and applications of such particles (also referred to herein as CNM-g-polyamide particles).

[0010] 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.

[0011] 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).

[0012] Examples of powder particles usable in 3D printing include thermoplastic polymers such as thermoplastic elastomers, metals, and other solidifiable materials. When using composites in 3D printing, the particles (e.g., carbon nanomaterials in polyamide-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.

[0013] This disclosure relates to extremely spherical particles comprising carbon nanomaterial-grafted polyamide (CNM-g-polyamide). Advantageously, the compositions and methods of this disclosure utilize in situ polymerization of polyamide. Thus, the desirable melt and flow properties of the polyamide can be utilized during additive manufacturing. CNM-g-polyamide particles may be particularly useful as starting materials for additive manufacturing, especially SLS 3D printing. Carbon nanomaterials (CNM) can improve the physical properties of objects manufactured by additive manufacturing and / or impart new physical properties to the fabricated objects. Furthermore, by using CNM-g-polyamide, the CNM can be well dispersed and / or distributed throughout the polymer particles. Thus, the carbon nanomaterial can be well dispersed and / or distributed throughout the objects (or parts thereof) fabricated by additive manufacturing.

[0014] Furthermore, this disclosure relates to polyamide thermoplastic polymer composites covalently bonded to carbon nanotubes (CNTs), such as carbon nanotubes (CNTs), and to methods for preparing extremely spherical CNM-g-polyamide particles from such polyamide 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). For example, CNTs may be functionalized with diamines and / or diacids by polycondensation, interfacial polymerization, or ring-open polymerization (ROP) with lactams. In some cases, functionalization of CNTs using carboxylic acid moieties may be carried out in the presence of oxidation with sulfuric acid, nitric acid, chlorate, or ammonium persulfate. Alternatively, functionalization of CNTs may be carried out by direct sulfonation, metallization, or electrophilic addition to the deoxygenated surface of the CNTs. By covalently modifying CNTs with functional groups (e.g., amino groups or carboxylic acids), further reacting them with monomer units, oligomers, or directly reacting them with longer polymer chains of polyamide, the dispersion ability of CNTs within the polymer matrix can be improved, and synergy within the polymer can be facilitated to form the corresponding polyamide thermoplastic polymer nanocomposites.

[0015] Advantageously, highly spherical CNM-g-polyamide particles / powder can be produced from the polyamide thermoplastic polymer composites of this disclosure, for example, by melt emulsification, freeze-grinding, and / or precipitation. The highly spherical CNM-g-polyamide particles can be sintered for 3D printing applications using an SLS printer.

[0016] As a result, advantageously, parts or objects printed using SLS from the highly spherical CNM-g-polyamide particles of this disclosure have improved mechanical properties compared to polyamide-based fine particles that do not combine with the polyamide thermoplastic polymer composite of this disclosure. Definitions and Test Methods

[0017] 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.

[0018] As used herein, the term "polyamide monomer" refers to the monomer that forms a polyamide.

[0019] As used herein, the term "polyacid" refers to a compound having two or more carboxylic acid moieties. In this specification, the anhydride moiety is considered a carboxylic acid moiety because the anhydride undergoes ring-opening to a carboxylic acid during synthesis.

[0020] As used herein, the term "polyamine" refers to a compound having two or more amine moieties.

[0021] As used herein, the term "amino acid" refers to 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.

[0022] When a polymer is referred to using the term -mer unit (e.g., polyamide monomer), those skilled in the art will understand that the -mer unit is in a polymerized form within the polymer.

[0023] 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.

[0024] 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.

[0025] As used herein, the term "polyurethane" refers to the polymer reaction product between a diisocyanate, a polyol, and an optional chain extender.

[0026] 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.

[0027] As used herein, the terms “carbon nanomaterial-grafted-polyamide” and “CNM-g-polyamide” refer to carbon nanomaterials as central or skeletal structures having polyamides extending from them. These terms describe the structure itself, rather than implying how the structure is produced.

[0028] 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.

[0029] 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.

[0030] 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).

[0031] As used herein, the term "graphene" refers to particles or molecules having a planar graphite structure, and includes monolayer to trilayer graphene.

[0032] As used herein, the term "graphite" refers to a particle or molecule having more than three layers of planar graphite.

[0033] The terms "carbon nanomaterials," "fullerenes," "carbon nanotubes," "graphite," and "graphene" encompass these functionalized versions.

[0034] 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.

[0035] 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 (unless otherwise specified, relative to the volume-based distribution) is found to be below this size. 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 (unless otherwise specified, relative to the volume-based median mean) is found to be below this size. As used herein, the term "D90" refers to the particle size at which 90% of the particle population (unless otherwise specified, relative to the volume-based distribution) is found to be below this size. 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.

[0036] 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 diameters ranging from 15 μm to 150 μm, obtained from Malvern Analytical Ltd., under the trademark 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.

[0037] When used herein, if sieving is mentioned, the pore / screen size is as described by the USA Standard Sieve (ASTM E11-17).

[0038] As used herein, the term “circularity” in relation to a particle refers to how close the particle is to a perfect sphere. To measure circularity, flow particle imaging is used to acquire an optical microscope image of the particle. 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 circularity of the particle is C EA / P is and in the formula, C EA This is the outer circumference of a circle having an area equivalent to the actual particle area (A). In this specification, roundness is based on three analyses using a SYSMEX FPIA 3000 particle shape and particle size analyzer, analyzing 6,000 to 10,000 particles each time. The reported roundness is the median mean roundness based on the number of particles. In the analysis, the 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.

[0039] As used herein, the term “shear force” refers to agitation or similar processes that induce mechanical agitation in a fluid.

[0040] As used herein, the term "aspect ratio" refers to the length divided by the width, where the length is greater than the width.

[0041] Unless otherwise specified, the melting point of the polymer is determined according to ASTM E794-06 (2018) with a heating rate and a cooling rate of 10°C / min.

[0042] 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.

[0043] The angle of repose is a measure of the fluidity of the powder. The measured value of the angle of repose was determined using the Hosokawa Micron Powder Characteristics Tester PT-R in accordance with ASTM D6393-14, "Standard Test Method for Bulk Solids Characterized by Carr Indices".

[0044] The aerated density (ρ aer ) is measured in accordance with ASTM D6393-14.

[0045] The bulk density (ρ bulk ) is measured in accordance with ASTM D6393-14.

[0046] The tapped density (ρ tap ) is measured in accordance with ASTM D6393-14.

[0047] The Hausner ratio (H r ) is a measure of the fluidity of the powder, and H r = ρ tap / ρ bulk and is calculated, where ρ bulk is the bulk density according to ASTM D6393-14 and ρ tap is the tapped density according to ASTM D6393-14.

[0048] As used herein, the viscosity of the dispersion medium is the kinematic viscosity at 25°C, measured in accordance with ASTM D445-19, unless otherwise specified. For commercially available dispersion media (e.g., polydimethylsiloxane oil), the kinematic viscosity data cited herein are provided by the manufacturer, regardless of whether they are measured in accordance with the aforementioned ASTM or another standard measurement technique.

[0049] Unless otherwise specified, the crystallization temperature (°C) is determined according to ASTM D3417. The crystallization temperature is the temperature at which a polymer crystallizes (i.e., solidifies) and takes on a structural form, either naturally or artificially initiated, at which point atoms or molecules become highly organized into crystals. 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.

[0050] Unless otherwise specified, the degree of crystallinity (%) of a polymer is determined by ASTMD 3417 by quantifying the heat associated with the melting (fusion) of the polymer.

[0051] The melt flow index (MFI) is a measure of the resistance of a polymer molten material to flow under a defined set of conditions (unit: g / 10 min). As it is a measure under low shear rate conditions, the MFI is inversely proportional to the molecular weight of the polymer.

[0052] The dimensional accuracy (%) of the SLS portion is a quantitative measure of the accuracy of the sintered portion of a 3D printed SLS.

[0053] As used herein, the "tensile modulus" (MPa) of a solid material is a mechanical property that measures its stiffness. MPa is defined as the ratio of its tensile stress (force per unit area) to its strain (relative deformation) when subjected to elastic deformation. MPa may be expressed in pascals or pounds (psi) per square inch. The tensile modulus of a polymer may be determined using ASTMD638-14. CNM-g polyamide complex

[0054] Examples of CNMs that may have grafted polyamides include, but are not limited to, fullerenes, carbon nanotubes (e.g., single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), graphite (e.g., graphite particles, highly oxidized graphite particles, etc.), graphene (e.g., graphene particles, graphene ribbons, graphene sheets, etc., and their highly oxidized derivatives), and any combination thereof.

[0055] CNM-g-polyamide may consist of about 50% to about 99.95% by weight (or about 55% to about 95% by weight, or about 60% to about 90% by weight, or about 65% to about 85% by weight, or about 70% to about 80%) of polyamide and about 0.05% to about 50% by weight (or about 5% to about 45% by weight, or about 10% to about 40% by weight, or about 15% to about 35% by weight, or about 20% to about 30% by weight, or about 25% to about 50%) of CNM, based on the total weight of CNM-g-polyamide.

[0056] Polyamides can be grafted onto the surface of CNM by polycondensation, interfacial polymerization, or in situ ring-opening polymerization (ROP) using lactams, as further described herein, to produce CNM-g-polyamides.

[0057] For example, CNM is one or more primary amines (e.g., CMN-NH2) and / or one or more secondary amines (e.g., CMN-NRH, where R is methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and their isomers C1-C2). 20 Alkyl alkyl groups, C1-C 20 Cycloalkyl groups, C1-C 20These may include amino-functionalized CNMs containing arylalkyl groups, carboxylic acid-functionalized CNMs (e.g., CMN-COOH), amino acid-functionalized CNMs (e.g., NH2-CMN-COOH), acid chloride-functionalized CNMs (e.g., CMN-COCl), and any combination thereof. These functional groups can either directly bond the polyamide to the CNM or act as handles for polymerizing the polyamide from the handles, and the resulting polymer is grafted onto the CNM.

[0058] For example, the functionalization of CMN using a carboxylic acid moiety can be carried out in the presence of oxidation with sulfuric acid, nitric acid, chlorate, or ammonium persulfate. Alternatively, the functionalization of CMN can be carried out by direct sulfonation, metallization, or electrophilic addition to the deoxygenated surface of CNTs.

