Engineered three-dimensional (3D) graphene hybrid materials for high performance polymer composites

Abstract

The present disclosure addresses challenges in polymer composite materials including poor compatibilization between graphene and polymer matrices, the trade-off between stiffness and ductility in reinforced polymers, and the hygroscopic nature of polyamide materials that causes processing difficulties. Solutions are provided through covalent bonding of oxidized three-dimensional graphene to polyolefin hydrocarbon groups, coupling of shape-anisotropic silica nanoparticles to oxidized three-dimensional graphene surfaces via silane linkage, and incorporation of three-dimensional graphene with carbon fibers in a polyamide matrix for additive manufacturing applications. The polyamide-graphene composite comprises a polyamide matrix, a plurality of carbon fibers dispersed within the polyamide matrix, and a plurality of three-dimensional graphene. The three-dimensional graphene increases surface hydrophobicity of the polyamide matrix, reducing the hygroscopic nature of the polyamide and improving processability without extensive pre-drying. The carbon fibers may comprise sizing agents that cooperate with the three-dimensional graphene to enhance interfacial adhesion and load transfer.

Description

DOCKET: LYT1P050.P_LYTEP213WOENGINEERED THREE-DIMENSIONAL (3D) GRAPHENE HYBRID MATERIALS FOR HIGH PERFORMANCE POLYMER COMPOSITESRELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No.63 / 776,852, titled “Engineered Three-Dimensional (3D) Graphene Hybrid Materials for High Performance Polyolefin Composites,” filed March 24, 2025, which is incorporated by reference in its entirety.FIELD OF THE INVENTION

[0002] This disclosure relates to carbon-containing composites, especially pertaining to graphene-containing polymers. More particularly, the inventive aspects presented herein relate to techniques for forming graphene hybrid materials and grafting graphene to polyolefins.BACKGROUND

[0003] Ongoing efforts in the field of material synthesis seek continuing improvements in the quality and efficiency of fabricating various compositions of matter for myriad industrial, commercial, locomotive, and other applications. Of particular interest is the ability to fabricate stronger, lighter materials while concurrently reducing the cost of fabrication, both from a financial perspective and in terms of reducing amount of raw materials required to produce final products.

[0004] Graphene remains a material of interest in a growing field of practical applications, and is a major focus for development and advancement of materials science, particularly composite materials. However, substantial challenges and obstacles have thus far presented equally substantial limitations on the ability to synthesize materials theorized-2- LYT1P050.P_LYTEP213WOto be capable of conveying advantageous characteristics such as mechanical strength, thermal and electrical conductivity, chemical stability, specific chemical functionality, etc. as known in the art.

[0005] Among these challenges include the capacity to dissolve, incorporate, integrate, infuse, coordinate, or otherwise combine or include graphene in various base materials to form desired composites, particularly in amounts exceeding about 1-5 wt% (depending on the base materials and fabrication techniques in question). Rather than dissolving into the native structure of the base material (e.g., a crystalline lattice, a polymer matrix, etc.), in amounts greater than about 1-5 wt% graphene tends to precipitate and form agglomerates and occupy space adjacent to the base material (e.g., in grain boundaries, at peripheral sites, on external surfaces, etc.). Given the low amounts of graphene that can be included in the base material native structure, achieving uniform dispersion or homogenous distribution of carbon in the base material native structure remains yet another unfulfilled objective.

[0006] Moreover, the resulting composite materials tend to include polar covalent bonds between the carbon atoms of the graphene and / or between carbon atoms of the graphene and atoms of the base material, as well as including ionic bonds between atoms of the base material. These types of bonds undesirably alter (and may even dictate) the electronic properties of the composite material, further frustrating efforts to develop new composites with desired chemical and electrical properties.

[0007] Further still, conventional fabrication techniques and apparatuses (such as legacy plasma flame, plasma spray, induction melting, and plasma spark sintering techniques, etc.) are unsuitable for forming composite materials having the desired characteristics noted above. While conventional techniques may be capable of producing diamond, or diamond-like carbon, these carbon materials form on the surface of the base material rather than dissolving into the base material structure (e.g., occupying sites of the lattice or matrix, or being present in interstitial sites of a crystalline lattice, etc.).

[0008] Accordingly, there is both a well-documented need and long-felt desire to overcome the foregoing challenges and obstacles, realizing the ability to synthesize graphene composite materials with graphene present (e.g., dissolved) in the native structure of the base material (e.g., crystalline lattice or polymeric matrix), uniformly dispersed throughout the base material, present in amounts greater than about 5 wt%, and / or where-3- LYT1P050.P_LYTEP213WOthe graphene is “pristine” such that the composite substantially lacks defects, and / or carbon agglomerates, particularly in or at grain boundaries. Polyolefins for instance, are generally very hydrophobic, and have low polarity, and thus it has been difficult to form graphene-polyolefin composite materials. Due to the very different physical properties of graphene and polyolefin, it is difficult to achieve a good dispersion of graphene in a polyolefin resin.SUMMARY

[0009] This Summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Moreover, the systems, methods, and devices of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0010] According to one aspect, a polyolefin-graphene composite is provided. The polyolefin-graphene composite includes a polyolefin having a plurality of hydrocarbon groups, and a plurality of oxidized three-dimensional graphene. Each oxidized three-dimensional graphene is covalently bonded to one of the plurality of hydrocarbon groups.

[0011] According to other aspects of the present disclosure, the polyolefin-graphene composite may include one or more of the following features. The polyolefin may be polypropylene or polyethylene. In some aspects, each oxidized three-dimensional graphene is bound to the corresponding hydrocarbon group via a silane functional group. In some aspects, each oxidized three-dimensional graphene is bound to the corresponding hydrocarbon group via an isocyanate functional group. In some aspects, the polyolefin-graphene composite has a uniform distribution of the plurality of oxidized three-dimensional graphene structures bound to the plurality of hydrocarbon groups of the polyolefin. In preferred aspects, the polyolefin has a chemical formula (CIUCHRjn and the polyolefin-graphene composite has a chemical formula (CH(3DG)CHR)n, wherein a mechanical strength the polyolefin-graphene composite is greater than a mechanical strength of the polyolefin.

[0012] According to other aspects of the present disclosure, the polyolefin-graphene composite includes one or more of the following features. Each oxidized three-dimensional-4- LYT1P050.P_LYTEP213WOgraphene is a carbon nanoparticle. In some aspects, the carbon nanoparticle has a structural morphology characterized by a plurality of spikes and nodules. The carbon nanoparticle includes two or more connected multi-walled spherical fullerenes and layers of graphene coating the connected multi-walled spherical fullerenes. The multi-walled spherical fullerenes do not contain a core composed of impurity elements other than carbon.

[0013] According to one aspect, a silica-graphene compound is provided. The silica-graphene compound includes oxidized three-dimensional graphene, and a plurality of silica nanoparticles coupled to a surface of the oxidized three-dimensional graphene.

[0014] According to other aspects of the present disclosure, the silica-graphene compound may include one or more of the following features. Some of the silica nanoparticles are coupled to hydroxyl groups on the surface of the oxidized three-dimensional graphene. The plurality of silica nanoparticles are evenly distributed on the surface of the oxidized three-dimensional graphene. The silica-graphene compound may have a weight ratio of graphene to silica in a range of about 0.1 to about 15. Some of the silica nanoparticles are associated with the surface of the oxidized three-dimensional graphene via a coupling agent. In some aspects, the couple agent is an amino-functionalized silane.

[0015] According to other aspects of the present disclosure, a polyolefin-graphene composite is formed from the silica-graphene hybrid compound. A mechanical strength of the polyolefin-graphene composite is greater than a mechanical strength of a polyolefin without the silica-graphene hybrid compound by at least 10%. In some aspects, a shape of the plurality of silica nanoparticles is a rod-shaped nanoparticle. The rod-shaped nanoparticle has an aspect ratio (LAV) in a range of 5 < LAV < 20. In some aspects, a flexibility of the polyolefin-graphene composite is greater than a flexibility of a polyolefin without a silica-graphene hybrid compound.

