Spherical particles containing carbon nanomaterial-grafted polyolefin, method for producing the same, and method for using the same

Abstract

To provide a method of forming highly spherical carbon nanomaterial-graft-polyolefin (CNM-g-polyolefin) particles.SOLUTION: The method may comprise: mixing a mixture comprising (a) a carbon nanomaterial-graft-polyolefin (CNM-g-polyolefin), (b) a carrier fluid that is immiscible with the polyolefin of the CNM-g-polyolefin, 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 polyolefin of the CNM-g-polyolefin and the thermoplastic polymer, if included, and at a shear rate sufficiently high to disperse the CNM-g-polyolefin in the carrier fluid; cooling the mixture to below the melting point or softening temperature to form the CNM-g-polyolefin particles; and isolating the CNM-g-polyolefin particles from the carrier fluid.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to highly spherical particles comprising carbon nanomaterial-grafted polyolefins (CNM-g-polyolefins). This disclosure further relates, as herein, to compositions, synthesis methods, and applications of such particles (also referred herein as CNM-g-polyolefin particles). [Background technology]

[0002] Thermoplastic polymers are often used to produce extruded objects such as films, bags, particles, and filaments. Many thermoplastic polymers have the ability to withstand temperature increases and / or decreases without losing their physical properties. Therefore, objects formed from thermoplastic polymers can be used in demanding applications such as power tools, automotive parts, gears, and electrical appliance components.

[0003] Polyolefins, such as polyethylene and polypropylene, are among the largest classes of commercially available polymers due to their versatile properties, easily modifiable microstructures, and relatively low cost. One way to modify the physical properties of polyolefins and / or impart new properties to them is by incorporating fillers. For example, carbon nanomaterials such as carbon nanotubes and graphene have been used to improve the mechanical, thermal, and electrical properties of polyolefins. These polyolefin-carbon nanomaterial composites are used in conventional methods such as extrusion to produce a variety of objects. Expanding the methods by which polyolefin-carbon nanomaterial composites can be manufactured into objects would further expand the polymer composite industry. [Overview of the Initiative]

[0004] This disclosure relates to highly spherical particles comprising CNM-g-polyolefin. This disclosure further relates to compositions, synthesis methods, and uses of such particles.

[0005] Disclosed herein is a method of selective laser sintering, comprising depositing carbon nanomaterial-grafted-polyolefin (CNM-g-polyolefin) particles, optionally in combination with other thermoplastic polymer particles, onto a surface, wherein the CNM-g-polyolefin particles comprise polyolefin grafted to a carbon nanomaterial, volumizing; and upon deposition, exposing at least a portion of the CNM-g-polyolefin particles to a laser to fuse the polymer particles and form a consolidated body by selective laser sintering.

[0006] Disclosed herein is a method comprising: (a) mixing a mixture comprising CNM-g-polyolefin comprising polyolefin grafted to a carbon nanomaterial, (b) a dispersion medium immiscible with the polyolefin of the CNM-g-polyolefin, 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 polyolefin of the CNM-g-polyolefin and the thermoplastic polymer, which, when included, is an emulsifying stabilizer at a shear rate high enough to disperse the CNM-g-polyolefin in the dispersion medium; cooling the mixture to below the melting point or softening temperature to form CNM-g-polyolefin particles; and separating the CNM-g-polyolefin particles from the dispersion medium.

Brief Description of the Drawings

[0007] The following figures are included to illustrate certain aspects of the embodiments and should not be regarded as exclusive embodiments. The disclosed subject matter is capable of considerable modification, variation, combination, and equivalents in form and function as would be apparent to one of ordinary skill in the art having the benefit of this disclosure.

[0008] [Figure 1] FIG. 1 shows a flowchart of a non-limiting exemplary method of the present disclosure.

Modes for Carrying Out the Invention

[0009] 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.

[0010] 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 carried out in a 3D printing system that uses a laser to facilitate selective laser sintering (SLS).

[0011] Powder particles usable in 3D printing include thermoplastic polymers, including thermoplastic elastomers, metals, and other solidifiable materials. When using composites in 3D printing, the particles (e.g., carbon nanomaterials in polyolefin-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 non-uniform. Consequently, the properties of the object (e.g., strength and / or conductivity) may also be irregular, which can introduce points of failure into the object.

[0012] This disclosure relates to highly spherical particles comprising carbon nanomaterial-grafted polyolefin (CNM-g-polyolefin). CNM-g-polyolefin particles may be useful, in particular, as a starting material for additive manufacturing, especially SLS3-D printing. Carbon nanomaterials can improve physical properties and / or impart new physical properties to objects produced by additive manufacturing. Furthermore, by using CNM-g-polyolefins, carbon nanomaterials can be well dispersed and / or distributed within polymer particles. Thus, carbon nanomaterials can be well dispersed and / or distributed in objects (or parts thereof) produced by additive manufacturing. Definitions and Test Methods

[0013] As used herein, the term “catalyst” refers to a compound that, when used in a reaction medium at very low concentrations, allows for an increase in the rate of a reaction (e.g., polymerization) through interaction with a reagent, without undergoing any chemical change at the end of the reaction.

[0014] As used herein, the term “cocatalyst” refers to a compound that can act synergistically with a catalyst to increase the rate of a reaction (e.g., polymerization).

[0015] 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.

[0016] 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.

[0017] 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 optional chain-extending groups, and the soft portion may include, for example, a polyol.

[0018] As used herein, the term "polyurethane" refers to the polymer reaction product between a diisocyanate, a polyol, and an optional chain extender.

[0019] 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.

[0020] As used herein, "carbon nanomaterial-grafted-polyolefin" and "CNM-g-polyolefin" refer to carbon nanomaterials as a central or skeletal structure having polyolefins extending from it. These terms describe the structure itself, rather than the method of fabricating it.

[0021] 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 which has at least one dimension of 50 nm or less. Examples of carbon nanomaterials include, but are not limited to, fullerenes, carbon nanotubes, graphite, graphene, and any combination thereof.

[0022] As used herein, the term "fullerene" refers to a particle or molecule having a cage as its core structure, the cage structure having an aspect ratio of 10 or less. As used herein, the term "carbon nanotube" refers to a particle or molecule having an elongated cylindrical structure as its core structure, the elongated cylindrical structure having an aspect ratio greater than 10. As used herein, the term "carbon nanotube" includes 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). As used herein, the term "graphene" refers to a particle or molecule having a planar graphite structure, including single-walled to triple-walled graphene. As used herein, the term "graphite" refers to a particle or molecule having four or more layers of planar graphite.

[0023] The terms "carbon nanomaterials," "fullerenes," "carbon nanotubes," "graphite," and "graphene" encompass their functionalized versions.

[0024] 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 into 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.

[0025] Hereinafter, D10, D50, D90, and diameter span are used primarily to describe particle size. As used herein, the term "D10" refers to the diameter at which 10% of a particle population (unless otherwise specified, in a volume-based distribution) is less than its diameter. As used herein, the terms "D50," "average particle diameter," and "average particle size" refer to the diameter at which 50% of a particle population (unless otherwise specified, in a volume-based median mean) is less than its diameter. As used herein, the term "D90" refers to the diameter at which 90% of a particle population (unless otherwise specified, in a volume-based distribution) is less than its diameter. As used herein, the terms "diameter span," "span," and "span size" when referring to diameter provide an indicator of the spread of the particle size distribution and are calculated as (D90-D10) / D50.

[0026] Particle diameter 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.

[0027] When used herein, if sieving is mentioned, the pore / screen size is as described by the USA Standard Sieve (ASTM E11-17).

[0028] As used herein, the term “circularity” in relation to a particle refers to how close the particle is to a perfect sphere. To determine the circularity, optical microscope images are taken of the particle using flow particle imaging. The perimeter (P) and area (A) of the particle in the plane of the microscope image are calculated (for example, using a SYSMEX FPIA 3000 particle shape and particle size analyzer available from Malvern Instruments). The circularity of the particle is C EA / P is and in the formula, C EA This is the circumference of a circle having an area equivalent to the actual particle area (A). In this specification, roundness is based on three runs on a SYSMEX FPIA 3000 particle shape and particle size analyzer, analyzing 6,000 to 10,000 particles per run. The reported roundness is the median mean roundness based on the number of particles. In the analysis, a threshold for distinguishing the grayscale level between background pixels and particle pixels (e.g., to compensate for non-uniform lighting conditions) was set to 90% of the background modal value.

[0029] As used herein, the term “shear force” refers to agitation or similar processes that induce mechanical agitation in a fluid.

[0030] As used herein, the term "aspect ratio" refers to the length divided by the width, where the length is greater than the width.

[0031] Unless otherwise specified, the melting point of the polymer shall be determined according to ASTM E794-06 (2018) with a heating rate and a cooling rate of 10°C / min.

[0032] 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.

[0033] The angle of repose is a measure of the fluidity of a powder. The angle of repose was determined using Hosokawa Micron's Powder Characteristics Tester PT-R, which follows ASTM D6393-14 "Standard Test Method for Bulk Solids Characterized by Carr Indices".

[0034] The air permeability density (ρaer) is measured according to ASTM D6393-14.

[0035] Bulk density (ρbulk) is measured according to ASTM D6393-14.

[0036] Tap density (ρtap) is measured according to ASTM D6393-14.

[0037] The Hausner ratio (Hr) is a measure of the fluidity of a powder and is calculated using the formula Hr = ρtap / ρbulk, where ρbulk is the bulk density according to ASTM D6393-14 and ρtap is the tap density according to ASTM D6393-14.

[0038] When used herein, the viscosity of the dispersion medium is the kinematic viscosity at 25°C, measured according to ASTM D445-19, unless otherwise specified. For commercially sourced dispersion mediums (e.g., polydimethylsiloxane oil), the kinematic viscosity data referenced herein were provided by the manufacturer, whether or not they were measured according to the aforementioned ASTM or other standard measurement techniques. CNM-g-polyolefin complex

[0039] A CNM-g-polyolefin complex comprises one or more polyolefins grafted onto one or more CNMs. A CNM-g-polyolefin complex may comprise a mixture of CNMs, each having the same or different polyolefins grafted onto it. A CNM-g-polyolefin complex may comprise a single CNM having one or more polyolefins grafted onto it. A CNM-g-polyolefin complex may comprise a first CNM having a first polyolefin grafted onto it, and a second CNM (same as or different from the first CNM) having a second polyolefin grafted onto it (same as or different from the first polyolefin), wherein (a) the first and second CNMs are different, and / or (b) the first and second polyolefins are different.

[0040] Examples of CNMs that may have grafted polyolefins 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 highly oxidized derivatives thereof), and any combination thereof.