[0059] In another example, CNM is graphene oxide prepared from natural graphite by the modified Hummers process, which can be further functionalized to, for example, carboxylic acid-modified graphite oxide (GO-COOH) or amino acid-modified graphite oxide (GO-NH2). Carboxylic acid-functionalized CNM (e.g., carboxylic acid-modified graphite oxide (GO-COOH)) can be conjugated with diamine monomers and / or dicarboxylic acid monomers by condensation reactions. CNM-g-polyamides can be formed by condensation reactions between diamine-functionalized graphene oxide and dicarboxylic acid monomers. Preferred examples of diamines, but not limited to, include ethylenediamine, 1,6-diaminohexane, p-phenylenediamine, propylamine, or butylamine.

[0060] In yet another example, CNM-g-polyamides may be polyamides containing fullerenes, produced from covalent bonding reactions between functional polymers and fullerenes, or from the synthesis of polymers in the presence of fullerenes. High molecular weight fullerenes can be prepared by side-chain polymers, main-chain polymers, dendritic fullerenes, star-shaped polymers, fullerene end-binding, etc. In this specification, functionalized CNM is, for example, amino-functionalized C 60 Fullerene system, carboxamide functionalized C60 It may be a fullerene system. Fullerene-g-polyamide is amino-functionalized C 60 By reacting fullerenes with acid chloride-functionalized polyamides, C is formed under mild conditions at room temperature. 60 - An amide bond may be formed between primary and / or secondary amines.

[0061] In another non-limiting example, CNM-g-polyamides can be polymerized using soluble amino polymers (e.g., monomers containing NH2 groups or branched amino groups from the polyamide terminal group) that can be added to the fullerene double bond. 60 It may be a polyamide containing fullerene produced from CNM-g-polyamide (e.g., C 60 -g-polyamide) is an amino polymer that, under mild conditions at room temperature, is C 60 This can be obtained by making it possible to react with C. 60 The polyamide can be extended by incorporating 1,2,3-propanetriamine as an addition monomer to the polyamide design, so that it can be covalently bonded to the polymer, or so that other common polyamides such as PA6, PA11, or PA12 can be used in end-closing reactions (-NH2 terminal groups in PA).

[0062] 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 ( 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. A polyamide followed by a first number, a comma, and a second number is a polyamide having a first number of skeletal carbons between nitrogen atoms in the portion without a pendant=O and a second number of skeletal carbons between two nitrogen atoms in the portion with a pendant=O. As a non-limiting example, nylon 6,10 is [NH-(CH2)6-NH-CO-(CH2)8-CO] n The polyamide following the numerical value is a copolymer of polyamides indicated by the numerical values ​​before and after the backslash.

[0063] The polycondensation reaction may be carried out in the presence of (a) one or more polyamine monomers and one or more polyacid monomers, (b) one or more amino acid monomers, (c) one or more polyamine monomers and one or more amino acid monomers, (d) one or more polyacid monomers and one or more amino acid monomers, or (e) one or more polyamine monomers, one or more polyacid monomers, and one or more amino acid monomers. In some cases, at least one of the monomers may contain at least one unsaturated aliphatic carbon-carbon bond. As described above, functional groups on the CNM may be used as handles involved in the polycondensation reaction so that the resulting polyamide is grafted onto the CNM at the functional groups.

[0064] Examples of amino acid polyamide monomers suitable for use in polycondensation include, but are not limited to, HN-(CH2) with n = 1 to 20. n -COOH, branched aliphatic amino acids (e.g., C4~C) 20 ), cyclic aliphatic amino acids (e.g., C4~C) 20 Examples include ), aromatic amino acids (e.g., 3-aminobenzoic acid, 4-aminobenzoic acid), and any combination thereof. Examples of amino acid polyamide monomers suitable for use in polycondensation that do not have at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, HN-(CH2) with n 1 to 20. n -COOH, branched aliphatic amino acids (e.g., C4~C) 20 ), cyclic aliphatic amino acids (e.g., C4~C) 20 Examples include ), aromatic amino acids (e.g., 3-aminobenzoic acid, 4-aminobenzoic acid), and any combination thereof. Examples of amino acid polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, maleamic acid, N-propylmaleamic acid, and any combination thereof.

[0065] Examples of polyacid polyamide monomers suitable for use in polycondensation include, but are not limited to, HOOC-(CH2) with n = 1 to 20.n -COOH (e.g., adipic acid, terephthalic acid, isophthalic acid, pimelic acid, suberic acid, decandioic acid, dodecandioic acid), isophthalic acid, terephthalic acid, pento-2-endioic acid, dodeca-2-endioic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, adic acid, sebacic acid, undecandioic acid, dodecandioic acid, 1,3-cyclohexanedicarboxylic acid, and any combination thereof. Examples of polyacid polyamide monomers that do not have at least one unsaturated aliphatic carbon-carbon bond and are suitable for use in polycondensation include, but are not limited to, HOOC-(CH2) with n 1 to 20. n Examples include -COOH (e.g., adipic acid, terephthalic acid, isophthalic acid, pimelic acid, suberic acid, decandioic acid, dodecandioic acid), isophthalic acid, terephthalic acid, pento-2-endioic acid, dodeca-2-endioic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, adic acid, sebacic acid, undecandioic acid, dodecandioic acid, 1,3-cyclohexanedicarboxylic acid, and any combination thereof. Examples of polyacid polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, fumaric acid, maleic acid, glutaconic acid, aconitic acid, itaconic acid, and any combination thereof.

[0066] Examples of polyamine polyamide monomers suitable for use in polycondensation include, but are not limited to, HN-(CH2) with n = 1 to 20. n-NH, 1,5-diamino-2-methylpentane, 1,2-diaminopropane, trimethylhexamethylenediamine, 2-methyloctane-1,8-diamine, n-methyl1,6-hexamethylenediamine with N = 2 or 3, n-methyl1,7-heptamethylenediamine with N = 2 to 4, n-methyl1,8-octamethylenediamine with N = 2 to 4, n-methyl1,12-dodecamethylenediamine with N = 2 to 6, 1,3-bis(aminomethyl)benzene, o Examples include tetraphenylene-bis(methylamine), 1,4-bis(aminomethyl)benzene, 1,4-cyclohexanediamine, 4-methylcyclohexane-1,3-diamine, 4-methylcyclohexane-1,3-diamine, diphenylethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 4,4'-methylenebis(cyclohexylamine), 4,4'-biphenyldiamine, 1,8-diaminonaphthalene, and any combination thereof. Examples of polyamine polyamide monomers that do not have at least one unsaturated aliphatic carbon-carbon bond and are suitable for use in polycondensation include, but are not limited to, HN-(CH2) with n 1 to 20. n-NH, 1,5-diamino-2-methylpentane, 1,2-diaminopropane, trimethylhexamethylenediamine, 2-methyloctane-1,8-diamine, n-methyl1,6-hexamethylenediamine with N = 2 or 3, n-methyl1,7-heptamethylenediamine with N = 2 to 4, n-methyl1,8-octamethylenediamine with N = 2 to 4, n-methyl1,12-dodecamethylenediamine with N = 2 to 6, 1,3-bis(aminomethyl)benzene, ortho-phenyl Examples include n-bis(methylamine), 1,4-bis(aminomethyl)benzene, 1,4-cyclohexanediamine, 4-methylcyclohexane-1,3-diamine, 4-methylcyclohexane-1,3-diamine, diphenylethylenediamine, diphenylethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 4,4'-methylenebis(cyclohexylamine), 4,4'-biphenyldiamine, 1,8-diaminonaphthalene, and any combination thereof. Examples of polyamine polyamide monomers having at least one unsaturated aliphatic carbon-carbon bond include, but are not limited to, 1,4-diamino-2-butene, 1,5-bis(3-aminophenyl)-1,4-pentadiene-3-one (DADBA), trans-4-cyclohexene-1,2-diamine, and any combination thereof.

[0067] Polycondensation reactions can be carried out in the presence of activators and / or metal salts. Examples of activators include, but are not limited to, triphenylphosphine and any combination thereof. Examples of metal salts include calcium chloride, cesium fluoride and any combination thereof.

[0068] Polycondensation reactions can occur at temperatures ranging from approximately 50°C to 200°C (or approximately 50°C to 100°C, or approximately 75°C to 150°C, or approximately 125°C to 200°C).

[0069] The polycondensation reaction can take place over a period of approximately 5 minutes to 24 hours (or approximately 5 minutes to 6 hours, or approximately 2 hours to 12 hours, or approximately 6 hours to 24 hours).

[0070] Polycondensation reactions can be carried out in solvents such as, but are not limited to, N-methylpyrrolidone (NMP), pyridine, dichloromethane, dimethyl sulfoxide (DMSO), N,N-dimethylformamide, acetonitrile, tetrahydrofuran, and any combination thereof.

[0071] Polycondensation reactions can be carried out with a molar ratio of polyamide monomer to CMN of approximately 500:1 to approximately 1:500 (or approximately 500:1 to approximately 100:1, or approximately 250:1 to approximately 50:1, or approximately 100:1 to approximately 10:1, or approximately 50:1 to approximately 1:1, or approximately 25:1 to approximately 1:25, or approximately 1:1 to approximately 1:50, or approximately 1:10 to approximately 1:100, or approximately 1:50 to approximately 1:250, or approximately 1:100 to approximately 1:500). In some cases, polycondensation reactions can be carried out with a molar ratio of polyamide monomer to CMN of approximately 100:1 to approximately 0.5:1, or approximately 50:1 to approximately 5:1, or approximately 20:1 to approximately 10:1.

[0072] In another non-limiting example, the polyamides of this disclosure may be grafted by ring-opening polymerization (ROP), such as insitu anionic ring-opening polymerization (AROP) of CNM. The CNM may be covalently functionalized with a copolymer (e.g., styrene maleic anhydride). Herein, AROP may be carried out at a temperature of about 50°C to about 150°C and / or a reaction time of about 60 minutes or less, e.g., about 40 minutes or less, e.g., about 20 minutes or less, e.g., 5 minutes to 60 minutes, and thus by using an initiator (e.g., caprolactam magnesium bromide) in combination with an activator. Examples of activators include, but are not limited to, dicarbamoyl caprolactam (e.g., bifunctional hexamethylene-1,6-dicarbamoyl caprolactam).