[0016] According to an aspect of the present disclosure, a polyamide-graphene composite is provided. The polyamide-graphene composite includes a polyamide matrix. The polyamide-graphene composite includes a plurality of carbon fibers dispersed within the polyamide matrix. The polyamide-graphene composite includes a plurality of three-dimensional graphene (3DG).-5- LYT1P050.P_LYTEP213WO

[0017] According to other aspects of the present disclosure, the polyamide-graphene composite may include one or more of the following features. Surface hydrophobicity of the polyamide matrix may be increased by the presence of the three-dimensional graphene. The three-dimensional graphene may have a structural morphology characterized by a plurality of spikes and nodules, and the structural morphology may promote mechanical interlocking with the polyamide matrix. The carbon fibers may comprise an epoxy -based sizing, and the composite may exhibit both improved mechanical strength and improved printability relative to a carbon fiber-reinforced polyamide without the three-dimensional graphene.

[0018] The polyamide matrix may comprise at least one of nylon 12, nylon 6, nylon 11, nylon 6 / 6, nylon 6 / 12, poly etherimide (PEI), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polycarbonate, or polyphenylene sulfide (PPS). The plurality of three-dimensional graphene may be uniformly dispersed within the polyamide matrix. The carbon fibers may have a diameter in a range of about 5 pm to about 10 pm. The carbon fibers may have a length in a range of about 0.01 mm to about 1 mm. The carbon fibers may have a length in a range of about 3 mm to about 6 mm. The carbon fibers may be chopped carbon fibers. The carbon fibers may be continuous carbon fibers. The carbon fibers may comprise a sizing agent on a surface thereof. The sizing agent may comprise an epoxy-based sizing, a polyurethane-based sizing, or a polyamide-compatible sizing. The three-dimensional graphene may be grown directly on a surface of the carbon fibers.

[0019] The carbon fibers may be present in an amount of about 5 wt% to about 40 wt% of the composite. The three-dimensional graphene may be present in an amount of about 0.01 wt% to about 5 wt% of the composite. A mechanical strength of the polyamide-graphene composite may be greater than a mechanical strength of a polyamide without the three-dimensional graphene. The composite may be configured for additive manufacturing. The composite may be in the form of a filament for fused deposition modeling. The increased surface hydrophobicity may reduce a hygroscopic nature of the polyamide matrix. The three-dimensional graphene may be dispersed at an interface between the-6- LYT1P050.P_LYTEP213WOcarbon fibers and the polyamide matrix. The epoxy-based sizing may increase dispersibility of the carbon fibers within the polyamide matrix. The sizing agent on the carbon fibers and the three-dimensional graphene may cooperatively enhance interfacial adhesion between the carbon fibers and the polyamide matrix, and the composite may exhibit improved processability for fused deposition modeling relative to a carbon fiber-reinforced polyamide without the three-dimensional graphene.

[0020] Further details of aspects, objectives, and advantages of the technological aspects are described herein, and in the drawings and claims. The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.-7- LYT1P050.P_LYTEP213WOBRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described below are for illustration purposes only. The drawings are not intended to limit the scope of the present disclosure. This patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the U.S. Patent and Trademark Office upon request and payment of the necessary fee.

[0022] FIG. 1A through FIG. 1Y depict structured carbons, various carbon nanoparticles, various carbon-containing aggregates, and various three-dimensional carbon-containing structures that are grown over other materials, according to some embodiments of the present disclosure

[0023] FIG. 2A illustrates a reaction pathway of forming a 3DG-grafted polyolefin in a two-step process, according to one aspect. Part (a) functionalization of 3DG, part (b) functionalization of polyolefin, part (c) 3DG grafted polyolefin.

[0024] FIG. 2B illustrates a reaction pathway of forming a 3DG-grafted polyolefin in a one-step process, according to one aspect. Part (a) functionalization of 3DG, part (b) formation of 3DG functionalized polyolefin.

[0025] FIG. 2C illustrates a peroxide-based reaction pathway of forming a 3DG-grafted polyolefin, according to one aspect.

[0026] FIG. 2D illustrates a m-TMI-mediated pathway for forming a 3DG-grafted polyolefin, according to one aspect.

[0027] FIG. 3 are scanning electron micrograph (SEM) images of various magnifications of formulations of silica-graphene hybrid compounds, in accordance with the presently disclosed inventive concepts. Part (a) in situ silica particle synthesis, part (b) separate synthesis of silica nanoparticles.

[0028] FIG. 4 illustrates a multiple reaction pathway of forming silica condensation on a surface of a graphene oxide, according to one aspect. Part (a) Method 1 of direct silica condensation, part (b) method 2 of silane / silica condensation.

[0029] FIG. 5 illustrates a plot demonstrating the flexural modulus of polyolefin composite material and silica-graphene hybrid compounds, according to one aspect.

[0030] FIG. 6 are scanning electron micrograph (SEM) images of various magnifications of formulations of silica-graphene hybrid compounds, in accordance with-8- LYT1P050.P_LYTEP213WOthe presently disclosed inventive concepts. Part (a) 3DGO-ASiO2, part (b) 5X scaled up formulation of 3DGO-ASiO2.

[0031] FIG. 7 are scanning electron micrograph (SEM) images of various magnifications of a silica-3DGO hybrid compound (part (a)) and a silica-commercial-GO hybrid compound (part (b)), in accordance with the presently disclosed inventive concepts.

[0032] FIG. 8 are scanning electron micrograph (SEM) images of various magnifications of a silica-graphene compounds prepared in the presence of an aminofunctionalized silane coupling agent, in accordance with the presently disclosed inventive concepts. Part (a) 3DGO hybrid compound, and part (b) commercial-GO hybrid compound.

[0033] FIGS. 9 A and 9B illustrate plots demonstrating the flexural modulus of polyolefin composite material having silica-commercial-GO hybrid compounds and silica-3DGO hybrid compounds, according to one aspect.

[0034] FIG. 10 are scanning electron micrograph (SEM) images of various magnifications of a silica-3DGO hybrid compounds prepared in the presence of varying amounts of TEOS, in accordance with the presently disclosed inventive concepts. Part (a) 20:1 TEOS:3DGO, part (b) 5:1 TEOS:3DGO.

[0035] FIG. 11 illustrates a plot demonstrating the flexural modulus of polyolefin composite material having silica-commercial-GO hybrid compounds formed with varying amounts of TEOS, according to one aspect.

[0036] FIG. 12 are scanning electron micrograph (SEM) images of various magnifications of a silica-3DGO hybrid compounds formed in the presence of a catalyst, in accordance with the presently disclosed inventive concepts. Part (a) the catalyst is an acid catalyst, and part (b) the catalyst is a base catalyst.

[0037] FIG. 13 illustrates a plot demonstrating the flexural modulus of polyolefin composite material having silica-commercial-GO hybrid compounds formed in the presence of different catalysts, according to one aspect.

[0038] FIG. 14 are scanning electron micrograph (SEM) images of various magnifications preparations of anisotropic silica nanoparticles, in accordance with the presently disclosed inventive concepts. Part (a) bullet-shaped silica nanoparticles, part (b) rod-shaped silica nanoparticles.-9- LYT1P050.P_LYTEP213WO

[0039] FIG. 15 are scanning electron micrograph (SEM) images of various magnifications preparations of silica-3DGO hybrid compounds having anisotropic-shaped silica nanoparticles, in accordance with the presently disclosed inventive concepts. Part (a) bullet-shaped silica nanoparticles on the surface of 3DGO, part (b) rod-shaped silica nanoparticles on the surface of 3DGO, part (c) noodle-shaped silica nanoparticles on the surface of 3DGO.

[0040] FIG. 16 illustrates a plot demonstrating EGA analysis of silica-graphene hybrid compounds, according to one aspect.

[0041] FIG. 17 illustrates plots of flexural modulus (upper plot) and elongation at break (lower plot) of polyethylene composite material having anisotropic silica nanoparticlegraphene hybrid compounds, according to one aspect.

[0042] FIG. 18 are scanning electron micrograph (SEM) images of various magnifications preparations of silica-3DGO hybrid compounds having rod-shaped silica nanoparticles showing alignment of rods in direction of injection molding, according to one aspect.

[0043] FIG. 19 depicts a comparison table of composite material approaches for polymer reinforcement, according to aspects of the present disclosure.