[0041] Examples of polyolefins that can be grafted onto CNM include one or more C2-C2 polyolefins. 40 Examples include, but are not limited to, polymers and copolymers derived from olefin monomers.

[0042] CNM-g-polyolefin may contain about 50% to about 99.95% by weight of polyolefin (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%) and about 0.05% to about 50% by weight of CNM (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%) based on the total weight of CNM-g-polyolefin.

[0043] Polyolefins can be grafted onto the surface of carbon nanomaterials by any preferred method, including, for example, in-situ polymerization, in-situ free radical functionalization, and amidation reactions.

[0044] As a non-limiting example, polyolefins can be grafted onto the surface of carbon nanomaterials by in-situ polymerization. In-situ polymerization can be a polymerization packing technique (PFT). In-situ polymerization can be carried out by pretreatment of the carbon nanomaterial, which includes contacting / bonding a catalyst and optionally a co-catalyst to the surface of the carbon nanomaterial, and the catalyst is a heterogeneous catalyst, a homogeneous metallocene catalyst, or a homogeneous non-metallocene catalyst.

[0045] In-situ polymerization can be carried out using a Ziegler-Natta catalyst. Alternatively, in-situ polymerization can be carried out using a metallocene catalyst in the presence of a co-catalyst that may contain an aluminoxane. The aluminoxane may be present in a molar ratio of aluminum to catalyst compound transition metal of 100:1 or greater (or about 100:1 to about 500:1, or about 200:1 to 300:1).

[0046] The polymerization process of this disclosure may comprise a monomer (such as propylene) and optionally a comonomer, which may be contacted with a catalytic system comprising an activator and at least one catalyst, as described above. The catalyst and activator may be combined in any order, typically before contact with the monomer.

[0047] Monomers useful herein are substituted or unsubstituted C2-C 40 alpha-olefins, preferably C2-C 20 alpha-olefins, preferably C2-C 12 alpha-olefins, preferably ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, and their isomers. The monomers may include propylene, and one or more ethylene or C4-C 40 olefins, preferably C4-C 20 olefins, or preferably C6-C 12 olefins as optional comonomers. C4-C 40 olefin monomers can be linear, branched, or cyclic. C4-C 40 Cyclic olefins can be strained or unstrained, monocyclic or polycyclic, and optionally contain heteroatoms and / or one or more functional groups.

[0048] [[ID=:21]]Further, the monomers may include ethylene and one or more C3-C 40 olefins, preferably C4-C 20 olefins, or preferably C6-C 12 olefins as optional comonomers. C3-C 40 olefin monomers can be linear, branched, or cyclic. C3-C 40 Cyclic olefins can be strained or unstrained, monocyclic or polycyclic, and optionally contain heteroatoms and / or one or more functional groups.

[0049] Exemplary C2-C 40Examples of olefin monomers and optionally selected comonomers include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, norbornene, norbornadiene, dicyclopentadiene, cyclopentene, cycloheptene, cyclooctene, cyclooctadiene, cyclododecene, 7-oxanorbornene, 7-oxanorbornadiene, their substituted derivatives, and their isomers, preferably hexene, heptene, octene, nonene, decene, dodecene, cyclooctene, 1,5-cyclooctadiene, 1-hydroxy-4-cyclooctene, 1-acetoxy-4-cyclooctene, 5-methylcyclopentene, cyclopentene, dicyclopentadiene, norbornene, norbornadiene, and their respective homologs and derivatives, preferably norbornene, norbornadiene, and dicyclopentadiene.

[0050] For example, the methods of the present disclosure may include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-cyclopentene, cyclohexene, norbornene, ethylidene-norbornene, vinylidene-norbornene, and combinations thereof.

[0051] In some cases, aluminoxanes are used little to no in the process for producing the polymer. Preferably, aluminoxanes are present in zero mol%, and alternatively, aluminoxanes are present in an aluminum-to-transition metal molar ratio of less than 500:1, for example less than 300:1, for example less than 100:1, for example less than 1:1.

[0052] Furthermore, in the process for producing ethylene polymers, little to no scavenging agents are used. Preferably, the scavenging agent (such as trialkylaluminum) is present in zero mol%, and alternatively, the scavenging agent is present in a scavenging metal to transition metal molar ratio of less than 100:1, preferably less than 50:1, preferably less than 15:1, and preferably less than 10:1.

[0053] The methods disclosed herein can produce olefin polymers, preferably polyethylene and polypropylene homopolymers and copolymers. The polymers produced herein may be homopolymers of ethylene or propylene, and may contain 0 to 25 mol% (alternatively 0.5 to 20 mol%, alternatively 1 to 15 mol%, preferably 3 to 10 mol%) of one or more C3-C3 polymers. 20 Olefin comonomer (preferably C3-C3) 12 It may be an ethylene copolymer having an alpha-olefin, preferably propylene, butene, hexene, octene, decene, dodecene, preferably propylene, butene, hexene, octene), or preferably 0 to 25 mol% (alternatively 0.5 to 20 mol%, alternatively 1 to 15 mol%, preferably 3 to 10 mol%) of C2 or C4-C 20 Olefin comonomers (preferably ethylene or C4-C4) 12 It may be a copolymer of propylene having one or more alpha-olefins, preferably ethylene, butene, hexene, octene, decene, dodecene (preferably ethylene, butene, hexene, octene).

[0054] In-situ polymerization may be performed using metallocene / methylaluminoxane (MAO) catalyzed polymerization packing technology (PFT), in which carbon nanomaterials are pre-treated with MAO co-catalysts, and subsequently, monomers (e.g., ethylene or propylene) are homopolymerized in the presence of the pre-treated carbon nanomaterials using MAO as a co-catalyst and Cp2ZrCl2 as a catalyst.

[0055] In another non-limiting example of in-situ polymerization, the Ziegler-Natta catalyst can be used as follows: A graphene oxide-supported Ziegler-Natta catalyst can be formed via a Grignard reagent (e.g., n-BuMgCl) and further treated with a Lewis acid (e.g., TiCl4). CNM-g-polyolefins can be produced via in-situ monomer (e.g., propylene) polymerization on a graphene oxide-supported Ziegler-Natta catalyst.

[0056] In-situ polymerization can occur at pressures ranging from approximately 0.35 MPa to approximately 10 MPa, in a maximum time of 300 minutes, and at temperatures ranging from approximately 0°C to approximately 300°C.

[0057] In another non-limiting example, polyolefins can be grafted onto carbon nanomaterials (e.g., carbon nanotubes (CNTs), single-walled carbon nanotubes (SWCNTs)) by in-situ free radical functionalization. In-situ free radical functionalization can be carried out by melt compounding in the presence of a peroxide initiator (e.g., benzoyl peroxide initiator). For example, a wet polypropylene pellet / powder containing SWCNTs can be suspended in chloroform to create an initial dispersion between the polymer and the SWCNTs. A peroxide (e.g., benzoyl peroxide) can then be added to functionalize the SWCNTs. The solvent can be removed under reduced pressure by solvent evaporation before initiating the in-situ reaction with high-temperature, high-shear mixing in Haake (e.g., temperatures in the range of about 100°C to about 200°C), which allows for covalent bonding of the SWCNTs to the polymer.

[0058] In yet another non-limiting example, polyolefins can be grafted onto carbon nanomaterials (e.g., graphene oxide sheets (GOS)) by amidation reactions. The amidation reaction between graphene oxide and polyolefins may include graphene oxide sheets covalently grafted onto polyolefins (e.g., polypropylene (PP)) by generating amine-modified oxides such as NH2-terminated GOS via a nucleophilic substitution reaction of 4,4'-methylenedianiline with GOS. PP-g-GOS is obtained by grafting maleated PP onto NH2-t-GOS. For example, graphene oxide containing polyolefins (e.g., polypropylene graphene oxide sheets PP-g-GOS) can be used as a compatibilizer in polyolefin-based blends via a) solvent blends or b) melt compounding. Graphene oxide (GO) can be prepared from natural graphite by a chemical conversion process from the carboxyl group of GO to acyl-bonded GO chloride via the introduction of thionyl chloride, a method also known as the modified Hammers process. CNM-g-polyolefin particles and method for producing the same.

[0059] The CNM-g-polyolefins of this disclosure may be used to produce spherical microparticles, pellets, or filaments. Spherical microparticles (or powders) containing the CNM-g-polyolefins 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-polyolefins of this disclosure may be used in three-dimensional (3D) printing technologies by fusion filament manufacturing (FFF).

[0060] The methods and compositions described herein relate to highly spherical particles comprising CNM-g-polyolefin. While not limited to theory, having polyolefin grafted onto CNM is thought to facilitate a more homogeneous distribution of CNM within the polymer particles, thereby resulting in a more homogeneous distribution in objects (or portions thereof) produced by additive manufacturing methods using such polymer particles.

[0061] For example, the present disclosure includes a method comprising: mixing a mixture comprising (a) a CNM-g-polyolefin, (b) a dispersion medium immiscible with the polyolefin of the CNM-g-polyolefin, optionally (c) a thermoplastic polymer not grafted onto CNM (which may be the same as or different from the polyolefin of the CNM-g-polyolefin), and optionally (d) an emulsifying stabilizer at a temperature higher than the melting or softening temperature of the polyolefin and at a shear rate high enough to disperse the CNM-g-polyolefin in the dispersion medium; cooling the mixture to below the melting or softening temperature of the polyolefin to form spherical polymer particles; and separating the spherical polymer particles from the dispersion medium.

[0062] The figure is a flowchart of a non-limiting exemplary method 100 of the present disclosure. Combining CNM-g-polyolefin 102, a dispersion medium 104, optionally an emulsifying stabilizer 106, and optionally a thermoplastic polymer not grafted onto CNM 108 (e.g., the polyolefin of CNM-g-polyolefin 102, a polyolefin not of NM-g-polyolefin 102, another thermoplastic polymer, or any combination thereof) to produce a mixture 112. Components 102, 104, 106, and 108 can be added individually or in a blend of components in any order, and the process of combining components 102, 104, 106, and 108 includes mixing and / or heating during the process 110. For example, CNM-g-polyolefin 102 and the thermoplastic polymer not grafted onto CNM 108, if present, may be pre-mixed before combining 110. In this specification, CNM-g-polyolefin refers to polyolefins that are not grafted onto CNM.

[0063] Next, the mixture 112 is treated by providing the mixture 112 with a sufficiently high shear at a temperature higher than the higher of the melting point or softening temperature of (a) CNM-g-polyolefin 102 or (b) the thermoplastic polymer not grafted onto CNM 108, thereby forming a molten emulsion 116. This is because the temperature is higher than the melting point or softening temperature of the mixture 112 (i.e., the polyurethane of CNM-g-polyolefin 102, and, if included, the thermoplastic polymer not grafted onto CNM 108), the polymer molten form containing CNM-g-polyolefin 102, and, if included, the polymer portion of the thermoplastic polymer not grafted onto CNM 108. The shear rate should be sufficient to disperse the polymer molten form (e.g., containing CNM-g-polyolefin) 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.