[0073] Examples of cyclic polyamide monomers suitable for use in ring-opening polymerization include, but are not limited to, azelidinone, 2-azetidinone, 2-pyrrolidinone, 2-piperidinone, ε-caprolactam, 2-azacyclooctanone, 2-azacyclononanone, 2-azacyclodecanone, 2-azacycloundecanone, 2-aza-cyclododecanone, laurolactam, butyrolactam, pivalolactam, ε-caprolactam, capryloractam, enantractam, undecanone lactam, laurolactam (dodecanolactam), caprolactam magnesium bromide, and any combination thereof.

[0074] Ring-opening polymerization reactions can be carried out in the presence of activators and / or metal salts. Examples of activators include, but are not limited to, triphenylphosphine or hexamethylene-1,6-dicarbamoylcaprolactam, and any combination thereof. Examples of metal salts include calcium chloride, cesium fluoride, and any combination thereof.

[0075] Ring-opening polymerization reactions can be carried out at approximately 200°C (or room temperature to approximately 150°C, or approximately 50°C to approximately 100°C, or approximately 75°C to approximately 150°C, or approximately 125°C to approximately 200°C).

[0076] The ring-opening polymerization reaction can take place over a period of approximately 5 minutes to 24 hours (or approximately 5 minutes to 6 hours, or approximately 2 hours to 12 hours, or approximately 6 hours to 24 hours).

[0077] Ring-opening polymerization reactions can be carried out in solvents such as, but are not limited to, N-methylpyrrolidone (NMP), pyridine, dichloromethane, dimethyl sulfoxide (DMSO), N,N-dimethylformamide, acetonitrile, tetrahydrofuran, and any combination thereof.

[0078] Ring-opening polymerization reactions may be carried out with a molar ratio of polyamide monomer to CMN of approximately 500:1 to approximately 1:500 (or approximately 500:1 to approximately 100:1, or approximately 250:1 to approximately 50:1, or approximately 100:1 to approximately 10:1, or approximately 50:1 to approximately 1:1, or approximately 25:1 to approximately 1:25, or approximately 1:1 to approximately 1:50, or approximately 1:10 to approximately 1:100, or approximately 1:50 to approximately 1:250, or approximately 1:100 to approximately 1:500). In some cases, polycondensation reactions may be carried out with a molar ratio of polyamide monomer to CMN of approximately 100:1 to approximately 0.5:1, or approximately 50:1 to approximately 5:1, or approximately 20:1 to approximately 10:1. The more polyamide monomers containing at least one unsaturated aliphatic carbon-carbon bond that are included in the polycondensation reaction, the more potential crosslinking sites there will be.

[0079] The CNM-g-polyamides of this disclosure can be produced by interfacial polymerization, where the polymerization process occurs at the interface between two immiscible phases (e.g., CMN and polyamide), resulting in a polymer constrained at the interface. CNM-g-polyamide composites, including polyamide (e.g., nylon 6,6) grafted onto CNM (e.g., MWCNT), can be produced by reactive extrusion from polyamide (e.g., nylon 6,6) and acyl chloride-grafted CMN "CMN-COCl" (e.g., acyl chloride-grafted MWCNT "MWCNT-COCl"). CMN-COCl can be produced by reacting acid-treated CMN with thionyl chloride. The formation of CNM-g-polyamides (e.g., nylon 6,6-g-MWCNT) by reactive extrusion can be analyzed / confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The contact angle of a cylindrical drop-on-fiber system can be determined by using general-purpose droplet shape analysis to quantify the interfacial adhesion energy of polyamide (e.g., nylon 6,6) and untreated functionalized CMN (e.g., untreated functionalized MWCNT). In at least one embodiment, the interfacial adhesion energy of polyamide / CNM-g-polyamide (e.g., nylon 6,6 / nylon 6,6-g-MWCNT composite) is greater than that of polyamide / untreated CMN-g-polyamide (e.g., nylon 6,6 / untreated MWCNT composite). CMN-g-polyamide (e.g., nylon 6,6-g-MWCNT) exhibits excellent dispersion in the composite, while untreated CMN-g-polyamide (e.g., untreated MWCNT) exhibits poor dispersion when the composite film is prepared by solution casting. As the CMN content (e.g., MWCNT content) increases, the level of reinforcement of the composite increases. CNM-g polyamide particles and method of production

[0080] The CNM-g-polyamide of this disclosure may be used to produce spherical microparticles, pellets, or filaments. Spherical microparticles (or powder) containing the CNM-g-polyamide 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-polyamide of this disclosure may be used in three-dimensional (3D) printing technologies by fused filament fabrication (FFF).

[0081] The methods and compositions described herein relate to extremely spherical polymer particles comprising CNM-g-polyamide. While not limited to theory, having polyamide grafted onto CNM is thought to support a more homogeneous distribution of CNM within the polymer particles, thereby resulting in a more homogeneous distribution in objects (or parts thereof) fabricated by additive manufacturing using these polymer particles.

[0082] The disclosure also relates to a method comprising mixing a mixture comprising (a) a CNM-g-polyamide, (b) a dispersion medium immiscible with the polyamide of CNM-g-polyamide, optionally (c) a thermoplastic polymer that is not a polyamide but is not grafted onto CNM (which may or may not be the same as the polyamide of CNM-g-polyamide), and optionally (d) an emulsifying stabilizer, at a temperature higher than the melting or softening temperature of the polyamide of CNM-g-polyamide and at a shear rate high enough to disperse the CNM-g-polyamide in the dispersion medium; cooling the mixture to below the melting or softening temperature of the polyamide to form spherical polymer particles; and isolating the spherical polymer particles from the dispersion medium.

[0083] The figure is a flow chart of a non-limiting exemplary method 100 of the present disclosure. A mixture 112 is produced by mixing (110) CNM-g-polyamide 102, a dispersion medium 104, optionally an emulsifying stabilizer 106, and optionally a thermoplastic polymer 108 not grafted onto CNM (e.g., the polyamide of CNM-g-polyamide 102, a polypolyamide that is not the polyamide of CNM-g-polyamide 102, another thermoplastic polymer, or any combination thereof). Components 102, 104, 106, and 108 may be added individually or in any order in a blend of components, and the process of mixing (110) components 102, 104, 106, and 108 includes mixing and / or heating. For example, CNM-g-polyamide 102 and the thermoplastic polymer 108 not grafted onto CNM (if included) may be pre-mixed before mixing (110). In this specification, if the polyamide in CNM-g-polyamide is not grafted onto the CNM, this will be referred to as v.

[0084] Next, the mixture 112 is treated (114) by applying a sufficiently high shear force to the mixture 112 at a temperature higher than the melting point or softening temperature (whichever is higher) of (a) the polyamide of CNM-g-polyamide 102, or (b) the thermoplastic polymer 108 that is not grafted onto CNM, to form a molten emulsion 116. Since this temperature exceeds the melting point or softening temperature of the polymer portion of the mixture 112 (i.e., the polyamide of CNM-g-polyamide 102, and, if present, the thermoplastic polymer 108 that is not grafted onto CNM), a polymer melt containing CNM-g-polyamide 102, and, if present, the thermoplastic polymer 108 that is not grafted onto CNM, is formed. The shear rate should be sufficient to disperse the polymer melt (e.g., containing CNM-g-polyamide) 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.

[0085] Next, the molten emulsion 116 in and / or outside the mixing vessel is cooled (118) to solidify the polymer droplets into CNM-g-polyamide particles 124. The term "CNM-g-polyamide particles" refers to polymer particles containing CNM-g-polyamide 102, which may include other components in the polymer particles (e.g., thermoplastic polymer 108 not grafted onto CNM).

[0086] Next, the cooled mixture 120 may be processed (122) to isolate the CNM-g-polyamide particles 124 from the other components 126 (e.g., dispersion medium 104, excess emulsifying stabilizer 106, etc.) and wash, or otherwise purify the CNM-g-polyamide particles 124. The CNM-g-polyamide particles 124 comprise CNM-g-polyamide 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-polyamide particles 124. The emulsifying stabilizer 106 or a portion thereof may be deposited on the CNM-g-polyamide 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-polyamide 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-polyamide particles 124. Even without embedding, at least some of the nanoparticles in the emulsifying stabilizer 106 remain firmly associated with the CNM-g-polyamide particles 124, facilitating their 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.

[0087] The CNM-g-polyamide particles 124 can be optionally further purified (128) (described in more detail below) to obtain purified CNM-g-polyamide particles 130.

[0088] The dispersion medium 104 should be selected such that the CNM-g-polyamide 102 and the dispersion medium 104 are immiscible at various processing temperatures (e.g., room temperature to process temperature). An additional factor to consider is the difference in viscosity (e.g., difference or ratio) between the CNM-g-polyamide 102 and the dispersion medium 104 at the process temperature. The difference in viscosity can affect droplet breakdown and particle size distribution. While not theoretically bound, if the viscosities of the CNM-g-polyamide 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.

[0089] CNM-g-polyamide 102 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 mixed CNM-g-polyamide 102, the thermoplastic polymer 108 that is not grafted onto CNM, and the dispersion medium 104. If the mixture contains ungrafted thermoplastic polymer 108, the mixed CNM-g-polyamide 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 mixed CNM-g-polyamide 102, the ungrafted thermoplastic polymer 108, and the dispersion medium 104. If present, the weight ratio of CNM-g-polyamide 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).

[0090] Thermoplastic polymer 108 that is not grafted onto CNM may be a functionalized nonpolar polymer. The mismatch of heterogeneous blends of polyamide / nonpolar polymers (PA / NPP) (e.g., PA / PE heterogeneous blends) may be due to the introduction of a small number of polar groups (e.g., maleic anhydride, vinyl acetate, (meth)acrylic acid, or (meth)acrylic acid esters) into the polyolefin backbone. Another method to improve the mismatch of heterogeneous blends of polyamide / nonpolar polymers (PA / NPP) (e.g., PA / PE heterogeneous blends) may be to graft polar groups onto the nonpolar polymer chains (e.g., PE chains).