[0044] FIG. 20 illustrates an isometric view of a polyamide-graphene composite, according to an embodiment.

[0045] FIG. 21 depicts a comparison diagram illustrating a nylon matrix and a nylon matrix with 3D graphene, according to aspects of the present disclosure.-10- LYT1P050.P_LYTEP213WODETAILED DESCRIPTION

[0046] The present disclosure relates to polymer composite materials, and more particularly to graphene-reinforced polymer composites spanning polyolefin-based systems for injection molding applications and polyamide-based systems for additive manufacturing applications.

[0047] Polymer composite materials incorporating graphene reinforcement face fundamental challenges related to compatibilization between the sp2-hybridized carbon structure of graphene with its planar geometry and it-it stacking interactions and the sp3-hybridized tetrahedral geometry of polymer chains. In polyolefin systems such as polyethylene and polypropylene, poor dispersion, agglomeration of graphene particles, and weak interfacial adhesion limit load transfer and mechanical property enhancement. Additionally, achieving both high stiffness and ductility in polyolefin materials presents a persistent trade-off that typically forces engineers to sacrifice one property for the other. In polyamide systems such as nylon, the inherent hygroscopic nature of the polymer matrix causes moisture absorption from the environment, leading to dimensional instability, reduced mechanical properties, and processing difficulties during extrusion-based fabrication processes. Furthermore, existing carbon fiber-reinforced polyamide systems suffer from compromised interfacial adhesion between the fibers and the polymer matrix, resulting in suboptimal load transfer and reduced composite performance.

[0048] The present disclosure addresses these challenges through multiple approaches tailored to specific polymer matrix systems and applications. For polyolefin-based systems, covalent bonding of oxidized three-dimensional graphene to hydrocarbon groups of the polyolefin via silane or isocyanate functional groups provides direct chemical linkage that overcomes the inherent incompatibility between graphene and polyolefin structures, enabling uniform distribution of graphene throughout the polymer matrix and efficient load transfer for injection molding applications. The coupling of shape-anisotropic silica nanoparticles to oxidized three-dimensional graphene surfaces via silane linkage further advances polyolefin composite performance by providing improved flexural modulus while maintaining full elongation properties that prevent brittle failure. For polyamide-based systems, the incorporation of three-dimensional graphene along with carbon fibers-11- LYT1P050.P_LYTEP213WOdispersed within a polyamide matrix addresses the unique challenges of additive manufacturing, where the innately hydrophobic three-dimensional graphene increases the surface hydrophobicity of the polyamide matrix, thereby reducing its hygroscopic nature and improving processability without requiring extensive drying procedures prior to processing.

[0049] The present disclosure further provides composite systems wherein the reinforcing components cooperatively enhance mechanical properties and processability across different polymer matrices and fabrication methods. In polyolefin systems, rodshaped silica nanoparticles align with polymer flow during injection molding to provide significant improvement in flexural modulus while maintaining full elongation. In polyamide systems, the three-dimensional graphene dispersed at the interface between the carbon fibers and the polyamide matrix cooperatively enhances interfacial adhesion and load transfer, while carbon fibers with epoxy-based, polyurethane-based, or polyamide-compatible sizing agents increase dispersibility within the polyamide matrix. The polyamide-graphene composite may be configured as a filament for fused deposition modeling, achieving both improved mechanical strength and improved printability relative to carbon fiber-reinforced polyamides without the three-dimensional graphene, enabling applications in additive manufacturing where both high performance and consistent processability are required.Definitions and Use of Figures

[0050] Some of the terms used in this description are defined below for easy reference. The presented terms and their respective definitions are not rigidly restricted to these definitions — a term may be further defined by the term’s use within this disclosure. The term “exemplary” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion. As used in this application and the appended claims, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or is clear from the context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs-12- LYT1P050.P_LYTEP213WOA, X employs B, or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. As used herein, at least one of A or B means at least one of A, or at least one of B, or at least one of both A and B. In other words, this phrase is disjunctive. The articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or is clear from the context to be directed to a singular form.

[0051] Various aspects are described herein with reference to the figures. It should be noted that the figures are not necessarily drawn to scale, and that elements of similar structures or functions are sometimes represented by like reference characters throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the disclosed aspects — they are not representative of an exhaustive treatment of all possible aspects, and they are not intended to impute any limitation as to the scope of the claims. In addition, an illustrated aspect need not portray all aspects or advantages of usage in any particular environment.

[0052] An aspect or an advantage described in conjunction with a particular aspect is not necessarily limited to that aspect and can be practiced in any other aspects even if not so illustrated. References throughout this specification to “some aspects” or “other aspects” refer to a particular feature, structure, material or characteristic described in connection with the aspects as being included in at least one aspect. Thus, the appearance of the phrases “in some aspects” or “in other aspects” in various places throughout this specification are not necessarily referring to the same aspect or aspects. The disclosed aspects are not intended to be limiting of the claims.Descriptions of Exemplary Aspects of the Invention

[0053] According to one general aspect, a polyolefin-graphene composite includes a polyolefin having a plurality of hydrocarbon groups, and a plurality of oxidized three-dimensional graphene (3DGO). Each oxidized three-dimensional graphene is covalently bonded to one of the plurality of hydrocarbon groups.

[0054] According to another general aspect, a silica-graphene compound includes oxidized three-dimensional graphene (3DGO) and a plurality of silica nanoparticles coupled to a surface of the oxidized three-dimensional graphene.-13- LYT1P050.P_LYTEP213WO

[0055] More illustrative information will now be set forth regarding various optional architectures and uses in which the foregoing method may or may not be implemented, per the desires of the user. It should be strongly noted that the following information is set forth for illustrative purposes and should not be construed as limiting in any manner. Any of the following features may be optionally incorporated with or without the exclusion of other features described.

[0056] In some embodiments, carbon nanoparticles and aggregates are characterized by a high “uniformity” (i.e., high mass fraction of desired carbon allotropes), a high degree of “order” (i.e., low concentration of defects), and / or a high degree of “purity” (i.e., low concentration of elemental impurities), in contrast to the lower uniformity, less ordered, and lower purity particles achievable with conventional systems and methods.

[0057] In some embodiments, the nanoparticles produced using the methods described herein contain multi-walled spherical fullerenes (MWSFs) or connected MWSFs and have a high uniformity (e.g., a ratio of graphene to MWSF from 20% to 80%), a high degree of order (e.g., a Raman signature with an ID / IG ratio from 0.95 to 1.05), and a high degree of purity (e.g., the ratio of carbon to other elements (other than hydrogen) is greater than 99.9%). In some embodiments, the nanoparticles produced using the methods described herein contain MWSFs or connected MWSFs, and the MWSFs do not contain a core composed of impurity elements other than carbon. In some cases, the particles produced using the methods described herein are aggregates containing the nanoparticles described above with large diameters (e.g., greater than 10 pm across).

[0058] Conventional methods have been used to produce particles containing multiwalled spherical fullerenes with a high degree of order, but the conventional methods lead to carbon products with a variety of shortcomings. For example, high temperature synthesis techniques lead to particles with a mixture of many carbon allotropes and therefore low uniformity (e.g., less than 20% fullerenes to other carbon allotropes) and / or small particle sizes (e.g., less than 1pm, or less than 100 nm in some cases). Methods using catalysts lead to products including the catalyst elements and therefore have low purity (e.g., less than 95% carbon to other elements) as well. These undesirable properties also often lead to undesirable electrical properties of the resulting carbon particles (e.g., electrical conductivity of less than 1000 S / m).-14- LYT1P050.P_LYTEP213WO

[0059] In some embodiments, the carbon nanoparticles and aggregates described herein are characterized by Raman spectroscopy that is indicative of the high degree of order and uniformity of structure. In some embodiments, the uniform, ordered and / or pure carbon nanoparticles and aggregates described herein are produced using relatively high speed, low cost improved thermal reactors and methods, as described below. Additional advantages and / or improvements will also become apparent from the following disclosure.

[0060] In the present disclosure, the term “graphene” refers to an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one atom forms each vertex. The carbon atoms in graphene are sp2-bonded. Additionally, graphene has a Raman spectrum with two main peaks: a G-mode at approximately 1580 cm'1and a D-mode at approximately 1350 cm1(when using a 532 nm excitation laser).