[0064] Next, the molten emulsion 116 inside and / or outside the mixing vessel is cooled 118 to solidify the polymer droplets into CNM-g-polyolefin particles 124. The term "CNM-g-polyolefin particles" refers to polymer particles containing CNM-g-polyolefin 102, which may include other components in the polymer particles (e.g., thermoplastic polymers not grafted onto CNM 108).

[0065] Next, the cooled mixture 120 is processed 122 to isolate the CNM-g-polyolefin particles 124 from the other components 126 (e.g., dispersion medium 104, excess emulsifying stabilizer 106, etc.), and the CNM-g-polyolefin particles 124 can be washed or otherwise purified. The CNM-g-polyolefin particles 124 comprise CNM-g-polyolefin 102, and, if present, a thermoplastic polymer not grafted onto CNM 108, and, if present, at least a portion of the emulsifying stabilizer 106 coating the outer surface of the CNM-g-polyolefin particles 124. The emulsifying stabilizer 106 or a portion thereof can be deposited on the CNM-g-polyolefin 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-polyolefin 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-polyolefin particles 124. Even without embedding, at least a portion of the nanoparticles in the emulsifying stabilizer 106 may remain firmly associated with the CNM-g-polyolefin 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 yield a firm and uniform coating of the flow aid on the polymer microparticles.

[0066] CNM-g-polyolefin particles 124 can be optionally further purified to obtain 128 (described in more detail below), which may yield purified CNM-g-polyolefin particles 130.

[0067] The dispersion medium should be selected such that the CNM-g-polyolefin and the dispersion medium are immiscible at various processing temperatures (e.g., from room temperature to the process temperature). An additional factor to consider is the difference in viscosity (e.g., difference or ratio) between the CNM-g-polyolefin and the dispersion medium at the process temperature. Viscosity differences can affect droplet breakdown and particle size distribution. While not theoretically bound, if the viscosities of the CNM-g-polyolefin and the dispersion medium are too similar, the overall circularity of the product may be reduced, and particles may become more oval and elongated.

[0068] CNM-g-polyolefin 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 combined CNM-g-polyolefin 102, the thermoplastic polymer not grafted onto CNM 108, and the dispersion medium 104. If CNM108 contains an ungrafted thermoplastic polymer, the combined CNM-g-polyolefin 102 and the ungrafted thermoplastic polymer in CNM108 may be present in the mixture 112 in amounts of about 5% to about 60% by weight (or about 5% to about 25% by weight, or about 10% to about 30% by weight, or about 20% to about 45% by weight, or about 25% to about 50% by weight, or about 40% to about 60% by weight) of the combined CNM-g-polyolefin 102, the ungrafted thermoplastic polymer in CNM108, and the dispersion medium 104. If present, the weight ratio of CNM-g-polyolefin 102 to thermoplastic polymer not grafted onto CNM108 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).

[0069] Examples of thermoplastic polymers not grafted onto CNM108 include polyamides, polyurethanes, polyethylene, polypropylene, polyacetals, polycarbonates, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytrimethylene terephthalate (PTT), ethylene vinyl acetate copolymer (EVA), ethylene propylene diene rubber (EPDM), ethylene propylene elastomer (EPR), poly(4-methyl-1-pentene), polyhexamethylene terephthalate, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polyesters (e.g., polylactic acid), polyethers, polyethersulfones, polyetheretherketones, polyacrylates, polymethacrylates, polyimides, and acrylonitrile butadiene styrene.Styrene, ABS), polyphenylene sulfide, vinyl polymer, polyarylene ether, polyarylene sulfide, polysulfone, polyether ketone, polyamide-imide, polyether-imide, polyether ester, copolymers containing polyether blocks and polyamide blocks (PEBA or polyether block amide), thermoplastic polyolefin, functionalized or unfunctionalized ethylene / vinyl monomer polymer, functionalized or unfunctionalized ethylene / alkyl (meth)acrylate, functionalized or unfunctionalized (meth)acrylic acid polymer, functionalized or unfunctionalized ethylene / Examples of such copolymers include, but are not limited to, 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, chlorinated or chlorosulfonated polyethylene, polyvinylidene fluoride (PVDF), phenolic resins, poly(ethylene / vinyl acetate), polybutadiene, polyisoprene, styrene-based block copolymers, polyacrylonitrile, silicones, and any combination thereof. Copolymers containing one or more of the above may also be used in the methods and systems of this disclosure. In some cases, copolymers of PE with polar monomers such as poly(ethylene-co-vinyl acetate), poly(ethylene-co-methyl acrylate), poly(ethylene-co-glycidyl methacrylate), and poly(ethylene-co-vinyl alcohol) can improve compatibility in polyethylene-poly(methyl methacrylate) (PE / PMMA) blends.

[0070] The thermoplastic polymers not grafted onto CNM108 in the compositions and methods of this disclosure may be elastomers or non-elastomers. 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 elastomers or non-elastomers depending on the amount of propylene in the polymer.

[0071] 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.

[0072] Polyolefin polymers not grafted onto CNM include polyacrylate, polybenzimidazole, polycarbonate, polyethersulfone, polyaryletherketone, polyetheretherketone, polyetherimide, polyethylene, poly(ethylene-co-vinyl acetate), polyphenylene oxide, polypropylene, polystyrene (e.g., poly(styreneisoprenestyrene), acrylonitrile butadiene styrene (ABS), poly(styreneethylenebutylene styrene) (SEBS), styrene-n-butyl acrylate), styrene-butyl acrylate, polyester, polyurethane, polyamide, poly(vinylidene fluoride) (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene), polyethylene terephthalate, polylactic acid (PLA), polycaprolactone, and poly(propoxylated bisphenol A The following materials may be selected: co-fumarates, polyvinyl chloride, ethylene vinyl acetate copolymer (EVA), ethylene propylene diene rubber (EPDM), ethylene-propylene elastomer (EPR), poly(4-methyl-1-pentene), and combinations thereof.

[0073] 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. Polyamides where the first number is followed by a second number are polyamides with a first number of main-chain carbons between nitrogen=O in the non-pendant portion, and the second number of main-chain carbons are between two nitrogens in the pendant=O portion. As a non-limiting example, nylon 6,10 is [NH-(CH2)6-NH-CO-(CH2)8-CO] n Polyamides followed by a number (multiple) and a backslash (multiple) are copolymers of polyamides, indicated by the numbers before and after the backslash.

[0074] 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.

[0075] Compatibilizers may be optionally used to improve the blending efficiency and effectiveness of CNM-g-polyolefins with one or more thermoplastic polymers, such as nonpolar 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.

[0076] The ungrafted thermoplastic polymer of CNM-g-polyolefin 102 and / or CNM108 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).

[0077] The polyolefin and / or thermoplastic polymer not grafted onto CNM-g-polyolefin 102 and / or CNM108 may have a glass transition temperature (using heating and cooling rates of 10°C / min as defined in ASTM E1356-08 (2014)) of about -50°C to about 400°C (or about -50°C to about 0°C, or about -25°C to about 50°C, or about 0°C to about 150°C, or about 100°C to about 250°C, or about 150°C to about 300°C, or about 200°C to about 400°C).

[0078] Thermoplastic polymers not grafted onto CNM108 may optionally contain additives. Typically, the additives are present before the thermoplastic polymer is added to the mixture. Thus, in the polymer molten droplets and the resulting CNM-g-polyolefin 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.” Internal additives may be blended with the thermoplastic polymer immediately before the mixture or wells are prepared.

[0079] When describing the amounts of components in the compositions described herein (e.g., mixtures and CNM-g-polyolefin particles), the amounts are weight percent based on the thermoplastic polymer without internal additives. For example, a composition containing 1% by weight of emulsifying stabilizer 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, 90 g of thermoplastic polymer, and 10 g of internal additives.

[0080] The internal additive may be present within the thermoplastic polymer 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) of the thermoplastic polymer not grafted onto CNM108. 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.

[0081] 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 expanded graphite (EG), expanded graphite nanoplatelets (xGnP), carbon black, carbon nanofibers (CNF), carbon nanotubes (CNT), graphene, graphene oxide, graphite oxide, graphene oxide nanosheets, and fullerenes.

[0082] A suitable dispersion medium may have a viscosity at 25°C of approximately 1,000 cSt to approximately 150,000 cSt (or approximately 1,000 cSt to approximately 60,000 cSt, or approximately 40,000 cSt to approximately 100,000 cSt, or approximately 75,000 cSt to approximately 150,000 cSt). For example, a suitable dispersion medium may have a viscosity of approximately 10,000 cSt to approximately 60,000 cSt at 25°C.

[0083] Examples of dispersion media include, but are not limited to, silicone oils, fluorinated silicone oils, perfluorinated silicone oils, polyethylene glycols, alkyl-terminated polyethylene glycols (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 include, but are not limited to, 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 contains two or more of the above, the dispersion medium may have one or more phases. For example, polysiloxanes modified with fatty acids and polysiloxanes modified with aliphatic alcohols (preferably having similar chain lengths to fatty acids and aliphatic alcohols) may form a single-phase dispersion medium. In another example, a dispersion medium containing a silicone oil and alkyl-terminated polyethylene glycol may form a two-phase dispersion medium. In at least one embodiment, the dispersion medium is polydimethylsiloxane (PDMS).

[0084] The dispersion medium 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 combination of CNM-g-polyolefin 102, thermoplastic polymer not grafted onto CNM 108, and dispersion medium 104.

[0085] In some cases, the dispersion medium has a density of approximately 0.6 g / cm³. 3 ~Approx. 1.5g / cm 3 Thermoplastic polymers can have a density of approximately 0.7 g / cm³. 3 ~Approx. 1.7g / cm 3 The thermoplastic polymer may have a density that is similar to, lower than, or higher than the density of the dispersion medium.

[0086] Carbon nanomaterials should be sufficiently stable so as not to decompose at the processing temperature. Examples of carbon nanomaterials may include carbon nanotubes, graphite, graphene, fullerenes, carbon black, and any combination thereof.

[0087] The emulsifying stabilizers used in the methods and compositions of this disclosure may include nanoparticles (e.g., oxide nanoparticles, carbon black, polymer nanoparticles, and combinations thereof), surfactants, and any combination thereof.

[0088] 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 hydrophobic surface treatments such as dimethylsilyl and trimethylsilyl may be used in the methods and compositions of this disclosure. In addition, silica with functional surface treatments 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.

[0089] 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 BET surface area of ​​1 / g, and any combination thereof.

[0090] 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.