[0091] Examples of thermoplastic polymers not grafted onto CNM108 include, but are not limited to, polyamides, polyurethanes, polyethylene (preferably functionalized polyethylene), polypropylene (preferably functionalized polypropylene), polyacetals (which may be in the presence of polyethylene glycol), polycarbonates (e.g., maleized polyalkenes (maleized PP or EPR)), polyesteramides, acrylonitrile butadiene styrene (ABS) and maleized ABS (MA-g-ABS), butadiene-styrene-acrylonitrile-acrylate copolymers, styrene maleic anhydride (SMA), and styrene-propylene-ethylene-butylene-styrene (styrene--propylene ethylene-butylene-styrene (SEBS) and MA-g-SEBS, polyethyl oxazoline, ethylene-glycidyl methacrylate graft copolymer (may be in the presence of a compatibilizer), polybutyl terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), ethylene vinyl acetate copolymer (EVA), ethylene polypylene diene rubber (EPDM), ethylene elastomer (ethylenecelastomer)(EPR) (may be in the presence of a compatibilizer such as MA-grafted ethylene propylene copolymer), poly(4-methyl-1-pentene), polyhexamethylene terephthalate, polystyrene (e.g., statistical or block styrene copolymer, grafted styrene, or compatibilizer), polyvinyl chloride, polytetrafluoroethylene, polyester (e.g., polylactic acid), polyether, polyethersulfone (PESU), polysulfone (PSU) (preferably functionalized PSU), polyetheretherketone, polyacrylate, polymethacrylate, polyimide, acrylonitrile butadiene styrene (ABS), polyphenylene sulfide, vinyl polymer, polyarylene ether, polyarylene sulfide, polysulfone, polyetherketone, polyamide-imide, polyetherimide, polyetherether, copolymer containing polyether blocks and polyamide blocks (PEBA or polyether block amide), grafted or Examples include ungrafted thermoplastic polyamides, functionalized or unfunctionalized ethylene / vinyl monomer polymers, functionalized or unfunctionalized ethylene / alkyl (meth)acrylates, functionalized or unfunctionalized (meth)acrylic acid polymers, functionalized or unfunctionalized ethylene / vinyl monomer / alkyl (meth)acrylate terpolymers, ethylene / vinyl monomer / carbonyl terpolymers, ethylene / alkyl (meth)acrylate / carbonyl terpolymers, methyl methacrylate-butadiene-styrene (MBS) type core-shell polymers, polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (SBM) block terpolymers, chlorided or chlorosulfonated polyethylene, polyvinylidene fluoride (PVDF) (which may be in compatibilization with polyetheramide block copolymers), phenolic resins, poly(ethylene / vinyl acetate), polybutadiene, polyisoprene, styrene block copolymers, polyacrylonitrile, silicones, and any combination thereof. Copolymers containing one or more of the above may also be used in the methods and systems of this disclosure.

[0092] The thermoplastic polymer 108 not grafted onto the CNM in the compositions and methods of this disclosure may be an elastomer or a non-elastomer. 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 a non-elastomer depending on the amount of propylene in the polymer.

[0093] 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.While not bound by any particular theory, thermoplastic elastomers (e.g., butyl rubber) using compatibilizers such as ethylene-methacrylate-isobutyl acrylate copolymer can improve interfacial adhesion between two phases and the dispersion of thermoplastic elastomer domains in the PA matrix.

[0094] 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.

[0095] Compatibilizers may be optionally used to improve the efficiency and effectiveness of blending CNM-g-polyamide 102 with one or more thermoplastic polymers. Examples of polymer phase solvents 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 binder, available from Kenrich Petrochemicals), KEN-REACT® CAPOW® L® 12 / H (organometallic binder, available from Kenrich Petrochemicals), KEN-REACT® LICA® 12 (organometallic binder, available from Kenrich Petrochemicals), and KEN-REACT® CAPS® KPR® 12 / LV (organometallic binder, available from Kenrich Petrochemicals). Available from Petrochemicals), KEN-REACT(trademark) CAPOW(trademark) KPR(trademark) 12 / H (organometallic binder, available from Kenrich Petrochemicals), KEN-REACT(trademark) titanate & zirconate (organometallic binder, KenrichAvailable from Petrochemicals), VISTAMAXX (Trademark) (Ethylene-propylene copolymer, available from ExxonMobil), SANTOPRENE (Trademark) (Thermoplastic vulcanized rubber of 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), 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) Polymers (available from Arkema), LOTADER® 3430 (ethylene acrylate terpolymer, available from Arkema), LOTADER® 4700 (ethylene acrylate terpolymer, available from Arkema), LOTADER® AX8900 (ethylene acrylate terpolymer, available from Arkema), LOTADER® 4720 (ethylene acrylate terpolymer, available from Arkema), BAXXODUR® EC 301 (amine for epoxy, available from BASF), BAXXODUR® EC 311 (amine for epoxy, available from BASF), BAXXODUR® ECExamples include, but are not limited to, 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, polypropylene, polyamide, 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.

[0096] The CNM-g-polyamide 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).

[0097] The CNM-g-polyamide 102 and the ungrafted thermoplastic polymer 108 on CNM may have a glass transition temperature 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) (using a heating and cooling rate of 10°C / min as in ASTM E1356-08 (2014)).

[0098] The thermoplastic polymer 108, which is not grafted onto the CNM, may optionally contain additives. Typically, the additives are present before the addition of the thermoplastic polymer to the mixture. Thus, in the polymer molten droplets and the resulting CNM-g-polyamide 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.

[0099] When describing the amounts of components in the compositions described herein (e.g., mixture 112 and CNM-g-polyamide particles 124), the amounts are given as 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.

[0100] This disclosure provides a composition comprising CNM-g-polyamide particles containing polyamide grafted onto carbon nanomaterials. The CNM-g-polyamide 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-polyamide particles may contain about 0.05% to about 50% by weight of CNM, and the CNM may be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerene, and any combination thereof.

[0101] The internal additive may be present in the thermoplastic polymer 108 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.

[0102] 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 nanoplatelets (xGnP), carbon black, carbon nanofibers (CNF), carbon nanotubes (CNT), graphene, graphene oxide, graphite oxide, graphene oxide nanosheets, and fullerenes.

[0103] A suitable dispersion medium (e.g., dispersion medium 104) may have a viscosity of about 1,000 cSt to about 150,000 cSt (or about 1,000 cSt to about 60,000 cSt, or about 40,000 cSt to about 100,000 cSt, or about 75,000 cSt to about 150,000 cSt) at 25°C. For example, a suitable dispersion medium (e.g., dispersion medium 104) may have a viscosity of about 10,000 cSt to about 60,000 cSt at 25°C.

[0104] Examples of dispersion media (e.g., dispersion media 104) include, but are not limited to, silicone oil, fluorinated silicone oil, perfluorinated silicone oil, polyethylene glycol, alkyl-terminated polyethylene glycol (e.g., C1-C4 terminal alkyl groups such as tetraethylene glycol dimethyl 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, fatty acid-modified polysiloxane and aliphatic alcohol-modified polysiloxane (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 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).

[0105] 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 mixed CNM-g-polyamide 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 dispersion medium to the combination of CNMg-polyamide 102 and thermoplastic polymer in the range of 50:50 to 90:10.

[0106] In some cases, the dispersion medium 104 is approximately 0.6 g / cm³. 3 ~Approx. 1.5g / cm 3 The thermoplastic polymer may have 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 that of the dispersion medium 104.

[0107] CNM should be sufficiently stable so as not to decompose at the processing temperature. Examples of CNM, but not limited to, include carbon nanotubes, graphite, graphene, fullerenes, carbon black, and any combination thereof.

[0108] 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.

[0109] 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.

[0110] 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 diameter of approximately 7 nm and a BET surface area of ​​1 / g, AEROSIL® RX50 (hydrophobic modified surface and 35±10 m 2 Silica nanoparticles with an average diameter 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.

[0111] 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.

[0112] 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.

[0113] Surfactants may be anionic, cationic, nonionic, or dipolar ionic. Examples of surfactants, but are not limited to, include 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.

[0114] Surfactants may be present in the mixture at concentrations 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-polyamide 102. Alternatively, the mixture may be surfactant-free (i.e., surfactant-free).

[0115] 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).

[0116] 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 mixed CNM-g-polyamide 102 and the thermoplastic polymer 108 that is not grafted onto the CNM.

[0117] In relation to the mixing (110) in the figure, in some cases, the emulsifying stabilizer 106 is first dispersed in the dispersion medium 104 before the addition of the CNM-g-polyamide 102 and / or the thermoplastic polymer 108 not grafted onto CNM, and optionally, the dispersion may be heated. In another non-limiting example, the CNM-g-polyamide 102 and / or the thermoplastic polymer 108 not grafted onto CNM may be heated to produce a polymer melt to which the dispersion medium 104 and the emulsifying stabilizer 106 are added together or in any order. In yet another non-limiting example, the CNM-g-polyamide 102 and / or the thermoplastic polymer 108 not grafted onto CNM may be mixed 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.

[0118] Mixing CNM-g-polyamide 102, ungrafted thermoplastic polymer 108, dispersion medium 104, and optionally emulsifying stabilizer 106 in any combination may occur in a mixing apparatus and / or another suitable container used for processing. As a non-limiting example, the CNM-g-polyamide 102 and / or ungrafted thermoplastic polymer 108 may be heated in the mixing apparatus used for processing to a temperature higher than 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 may then be added to the molten material in the mixing apparatus used for processing.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] The temperature of the treatment (114) and the formation of the molten emulsion 116 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-polyamide 102, thermoplastic polymer 108 not grafted onto CNM, dispersion medium 104, emulsifying stabilizer 106). For example, the temperature of the treatment (114) and the formation of the molten emulsion 116 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 of the treatment and the formation of the molten emulsion 116 is lower than the decomposition temperature of any component in the mixture 112 (i.e., CNM-g-polyamide 102, thermoplastic polymer 108 not grafted onto CNM, dispersion medium 104, emulsifying stabilizer 106).

[0123] 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. The droplets should include droplets with a diameter 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).

[0124] 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 assumed that a steady state of droplet diameter 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-polyamide 102, the thermoplastic polymer 108 not grafted onto CNM, the dispersion medium composition 104, and the emulsifying stabilizer composition 106.

[0125] 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 (118) under ambient conditions) or fast (e.g., quenching). For example, the rate of cooling (118) can range from about 10°C / hour to about 100°C / second, or even nearly instantaneous by quenching (e.g., in 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).

[0126] During cooling, shear forces may be applied little to no to the molten emulsion 116. In some cases, shear forces applied during heating may be applied during cooling (118).

[0127] The cooled mixture obtained from the cooling (118) of the molten emulsion 116 may contain solidified CNM-g-polyamide particles 124 and other components (e.g., dispersion medium 104, excess emulsifying stabilizer 106, etc.). The solidified CNM-g-polyamide particles 124 may be dispersed in the dispersion medium 104 or settle in the dispersion medium 104.