[0061] In the present disclosure, the term “fullerene” refers to a molecule of carbon in the form of a hollow sphere, ellipsoid, tube, or other shapes. Spherical fullerenes can also be referred to as Buckminsterfullerenes, or buckyballs. Cylindrical fullerenes can also be referred to as carbon nanotubes. Fullerenes are similar in structure to graphite, which is composed of stacked graphene sheets of linked hexagonal rings. Fullerenes may also contain pentagonal (or sometimes heptagonal) rings.

[0062] In the present disclosure, the term “multi-walled fullerene” refers to fullerenes with multiple concentric layers. For example, multi-walled nanotubes (MWNTs) contain multiple rolled layers (concentric tubes) of graphene. Multi-walled spherical fullerenes (MWSFs) contain multiple concentric spheres of fullerenes.

[0063] In the present disclosure, the term “nanoparticle” refers to a particle that measures from 1 nm to 989 nm. The nanoparticle can include one or more structural characteristics (e.g., crystal structure, defect concentration, etc.), and one or more types of atoms. The nanoparticle can be any shape, including but not limited to spherical shapes, spheroidal shapes, dumbbell shapes, cylindrical shapes, elongated cylindrical type shapes, rectangular prism shapes, disk shapes, wire shapes, irregular shapes, dense shapes (i.e., with few voids), porous shapes (i.e., with many voids), etc.

[0064] In the present disclosure, the term “aggregate” refers to a plurality of nanoparticles that are connected together by electrostatic forces (e.g., Van der Waals forces, London dispersion forces, dipole-dipole interactions, hydrogen bonding, etc.) by-15- LYT1P050.P_LYTEP213WOcovalent bonds, by ionic bonds, by metallic bonds, or by other physical or chemical interactions. Aggregates can vary in size considerably, but in general are larger than about 500 nm.

[0065] In some embodiments, a carbon nanoparticle, as described herein, includes two or more connected multi-walled spherical fullerenes (MWSFs) and layers of graphene coating the connected MWSFs. In some embodiments, a carbon nanoparticle, as described herein, includes two or more connected multi-walled spherical fullerenes (MWSFs) and layers of graphene coating the connected MWSFs where the MWSFs do not contain a core composed of impurity elements other than carbon. In some embodiments, a carbon nanoparticle, as described herein, includes two or more connected multi-walled spherical fullerenes (MWSFs) and layers of graphene coating the connected MWSFs where the MWSFs do not contain a void (i.e., a space with no carbon atoms greater than approximately 0.5 nm, or greater than approximately 1 nm) at the center. In some embodiments, the connected MWSFs are formed of concentric, well-ordered spheres of sp2-hybridized carbon atoms, as contrasted with spheres of poorly-ordered, non-uniform, amorphous carbon particles.

[0066] In some embodiments, the nanoparticles containing the connected MWSFs have an average diameter in a range from 5 to 500 nm, or from 5 to 250 nm, or from 5 to 100 nm, or from 5 to 50 nm, or from 10 to 500 nm, or from 10 to 250 nm, or from 10 to 100 nm, or from 10 to 50 nm, or from 40 to 500 nm, or from 40 to 250 nm, or from 40 to 100 nm, or from 50 to 500 nm, or from 50 to 250 nm, or from 50 to 100 nm. Of course, nanoparticles containing connected MWSFs may have an average diameter characterized by having any of the foregoing values or being within any of the foregoing exemplary ranges, or an average diameter characterized by having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0067] In some embodiments, the carbon nanoparticles described herein form aggregates, wherein many nanoparticles aggregate together to form a larger unit. In some embodiments, a carbon aggregate includes a plurality of carbon nanoparticles. A diameter across the carbon aggregate is in a range from 10 to 500 pm, or from 50 to 500 pm, or from 100 to 500 pm, or from 250 to 500 pm, or from 10 to 250 pm, or from 10 to 100 pm, or-16- LYT1P050.P_LYTEP213WOfrom 10 to 50 pm. Of course, carbon aggregates may have an average diameter characterized by having any of the foregoing values or being within any of the foregoing exemplary ranges, or an average diameter characterized by having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0068] In some embodiments, the aggregate is formed from a plurality of carbon nanoparticles, as defined above. In some embodiments, aggregates contain connected MWSFs. In some embodiments, the aggregates contain connected MWSFs with a high uniformity metric (e.g., a ratio of graphene to MWSF from 20% to 80%), a high degree of order (e.g., a Raman signature with an ID / IG ratio from 0.95 to 1.05), and a high degree of purity (e.g., greater than 99.9% carbon).

[0069] One benefit of producing aggregates of carbon nanoparticles, particularly with diameters in the ranges described above, is that aggregates of particles greater than 10 pm are easier to collect than particles or aggregates of particles that are smaller than 500 nm. The ease of collection reduces the cost of manufacturing equipment used in the production of the carbon nanoparticles and increases the yield of the carbon nanoparticles. Additionally, particles greater than 10 pm in size pose fewer safety concerns compared to the risks of handling smaller nanoparticles, e.g., potential health and safety risks due to inhalation of the smaller nanoparticles. The lower health and safety risks, thus, further reduce the manufacturing cost.

[0070] In some embodiments, a carbon nanoparticle has a ratio of graphene to MWSFs from 10% to 90%, or from 10% to 80%, or from 10% to 60%, or from 10% to 40%, or from 10% to 20%, or from 20% to 40%, or from 20% to 90%, or from 40% to 90%, or from 60% to 90%, or from 80% to 90%. In some embodiments, a carbon aggregate has a ratio of graphene to MWSFs is from 10% to 90%, or from 10% to 80%, or from 10% to 60%, or from 10% to 40%, or from 10% to 20%, or from 20% to 40%, or from 20% to 90%, or from 40% to 90%, or from 60% to 90%, or from 80% to 90%. Of course, carbon nanoparticles may have a graphene-to-MWSF ratio characterized by having any of the foregoing values or being within any of the foregoing exemplary ranges, or an average graphene-to-MWSF ratio characterized by having a value or being within a range between-17- LYT1P050.P_LYTEP213WOany of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0071] In some embodiments, a carbon nanoparticle has a ratio of graphene to connected MWSFs from 10% to 90%, or from 10% to 80%, or from 10% to 60%, or from 10% to 40%, or from 10% to 20%, or from 20% to 40%, or from 20% to 90%, or from 40% to 90%, or from 60% to 90%, or from 80% to 90%. In some embodiments, a carbon aggregate has a ratio of graphene to connected MWSFs is from 10% to 90%, or from 10% to 80%, or from 10% to 60%, or from 10% to 40%, or from 10% to 20%, or from 20% to 40%, or from 20% to 90%, or from 40% to 90%, or from 60% to 90%, or from 80% to 90%. Of course, carbon nanoparticles may have a graphene-to-connected MWSF ratio characterized by having any of the foregoing values or being within any of the foregoing exemplary ranges, or an average graphene-to-connected MWSF ratio characterized by having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0072] In some embodiments, Raman spectroscopy is used to characterize carbon allotropes to distinguish their molecular structures. For example, graphene can be characterized using Raman spectroscopy to determine information such as order / disorder, edge and grain boundaries, thickness, number of layers, doping, strain, and thermal conductivity. MWSFs have also been characterized using Raman spectroscopy to determine the degree of order of the MWSFs.

[0073] In some embodiments, Raman spectroscopy is used to characterize the structure of MWSFs or connected MWSFs. The main peaks in the Raman spectra are the G-mode and the D-mode. The G-mode is attributed to the vibration of carbon atoms in sp2-hybridized carbon networks, and the D-mode is related to the breathing of hexagonal carbon rings with defects. In some cases, defects may be present, yet may not be detectable in the Raman spectra. For example, if the presented crystalline structure is orthogonal with respect to the basal plane, the D-peak will show an increase. On the other hand, if presented with a perfectly planar surface that is parallel with respect to the basal plane, the D-peak will be zero.-18- LYT1P050.P_LYTEP213WO

[0074] When using 532 nm incident light, the Raman G-mode is typically at 1582 cm1for planar graphite, however, can be downshifted for MWSFs or connected MWSFs (e.g., down to 1565cm1or down tol580 cm-1). The D-mode is observed at approximately 1350 cm1in the Raman spectra of MWSFs or connected MWSFs. The ratio of the intensities of the D-mode peak to G-mode peak (i.e., the ID / IG) is related to the degree of order of the MWSFs, where a lower ID / IG indicates a higher degree of order. An ID / IG near or below 1 indicates a relatively high degree of order, and an ID / IG greater than 1.1 indicates a lower degree of order.