[0091] Polymer nanoparticles are another type of nanoparticle that may be present as emulsifying stabilizers in this disclosure. 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 this disclosure. High molecular weight thermoplastic polymers having high melting or decomposition points may similarly constitute suitable polymer nanoparticle emulsifying stabilizers.

[0092] Surfactants can be anionic, cationic, nonionic, or zwitterionic. Examples of surfactants include, but are not limited to, sodium dodecyl sulfate, sorbitan oleate, poly[dimethylsiloxane-co-[[3-(2-(2-hydroxyethoxy)ethoxy)propylmethylsiloxane], sodium docusate (sodium 1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate), and any combination thereof. Examples of commercially available surfactants include, but are not limited to, CALFAX® DB-45 (sodium dodecyldiphenyl oxide disulfonate, available from Pilot Chemicals), SPAN® 80 (sorbitan maleate nonionic surfactant), MERPOL® surfactant (available from Stepan Company), TERGITOL® TMN-6 (water-soluble nonionic surfactant, available from DOW), TRITON® X-100 (octylphenol ethoxylate, available from Sigma-Aldrich), IGEPAL® CA-520 (polyoxyethylene(5) isooctylphenyl ether, available from Sigma-Aldrich), BRIJ® S10 (polyethylene glycol octadecyl ether, available from Sigma-Aldrich), and any combination thereof.

[0093] 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-polyolefin 102. Alternatively, the mixture may be surfactant-free (or surfactant-absent).

[0094] The weight ratio of nanoparticles to surfactant in 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).

[0095] 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 combination of CNM-g-polyolefin 102 and the thermoplastic polymer not grafted onto CNM 108.

[0096] With respect to combination 110 in the figure, in some examples, the emulsifying stabilizer may first be dispersed in the dispersion medium while optionally heating the dispersion before adding the thermoplastic polymer that is not grafted onto CNM-g-polyolefin 102 and / or CNM108. In another non-limiting example, the thermoplastic polymer that is not grafted onto CNM-g-polyolefin 102 and / or CNM108 may be heated to produce a polymer melt into which the dispersion medium and emulsifying stabilizer are added together or in either order. In yet another non-limiting example, the thermoplastic polymer that is not grafted onto CNM-g-polyolefin 102 and / or CNM108 may be mixed with the dispersion medium 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. The emulsifying stabilizer can then be added to form a mixture and maintain it under suitable process conditions over a set period of time.

[0097] Combinations of CNM-g-polyolefin 102, thermoplastic polymers not grafted onto CNM108, a dispersion medium, and optionally an emulsifying stabilizer in any combination may occur in a mixing apparatus and / or another suitable container used for processing. As a non-limiting example, the thermoplastic polymers not grafted onto CNM-g-polyolefin 102 and / or CNM108 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 may be dispersed in a dispersion medium in a separate container. This dispersion may then be added to the molten material in the mixing apparatus used for processing.

[0098] The mixing apparatus used in the process to produce the molten emulsion should be able to maintain the molten emulsion at a temperature above the required melting or softening temperature as described herein, and apply a shear rate sufficient to disperse the polymer melt as droplets in the dispersion medium.

[0099] Examples of mixing equipment used in the process of producing molten emulsions 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.

[0100] Processing under suitable process conditions (e.g., temperature, shear rate, etc.) over a set period of time, and formation of a molten emulsion.

[0101] The temperature at which the molten emulsion is processed and formed should be higher than the required melting or softening temperature described herein and lower than the decomposition temperature of any component in the mixture (i.e., CNM-g-polyolefin 102, thermoplastic polymer not grafted onto CNM108, dispersion medium, emulsifying stabilizer). For example, the temperature at which the molten emulsion is processed and formed may be about 1°C to about 50°C (or about 1°C to about 25°C, or about 5°C to about 30°C, or about 20°C to about 50°C) higher than the melting or softening temperature described herein, provided that the temperature at which the molten emulsion is processed and formed is below the decomposition temperature of any component in the mixture (i.e., CNM-g-polyolefin 102, thermoplastic polymer not grafted onto CNM108, dispersion medium, emulsifying stabilizer).

[0102] The shear rate for processing and forming the molten emulsion should be high enough to disperse the polymer molten material as droplets in the dispersion medium. These droplets should include droplets with a diameter of approximately 1000 μm or less (or approximately 1 μm to approximately 1000 μm, or approximately 1 μm to approximately 50 μm, or approximately 10 μm to approximately 100 μm, or approximately 10 μm to approximately 250 μm, or approximately 50 μm to approximately 500 μm, or approximately 250 μm to approximately 750 μm, or approximately 500 μm to approximately 1000 μm).

[0103] The time for maintaining the temperature and shear rate during the processing and formation of the molten emulsion 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). While not theoretically bound, it is believed that a steady state of droplet diameter is reached at the point when the processing can be stopped. This time may depend, in particular, on the temperature, shear rate, thermoplastic polymer not grafted onto CNM-g-polyolefin 102 or CNM108, the dispersion medium composition, and the emulsifying stabilizer composition.

[0104] The molten emulsion can then be cooled. Cooling can be slow (e.g., allowing the molten emulsion to be cooled under ambient conditions) or fast (e.g., rapid cooling). For example, the cooling rate can range from about 10°C / hour to about 100°C / second, or even nearly instantaneous by rapid cooling (e.g., with 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).

[0105] During cooling, shear force may be applied little to no to the molten emulsion. In some cases, the shear force applied during heating may be applied during cooling.

[0106] The cooled mixture obtained from the cooling of the molten emulsion may contain solidified CNM-g-polyolefin particles and other components (e.g., dispersion medium, excess emulsifying stabilizer, etc.). The solidified CNM-g-polyolefin particles may be dispersed in the dispersion medium or precipitate in the dispersion medium.

[0107] The cooled mixture can then be processed to separate the CNM-g-polyolefin particles from the other components. Suitable processing methods include, but are not limited to, washing, filtration, centrifugation, and decanting, as well as any combination thereof.

[0108] The solvent used to wash CNM-g-polyolefin particles should generally be (a) miscible with the dispersion medium and (b) nonreactive (e.g., non-swelling and non-soluble) with thermoplastic polymers not grafted onto CNM-g-polyolefin 102 and / or CNM108. The choice of solvent depends, in particular, on the composition of the dispersion medium, CNM-g-polyolefin 102, and thermoplastic polymers not grafted onto CNM108.

[0109] 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.

[0110] The solvent can be removed from the CNM-g-polyolefin particles by drying using appropriate methods such as air drying, heat drying, vacuum drying, freeze-drying, or a mixture thereof. Heating may preferably be carried out at a temperature lower than the glass transition temperature of the polyolefin of CNM-g-polyolefin 102 and the thermoplastic polymer not grafted onto CNM 108, if present (e.g., about 50°C to about 150°C).

[0111] Advantageously, the dispersions and cleaning solvents of the systems and methods described herein can be regenerated and reused. Those skilled in the art will recognize any necessary cleaning of the used dispersions and solvents required in the regeneration process.

[0112] CNM-g-polyolefin particles can be optionally further purified after separation from other components. For example, to narrow the particle size distribution (or reduce the diameter span), the CNM-g-polyolefin particles can be passed through a sieve with a pore size of approximately 10 μm to 250 μm (or approximately 10 μm to 100 μm, or approximately 50 μm to 200 μm, or approximately 150 μm to 250 μm).

[0113] In another example of a purification technique, CNM-g-polyolefin particles may be washed with water to remove surfactants while retaining substantially all of the nanoparticles associated on the surface of the CNM-g-polyolefin particles. In yet another exemplary purification technique, CNM-g-polyolefin particles may be blended with additives to obtain the desired final product. For clarity, such additives are blended with the CNM-g-polyolefin particles described herein after the particles have solidified, and such additives are referred to herein as “external additives.” Examples of external additives include flow aids, other polymer particles, fillers, and any combination thereof.

[0114] In some cases, the surfactants used in the preparation of CNM-g-polyolefin particles may be undesirable for downstream applications. Therefore, yet another exemplary purification technique may include removing the surfactant from the CNM-g-polyolefin particles at least substantially (e.g., by washing and / or thermal decomposition).

[0115] CNM-g-polyolefin particles and / or purified CNM-g-polyolefin particles may be characterized by their composition, physical structure, etc.

[0116] As described above, the emulsifying stabilizer is located at the interface between the polymer melt and the dispersion medium. As a result, when the mixture cools, the emulsifying stabilizer remains at or near this interface. Therefore, the structure of CNM-g-polyolefin particles generally includes, when the emulsifying stabilizer is used, (a) the emulsifying stabilizer dispersed on the outer surface of the CNM-g-polyolefin particles and / or (b) the emulsifying stabilizer embedded in the outer portion of the CNM-g-polyolefin particles (e.g., outer 1 vol%).

[0117] Furthermore, if voids are formed inside the polymer molten droplets, the emulsifying stabilizer should generally be located at (and / or embedded in) the interface between the void and the CNM-g-polyolefin and / or thermoplastic polymer. The voids generally do not contain CNM-g-polyolefin and / or thermoplastic polymer. Rather, the voids may contain, for example, a dispersion medium, air, or be empty. The CNM-g-polyolefin particles may contain a dispersion medium 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-polyolefin particles.

[0118] If the CNM does not contain an ungrafted thermoplastic polymer, the CNM-g-polyolefin and the ungrafted thermoplastic polymer may be combined and present in the CNM-g-polyolefin particles at a concentration of about 90% to about 99.5% by weight (or about 90% to about 95% by weight, or about 92% to about 97% by weight, or about 95% to about 99.5% by weight) of the CNM-g-polyolefin particles. If the CNM contains an ungrafted thermoplastic polymer, the CNM-g-polyolefin and the ungrafted thermoplastic polymer may be combined and present in the CNM-g-polyolefin particles at a concentration of about 90% to about 99.5% by weight (or about 90% to about 95% by weight, or about 92% to about 97% by weight, or about 95% to about 99.5% by weight) of the CNM-g-polyolefin particles. The weight ratio of CNM-g-polyolefin to thermoplastic polymer 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) if present.

[0119] If present, the emulsifying stabilizer may be present in the CNM-g-polyolefin particles at a concentration 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, the emulsifying stabilizer may be present in the CNM-g-polyolefin particles 124 / 130 at a concentration of less than 0.01% by weight (or 0% to about 0.01% by weight, or 0% to 0.001% by weight).