[0128] The cooled mixture can then be processed to isolate the CNM-g-polyamide particles 124 from the other components. Suitable processing methods include, but are not limited to, washing, filtration, centrifugation, and decanting, as well as any combination thereof.

[0129] The solvent used to wash the CNM-g-polyamide 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-polyamide 102 and / or the thermoplastic polymer 108 not grafted onto the CNM. The choice of solvent will depend, in particular, on the composition of the dispersion medium 104, the CNM-g-polyamide 102 and the thermoplastic polymer 108 not grafted onto the CNM.

[0130] 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.

[0131] The solvent can be removed from the CNM-g-polyamide particles 124 by drying using an appropriate 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 polyamide (e.g., about 50°C to about 150°C) of the CNM-g-polyamide 102 and the thermoplastic polymer 108 (if present) that is not grafted onto the CNM.

[0132] Advantageously, the dispersion medium (e.g., dispersion medium 104) and washing solvent of the systems and methods described herein are regenerative and reusable. Those skilled in the art will recognize any necessary washing of the used dispersion medium 104 and solvent required for the regeneration process.

[0133] The CNM-g-polyamide particles 124, after isolation from other components, can be optionally further purified. For example, to narrow the particle size distribution (i.e., reduce the particle size span), the CNM-g-polyamide particles 124 can be passed through a sieve having a pore size of about 10 μm to about 250 μm (or about 10 μm to about 100 μm, or about 50 μm to about 200 μm, or about 150 μm to about 250 μm).

[0134] In another exemplary purification technique, the CNM-g-polyamide 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-polyamide particles 124. In yet another exemplary purification technique, the CNM-g-polyamide particles 124 may be blended with additives to obtain the desired final product. For clarity, such additives are blended with the CNM-g-polyamide particles 124 after solidification as described herein, and are therefore referred to herein as “external additives.” Examples of external additives include flow aids, other polymer particles, fillers, and any combination thereof.

[0135] In some cases, the surfactants used to prepare the CNM-g-polyamide particles 124 may be undesirable in downstream applications. Therefore, yet another exemplary purification technique may include removing the surfactant from the CNM-g-polyamide particles 124 (e.g., by washing and / or thermal decomposition), at least substantially.

[0136] CNM-g-polyamide particles 124 and / or purified CNM-g-polyamide particles 124 can be characterized by their composition, physical structure, and the like.

[0137] 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-polyamide 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-polyamide particles 124 and / or (b) embedded in the outer portion of the CNM-g-polyamide particles 124 (e.g., outer 1 vol%).

[0138] Furthermore, if voids are formed inside the polymer molten droplets, the emulsifying stabilizer (e.g., emulsifying stabilizer 106) should generally be located at (and / or embedded in) the interface between the voids and the CNM-g-polyamide 124 and / or the thermoplastic polymer. The voids generally do not contain the CNM-g-polyamide 124 and / or the thermoplastic polymer. Rather, the voids may contain, for example, the dispersion medium 104, air, or voids. The CNM-g-polyamide 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-polyamide particles 124.

[0139] If the CNM does not contain ungrafted thermoplastic polymers, the mixed CNM-g-polyamide and the ungrafted thermoplastic polymers may be present in the CNM-g-polyamide particles at a concentration 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-polyamide particles. If the CNM does contain ungrafted thermoplastic polymers, the mixed CNM-g-polyamide and the ungrafted thermoplastic polymers may be present in the CNM-g-polyamide particles at a concentration 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-polyamide particles. The weight ratio of CNM-g-polyamide to thermoplastic polymer 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).

[0140] If present, emulsifying stabilizers (e.g., emulsifying stabilizer 106) may be present in CNM-g-polyamide 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-polyamide 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).

[0141] When forming thermoplastic microparticles according to the disclosure herein using particulate emulsifying stabilizers, at least a portion of the particulate emulsifying stabilizers, such as silica nanoparticles, may be disposed as a coating on the outer surface of the CNM-g-polyamide 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. When 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-polyamide particles. After purification to remove at least substantially any surfactant or other emulsifying stabilizer, the emulsifying stabilizer may be present in CNM-g-polyamide particles 124 / 130 in amounts less than 25% of the surface area of ​​the CNM-g-polyamide 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-polyamide particles 124 / 130 can 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-polyamide particles 124 / 130 (and coated CNM-g-polyamide particles (if produced)).After purification to remove at least substantially any surfactant or other emulsifying stabilizer, the emulsifying stabilizer may be present in CNM-g-polyamide particles 124 / 130 in amounts less than 25% of the surface area of ​​the CNM-g-polyamide 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-polyamide particles can be determined using image analysis of SEM micrographs.

[0142] The CNM-g-polyamide 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).

[0143] The CNM-g-polyamide particles 124 / 130 may comprise one or more carbon nanomaterials. For example, two or more different carbon nanomaterials may be grafted onto a polyamide in the same reaction and then used as CNM-g-polyamide 102 in the methods and compositions described herein. In another example, two different CNM-g-polyamides may be produced and blended before (or during) the mixing process of the melt emulsification process described herein.

[0144] CNM-g-polyamide particles 124 / 130 may have a roundness of approximately 0.90 to approximately 1.0.

[0145] CNM-g-polyamide particles 124 / 130 are approximately 10m 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 approximately 100m 2 / g to about 250 m 2 / g, or about 250 m 2 / g to about 500 m 2 may have a BET surface area of ( / g).

[0146] The CNM-g-polyamide 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), and 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), with D10 < D50 < D90. The CNM-g-polyamide 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 particle size 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, the CNM-g-polyamide particles 124 / 130 have a particle size span of about 0.2 to about 1.

[0147] In a first non-limiting example, the CNM-g-polyamide 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, and a D90 of about 3 μm to about 50 μm, with D10 < D50 < D90. The CNM-g-polyamide particles 124 / 130 may have a particle size span of about 0.2 to about 2.

[0148] In a second non-limiting example, the CNM-g-polyamide particles 124 / 130 can have a D10 of about 5 μm to about 30 μm, a D50 of about 30 μm to about 70 μm, and a D90 of about 70 μm to about 120 μm, with D10 < D50 < D90. The CNM-g-polyamide particles 124 / 130 can have a particle size span of about 1.0 to about 2.5.

[0149] In a third non-limiting example, the CNM-g-polyamide particles 124 / 130 can have a D10 of about 25 μm to about 60 μm, a D50 of about 60 μm to about 110 μm, and a D90 of about 110 μm to about 175 μm, with D10 < D50 < D90. The CNM-g-polyamide particles 124 / 130 can have a particle size span of about 0.6 to about 1.5.

[0150] In a fourth non-limiting example, the CNM-g-polyamide particles 124 / 130 can have a D10 of about 75 μm to about 125 μm, a D50 of about 100 μm to about 200 μm, and a D90 of about 125 μm to about 300 μm, with D10 < D50 < D90. The CNM-g-polyamide particles 124 / 130 can have a particle size span of about 0.2 to about 1.2.

[0151] In a fifth non-limiting example, the CNM-g-polyamide particles 124 / 130 can 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), and 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), with D10 < D50 < D90. The CNM-g-polyamide particles 124 / 130 can 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).

[0152] CNM-g-polyamide 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).

[0153] CNM-g-polyamide 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°).

[0154] CNM-g-polyamide particles 124 / 130 may have a Hausner ratio of about 1.0 to about 1.5 (or about 1.0 to about 1.2, or about 1.1 to about 1.3, or about 1.2 to about 1.35, or about 1.3 to about 1.5).

[0155] CNM-g-polyamide particles 124 / 130 are 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 It may have a bulk density of ).

[0156] CNM-g-polyamide particles 124 / 130 are 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 It may have the following air permeability density.

[0157] CNM-g-polyamide particles 124 / 130 are 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 ) may have a tap density of .

[0158] Depending on the processing temperature and shear rate, as well as the composition and relative concentration of the components (CNM-g-polyamide 102, thermoplastic polymer, dispersion medium 104, excess emulsifying stabilizer 106, etc.), different structural shapes constituting CNM-g-polyamide 124 / 130 can be produced. Typically, CNM-g-polyamide particles 124 / 130 include substantially spherical particles (with a roundness of about 0.97 or greater). However, other structures, such as disc-shaped and elongated structures, may be observed in CNM-g-polyamide particles 124 / 130. Therefore, CNM-g-polyamide particles 124 / 130 may include one or more of the following: (a) substantially spherical particles with a 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).

[0159] CNM-g-polyamide particles 124 / 130 may have a sintering window that is within 10°C, preferably within 5°C, of ​​the sintering window for polyamides of CNM-g-polyamide.

[0160] CNM-g-polyamide 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).

[0161] CNM-g-polyamide particles 124 / 130 may have crystallization temperatures 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).

[0162] CNM-g-polyamide particles 124 / 130 may have a degree of crystallinity ranging from about 20% to about 40% (or about 22% to about 38%, or about 24% to about 36%, or about 26% to about 34%, or about 28% to about 32%, or about 20% to about 30%, or about 22% to about 28%).

[0163] CNM-g-polyamide particles 124 / 130 may have MFI flow rates 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).

[0164] CNM-g-polyamide 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%).

[0165] CNM-g-polyamide 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).

[0166] The tensile strength and dimensional accuracy of the SLS portion of CNM-g-polyamide particles 124 / 130 may be advantageously higher than those of the SLS portion of typical polyamide particles with the same processing parameters.

[0167] CNM-g-polyamide particles 124 / 130 may have a tensile modulus (as fibers) 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).

[0168] CNM-g-polyamide particles 124 / 130 may have an extreme 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).

[0169] CNM-g-polyamide particles 124 / 130 may have a flexural 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).

[0170] CNM-g-polyamide particles 124 / 130 may have an elongation range of about 2% to about 20% (or about 4% to about 18%, or about 6% to about 16%, or about 8% to about 14%, or about 10% to about 12%, or about 5% to about 15%, or about 6% to about 12%, or about 7% to about 10%). Applications of CNM-g-polyamide

[0171] The disclosure also relates to a method of selective laser sintering, which may include depositing (a) (a1) CNM-g-polyamide and optionally (a2) a thermoplastic polymer that is not a polyamide of CNM-g-polyamide but is not grafted onto CNM, and optionally (b) other thermoplastic polymer particles that do not contain CNM-g-polyamide, on a surface, and after deposition, exposing at least a portion of the spherical polymer particles to a laser to melt the polymer particles and form a solidified body.