[0075] In some embodiments, a carbon nanoparticle or a carbon aggregate containing MWSFs or connected MWSFs, as described herein, has a Raman spectrum with a first Raman peak at about 1350 cm'1and a second Raman peak at about 1580 cm'1when using 532 nm incident light. In some embodiments, the ratio of an intensity of the first Raman peak to an intensity of the second Raman peak (i.e., the ID / IG) for the nanoparticles or the aggregates described herein is in a range from 0.95 to 1.05, or from 0.9 to 1.1, or from 0.8 to 1.2, or from 0.9 to 1.2, or from 0.8 to 1.1, or from 0.5 to 1.5, or less than 1.5, or less than 1.2, or less than 1.1, or less than 1, or less than 0.95, or less than 0.9, or less than 0.8. Of course, carbon nanoparticles or aggregates including MWSFs or connected MWSFs may be characterized by a ratio of first and second Raman peak intensities having any of the foregoing values or being within any of the foregoing exemplary ranges, or a ratio of first and second Raman peak intensities characterized by having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0076] In some embodiments, a carbon aggregate containing MWSFs or connected MWSFs, as defined above, has a high purity. In some embodiments, the carbon aggregate containing MWSFs or connected MWSFs has a ratio of carbon to metals of greater than 99.99%, or greater than 99.95%, or greater than 99.9%, or greater than 99.8%, or greater than 99.5%, or greater than 99%. In some embodiments, the carbon aggregate has a ratio of carbon to other elements of greater than 99.99%, or greater than 99.95%, or greater than 99.9%, or greater than 99.5%, or greater than 99%, or greater than 90%, or greater than 80%, or greater than 70%, or greater than 60%. In some embodiments, the carbon aggregate has a ratio of carbon to other elements (except for hydrogen) of greater than 99.99%, or-19- LYT1P050.P_LYTEP213WOgreater than 99.95%, or greater than 99.9%, or greater than 99.8%, or greater than 99.5%, or greater than 99%, or greater than 90%, or greater than 80%, or greater than 70%, or greater than 60%. Of course, carbon aggregates including MWSFs or connected MWSFs may be characterized by a ratio of carbon to metal having any of the foregoing values or being within any of the foregoing exemplary ranges, or a ratio of carbon to metal having value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0077] In some embodiments, a carbon aggregate containing MWSFs or connected MWSFs, as defined above, has a high specific surface area. In some embodiments, the carbon aggregate has aBrunauer, Emmett and Teller (BET) specific surface area from 10 to 200 m2 / g, or from 10 to 100 m2 / g, or from 10 to 50 m2 / g, or from 50 to 200 m2 / g, or from 50 to 100 m2 / g, or from 10 to 1000 m2 / g. Of course, carbon aggregates including MWSFs or connected MWSFs may be characterized by a BET specific surface area having any of the foregoing values or being within any of the foregoing exemplary ranges, or a BET specific surface area characterized by having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0078] In some embodiments, a carbon aggregate containing MWSFs or connected MWSFs, as defined above, has a high electrical conductivity. In some embodiments, a carbon aggregate containing MWSFs or connected MWSFs, as defined above, is compressed into a pellet and the pellet has an electrical conductivity greater than 500 S / m, or greater than 1000 S / m, or greater than 2000 S / m, or greater than 3000 S / m, or greater than 4000 S / m, or greater than 5000 S / m, or greater than 10000 S / m, or greater than 20000 S / m, or greater than 30000 S / m, or greater than 40000 S / m, or greater than 50000 S / m, or greater than 60000 S / m, or greater than 70000 S / m, or from 500 S / m to 100000 S / m, or from 500 S / m to 1000 S / m, or from 500 S / m to 10000 S / m, or from 500 S / m to 20000 S / m, or from 500 S / m to 100000 S / m, or from 1000 S / m to 10000 S / m, or from 1000 S / m to 20000 S / m, or from 10000 to 100000 S / m, or from 10000 S / m to 80000 S / m, or from 500 S / m to 10000 S / m. Of course, carbon aggregates including MWSFs or connected MWSFs may be characterized by an electrical conductivity having any of the-20- LYT1P050.P_LYTEP213WOforegoing values or being within any of the foregoing exemplary ranges, or an electrical conductivity characterized by having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0079] In some cases, the density of the pellet is approximately 1 g / cm3, or approximately 1.2 g / cm3, or approximately 1.5 g / cm3, or approximately 2 g / cm3, or approximately 2.2 g / cm3, or approximately 2.5 g / cm3, or approximately 3 g / cm3. Of course, pellets may be characterized by a density having any of the foregoing values or being within any of the foregoing exemplary ranges, or a density having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0080] Additionally, tests have been performed in which compressed pellets of the carbon aggregate materials have been formed with compressions of 2000 psi and 12000 psi and with annealing temperatures of 800°C and 1000°C. The higher compression and / or the higher annealing temperatures generally result in pellets with a higher degree of electrical conductivity, including in the range of 12410.0 S / m to 13173.3 S / m.HIGH PURITY CARBON ALLOTROPES PRODUCED USING THERMAL PROCESSING SYSTEMS

[0081] In some embodiments, the carbon nanoparticles and aggregates described herein are produced using thermal reactors and methods, such as any appropriate thermal reactor and / or method. Additionally, precursors (e.g., including methane, ethane, propane, butane, and natural gas) can be used with the thermal reactors to produce the carbon nanoparticles and the carbon aggregates described herein.

[0082] In some embodiments, the carbon nanoparticles and aggregates described herein are produced using the thermal reactors with gas flow rates from 1 slm to 10 slm, or from 0.1 slm to 20 slm, or from 1 slm to 5 slm, or from 5 slm to 10 slm, or greater than 1 slm, or greater than 5 slm. In some embodiments, the carbon nanoparticles and aggregates described herein are produced using the thermal reactors with gas residence times from 0.1 seconds to 30 seconds, or from 0.1 seconds to 10 seconds, or from 1 seconds to 10 seconds, or from 1 seconds to 5 seconds, from 5 seconds to 10 seconds, or greater than 0.1 seconds, or greater than 1 seconds, or greater than 5 seconds, or less than 30 seconds. Of course,-21- LYT1P050.P_LYTEP213WOcarbon nanoparticles and aggregates may be produced using thermal reactors with gas flow rates having any of the foregoing values or being within any of the foregoing exemplary ranges, or gas flow rates having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0083] In some embodiments, the carbon nanoparticles and aggregates described herein are produced using the thermal reactors with production rates from 10 g / hr to 200 g / hr, or from 30 g / hr to 200 g / hr, or from 30 g / hr to 100 g / hr, or from 30 g / hr to 60 g / hr, or from 10 g / hr to 100 g / hr, or greater than 10 g / hr, or greater than 30 g / hr, or greater than 100 g / hr. Of course, carbon nanoparticles and aggregates may be produced using thermal reactors with production rates having any of the foregoing values or being within any of the foregoing exemplary ranges, or production rates having a value or being within a range between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0084] In some embodiments, thermal reactors or other cracking apparatuses and thermal reactor methods or other cracking methods can be used for refining, pyrolyzing, dissociating or cracking feedstock process gases into its constituents to produce the carbon nanoparticles and the carbon aggregates described herein, as well as other solid and / or gaseous products (e.g., hydrogen gas and / or lower order hydrocarbon gases). The feedstock process gases generally include, for example, hydrogen gas (H2), carbon dioxide (CO2), Ci to C10 hydrocarbons, aromatic hydrocarbons, and / or other hydrocarbon gases such as natural gas, methane, ethane, propane, butane, isobutane, saturated / unsaturated hydrocarbon gases, ethene, propene, etc., and mixtures thereof. The carbon nanoparticles and the carbon aggregates can include, for example, multi-walled spherical fullerenes (MWSFs), connected MWSFs, carbon nanospheres, graphene, graphite, highly ordered pyrolytic graphite, single-walled nanotubes, multi-walled nanotubes, other solid carbon products, and / or the carbon nanoparticles and the carbon aggregates described herein.