[0120] When forming thermoplastic microparticles according to the disclosure herein using particulate emulsifying stabilizers, at least a portion of the particulate emulsifying stabilizer, such as silica nanoparticles, may be arranged as a coating on the outer surface of the CNM-g-polyolefin 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-polyolefin particles. After purification to remove at least substantially any surfactant or other emulsifying stabilizer, the emulsifying stabilizer may be present in CNM-g-polyolefin particles 124 / 130 in an area of ​​less than 25% of the surface area of ​​the CNM-g-polyolefin 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-polyolefin particles can be determined using image analysis of scanning electron microscope (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-polyolefin particles (and, if manufactured, coated CNM-g-polyolefin particles).After purification to remove at least substantially any surfactant or other emulsifying stabilizer, the emulsifying stabilizer may be present in CNM-g-polyolefin particles 124 / 130 at a rate of less than 25% of the surface area of ​​the CNM-g-polyolefin 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-polyolefin particles can be determined using image analysis of SEM micrographs.

[0121] The CNM-g-polyolefin 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 nanomaterials (or, if two or more are used, cumulative carbon nanomaterials).

[0122] CNM-g-polyolefin particles 124 / 130 may comprise one or more carbon nanomaterials. For example, two or more different carbon nanomaterials may be grafted onto a polyolefin in the same reaction and then used as the CNM-g-polyolefin in the methods and compositions described herein. In another example, two different CNM-g-polyolefins may be generated and blended before (or during) the mixing process of the melt emulsification process described herein.

[0123] CNM-g-polyolefin particles 124 / 130 may have a roundness of approximately 0.90 to approximately 1.0.

[0124] CNM-g-polyolefin particles 124 / 130 have a BET surface area of ​​approximately 10 m². 2 / g~about 500m 2 / g (or approximately 10m 2 / g~about 150m 2 / g, or approximately 25m 2 / g~about 100m2 / g, or about 100 m 2 / g to about 250 m 2 / g, or about 250 m 2 / g to about 500 m 2 / g).

[0125] The CNM-g-polyolefin particles can 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 1 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-polyolefin particles can also have a diameter span of about 0.2 to about 10 (or about 0.2 to about 0.5, or about 0.4 to about 0.8, or about 0.5 to about 1, or about 1 to about 3, or about 2 to about 5, or about 5 to about 10). Without limitation, a diameter span value of 1.0 or more is considered broad, and a diameter span value of 0.75 or less is considered narrow. Preferably, the CNM-g-polyolefin particles have a diameter span of about 0.2 to about 1.

[0126] In a first non-limiting example, the CNM-g-polyolefin particles can 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-polyolefin particles can have a diameter span of about 0.2 to about 2.

[0127] In a second non-limiting example, the CNM-g-polyolefin particles 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-polyolefin particles can have a diameter span of about 1.0 to about 2.5.

[0128] In a third non-limiting example, the CNM-g-polyolefin particles 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-polyolefin particles can have a diameter span of about 0.6 to about 1.5.

[0129] In a fourth non-limiting example, the CNM-g-polyolefin particles 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-polyolefin particles can have a diameter span of about 0.2 to about 1.2.

[0130] In a fifth non-limiting example, the CNM-g-polyolefin particles 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-polyolefin particles can also have a diameter 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).

[0131] The CNM-g-polyolefin particles can have a circularity of about 0.9 or greater (or about 0.90 to about 1.0, or about 0.93 to about 0.99, or about 0.95 to about 0.99, or about 0.97 to about 0.99, or about 0.98 to 1.0).

[0132] CNM-g-polyolefin particles 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°).

[0133] CNM-g-polyolefin particles 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).

[0134] CNM-g-polyolefin particles 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 ).

[0135] CNM-g-polyolefin particles 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.

[0136] CNM-g-polyolefin particles 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 .

[0137] Depending on the processing temperature and shear rate, as well as the composition and relative concentration of the components (e.g., CNM-g-polyolefin, thermoplastic polymer, dispersion medium, excess emulsifying stabilizer, etc.), different structural shapes constituting CNM-g-polyolefin particles can be generated. Typically, CNM-g-polyolefin particles include substantially spherical particles (with a roundness of about 0.97 or greater). However, other structures, including disc-shaped and elongated structures, can be observed in CNM-g-polyolefin particles. Therefore, CNM-g-polyolefin particles 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). CNM-g-polyolefin particles may have a sintering window of 10°C, preferably 5°C, within the sintering window of CNM- polyolefins. Applications of polymer particles

[0138] The disclosure also relates to a method of selective laser sintering which may include depositing highly spherical polymer particles comprising (a) (a1) CNM-g-polyolefin and optionally (a2) a thermoplastic polymer that is not a polyolefin of CNM-g-polyolefin and is not grafted onto CNM, and optionally (b) other thermoplastic polymer particles that do not contain CNM-g-polyolefin, onto a surface, and after deposition, exposing at least a portion of the spherical polymer particles to a laser to fuse the polymer particles and form a solidified body.

[0139] The CNM-g-polyolefin particles 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-polyolefin particles described herein onto a surface (e.g., in layers and / or in a particular shape), and, after deposit, 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-polyolefin 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.

[0140] Examples of articles that can be manufactured by using CNM-g-polyolefin particles 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, prosthetics, orthopedic implants, manufacturing artifacts to aid learning in education, 3D anatomical models to assist surgery, robotics supplies, biomedical devices (orthotics), household appliances, dental supplies, electronic equipment, and sporting goods. Furthermore, the particles may be useful in applications such as, but are not limited to, paints, powder coatings, inkjet materials, electrophotographic toners, and 3D printing. Exemplary Embodiments

[0141] A first non-limiting exemplary embodiment is a selective laser sintering method comprising: depositing carbon nanomaterial-grafted-polyolefin (CNM-g-polyolefin) particles on a surface in optionally combination with other thermoplastic polymer particles, wherein the CNM-g-polyolefin particles contain polyolefins grafted onto the carbon nanomaterial; and, once deposited, exposing at least a portion of the CNM-g-polyolefin particles to a laser to fuse the polymer particles and form a solid by selective laser sintering. The first non-limiting exemplary embodiment may include one or more of the following: Element 1: The CNM-g-polyolefin comprises 50% to 99.95% by weight of polyolefin and about 0.05% to about 50% by weight of carbon nanomaterial, based on the total weight of the CNM-g-polyolefin. Element 2: Element 1 and the polyolefin are homopolymers or copolymers that form a coating around the carbon nanomaterial by contacting one or more olefins on the surface of the carbon nanomaterial. Element 3: A polyolefin is grafted onto the surface of the carbon nanomaterial by in-situ polymerization. Element 4: Element 3 and the in-situ polymerization are carried out by pretreatment of the carbon nanomaterial, which includes contacting a catalyst and optionally a co-catalyst onto the surface of the carbon nanomaterial, wherein the catalyst is a heterogeneous catalyst, a homogeneous metallocene catalyst, or a homogeneous non-metallocene catalyst. Element 5: Element 4 and the in-situ polymerization are performed using a polymerization packing technique (PFT). Element 6: Element 4 and the catalyst is a metallocene catalyst. Element 7: Element 4 and the co-catalyst contains an aluminoxane. Element 8: Element 7 and the aluminoxane are present in an aluminum to catalyst compound transition metal molar ratio of 100:1 or higher. Element 9: Element 3 and the in-situ polymerization occur at a temperature of approximately 0°C to approximately 300°C, at a pressure in the range of approximately 0.35 MPa to approximately 10 MPa, and for a maximum time of 300 minutes. Element 10: Polyolefins are grafted onto carbon nanomaterials by in-situ free radical functionalization, including melt compounding in the presence of a peroxide initiator. Element 11: Polyolefins are grafted onto carbon nanomaterials by an amidation reaction.Element 12: Element 11 and an amidation reaction occur between graphene oxide and polyolefin. Element 13: The CNM-g-polyolefin particles have a circularity of about 0.90 to about 1.0. Element 14: The CNM-g-polyolefin particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyolefin particles. Element 15: Element 14 and the emulsifying stabilizer contain nanoparticles. Element 16: At least some of Element 15 and the CNM-g-polyolefin particles have voids containing the emulsifying stabilizer at the void / polymer interface. Element 17: Element 15 and the emulsifying stabilizer contain nanoparticles, and the nanoparticles are embedded at the void / polymer interface. Element 18: The CNM-g-polyolefin particles further contain a thermoplastic polymer that is not grafted to the CNM. Element 19: The thermoplastic polymer is selected from the group consisting of polyacrylate, polybenzimidazole, polycarbonate, polyethersulfone, polyaryl ether ketone, polyether ether ketone, polyether imide, polyethylene, poly(ethylene-co-vinyl acetate), polyphenylene oxide, polypropylene, polystyrene, styrene-butyl acrylate, polyester, polyurethane, polyamide, poly(vinylidene fluoride) (PVDF), polyethylene terephthalate, polylactic acid (PLA), polycaprolactone, poly(propoxylated bisphenol A co-fumarate), polyvinyl chloride, ethylene vinyl acetate copolymer (EVA), ethylene propylene diene rubber (EPDM), ethylene propylene elastomer (EPR), poly(4-methyl-1-pentene), and combinations thereof. Element 20: 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. Element 21: The CNM-g-polyolefin particles have a diameter span of about 0.2 to about 10. Element 22: The CNM-g-polyolefin particles have an angle of repose of about 25° to about 45°, and Element 23: The CNM-g-polyolefin particles have a Hausner ratio of about 1.0 to about 1.5.

[0142] Examples of combinations include, but are not limited to, combinations of element 1 (arbitrarily combined with element 2) with one or more elements from 3 to 23. Combinations of element 3 with one or more elements from 4 to 23. Combinations of element 4 with one or more elements from 5 to 23. Combinations of element 5 with one or more elements from 6 to 23. Combinations of element 6 with one or more elements from 7 to 23. Combinations of element 7 with one or more elements from 8 to 23. Combinations of element 8 with one or more elements from 9 to 23. Combinations of element 9 with one or more elements from 10 to 23. Combinations of element 10 with one or more elements from 11 to 23. Combinations of element 11 with one or more elements from 12 to 23. Combinations of element 12 with one or more elements from 13 to 23. Combinations of element 13 with one or more elements from 14 to 23. A combination of element 14 with one or more elements from 15 to 23. A combination of element 15 with one or more elements from 16 to 23. A combination of element 16 with one or more elements from 17 to 23. A combination of element 18 with one or more elements from 19 to 23. A combination of two or more elements from 20 to 23, and a combination of two or more elements from element 1 (arbitrarily combined with element 2), element 3, element 4, and element 5 (arbitrarily combined with element 6).

[0143] A second non-limiting exemplary embodiment is a composition comprising CNM-g-polyolefin particles, which include polyolefins grafted onto carbon nanomaterials. The CNM-g-polyolefin particles may contain about 0.05% to about 50% by weight of CNM, where CNM can be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof. The second non-limiting exemplary embodiment may include one or more of the following: element 1; element 2; element 3; element 5; element 6; element 9; element 10; element 10; element 11; element 12; element 13; element 14; element 15; element 16; element 17; element 18; element 19; element 20; element 21; element 22; and element 23, including any combination according to the first non-limiting exemplary embodiment.