[0172] The CNM-g-polyamide 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-polyamide particles 124 / 130 described herein onto a surface (e.g., in layers and / or in a particular shape), and, after deposition, 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-polyamide 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.

[0173] Examples of articles that can be manufactured by using CNM-g-polyamide particles 124 / 130 to form all or part of an article 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, sporting goods, and more. Furthermore, the particles may be useful in applications such as paints, powder coatings, inkjet materials, electrophotographic toners, and 3D printing, but are not limited to these. Exemplary Embodiments

[0174] A first non-limiting exemplary embodiment of the present disclosure is a selective laser sintering method comprising depositing carbon nanomaterial-grafted-polyamide (CNM-g-polyamide) particles on a surface in optionally selective combination with other thermoplastic polymer particles, wherein the CNM-g-polyamide particles comprise polyamide grafted onto carbon nanomaterial (CNM), and, after deposition, exposing at least a portion of the CNM-g-polyamide particles to a laser by selective laser sintering to melt the polymer particles and form a solidified body. A first non-limiting exemplary embodiment may further include one or more of the following: Element 1: CNM-g-polyamide comprising 50% to 99.95% by weight of polyamide and about 0.05% to about 50% by weight of carbon nanomaterial, based on the total weight of CNM-g-polyamide; Element 2: polyamide comprising polycaproamide, poly(hexamethylene succinamide), polyhexamethylene adipamide, polypentamethylene adipamide, polyhexamethylene sevacamide, polyundekaamide, polydodekaamide, polyhexamethylene terephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, Element 3: CNM is selected from the group consisting of semi-aromatic polyamides, aromatic polyamides, any copolymers thereof, and any combination thereof; Element 4: The molar ratio of polyamide to CMN is approximately 500:1 to approximately 1:500; Element 5: Element 4, and the molar ratio of polyamide to CMN is approximately 20:1 to approximately 10:1; Element 6: The polyamide is grafted onto the surface of CNM by polycondensation, interfacial polymerization, or ring-opening polymerization (ROP) to produce CNM-g-polyamide; Element 7: Element 6, and ROP is insitu anionic ring-opening polymerization (AROP); Element 8: Element 7, and insitu AROP is performed in the presence of an initiator and optionally an activator; element 9: element 8, with a polyamide to initiator weight ratio of approximately 90:10 to approximately 99:1; element 10: CNM-g-polyamide particles are approximately 0.90 to approximately 1.Having a circularity of 0; Element 11: The CNM-g-polyamide particles have an emulsifier embedded in the outer surface of the CNM-g-polyamide particles; Element 12: Element 11, and the emulsifier contains nanoparticles; Element 13: Element 11, and at least a part of the CNM-g-polyamide particles has voids containing an emulsifier at the void / polymer interface; Element 14: Element 11, the emulsifier contains nanoparticles, and the nanoparticles are embedded at the void / polymer interface; Element 15: The CNM-g-polyamide containing polymer particles further contains a thermoplastic polymer not grafted to the CNM; Element 16: The CNM-g-polyamide containing polymer particles further contains a dispersion medium immiscible with the polyamide of the CNM-g-polyamide; Element 17: Element 16, and the dispersion medium is present at a weight ratio of the dispersion medium to the combination of the CNM-g-polyamide and the thermoplastic polymer in the range of 50:50 to 90:10; Element 18: The CNM-g-polyamide 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 19: The CNM-g-polyamide particles have a particle size span of about 0.2 to about 10; Element 20: The CNM-g-polyamide particles have an angle of repose of about 25° to about 45°; and Element 21: The CNM-g-polyamide particles have a Hausner ratio of about 1.0 to about 1.5. Examples of combinations include, but are not limited to, combinations of two or more of Elements 6, 7, and 10, combinations of Element 1 with one or more of Elements 2 to 21; combinations of Element 2 with one or more of Elements 3 to 21; combinations of Element 3 with one or more of Elements 4 to 21; combinations of Element 5 with one or more of Elements 6 to 21; combinations of Element 7 with one or more of Elements 8 to 21; combinations of Element 8 with one or more of Elements 9 to 21; combinations of Element 9 with one or more of Elements 10 to 21; combinations of Element 11 with one or more of Elements 12 to 21; combinations of Element 12 with one or more of Elements 13 to 21; combinations of two or more of Elements 14 to 21; and combinations of two or more of Elements 18 to 21.

[0175] A second non-limiting exemplary embodiment of the present disclosure is a composition comprising CNM-g-polyamide particles containing a polyamide grafted onto a carbon nanomaterial. The CNM-g-polyamide particles may contain about 0.05% to about 50% by weight of CNM, and the CNM may be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerene, and any combination thereof. The second non-limiting exemplary embodiment may further include one or more of the following: Element 18: Polyamide is polycaproamide, poly(hexamethylene succinamide), polyhexamethylene adipamide, The following are selected from the group consisting of polypentamethylene adipamide, polyhexamethylene sebaamide, polyundecaamide, polydodecaamide, polyhexamethylene terephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamides, aromatic polyamides, any copolymers thereof, and any combination thereof. A second non-limiting exemplary embodiment may further include one or more of elements 1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; and 21.

[0176] A third non-limiting exemplary embodiment is a method comprising: (a) a CNM-g-polyamide, wherein the CNM-g-polyamide particles are a carbon nanomaterial-grafted polyamide (CNM-g-polyamide), wherein the CNM-g-polyamide particles are a polyamide grafted onto a carbon nanomaterial; (b) a dispersion medium immiscible with the polyamide of the CNM-g-polyamide; optionally (c) a thermoplastic polymer not grafted onto the CNM; and optionally (d) an emulsifying stabilizer; mixing a mixture at a temperature higher than the melting or softening temperature of the polyamide and thermoplastic polymer (if included) and at a shear rate high enough to disperse the CNM-g-polyamide in the dispersion medium; cooling the mixture to below the melting or softening temperature to form CNM-g-polyamide particles; and isolating the CNM-g-polyamide particles from the dispersion medium. A third non-limiting exemplary embodiment may further include one or more of the following elements: Element 1; Element 2; Element 3; Element 4; Element 5; Element 6; Element 7; Element 8; Element 9; 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: The dispersion medium is polydimethylsiloxane (PDMS). Clause

[0177] Clause 1. A method of selective laser sintering, comprising: depositing carbon nanomaterial-grafted-polyamide (CNM-g-polyamide) particles on a surface in optionally selective combination with other thermoplastic polymer particles, wherein the CNM-g-polyamide particles contain polyamide grafted onto carbon nanomaterial (CNM); and, after deposition, exposing at least a portion of the CNM-g-polyamide particles to a laser by selective laser sintering to melt the polymer particles and form a solidified body.

[0178] Clause 2. The method according to Clause 1, wherein the CNM-g-polyamide comprises 50% to 99.95% by weight of polyamide and about 0.05% to about 50% by weight of carbon nanomaterial, based on the total weight of the CNM-g-polyamide.

[0179] Clause 3. The method according to Section 1, wherein the polyamide is selected from the group consisting of polycaproamide, poly(hexamethylenesuccinate), polyhexamethyleneadipamide, polypentamethyleneadipamide, polyhexamethylenesebamide, polyundekaamide, polydodekaamide, polyhexamethyleneterephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamide, aromatic polyamide, any copolymer thereof, and any combination thereof.

[0180] Clause 4. 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.

[0181] Clause 5. The molar ratio of polyamide to CMN is approximately 500:1 to approximately 1:500. The method described in Clause 1.

[0182] Clause 6. The method according to Clause 5, wherein the molar ratio of polyamide to CMN is approximately 20:1 to approximately 10:1.

[0183] Clause 7. The method according to Clause 1, wherein a polyamide is grafted onto the surface of CNM by polycondensation, interfacial polymerization, or ring-opening polymerization (ROP) to produce CNM-g-polyamide.

[0184] Clause 8. ROP is insitu anionic ring-opening polymerization (AROP) as described in Clause 7.

[0185] Clause 9. The method of Clause 8, wherein insitu AROP is performed in the presence of an initiator and optionally an activator.

[0186] Clause 10. The method according to Clause 9, wherein the weight ratio of polyamide to initiator is approximately 90:10 to approximately 99:1.

[0187] The method according to item 1, wherein the CNM-g-polyamide particles have a roundness of about 0.90 to about 1.0.

[0188] The method according to item 1, wherein the CNM-g-polyamide particles have an emulsifier stabilizer embedded in the outer surface of the CNM-g-polyamide particles.

[0189] The method according to item 12, wherein the emulsifier stabilizer contains nanoparticles.

[0190] The method according to item 12, wherein at least a part of the CNM-g-polyamide particles has voids containing an emulsifier stabilizer at the void / polymer interface.

[0191] The method according to item 12, wherein the emulsifier stabilizer contains nanoparticles, and the nanoparticles are embedded at the void / polymer interface.

[0192] The method according to item 1, wherein the CNM-g-polyamide containing polymer particles further contains a thermoplastic polymer not grafted to the CNM.

[0193] The method according to item 1, wherein the CNM-g-polyamide containing polymer particles further contains a dispersion medium immiscible with the polyamide of the CNM-g-polyamide.

[0194] The method according to item 17, wherein the dispersion medium is present in a weight ratio of the dispersion medium to the combination of the CNM-g-polyamide and the thermoplastic polymer in the range of 50:5 to 90:10.

[0195] The method according to item 1, wherein the CNM-g-polyamide 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.

[0196] The method according to item 1, wherein the CNM-g-polyamide particles have a particle size span of about 0.2 to about 10.

[0197] Clause 21. The method according to Clause 1, wherein the CNM-g-polyamide particles have an angle of repose of approximately 25° to approximately 45°.

[0198] Clause 22. The method according to Clause 1, wherein the CNM-g-polyamide particles have a Hausner ratio of approximately 1.0 to approximately 1.5.

[0199] Clause 23. A composition comprising CNM-g-polyamide particles containing polyamide grafted onto carbon nanomaterials. The CNM-g-polyamide 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.

[0200] Clause 24. The composition according to Clause 23, wherein the polyamide is selected from the group consisting of polycaproamide, poly(hexamethylenesuccinamide), polyhexamethyleneadipamide, polypentamethyleneadipamide, polyhexamethylenesebamide, polyundekaamide, polydodekaamide, polyhexamethyleneterephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamide, aromatic polyamide, any copolymer thereof, and any combination thereof.