[0085] Some embodiments for producing the carbon nanoparticles and the carbon aggregates described herein include thermal cracking methods that use, for example, an elongated longitudinal heating element optionally enclosed within an elongated casing, housing or body of a thermal cracking apparatus. The body generally includes, for example,-22- LYT1P050.P_LYTEP213WOone or more tubes or other appropriate enclosures made of stainless steel, titanium, graphite, quartz, or the like. In some embodiments, the body of the thermal cracking apparatus is generally cylindrical in shape with a central elongate longitudinal axis arranged vertically and a feedstock process gas inlet at or near a top of the body. The feedstock process gas flows longitudinally down through the body or a portion thereof. In the vertical configuration, both gas flow and gravity assist in the removal of the solid products from the body of the thermal cracking apparatus.

[0086] The heating element generally includes, for example, a heating lamp, one or more resistive wires or filaments (or twisted wires), metal filaments, metallic strips or rods, and / or other appropriate thermal radical generators or elements that can be heated to a specific temperature (i.e., a molecular cracking temperature) sufficient to thermally crack molecules of the feedstock process gas. The heating element is generally disposed, located or arranged to extend centrally within the body of the thermal cracking apparatus along the central longitudinal axis thereof. For example, if there is only one heating element, then it is placed at or concentric with the central longitudinal axis, and if there is a plurality of the heating elements, then they are spaced or offset generally symmetrically or concentrically at locations near and around and parallel to the central longitudinal axis.

[0087] Thermal cracking to produce the carbon nanoparticles and aggregates described herein is generally achieved by passing the feedstock process gas over, or in contact with, or within the vicinity of, the heating element within a longitudinal elongated reaction zone generated by heat from the heating element and defined by and contained inside the body of the thermal cracking apparatus to heat the feedstock process gas to or at a specific molecular cracking temperature.

[0088] The reaction zone is considered to be the region surrounding the heating element and close enough to the heating element for the feedstock process gas to receive sufficient heat to thermally crack the molecules thereof. The reaction zone is thus generally axially aligned or concentric with the central longitudinal axis of the body. In some embodiments, the thermal cracking is performed under a specific pressure. In some embodiments, the feedstock process gas is circulated around or across the outside surface of a container of the reaction zone or a heating chamber in order to cool the container or-23- LYT1P050.P_LYTEP213WOchamber and preheat the feedstock process gas before flowing the feedstock process gas into the reaction zone.

[0089] In some embodiments, the carbon nanoparticles and aggregates described herein and / or hydrogen gas are produced without the use of catalysts. In other words, the process is catalyst free.

[0090] Some embodiments to produce the carbon nanoparticles and aggregates described herein using thermal cracking apparatuses and methods to provide a standalone system that can advantageously be rapidly scaled up or scaled down for different production levels as desired. For example, some embodiments are scalable to provide a standalone hydrogen and / or carbon nanoparticle producing station, a hydrocarbon source, or a fuel cell station. Some embodiments can be scaled up to provide higher capacity systems, e.g., for a refinery or the like.

[0091] In some embodiments, a thermal cracking apparatus for cracking a feedstock process gas to produce the carbon nanoparticles and aggregates described herein include a body, a feedstock process gas inlet, and an elongated heating element. The body has an inner volume with a longitudinal axis. The inner volume has a reaction zone concentric with the longitudinal axis. A feedstock process gas is flowed into the inner volume through the feedstock process gas inlet during thermal cracking operations. The elongated heating element is disposed within the inner volume along the longitudinal axis and is surrounded by the reaction zone. During the thermal cracking operations, the elongated heating element is heated by electrical power to a molecular cracking temperature to generate the reaction zone, the feedstock process gas is heated by heat from the elongated heating element, and the heat thermally cracks molecules of the feedstock process gas that are within the reaction zone into constituents of the molecules.

[0092] In some embodiments, a method for cracking a feedstock process gas to produce the carbon nanoparticles and aggregates described herein includes: (1) providing athermal cracking apparatus having an inner volume that has a longitudinal axis and an elongated heating element disposed within the inner volume along the longitudinal axis; (2) heating the elongated heating element by electrical power to a molecular cracking temperature to generate a longitudinal elongated reaction zone within the inner volume; (3) flowing a feedstock process gas into the inner volume and through the longitudinal elongated reaction-24- LYT1P050.P_LYTEP213WOzone (e.g., wherein the feedstock process gas is heated by heat from the elongated heating element); and (4) thermally cracking molecules of the feedstock process gas within the longitudinal elongated reaction zone into constituents thereof (e.g., hydrogen gas and one or more solid products) as the feedstock process gas flows through the longitudinal elongated reaction zone.

[0093] In some embodiments, the feedstock process gas to produce the carbon nanoparticles and aggregates described herein includes a hydrocarbon gas. The results of cracking include hydrogen (e.g., H2) and various forms of the carbon nanoparticles and aggregates described herein. In some embodiments, the carbon nanoparticles and aggregates include two or more MWSFs and layers of graphene coating the MWSFs, and / or connected MWSFs and layers of graphene coating the connected MWSFs. In some embodiments, the feedstock process gas is preheated (e.g., to 100°C to 500°C) by flowing the feedstock process gas through a gas preheating region between a heating chamber and a shell of the thermal cracking apparatus before flowing the feedstock process gas into the inner volume. In some embodiments, a gas having nanoparticles therein is flowed into the inner volume and through the longitudinal elongated reaction zone to mix with the feedstock process gas, and a coating of a solid product (e.g., layers of graphene) is formed around the nanoparticles.POST-PROCESSING HIGH PURITY STRUCTURED CARBONS

[0094] In some embodiments, the carbon nanoparticles and aggregates containing multi-walled spherical fullerenes (MWSFs) or connected MWSFs described herein are produced and collected, and no post-processing is done. In other embodiments, the carbon nanoparticles and aggregates containing multi-walled spherical fullerenes (MWSFs) or connected MWSFs described herein are produced and collected, and some post-processing is done. Some examples of post-processing involved in the present disclosure include mechanical processing such as ball milling, grinding, attrition milling, micro fluidizing, and other techniques to reduce the particle size without damaging the MWSFs. Some further examples of post-processing include exfoliation processes such as sheer mixing, chemical etching, oxidizing (e.g., Hummer method), thermal annealing, doping by adding elements during annealing (e.g., sulfur, nitrogen), steaming, filtering, and lyophilizing,-25- LYT1P050.P_LYTEP213WOamong others. Some examples of post-processing include sintering processes such as spark plasma sintering (SPS), direct current sintering, microwave sintering, and ultraviolet (UV) sintering, which can be conducted at high pressure and temperature in an inert gas. In some embodiments, multiple post-processing methods can be used together or in a series. In some embodiments, the post-processing produces functionalized carbon nanoparticles or aggregates containing multi-walled spherical fullerenes (MWSFs) or connected MWSFs.

[0095] In some embodiments, the materials are mixed together in different combinations. In some embodiments, different carbon nanoparticles and aggregates containing MWSFs or connected MWSFs described herein are mixed together before postprocessing. For example, different carbon nanoparticles and aggregates containing MWSFs or connected MWSFs with different properties (e.g., different sizes, different compositions, different purities, from different processing runs, etc.) can be mixed together. In some embodiments, the carbon nanoparticles and aggregates containing MWSFs or connected MWSFs described herein can be mixed with graphene to change the ratio of the connected MWSFs to graphene in the mixture. In some embodiments, different carbon nanoparticles and aggregates containing MWSFs or connected MWSFs described herein can be mixed together after post-processing. For example, different carbon nanoparticles and aggregates containing MWSFs or connected MWSFs with different properties and / or different post-processing methods (e.g., different sizes, different compositions, different functionality, different surface properties, different surface areas) can be mixed together.