[0144] A third non-limiting exemplary embodiment is a method comprising: mixing a mixture comprising (a) a carbon nanomaterial-grafted polyolefin (CNM-g-polyolefin), wherein the CNM-g-polyolefin particles include a polyolefin grafted onto a carbon nanomaterial; (b) a dispersion medium immiscible with the polyolefin of the CNM-g-polyolefin; optionally (c) a thermoplastic polymer not grafted onto the CNM; and optionally (d) an emulsifying stabilizer having a temperature higher than the melting or softening temperature of the polyolefin and thermoplastic polymer of the CNM-g-polyolefin, and if included, an emulsifying stabilizer having a shear rate high enough to disperse the CNM-g-polyolefin in the dispersion medium; cooling the mixture to below its melting or softening temperature to form CNM-g-polyolefin particles; and separating the CNM-g-polyolefin particles from the dispersion medium. A third non-limiting exemplary embodiment may include one or more of the following: element 1; element 2; element 3; element 5; element 6; element 9; element 10; element 10; element 11; element 12; element 13; element 14; element 15; element 16; element 17; element 18; element 19; element 20; element 21; element 22; and element 23, including any combination according to the first non-limiting exemplary embodiment. Clause

[0145] Clause 1. A method of selective laser sintering, comprising: depositing carbon nanomaterial-grafted-polyolefin (CNM-g-polyolefin) particles on a surface in combination with other thermoplastic polymer particles, wherein the CNM-g-polyolefin particles contain polyolefin grafted onto carbon nanomaterials; and, once deposited, exposing at least a portion of the CNM-g-polyolefin particles to a laser to fuse the polymer particles and form a solidified body by selective laser sintering.

[0146] Clause 2. The method according to Clause 1, wherein the CNM-g-polyolefin comprises 50% to 99.95% by weight of polyolefin and about 0.05% to about 50% by weight of carbon nanomaterials, based on the total weight of the CNM-g-polyolefin.

[0147] Clause 3. The method according to Clause 1, wherein the polyolefin is a homopolymer or copolymer that forms a coating around the carbon nanomaterial by contacting one or more olefins onto the surface of the carbon nanomaterial.

[0148] Clause 4. The method according to Clause 1, wherein a polyolefin is grafted onto the surface of a carbon nanomaterial by in-situ polymerization.

[0149] Clause 5. The method according to Clause 4, wherein in-situ polymerization is carried out by pretreatment of carbon nanomaterials, the pretreatment comprising contacting a catalyst and optionally a co-catalyst onto the surface of the carbon nanomaterials, wherein the catalyst is a heterogeneous catalyst, a homogeneous metallocene catalyst, or a homogeneous non-metallocene catalyst.

[0150] Clause 6. The method according to Clause 5, wherein the in-situ polymerization is a polymerization-filling technique (PFT).

[0151] Clause 7. The method according to Clause 5, wherein the catalyst is a metallocene catalyst.

[0152] Clause 8. The method according to Clause 5, wherein the co-catalyst comprises an aluminoxane.

[0153] Clause 9. The method according to Clause 8, wherein the aluminoxane is present in an aluminum-to-catalyst compound transition metal molar ratio of 100:1 or higher.

[0154] Clause 10. The method according to Clause 4, wherein in-situ polymerization occurs at a temperature of approximately 0°C to approximately 300°C, at a pressure in the range of approximately 0.35 MPa to approximately 10 MPa, and in a time of up to 300 minutes.

[0155] Clause 11. The method according to Clause 1, wherein a polyolefin is grafted onto a carbon nanomaterial by in-situ free radical functionalization, including melt compounding in the presence of a peroxide initiator.

[0156] Clause 12. The method according to Clause 1, wherein a polyolefin is grafted onto a carbon nanomaterial by an amidation reaction.

[0157] Clause 13. The method according to Clause 12, wherein the amidation reaction occurs between graphene oxide and a polyolefin.

[0158] Clause 14. The method according to Clause 1, wherein the CNM-g-polyolefin particles have a roundness of about 0.90 to about 1.0.

[0159] Clause 15. The method according to Clause 1, wherein the CNM-g-polyolefin particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyolefin particles.

[0160] Clause 16. The method according to Clause 15, wherein the emulsifying stabilizer comprises nanoparticles.

[0161] Clause 17. The method according to Clause 16, wherein at least some of the CNM-g-polyolefin particles have voids containing an emulsifying stabilizer at the void / polymer interface.

[0162] Article 18. The method according to Article 17, wherein the emulsifying stabilizer contains nanoparticles and the nanoparticles are embedded in the void / polymer interface.

[0163] Article 19. The method according to Article 1, wherein the CNM-g-polyolefin particles further contain a thermoplastic polymer that is not grafted to the CNM.

[0164] Article 20. The method according to Article 19, wherein the thermoplastic polymer is selected from the group consisting of polyacrylate, polybenzimidazole, polycarbonate, polyethersulfone, polyaryl ether ketone, polyether ether ketone, polyether imide, polyethylene, poly(ethylene-co-vinyl acetate), polyphenylene oxide, polypropylene, polystyrene, styrene-butyl acrylate, polyester, polyurethane, polyamide, poly(vinylidene fluoride) (PVDF), polyethylene terephthalate, polylactic acid (PLA), polycaprolactone, poly(propoxylated bisphenol A co-fumarate), polyvinyl chloride, ethylene vinyl acetate copolymer (EVA), ethylene propylene diene rubber (EPDM), ethylene propylene elastomer (EPR), poly(4-methyl-1-pentene), and combinations thereof.

[0165] Article 21. The method according to Article 1, wherein the CNM-g-polyolefin particles further contain a thermoplastic polymer that is not grafted to the CNM.

[0166] Article 22. The method according to Article 1, 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.

[0167] Article 23. The method according to Article 1, wherein the CNM-g-polyolefin particles have a diameter span of about 0.2 to about 10.

[0168] The method according to clause 1, wherein the CNM-g-polyolefin particles have an angle of repose of about 25° to about 45°.

[0169] The method according to clause 1, wherein the CNM-g-polyolefin particles have a Hausner ratio of about 1.0 to about 1.5.

[0170] A composition comprising CNM-g-polyolefin particles comprising a polyolefin grafted to a carbon nanomaterial. The CNM-g-polyolefin particles may comprise about 0.05 wt% to about 50 wt% of CNM based on the CNM-g-polyolefin particles, and the CNM may be selected from the group consisting of carbon nanotubes, graphite, graphene, fullerenes, and any combination thereof.

[0171] The composition according to clause 26, wherein the CNM-g-polyolefin particles further comprise a thermoplastic polymer not grafted to the CNM.

[0172] The composition according to clause 26, 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.

[0173] The composition according to clause 26, wherein the CNM-g-polyolefin particles have a diameter span of about 0.2 to about 10.

[0174] The composition according to clause 26, wherein the CNM-g-polyolefin particles have an angle of repose of about 25° to about 45°.

[0175] The composition according to clause 26, wherein the CNM-g-polyolefin particles have a Hausner ratio of about 1.0 to about 1.5.

[0176] The composition according to clause 26, wherein the CNM-g-polyolefin particles have a roundness of about 0.90 to about 1.0.

[0177] Clause 33. The composition according to Clause 26, wherein the CNM-g-polyolefin particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyolefin particles.

[0178] Clause 34. The composition according to Clause 33, wherein the emulsifying stabilizer comprises nanoparticles.

[0179] Clause 35. A method comprising: mixing a mixture comprising (a) a carbon nanomaterial-grafted polyolefin (CNM-g-polyolefin) in which CNM-g-polyolefin particles include a polyolefin grafted onto a carbon nanomaterial; (b) a dispersion medium immiscible with the polyolefin of the CNM-g-polyolefin; optionally (c) a thermoplastic polymer not grafted onto the CNM; and optionally (d) an emulsifying stabilizer having a temperature higher than the melting or softening temperature of the polyolefin and thermoplastic polymer of the CNM-g-polyolefin, and if included, an emulsifying stabilizer having a shear rate sufficiently high to disperse the CNM-g-polyolefin in the dispersion medium; cooling the mixture to below its melting or softening temperature to form CNM-g-polyolefin particles; and separating the CNM-g-polyolefin particles from the dispersion medium.

[0180] Clause 36. The method according to Clause 35, wherein the CNM-g-polyolefin comprises 50% to 99.95% by weight of polyolefin and about 0.05% to about 50% by weight of carbon nanomaterials, based on the total weight of the CNM-g-polyolefin.

[0181] Clause 37. The method according to Clause 35, wherein the dispersion medium is present in a weight ratio of the dispersion medium to a combination of CNM-g-polyolefin and a thermoplastic polymer in the range of 50:50 to 90:10.

[0182] Clause 38. The method according to Clause 35, wherein the dispersion medium comprises polydimethylsiloxane (PDMS).

[0183] Clause 39. The method according to Clause 35, wherein the thermoplastic polymer is selected from the group consisting of polyacrylate, polybenzimidazole, polycarbonate, polyethersulfone, polyaryletherketone, polyetheretherketone, polyetherimide, polyethylene, poly(ethylene-co-vinyl acetate), polyphenylene oxide, polypropylene, polystyrene, styrene-butyl acrylate, polyester, polyurethane, polyamide, poly(vinylidene fluoride) (PVDF), polyethylene terephthalate, polylactic acid (PLA), polycaprolactone, poly(propoxylated bisphenol A cofumarate), polyvinyl chloride, ethylene vinyl acetate copolymer (EVA), ethylene propylene diene rubber (EPDM), ethylene propylene elastomer (EPR), poly(4-methyl-1-pentene), and combinations thereof.

[0184] Clause 40. The method according to Clause 35, wherein the polyolefin is a homopolymer or copolymer that forms a coating around the carbon nanomaterial by contacting one or more olefins onto the surface of the carbon nanomaterial.

[0185] Clause 41. The method according to Clause 35, wherein a polyolefin is grafted onto the surface of a carbon nanomaterial by in-situ polymerization, in-situ free radical functionalization, or amidation reaction.

[0186] Unless otherwise stated, all figures used in this specification and related claims, such as quantities of components, molecular weights and other properties, process conditions, etc., should be understood in all cases to be modified by the term "approximately." Therefore, unless otherwise indicated, the numerical parameters described in the following specification and the attached claims are approximations that may vary depending on the desired properties to be obtained by the embodiments of this disclosure. At the very least, without any attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter should be interpreted by applying the usual rounding method in light of the number of significant figures reported.