[0201] Clause 25. The composition according to Clause 23, wherein the CNM-g-polyamide particles have a roundness of about 0.90 to about 1.0.

[0202] Clause 26. The composition according to Clause 23, wherein the CNM-g-polyamide particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyamide particles.

[0203] Clause 27. The composition according to Clause 23, wherein the emulsifying stabilizer comprises nanoparticles.

[0204] Clause 28. The composition according to Clause 23, wherein the CNM-g-polyamide 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.

[0205] Clause 29. The composition according to Clause 23, wherein the CNM-g-polyamide particles have a particle size span of about 0.2 to about 10.

[0206] Clause 30. The composition according to Clause 23, wherein the CNM-g-polyamide particles have an angle of repose of about 25° to about 45°.

[0207] Clause 31. The composition according to Clause 23, wherein the CNM-g-polyamide particles have a Hausner ratio of about 1.0 to about 1.5.

[0208] Clause 32. A method comprising: (a) a carbon nanomaterial-graft-polyamide (CNM-g-polyamide), wherein the CNM-g-polyamide particles comprise polyamide grafted to a carbon nanomaterial, (b) a dispersion medium immiscible with the polyamide of the CNM-g-polyamide, optionally (c) a thermoplastic polymer not grafted to the CNM, and optionally (d) an emulsifying stabilizer, mixing a mixture containing the above components at a temperature higher than the melting point or softening temperature of the polyamide of the CNM-g-polyamide and the thermoplastic polymer (if any), and at a shear rate high enough to disperse the CNM-g-polyamide in the dispersion medium, cooling the mixture to below the melting point or softening temperature to form CNM-g-polyamide particles, and isolating the CNM-g-polyamide particles from the dispersion medium.

[0209] Clause 33. The method according to Clause 32, wherein the polyamide is selected from the group consisting of polycaproamide, poly(hexamethylenesuccinate), polyhexamethyleneadipamide, polypentamethyleneadipamide, polyhexamethylenesebamide, polyundekaamide, polydodekaamide, polyhexamethyleneterephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamide, aromatic polyamide, any copolymer thereof, and any combination thereof.

[0210] Clause 34. The method according to Clause 32, wherein the CNM-g-polyamide comprises 50% to 99.95% by weight of polyamide and about 0.05% to about 50% by weight of carbon nanomaterial, based on the total weight of the CNM-g-polyamide.

[0211] Clause 35. The method according to Clause 32, wherein the dispersion medium is present in a weight ratio of the dispersion medium to the combination of CNM-g-polyamide and thermoplastic polymer in the range of 50:50 to 90:10.

[0212] Clause 36. The method according to Clause 32, wherein the dispersion medium is polydimethylsiloxane (PDMS).

[0213] Clause 37. The method according to Clause 32, wherein the CNM-g-polyamide particles have a roundness of about 0.90 to about 1.0.

[0214] Clause 38. The method according to Clause 32, wherein the CNM-g-polyamide particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyamide particles.

[0215] Clause 39. The method according to Clause 32, wherein the emulsifying stabilizer includes nanoparticles.

[0216] Item 40. The method according to Item 32, wherein the CNM-g-polyolefin 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.

[0217] Item 41. The method according to Item 32, wherein the CNM-g-polyolefin particles have a particle size span of about 0.2 to about 10.

[0218] Item 42. The method according to Item 32, wherein the CNM-g-polyolefin particles have an angle of repose of about 25° to about 45°.

[0219] Item 43. The method according to Item 32, wherein the CNM-g-polyolefin particles have a Hausner ratio of about 1.0 to about 1.5.

[0220] Unless otherwise indicated, all numbers expressing amounts of ingredients, properties such as molecular weights, and process conditions used in this specification and the related claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter should be construed in light of the reported number of significant digits and by applying ordinary rounding techniques.

[0221] 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 system-related, business-related, government-related, and other compliance constraints, which vary depending on the 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.

[0222] 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.

[0223] 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]

[0224] Theoretical Example 1a. Preparation of amino-functionalized carbon nanotubes for polyamide synthesis is described. Scheme 1 shows an example of a non-restrictive synthetic route for amino-functionalized CNTs by acidification. CNTs, such as multi-walled carbon nanotubes (MWCNTs), can first be oxidized with a mixture of concentrated sulfuric acid and nitric acid in a volume ratio of 3:1. Acidification can be carried out by sonication of the CNTs in an acid solution in an ultrasonic bath at 50°C for 3 hours. The resulting CNM / 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 CNT product (CNT-COOH) can then be dried in a vacuum oven at 80°C for 6 hours. Approximately 1 g of CNM-COOH can be dispersed in 2 L of THF for at least 1 hour under sonication. 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 may be heated to 60°C and maintained at this temperature for 24 hours with stirring. The product may be a readily recoverable black solid and may be washed three times with THF (1 L to 1.5 L per wash). The product can be dried in a vacuum oven to obtain amino-functionalized CNTs. Further functionalization (e.g., amino groups) may improve the reactivity of the CNTs with polyamide monomers. The CNT-COOH direct pathway can be used directly to prepare polyamide / CNTs. However, a decrease in reaction may be observed because the mobility is reduced due to the COOH directly binding to the surface of the CNT and not extending like the amino groups. [ka]

[0225] Theoretical Example 1b describes the preparation of polyamide / amino-functionalized carbon nanotube (PA / CNT) nanocomposites by in-situ polycondensation. Scheme 2 shows a non-limiting example of the synthesis of polyamides using amino-functionalized carbon nanotube (FCNT), resulting in insoluble short-chain PA / FCNT and soluble long-chain PA / FCNT. A 2 wt% PA / CNT nanocomposite can be prepared by dispersing 0.497 g of amino-FCNT (e.g., from Example 1a) in N-methyl-2-pyrrolidone (NMP) (60 mL) during sonication for 30 minutes. The final mixture may be a homogeneous solution of amino-FCNT. The resulting mixture can be transferred to a 1 L three-necked flask equipped with a magnetic stirrer or overhead stirrer. To the flask, 10 g of adipic acid (68 mmol), 17 g of 4,4-diaminodiphenylsulfone (68 mmol), 3 g of calcium chloride (18 mmol), 42.4 mL of triphenyl phosphite (137 mmol), and pyridine (7 mL) may be added. The reaction can be carried out at 60°C for 1 hour, at 90°C for 2 hours, and at 120°C for 8 hours, respectively, which may yield a viscous mixture. The viscous mixture can be precipitated in 500 mL of methanol to obtain PA / CNT. The precipitate can be recovered by filtration and thoroughly washed with warm methanol at a temperature in the range of approximately 45°C to approximately 50°C. [ka]

[0226] If necessary, short-chain and long-chain polymer-grafted CNTs can be isolated based on differences in solvent solubility (Scheme 2). The grafted PA / CNTs can be dispersed in 250 mL of N,N-dimethylacetamide (DMAc) and stirred at 65°C for 1 hour. Materials with shorter polymer CNT chains can be filtered through filter paper to recover the solid product, which can be dried in a vacuum oven at 95°C for about 12 hours. To promote the precipitation of the long-chain polymer CNT product, a DMAc solution, which may be dark in color, can be added to 500 mL of water. The long-chain polymer CNT product can be recovered by filtration, thoroughly washed several times with methanol, and dried in a vacuum oven at 95°C for 12 hours.

[0227] Theoretical Example 2. Preparation of polyhexamethylene adipamide-MWCNT graft composites (polyamide 6,6-MWCNT graft composites) by reactive extrusion is described for the production of SLS powder by melt emulsification. Scheme 3 shows a non-limiting example of a reactive extrusion approach that can be used as a synthetic route for preparing polyamide 6,6-grafted MWCNTs, in which COCl-grafted MWCNTs can react with the amine-terminated groups of PA6,6. As described above, untreated MWCNTs can be functionalized with H2SO4 / HNO3, and 1 gram of MWCNTs can be mixed with H2SO4 (98 vol%) and HNO3 (70 vol%) in a 3 / 2 volume ratio of H2SO4:HNO3 (total 2000 mL). The mixture can be heated to 60°C under reflux for 24 hours. The mixture can then be diluted with about 1 L of deionized water (DIW) and filtered through a 450 nm nylon membrane. MWCNTs can be further washed with DIW (5 × 200 mL) and then dried in a vacuum oven at ambient temperature for 24 hours. The resulting COOH-functionalized MWCNTs (MWCNT-COOH) can be dispersed in thionyl chloride (SOCl2) (500 mL) in an ultrasonic device for 2 hours and then stirred at 70°C for another 24 hours. The mixture can then be vacuum filtered through a 450 nm nylon membrane and washed with tetrahydrofuran (3 × 200 mL) and ethanol (3 × 200 mL). The resulting MWCNT-COCl can be dried in a vacuum oven at ambient temperature for 12 hours. [ka]

[0228] Using reactive extrusion, polyamide 6,6-MWCNTs (50 g of PA6,6 with 2 wt% MWCNT-COCl) can be prepared using a twin-screw extruder having four different zones that can be used for feeding (265°C), melting (280°C), mixing (280°C), and discharge (260°C). The material feeding rate and extrusion rate can be kept constant at 10 g / min and 300 rpm, respectively. Once extruded, the molten mixed composite can be quenched in a water bath. Unreacted PA6,6 can be removed from PA6,6-MWCNTs by dissolving the composite in formic acid (about 3 L per 50 g of composite) and centrifugation at 4°C for about 4000xg to about 10,000xg for about 10 minutes or more (or about 20 minutes or more, or about 30 minutes or more). The recovered PA6,6-MWCNTs can be redispersed in formic acid (3L) and recovered again by centrifugation to further remove unreacted PA6,6. This procedure can be repeated five or more times, and the resulting product can be washed with formic acid (3L x 3) and dried in a vacuum oven at 30°C for 12 hours. The obtained PA6,6-MWCNTs can be confirmed by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). The tensile modulus and yield strength of the composite are expected to be higher than those of PA6,6 alone or the melt-mixed version of PA6,6 and untreated MWCNTs, and are therefore due to strong interfacial adhesion and reinforcement by hydrogen bonding and chain entanglement between the PA6,6 matrix and the PA6,6 grafted onto the MWCNTs. The resulting composite can be converted into its corresponding spherical particles for use in a selective laser sintering (SLS) 3D printer.