[0096] In some embodiments, the carbon nanoparticles and aggregates described herein are produced and collected, and subsequently processed by mechanical grinding, milling, and / or exfoliating. In some embodiments, the processing (e.g., by mechanical grinding, milling, exfoliating, etc.) reduces the average size of the particles. In some embodiments, the processing (e.g., by mechanical grinding, milling, exfoliating, etc.) increases the average surface area of the particles. In some embodiments, the processing by mechanical grinding, milling and / or exfoliation shears off some fraction of the carbon layers, producing sheets of graphite mixed with the carbon nanoparticles.

[0097] In some embodiments, the mechanical grinding or milling is performed using a ball mill, a planetary mill, a rod mill, a shear mixer, a high-shear granulator, an autogenous-26- LYT1P050.P_LYTEP213WOmill, or other types of machining used to break solid materials into smaller pieces by grinding, crushing or cutting. In some embodiments, the mechanical grinding, milling and / or exfoliating is performed wet or dry. In some embodiments, the mechanical grinding is performed by grinding for some period of time, then idling for some period of time, and repeating the grinding and idling for a number of cycles. In some embodiments, the grinding period is from 1 minute to 20 minutes, or from 1 minute to 10 minutes, or from 3 minutes to 8 minutes, or approximately 3 minutes, or approximately 8 minutes. In some embodiments, the idling period is from 1 minute to 10 minutes, or approximately 5 minutes, or approximately 6 minutes. In some embodiments, the number of grinding and idling cycles is from 1 minute to 100 minutes, or from 5 minutes to 100 minutes, or from 10 minutes to 100 minutes, or from 5 minutes to 10 minutes, or from 5 minutes to 20 minutes. In some embodiments, the total amount of time of grinding and idling is from 10 minutes to 1200 minutes, or from 10 minutes to 600 minutes, or from 10 minutes to 240 minutes, or from 10 minutes to 120 minutes, or from 100 minutes to 90 minutes, or from 10 minutes to 60 minutes, or approximately 90 minutes, or approximately 120 minutes. Of course, grinding, milling, or idling times within the scope of the presently disclosed inventive embodiments may have any of the foregoing values or be within any of the foregoing exemplary ranges, between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0098] In some embodiments, the grinding steps in the cycle are performed by rotating a mill in one direction for a first cycle (e.g., clockwise), and then rotating a mill in the opposite direction (e.g., counterclockwise) for the next cycle. In some embodiments, the mechanical grinding or milling is performed using a ball mill, and the grinding steps are performed using a rotation speed from 100 to 1000 rpm, or from 100 to 500 rpm, or approximately 400 rpm, or any value or range of values therebetween. In some embodiments, the mechanical grinding or milling is performed using a ball mill that uses a milling media with a diameter from 0.1 mm to 20 mm, or from 0.1 mm to 10 mm, or from 1 mm to 10 mm, or approximately 0.1 mm, or approximately 1 mm, or approximately 10 mm, or any value or range of values therebetween. In some embodiments, the mechanical grinding or milling is performed using a ball mill that uses a milling media composed of-27- LYT1P050.P_LYTEP213WOmetal such as steel, an oxide such as zirconium oxide (zirconia), yttria stabilized zirconium oxide, silica, alumina, magnesium oxide, or other hard materials such as silicon carbide or tungsten carbide.

[0099] In some embodiments, the carbon nanoparticles and aggregates described herein are produced and collected, and subsequently processed using elevated temperatures such as thermal annealing or sintering. In some embodiments, the processing using elevated temperatures is done in an inert environment such as nitrogen or argon. In some embodiments, the processing using elevated temperatures is done at atmospheric pressure, or under vacuum, or at low pressure. In some embodiments, the processing using elevated temperatures is done at a temperature from 500°C to 2500°C, or from 500°C to 1500°C, or from 800°C to 1500°C, or from 800°C to 1200°C, or from 800°C to 1000°C, or from 2000°C to 2400°C, or approximately 800°C, or approximately 1000°C, or approximately 1500°C, or approximately 2000°C, or approximately 2400°C. Of course, processing using elevated temperatures may be performed at any of the foregoing temperatures, or at a temperature within any of the foregoing exemplary ranges, or between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts.

[0100] In some embodiments, the carbon nanoparticles and aggregates described herein are produced and collected, and subsequently, in post processing steps, additional elements or compounds are added to the carbon nanoparticles, thereby incorporating the unique properties of the carbon nanoparticles and aggregates into other mixtures of materials.

[0101] In some embodiments, either before or after post-processing, the carbon nanoparticles and aggregates described herein are added to solids, liquids or slurries of other elements or compounds to form additional mixtures of materials incorporating the unique properties of the carbon nanoparticles and aggregates. In some embodiments, the carbon nanoparticles and aggregates described herein are mixed with other solid particles, polymers or other materials.

[0102] In some embodiments, either before or after post-processing, the carbon nanoparticles and aggregates described herein are used in various applications beyond applications pertaining to the present disclosure. Such applications including but not-28- LYT1P050.P_LYTEP213WOlimited to transportation applications (e.g., automobile and truck tires, couplings, mounts, elastomeric o-rings, hoses, sealants, grommets, etc.) and industrial applications (e.g., rubber additives, functionalized additives for polymeric materials, additives for epoxies, etc.).

[0103] FIG. 1A and IB show transmission electron microscope (TEM) images of as-synthesized carbon nanoparticles. The carbon nanoparticles of FIG. 1A (at a first magnification) and FIG. IB (at a second magnification) contain connected multi-walled spherical fullerenes 102 (MWSFs) with graphene layers 104 that coat the connected MWSFs. The ratio of MWSF to graphene allotropes in this example is approximately 80% due to the relatively short residence times. The MWSFs in FIG. 1A are approximately 5 nm to 10 nm in diameter, and the diameter can be from 5 nm to 500 nm using the conditions described above. In some embodiments, the average diameter across the MWSFs is in a range from 5 nm to 500 nm, or from 5 nm to 250 nm, or from 5 nm to 100 nm, or from 5 nm to 50 nm, or from 10 nm to 500 nm, or from 10 nm to 250 nm, or from 10 nm to 100 nm, or from 10 nm to 50 nm, or from 40 nm to 500 nm, or from 40 nm to 250 nm, or from 40 nm to 100 nm, or from 50 nm to 500 nm, or from 50 nm to 250 nm, or from 50 nm to 100 nm. Of course, average MWSF diameter within the scope of the presently disclosed inventive embodiments may have any of the foregoing values or be within any of the foregoing exemplary ranges, or between any of the foregoing exemplary ranges, without limitation and without departing from the scope of the presently described inventive concepts. No catalyst was used in this process, and therefore, there is no central seed containing contaminants. The aggregate particles produced in this example had a particle size of approximately 10 pm to 100 pm, or approximately 10 pm to 500 pm.

[0104] FIG. 1C shows the Raman spectrum of the as-synthesized aggregates in this example taken with 532 nm incident light. The ID / IG for the aggregates produced in this example is from approximately 0.99 to 1.03, indicating that the aggregates were composed of carbon allotropes with a high degree of order.

[0105] FIG. ID and FIG. IE show example TEM images of the carbon nanoparticles after size reduction by grinding in a ball mill. The ball milling was performed in cycles with a 3 minute counter-clockwise grinding step, followed by a 6 minute idle step, followed by a 3 minute clockwise grinding step, followed by a 6 minute idle step. The grinding steps-29- LYT1P050.P_LYTEP213WOwere performed using a rotation speed of 400 rpm. The milling media was zirconia and ranged in size from 0.1 mm to 10 mm. The total size reduction processing time was from 60 minutes to 120 minutes. After size reduction, the aggregate particles produced in this example had a particle size of approximately 1 pm to 5 pm. The carbon nanoparticles after size reduction are connected MWSFs with layers of graphene coating the connected MWSFs.

[0106] FIG. IF shows a Raman spectrum from these aggregates after size reduction taken with a 532 nm incident light. The ID / IG for the aggregate particles in this example after size reduction is approximately 1.04. Additionally, the particles after size reduction had a Brunauer, Emmett and Teller (BET) specific surface area of approximately 40 m2 / g to 50 m2 / g.

[0107] The purity of the aggregates produced in this sample were measured using mass spectrometry and x-ray fluorescence (XRF) spectroscopy. The ratio of carbon to other elements, except for hydrogen, measured in 16 different batches was from 99.86% to 99.98%, with an average of 99.94% carbon.