[0187] One or more exemplary embodiments incorporating the embodiments of the disclosure disclosed herein are presented herein. For clarity, not all features of physical implementations are described or represented in this application. It is understood that in developing physical implementations incorporating the embodiments of the disclosure, numerous implementation-specific decisions must be made to achieve the developer's objectives, such as compliance with system-related, business-related, government-related, and other constraints, which vary by implementation and time. While the developer's efforts may be time-consuming, such efforts are nonetheless routine for those skilled in the art and will benefit from this disclosure.

[0188] 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.

[0189] 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]

[0190] Example 1. Unfilled Polyolefin Powder: Unfilled polyolefin powder was prepared by melt extrusion using the following method. The extruder was heated to a temperature near the melting point of the polymer, and the rotor was started at a low speed. Polymer pellets were added to the heated extruder, followed by the addition of a dispersion medium. PDMS oil was used as the dispersion medium, having a viscosity in the range of 10,000 cSt to 60,000 cSt at room temperature. The ratio of PDMS oil to polymer was 70:30 (or 30% polymer pellets in 70% PDMS oil). Optional dispersants or flow aids may be added before the dispersion medium to aid in the flow of dry particles. The extruder was operated at 225°C at 200 rpm (maximum speed) for 30 minutes. The mixture was then released onto a metal tray with dry ice to provide rapid quenching. Once the dry ice sublimated, the PDMS oil was washed away from the particles with three heptane washes, and the particles were isolated by vacuum filtration. Next, the fine particles were dried overnight in a vacuum oven at room temperature to evaporate any residual heptane. The dried particles were then sieved through a 150 μm or 250 μm screen. The resulting sieved powder was obtained with a final average particle size (D50) of approximately 50 micrometers and a span of approximately 1.

[0191] Example 2 (Future Prediction) A polyolefin powder molten material is mixed with a CNT filler. CNM-g-polyolefin can be prepared by melt processing (e.g., melt extrusion). The extruder can be heated to a temperature near the melting point of the polymer and the rotor can be started. Polyolefin resin pellets can be fed into the chamber at a low speed. CNTs can then be added and melt-formed into the resin. PDMS oil can be used as a dispersion medium having a viscosity in the range of 10,000 cSt to 60,000 cSt at room temperature. The ratio of PDMS oil to polymer may be 70:30. At a temperature, the extruder can be operated at 200 rpm (maximum speed) for 30 minutes at 225°C. The mixture can then be released onto a metal tray with dry ice to provide rapid quenching. Once 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 remaining heptane. Next, the dried particles can be sieved through a 150 μm or 250 μm screen.

[0192] Example 3 (Future Prediction) Polymerization of Polyolefins to CNTs: Pretreatment of Carbon Nanotubes Using Co-Catalyzers: Crude nanotubes may be placed in a polymerization flask and flame-dried under high vacuum. The flask may then be filled with nitrogen and placed in an oil bath at 50°C. Drying and deoxygenating n-heptane and MAO may then be added under nitrogen. The CNTs in contact with aluminoxane may be stirred at 50°C for 1 hour. The solvent may then be distilled under reduced pressure at 50°C. The solvent may be captured in a flask cooled with liquid nitrogen for aluminum titration, along with any volatile organoaluminum compounds. The treated CNTs may be further heated at 150°C under reduced pressure for 90 minutes to bond MAO to the carbon nanotubes, thereby producing aluminoxane-treated CNTs.

[0193] Polymerization of polyolefins to CNTs: Homopolymerization of ethylene (or propylene) in the presence of carbon nanotubes pre-treated with a cocatalyst: Aluminoxane-treated CNTs can be dispersed in dry n-heptane. Cp*2ZrCl2 can then be added to the suspension. The stirred mixture can then be heated to 50°C for 15 minutes. To remove nitrogen, the reactor can be purged with ethylene (0.5 min). The polymerization reaction can be carried out at 50°C under a constant pressure of ethylene at 13 bar with vigorous stirring for a predetermined period of time. The final material can be precipitated in methanol acidified with 12M hydrochloric acid and filtered. This step can allow for the recovery of HDPE-coated nanotubes and inactivation of the catalyst complex, producing residual aluminum oxide (Al2O3). The obtained material can be dried in a ventilated oven at 60°C for about 12 hours.

[0194] Preparation of CNT-polyolefin microparticles - molten extruded product: Microparticles can be produced from CNM-g-polyolefin sample 1 by molten 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. Polymer pellets of sample 1 may be added to the heated extruder, followed by the addition of a dispersion medium. PDMS oil may be used as the dispersion medium, having a viscosity in the range of 10,000 cSt to 60,000 cSt at room temperature. The ratio of PDMS oil to polymer may be 70:30. Optional dispersants or flow aids may be added before the dispersion medium to aid in the flow of dry particles. At the specified temperature, the extruder may be operated at 200 rpm (maximum speed) for 30 minutes. The mixture may then be released onto a metal tray with dry ice to provide rapid quenching. Once the dry ice sublimes, the oil may be washed away from the microparticles by three heptane washes, and the microparticles may be isolated by vacuum filtration. The fine particles can be dried overnight in a vacuum oven at room temperature to evaporate any residual heptane. The dried particles can then be sieved through a 150 μm or 250 μm screen.

[0195] SLS Printing and Mechanical Testing: The baseline performance of a dry powder can be determined by sintering the sample. The sample can be 3D printed on a SNOWWHITE SLS printer (available from Sharebot). A laser can selectively fuse the sample by scanning the cross-section of the desired object, generated using a computer-aided design (CAD) model. After the first layer containing the sample has been scanned, the powder bed can be lowered, rolling another part of the sample upwards, and subsequent layers can be scanned until the part is complete. Advantageously, compared to current additive manufacturing techniques, the use of such a powder-based system can enable the elimination of printing supports and the ability to reuse materials.

[0196] The mechanical properties of Examples 1, 2, and 3 can be determined by printing ASTM Tensile D638, Type V Dogbone bars on a SNOWWHITE SLS printer. The mechanical properties of CNM-g-polyolefin are expected to be greater than those of unfilled polyolefin. Furthermore, polyolefins grafted with CNTs may have superior mechanical properties compared to polyolefins simply melt-mixed with CNTs (i.e., ungrafted). Without being constrained by any theory or mechanism, SLS printing should not alter the intrinsic mechanical properties of the material, and therefore CNM-g-polyolefin particles should result in SLS-printed objects with improved mechanical properties compared to polyolefin microparticles not compounded with CNTs or microparticles of mixed (ungrafted) polyolefin and CNTs.

[0197] Example 4 (Future Prediction) Metallocene Catalyst via Polymerization Packing Technology (PFT): Pretreatment of Carbon Nanotubes with Co-catalysis 26 grams of multi-walled carbon nanotubes (MWNTs) may be dried overnight at 100°C under vacuum and added under nitrogen to 2.6 L of dry and deoxygenated n-heptane and 221 mL of MAO (from which trimethylaluminum (TMA) has been removed by distillation). The TMA may be recovered and held for titration (Fraction 1). The system may then be stirred at 40°C for 1 hour. The solvent may be distilled under reduced pressure at 40°C. The solvent may be captured in a flask cooled with liquid nitrogen along with any volatile organoaluminum compounds (Fraction 2). The treated CNTs may be heated to 150°C for 90 minutes under reduced pressure. The MAO excess may be removed by washing three times with dry toluene (3 × 70 ml) at 60°C (Fraction 3). Fractions 1, 2, and 3 can be hydrolyzed and extracted by adding 150 ml of aqueous HCl solution (approximately 2 M). Aluminum can be back-titrated with EDTA to assess the amount of MAO fixed to the CNTs. The aluminum concentration can then be assessed by titrating with EDTA as the average of three aliquots. The organic solvent can be evaporated by boiling the solution under magnetic stirring. 5 ml of the acidic solution can be diluted 20-fold, and then 20 ml of a 0.025 M EDTA solution can be added. The solution can be heated to a boil and then cooled to room temperature. The solution can be buffered with sodium acetate at pH=4.76. Excess EDTA can be determined by titrating with a 0.05 M ZnSO4 solution with xylenol orange as an indicator. The determined concentration of the aluminum complex can be used to calculate the amount of aluminum that can be exhausted during the solvent evaporation and CNT washing processes.

[0198] Homopolymerization of ethylene in the presence of carbon nanotubes pre-treated with a cocatalyst: Treated CNTs (approximately 26 g) can be dispersed in 2.6 L of dry n-heptane and then transferred to a 250 ml glass reactor in a glove box. Then, 57.2 ml of Cp2 * ZrCl2(5.2 10 -3A molar concentration of M may be added to the suspension. The stirred mixture may be heated to 50°C for 15 minutes. To remove nitrogen, the reactor may be purged with ethylene (0.5 min). The synthesis may be carried out at 50°C under constant pressure of ethylene at 2.7 bar and with vigorous stirring for 1 hour. The final material may be precipitated in 15.6 L of methanol acidified with hydrochloric acid and dried under reduced pressure at 70°C for about 7 hours.

[0199] Preparation of carbon nanotube-polyethylene (CNT-PE) microparticles: Microparticles can be produced from the CNM-g-polyolefin prepared above by melt extrusion in a HAAKE® RHEOMIX twin-screw extruder equipped with a high-shear rotor. The extruder can be heated to a temperature near the melting point of the polymer (225°C), and the rotor can be started at 120 rpm. 65 g of MWNT-g-PE polymer (prepared above) can be added to the heated extruder, followed by 152 g of dispersion medium. The dispersion medium may be polydimethylsiloxane (PDMS) oil having a viscosity in the range of 10,000 cSt to 60,000 cSt at room temperature. The ratio of PDMS oil to polymer may be 70:30 (or 30% polymer solids in 70% oil). Using approximately 20 g of measured PDMS, a slurry can be formed by mixing the PDMS with 0.325 g of RX50 (0.5 wt% MWNT-g-PE polymer) fumed silica. The resulting slurry can then be added to an extruder. At a temperature of 10°C, the extruder can be operated at 120 rpm for 10 minutes. The mixture can then be released onto a metal tray with dry ice to provide rapid quenching. Once the dry ice sublimes, the oil can be washed away from the fine particles with 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 screen. The resulting powder may have a final average particle size (D50) of approximately 50 micrometers and a span of approximately 1.