[0229] Theoretical Example 3 describes the preparation of PA-CNT nanoparticles by melt emulsification. The nanoparticles can be produced from the polyamide-CNT nanocomposites prepared in Theoretical Examples 1b and 2 by melt extrusion in 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 low speed (in the range of 50 rpm to 100 rpm, then up to 250 rpm). PA-CNT polymer pellets from any of the above examples may be added to the heated extruder, followed by the addition of a dispersion medium. The dispersion medium may be PDMS oil having a viscosity of 10,000 cSt to 60,000 cSt at room temperature. The ratio of PDMS oil to polymer may be 70:30, i.e., 30% polymer solid in 70% oil. Any dispersant or flow aid may be added before the dispersion medium to assist the flow of dry particles. The extruder may be operated at 200 rpm (maximum speed) for 30 minutes. The mixture can be discharged onto a metal tray with dry ice and subjected to rapid cooling. After the dry ice sublimes, the oil can be washed away from the fine particles by three heptane washes, 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 residual heptane. The dried particles can be sieved through a 150 μm or 250 μm sieve. The resulting powder may have a final average particle size (D50) of about 50 micrometers and a span of about 1.000.

[0230] Theoretical Example 1 describes the preparation of polydodecaamide (nylon 12, polyamide 12, or PA12) and PA6,6 fine particles by melt emulsification. Unfilled PA12 or PA6,6 powder can be prepared from the corresponding pellets by melt extrusion using the same procedure as described in Theoretical Example 3.

[0231] Theoretical Example 2 describes the preparation of PA12 melt-mixed fine particles and PA6,6 melt-mixed fine particles using CNTs (e.g., MWCNTs) by melt emulsification. PA12 or PA6,6 can be physically melt-mixed with CNTs to produce fine particles by the same melt extrusion process described in Theoretical Example 3. CNTs can be added after the polyamide resin pellets have been sufficiently melted by supplying them to the chamber at a slower rate and bringing the temperature closer to the melting point of the polymer.

[0232] SLS printing and mechanical testing.

[0233] The baseline performance of dry powder can be determined by sintering the material using a SNOWWHITE SLS printer (available from Sharebot). The SNOWWHITE SLS printer is a commercial 3D printer that uses a CO2 laser to sinter thermoplastic powder layer by layer. The laser selectively fuses the material by scanning the cross-section of the desired object, created using a computer-aided design (CAD) model. After scanning the first layer, the powder layer is lowered, and a new powder material is rolled on top. Subsequent layers are scanned until that section is complete. The main advantages of this powder-based system compared to other additive manufacturing techniques are the elimination of printing supports and the ability to reuse materials.

[0234] The mechanical properties of Theoretical Example 1b, Theoretical Example 2, Comparative Example 1, and Comparative Example 2 can be determined by printing ASTM Tensile D638-14 Type V Dogbone bars on a SNOWWHITE SLS printer.

[0235] 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 are 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 selectively depositing carbon nanomaterial-grafted-polyamide (CNM-g-polyamide) particles onto a surface in combination with other thermoplastic polymer particles, wherein the CNM-g-polyamide particles contain polyamide grafted onto carbon nanomaterial (CNM). A method comprising: depositing the CNM-g-polyamide particles and then exposing at least a portion of them to a laser by selective laser sintering to melt the polymer particles and form a solidified body. [2] The method according to [1], wherein the CNM-g-polyamide comprises 50% to 99.95% by weight of the polyamide and about 0.05% to about 50% by weight of the carbon nanomaterial, based on the total weight of the CNM-g-polyamide. [3] The method according to [1], wherein the polyamide is selected from the group consisting of polycaproamide, poly(hexamethylenesuccinamide), polyhexamethyleneadipamide, polypentamethyleneadipamide, polyhexamethylenesebamide, polyundekaamide, polydodekaamide, polyhexamethyleneterephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamide, aromatic polyamide, any copolymers thereof, and any combination thereof. [4] The method according to [1], wherein the CNM is selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof. [5] The method according to [1], wherein the molar ratio of polyamide to CMN is approximately 500:1 to approximately 1:500. [6] The method according to [5], wherein the molar ratio of polyamide to CMN is approximately 20:1 to approximately 10:1. [7] The method according to [1], wherein the polyamide is grafted onto the surface of the CNM by polycondensation, interfacial polymerization, or ring-opening polymerization (ROP) to produce CNM-g-polyamide. [8] ROP is insitu anionic ring-opening polymerization (AROP), as described in [7]. [9] The method according to [8], wherein the insitu AROP is carried out in the presence of an initiator and optionally an activator. The method according to [9], wherein the weight ratio of the polyamide to the initiator is from about 90:10 to about 99:1. The method according to [1], wherein the CNM-g-polyamide particles have a roundness of from about 0.90 to about 1.0. The method according to [1], wherein the CNM-g-polyamide particles have an emulsifying stabilizer embedded in the outer surface of the CNM-g-polyamide particles. The method according to

[12] , wherein the emulsifying stabilizer contains nanoparticles. The method according to

[12] , wherein the emulsifying stabilizer contains nanoparticles, and the nanoparticles are embedded at the void / polymer interface. The method according to [1], wherein the CNM-g-polyamide containing polymer particles further contains a thermoplastic polymer not grafted to the CNM. The method according to [1], wherein the CNM-g-polyamide particles have a D10 of from about 0.1 μm to about 125 μm, a D50 of from about 0.5 μm to about 200 μm, and a D90 of from about 3 μm to about 300 μm, and D10 < D50 < D90. The method according to [1], wherein the CNM-g-polyamide particles have a particle size span of from about 0.2 to about 10. The method according to [1], wherein the CNM-g-polyamide particles have an angle of repose of from about 25° to about 45°. The method according to [1], wherein the CNM-g-polyamide particles have a Hausner ratio of from about 1.0 to about 1.5. A method comprising: (a) a carbon nanomaterial-grafted-polyamide (CNM-g-polyamide), wherein the CNM-g-polyamide particles comprise polyamide grafted to a carbon nanomaterial, a CNM-g-polyamide; (b) a dispersion medium immiscible with the polyamide of the CNM-g-polyamide; optionally (c) a thermoplastic polymer not grafted to the CNM; and optionally (d) an emulsifying stabilizer, mixing a mixture containing the above at a temperature higher than the melting point or softening temperature of the polyamide of the CNM-g-polyamide and the thermoplastic polymer (if any), and at a shear rate high enough to disperse the CNM-g-polyamide in the dispersion medium; cooling the mixture to below the melting point or the softening temperature to form CNM-g-polyamide particles; isolating the CNM-g-polyamide particles from the dispersion medium.

Claims

1. A method of selective laser sintering, A process for providing carbon nanomaterial-grafted-polyamide (CNM-g-polyamide) particles in combination with other thermoplastic polymer particles in an optional manner, The CNM-g-polyamide particles include a polyamide directly grafted onto the amine functional group of an amino-functionalized carbon nanomaterial (CNM), or a polyamide directly grafted onto the carboxylic acid functional group of a carboxylic acid-functionalized carbon nanomaterial (CNM), and the process of providing this, The process of depositing the CNM-g-polyamide particles on the surface, A method comprising the step of depositing the CNM-g-polyamide particles and then exposing at least a portion of them to a laser by selective laser sintering to melt the particles and form a solidified body.

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

3. The method according to claim 1, wherein the polyamide is selected from the group consisting of polycaproamide, poly(hexamethylenesuccinamide), polyhexamethyleneadipamide, polypentamethyleneadipamide, polyhexamethylenesebamide, polyundekaamide, polydodekaamide, polyhexamethyleneterephthalamide, nylon 10,10, nylon 10,12, nylon 10,14, nylon 10,18, nylon 6,18, nylon 6,12, nylon 6,14, nylon 12,12, semi-aromatic polyamide, aromatic polyamide, any copolymer thereof, and any combination thereof.

4. The method according to claim 1, wherein the amino-functionalized carbon nanomaterial is selected from the group consisting of amino-functionalized carbon nanotubes, amino-functionalized graphite, amino-functionalized graphene, amino-functionalized fullerene, and any combination thereof, and the carboxylic acid-functionalized carbon nanomaterial is selected from the group consisting of carboxylic acid-functionalized carbon nanotubes, carboxylic acid-functionalized graphite, carboxylic acid-functionalized graphene, carboxylic acid-functionalized fullerene, and any combination thereof.

5. The method according to claim 1, wherein the molar ratio of polyamide to carbon nanomaterial is 500:1 to 1:

500.

6. The method according to claim 5, wherein the molar ratio of polyamide to carbon nanomaterial is 20:1 to 10:

1.

7. The method according to claim 1, wherein the polyamide is formed by a polycondensation reaction in the presence of the amino-functionalized carbon nanomaterial or the carboxylic acid-functionalized carbon nanomaterial, the amine functional group or the carboxylic acid functional group is used as a handle involved in the polycondensation reaction, and the resulting polyamide is grafted onto the carbon nanomaterial at the amine functional group or the carboxylic acid functional group.

8. The method according to claim 7, wherein the polycondensation reaction is carried out in the presence of an activator and / or a metal salt.

9. The method according to claim 7, wherein the polycondensation reaction is carried out at a temperature of 50°C to 200°C for 5 minutes to 24 hours.

10. The method according to claim 7, wherein the polycondensation reaction is carried out in a solvent.

11. The method according to claim 1, wherein the CNM-g-polyamide particles have a roundness of 0.90 to 1.

0.

12. The method according to claim 1, wherein the CNM-g-polyamide particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyamide particles.

13. The method according to claim 12, wherein the emulsifying stabilizer comprises nanoparticles.

14. The method according to claim 12, wherein the emulsifying stabilizer comprises nanoparticles, and the nanoparticles are embedded in the void / polymer interface.

15. The method according to claim 1, wherein the CNM-g-polyamide further comprises a thermoplastic polymer that is not grafted onto a carbon nanomaterial.

16. The method according to claim 1, wherein the CNM-g-polyamide particles have D10 of 0.1 μm to 125 μm, D50 of 0.5 μm to 200 μm, and D90 of 3 μm to 300 μm, and D10 < D50 < D90.

17. The method according to claim 1, wherein the CNM-g-polyamide particles have a particle size span of 0.2 to 10.

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

19. The method according to claim 1, wherein the CNM-g-polyamide particles have a Hausner ratio of 1.0 to 1.5.

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