[0200] Example 5 (Future Prediction) Synthesis of Graphene Oxide-Supported Ziegler-Natta Catalyst: The Grignard reagent, C4H9MgCl (BuMgCl), can be prepared by reacting chlorobutane (10 mL) and magnesium powder (14.2 g) in tetrahydrofuran (250 mL) at reflux temperature (80 °C) under an N2 atmosphere for 20 hours. Then, 0.1 mol of BuMgCl / tetrahydrofuran solution can be added dropwise to a 4 L tetrahydrofuran suspension containing 4.06 g of graphene oxide (GO). After reacting at reflux temperature (80 °C) for 48 hours, excess Grignard reagent can be filtered off, and the solid can then be washed three times with tetrahydrofuran and hexane. The powdered product can then be dried under vacuum at 60 °C for 12 hours, which may yield 6.08 g of BuMgCl / GO. Next, 5 grams of BuMgCl / GO may be added to 250 mL of titanium tetrachloride (TiCl4) at room temperature, and the temperature may then be raised to 120°C and the mixture may be stirred for 4 hours. The reaction may then be filtered to remove unreacted TiCl4, and a second 150 mL volume of TiCl4 may be loaded into the reactor. After stirring at 120°C for 4 hours, the reaction may be completed. The reaction mixture may then be filtered, washed with hot hexane (e.g., 6 washes), and dried under vacuum at 60°C for 12 hours to produce approximately 4.57 g of GO-supported Ziegler-Natta catalyst, TiCl4 / (BuMgCl / GO).

[0201] In-situ polypropylene polymerization: The polymerization reaction can be carried out in a PARR stainless steel autoclave reactor equipped with a mechanical stirrer. 500 mL of hexane may be added to the reactor, and then the reactor may be filled with propylene under a constant pressure of 0.5 MPa. The reactor may be heated to 60°C, and powdered catalyst TiCl4 / (BuMgCl / GO) (0.193 g) may be added to a vigorously stirred liquid mixture saturated with propylene. The polymerization reaction may be initiated by filling the reactor with AlEt3 (3.04 mL, 1.08 mmol) and dimethyloxydiphenylsilane (0.108 mmol) using a syringe. After 30 minutes, polymerization may be stopped with 105 mL of acidified ethanol (containing 10% HCl). The polymer product may be collected by filtration and repeatedly washed with ethanol and distilled water. After drying under vacuum at 60°C for 24 hours, 65 g of the polymer product can be obtained as a gray powder (polypropylene / graphene oxide (PP / GO)).

[0202] Preparation of polypropylene-graphene oxide microparticles: Microparticles can be produced from the PP-g-GO prepared above by melt extrusion in a HAAKE® RHEOMIX twin-screw extruder equipped with a high-shear rotor. The extruder can be heated to a temperature near the melting point of the polymer (225°C), and the rotor can be started at 120 rpm. 65 g of PP-g-GO (prepared above) can be added to the heated extruder, followed by 152 g of dispersion medium. The dispersion medium may be polydimethylsiloxane (PDMS) oil having a viscosity in the range of 10,000 cSt to 60,000 cSt at room temperature. The PDMS oil to polymer ratio may be 70:30 (or 30% polymer solids in 70% oil). Using approximately 20 g of measured PDMS, a slurry can be formed by mixing the PDMS with 0.325 g of AEROSIL® RX50 (0.5 wt% PP-g-GO) fumed silica. Next, the resulting slurry can be added to an extruder. The extruder can be operated at 120 rpm for 10 minutes at a given temperature. The mixture can then be released onto a metal tray with dry ice to provide rapid quenching. Once the dry ice sublimes, the oil can be washed away from the fine particles with three heptane washes, and then 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 then be sieved through a 150 μm or 250 μm screen. The resulting powder may have a final average particle size (D50) of about 50 micrometers and a span of about 1.

[0203] Accordingly, this disclosure is well-adapted to achieve the objectives and benefits mentioned, as well as those inherent to them. The specific embodiments disclosed above are illustrative only, and this disclosure can be modified and implemented in different but equivalent ways, which will be obvious to those skilled in the art who are interested in the teachings herein. Furthermore, it is not intended to limit this disclosure to any structural or design details other than those described in the following claims. Accordingly, it is obvious that the specific exemplary embodiments disclosed above can be modified, combined, or altered, and all such variations are considered within the scope and spirit of this disclosure. The disclosures preferably illustrated herein can be implemented in the absence of any elements not specifically disclosed herein and / or any optional elements disclosed herein. Compositions and methods are described using the terms “comprising,” “containing,” or “including” various components or processes, but compositions and methods can also “essentially consist of” or “consist of” various components and processes. All the number and scope disclosed above may vary somewhat. Whenever a numerical range with lower and upper limits is disclosed, any number and any range included within that range are specifically disclosed. In particular, all ranges of values ​​disclosed herein (in the form of "about a to about b," or equivalently "approximately a to b," or equivalently "about a to b") should be understood to describe all numbers and ranges encompassed within a broad range of values. Furthermore, terms in the claims have plain, ordinary meanings unless explicitly and clearly defined by the patent holder. In addition, when used in claims, the indefinite article "a" or "an" is defined herein to mean one or more of the elements it introduces. Another aspect of the present invention may be as follows: [1] A method of selective laser sintering, wherein the method is: The method involves depositing carbon nanomaterial-grafted polyolefin (CNM-g-polyolefin) particles on a surface in combination with other thermoplastic polymer particles, wherein the CNM-g-polyolefin particles contain polyolefin grafted onto the carbon nanomaterial. A method comprising: when deposited, exposing at least a portion of the CNM-g-polyolefin particles to a laser to fuse the polymer particles and forming a solidified body by selective laser sintering. [2] The method according to [1], wherein the CNM-g-polyolefin comprises 50% to 99.95% by weight of polyolefin and about 0.05% to about 50% by weight of carbon nanomaterial, based on the total weight of the CNM-g-polyolefin. [3] The method according to [1], wherein the polyolefin is a homopolymer or copolymer that forms a coating around the carbon nanomaterial by contacting one or more olefins on the surface of the carbon nanomaterial. [4] The method according to [1], wherein the polyolefin is grafted onto the surface of the carbon nanomaterial by in-situ polymerization. [5] The in-situ polymerization is carried out by pre-treating the carbon nanomaterial, and the pre-treatment is The method according to [4], comprising contacting a catalyst and optionally a co-catalyst onto the surface of the carbon nanomaterial, wherein the catalyst is a heterogeneous catalyst, a homogeneous metallocene catalyst, or a homogeneous non-metallocene catalyst. [6] The method according to [1], wherein the polyolefin is grafted onto the carbon nanomaterial by in-situ free radical functionalization, including melt compounding in the presence of a peroxide initiator. [7] The method according to [1], wherein the polyolefin is grafted onto the carbon nanomaterial by an amidation reaction. [8] The method according to [7], wherein the amidation reaction occurs between graphene oxide and a polyolefin. [9] The method according to [1], wherein the CNM-g-polyolefin particles have a roundness of about 0.90 to about 1.0. 〔10〕The method according to 〔1〕, wherein the CNM-g-polyolefin particles have an emulsifying stabilizer embedded on the outer surface of the CNM-g-polyolefin particles. 〔11〕The method according to 〔10〕, wherein the emulsifying stabilizer contains nanoparticles. 〔12〕The method according to 〔10〕, wherein the emulsifying stabilizer contains nanoparticles, and the nanoparticles are embedded at the void / polymer interface. 〔13〕The method according to 〔1〕, wherein the CNM-g-polyolefin particles further contain a thermoplastic polymer that is not grafted to the CNM. 〔14〕The method according to 〔1〕, 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. 〔15〕The method according to 〔1〕, wherein the CNM-g-polyolefin particles have a diameter span of about 0.2 to about 10. 〔16〕The method according to 〔1〕, wherein the CNM-g-polyolefin particles have an angle of repose of about 25° to about 45°. 〔17〕The method according to 〔1〕, wherein the CNM-g-polyolefin particles have a Hausner ratio of about 1.0 to about 1.5. 〔18〕A method comprising: (a) Carbon nanomaterial-graft-polyolefin (CNM-g-polyolefin), wherein the CNM-g-polyolefin particles contain a polyolefin grafted to a carbon nanomaterial, (b) a dispersion medium immiscible with the polyolefin of the CNM-g-polyolefin, 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 polyolefin of the CNM-g-polyolefin and the thermoplastic polymer, and when included, an emulsifying stabilizer at a shear rate high enough to disperse the CNM-g-polyolefin in the dispersion medium, mixing a mixture comprising; cooling the mixture to below the melting point or softening temperature to form CNM-g-polyolefin particles; separating the CNM-g-polyolefin particles from the dispersion medium. 〔19〕The method according to 〔19〕, wherein the CNM-g-polyolefin particles have a circularity of about 0.90 to about 1.0.

[20] The method according to

[19] , wherein the CNM-g-polyolefin particles have an angle of repose of about 25° to about 45°.

Claims

1. A method of selective laser sintering, To provide carbon nanomaterial-grafted polyolefin (CNM-g-polyolefin) particles in combination with other thermoplastic polymer particles as optional, wherein the CNM-g-polyolefin particles are CNM-g-polyolefin particles containing polyolefin grafted onto carbon nanomaterial. Depositing the CNM-g-polyolefin particles onto the surface, and A method comprising, upon deposition, exposing at least a portion of the CNM-g-polyolefin particles to a laser to fuse the particles and forming a solidified body by selective laser sintering.

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

3. The method according to claim 1, wherein the polyolefin is a homopolymer or copolymer that forms a coating around the carbon nanomaterial.

4. The method according to claim 1, wherein the polyolefin is grafted onto the surface of the carbon nanomaterial by in-situ polymerization.

5. The in-situ polymerization is carried out by pre-treating the carbon nanomaterial, and the pre-treatment is The method according to claim 4, comprising contacting a catalyst and optionally a co-catalyst onto the surface of the carbon nanomaterial, wherein the catalyst is a heterogeneous catalyst, a homogeneous metallocene catalyst, or a homogeneous non-metallocene catalyst.

6. The method according to claim 1, wherein the polyolefin is grafted onto the carbon nanomaterial by in-situ free radical functionalization, including melt compounding in the presence of a peroxide initiator.

7. The method according to claim 1, wherein the polyolefin is grafted onto the carbon nanomaterial by an amidation reaction.

8. The method according to claim 7, wherein the amidation reaction occurs between graphene oxide and a polyolefin.

9. The method according to claim 1, wherein the CNM-g-polyolefin particles have a roundness of about 0.90 to about 1.

0.

10. The method according to claim 1, wherein the CNM-g-polyolefin particles have an emulsifying stabilizer embedded in the outer surface of the CNM-g-polyolefin particles.

11. The method according to claim 10, wherein the emulsifying stabilizer includes nanoparticles.

12. The method according to claim 10, wherein the emulsifying stabilizer comprises nanoparticles, and the nanoparticles are embedded in the void / polymer interface.

13. The method according to claim 1, further comprising a thermoplastic polymer that is not grafted onto carbon nanomaterials, wherein the CNM-g-polyolefin particles.

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

15. The method according to claim 1, wherein the CNM-g-polyolefin particles have a diameter span of about 0.2 to about 10.

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

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

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