[0108] In this example, carbon nanoparticles were generated using a thermal hot-wire processing system. The precursor material was methane, which was flowed from 1 slm to 5 slm. With these flow rates and the tool geometry, the residence time of the gas in the reaction chamber was from approximately 20 second to 30 seconds, and the carbon particle production rate was from approximately 20 g / hr.

[0109] Further details pertaining to such a processing system can be found in the previously mentioned U.S. Patent 9,862,602, titled “CRACKING OF A PROCESS GAS.”

[0110] FIG. 1G, FIG. 1H and FIG. II show TEM images of as-synthesized carbon nanoparticles of this example. The carbon nanoparticles contain connected multi-walled spherical fullerenes (MWSFs) with layers of graphene coating the connected MWSFs. The ratio of multi-walled fullerenes to graphene allotropes in this example is approximately 30% due to the relatively long residence times allowing thicker, or more, layers of graphene to coat the MWSFs. No catalyst was used in this process, and therefore, there is no central seed containing contaminants. The as-synthesized aggregate particles produced in this example had particle sizes of approximately 10 pm to 500 pm. FIG. I shows a Raman spectrum from the aggregates of this example. The Raman signature of the as-synthesized-30- LYT1P050.P_LYTEP213WOparticles in this example is indicative of the thicker graphene layers which coat the MWSFs in the as-synthesized material. Additionally, the as-synthesized particles had a Brunauer, Emmett and Teller (BET) specific surface area of approximately 90 m2 / g to 100 m2 / g.

[0111] FIG. IK and FIG. IL show TEM images of the carbon nanoparticles of this example. Specifically, the images depict the carbon nanoparticles after performance of size reduction by grinding in a ball mill. The size reduction process conditions were the same as those described as pertains to the foregoing FIG. 1G through FIG. II. After size reduction, the aggregate particles produced in this example had a particle size of approximately 1 pm to 5 pm. The TEM images show that the connected MWSFs that were buried in the graphene coating can be observed after size reduction. FIG. IM shows a Raman spectrum from the aggregates of this example after size reduction taken with 532 nm incident light. The ID / IG for the aggregate particles in this example after size reduction is approximately 1, indicating that the connected MWSFs that were buried in the graphene coating as-synthesized had become detectable in Raman after size reduction, and were well ordered. The particles after size reduction had a Brunauer, Emmett and Teller (BET) specific surface area of approximately 90 m2 / g to 100 m2 / g.

[0112] FIG. IN is a scanning electron microscope (SEM) image of carbon aggregates showing the graphite and graphene allotropes at a first magnification. FIG. 10 is a SEM image of carbon aggregates showing the graphite and graphene allotropes at a second magnification. The layered graphene is clearly shown within the distortion (wrinkles) of the carbon. The 3D structure of the carbon allotropes is also visible.

[0113] The particle size distribution of the carbon particles of FIG. IN and FIG. 10 is shown in FIG. IP. The mass basis cumulative particle size distribution 106 corresponds to the left y-axis in the graph (Q3(x) [%]). The histogram of the mass particle size distribution 108 corresponds to the right axis in the graph (dQ3(x) [%]). The median particle size is approximately 33 pm. The 10th percentile particle size is approximately 9 pm, and the 90th percentile particle size is approximately 103 pm. The mass density of the particles is approximately 10 g / L.

[0114] The particle size distribution of the carbon particles captured from a multiplestage reactor is shown in FIG. IQ. The mass basis cumulative particle size distribution 114 corresponds to the left y-axis in the graph (Q3(x) [%]). The histogram of the mass particle-31- LYT1P050.P_LYTEP213WOsize distribution 116 corresponds to the right axis in the graph (dQ3(x) [%]). The median particle size captured is approximately 11 pm. The 10th percentile particle size is approximately 3.5 pm, and the 90th percentile particle size is approximately 21 pm. The graph in FIG. IQ also shows the number basis cumulative particle size distribution 118 corresponding to the left y-axis in the graph (Q°(x) [%]). The median particle size by number basis is from approximately 0.1 pm to approximately 0.2 pm. The mass density of the particles collected is approximately 22 g / L.

[0115] Returning to the discussion of FIG. IP, the graph also shows a second set of example results. Specifically, in this example, the particles were size-reduced by mechanical grinding, and then the size-reduced particles were processed using a cyclone separator. The mass basis cumulative particle size distribution 110 of the size-reduced carbon particles captured in this example corresponds to the left y-axis in the graph (Q3(x) [%]). The histogram of the mass basis particle size distribution 112 corresponds to the right axis in the graph (dQ3(x) [%]). The median particle size of the size-reduced carbon particles captured in this example is approximately 6 pm. The 10th percentile particle size is from 1 pm to 2 pm, and the 90th percentile particle size is from 10 pm to 20 pm.HIGH PURITY CARBON ALLOTROPES PRODUCED USING MICROWAVE REACTOR SYSTEMS

[0116] In some cases, carbon particles and aggregates containing graphite, graphene and amorphous carbon can be generated using a microwave plasma reactor system using a precursor material that contains methane, or contains isopropyl alcohol (IPA), or contains ethanol, or contains a condensed hydrocarbon (e.g., hexane). In some other examples, the carbon-containing precursors are optionally mixed with a supply gas (e.g., argon). The particles produced in this example contained graphite, graphene, amorphous carbon and no seed particles. The particles in this example had a ratio of carbon to other elements (other than hydrogen) of approximately 99.5% or greater.

[0117] In one particular example, a hydrocarbon was the input material for the microwave plasma reactor, and the separated outputs of the reactor comprised hydrogen gas and carbon particles containing graphite, graphene and amorphous carbon. The carbon particles were separated from the hydrogen gas in a multi-stage gas-solid separation-32- LYT1P050.P_LYTEP213WOsystem. The solids loading of the separated outputs from the reactor was from 0.001 g / L to 2.5 g / L.

[0118] FIG. 1R, FIG. IS, and FIG. IT are TEM images of as-synthesized carbon nanoparticles. The images show examples of graphite, graphene and amorphous carbon allotropes. The layers of graphene and other carbon materials can be clearly seen in the images.

[0119] The particle size distribution of the carbon particles captured is shown in FIG.1U. The mass basis cumulative particle size distribution 120 corresponds to the left y-axis in the graph (Q3(x) [%]). The histogram of the mass particle size distribution 122 corresponds to the right axis in the graph (dQ3(x) [%]). The median particle size captured in the cyclone separator in this example was approximately 14 pm. The 10th percentile particle size was approximately 5 pm, and the 90th percentile particle size was approximately 28 pm. The graph in FIG. 1U also shows the number basis cumulative particle size distribution 124 corresponding to the left y-axis in the graph (Q°(x) [%]). The median particle size by number basis in this example was from approximately 0.1 pm to approximately 0.2 pm.

[0120] FIG. IV, FIG. 1W, and FIG. IX, and 1Y are images that show three-dimensional carbon-containing structures that are grown onto other three-dimensional structures. FIG. IV is a 100X magnification of three-dimensional carbon structures grown onto carbon fibers, whereas FIG. 1W is a 200X magnification of three-dimensional carbon structures grown onto carbon fibers. FIG. IX is a 10000X magnification of three-dimensional carbon structures grown onto carbon fibers. The three-dimensional carbon growth over the fiber surface is shown. FIG. 1Y is a 10000X magnification of three-dimensional carbon structures grown onto carbon fibers. The image depicts growth onto the basal plane as well as onto edge planes.

[0121] More specifically, FIGs. 1V-1Y show example SEM images of 3D carbon materials grown onto fibers using plasma energy from a microwave plasma reactor as well as thermal energy from a thermal reactor. FIG. IV shows an SEM image of intersecting fibers 131 and 132 with 3D carbon material 130 grown on the surface of the fibers. FIG.1W is a higher magnification image (the scale bar is 300 pm compared to 500 pm for FIG. IV) showing 3D carbon growth 130 on the fiber 132. FIG. IX is a further magnified view-33- LYT1P050.P_LYTEP213WO(scale bar is 40 p.m) showing 3D carbon growth 130 on fiber surface 135, where the 3D nature of the carbon growth 130 can be clearly seen. FIG. 1Y shows a close-up view (scale bar is 500 nm) of the carbon alone, showing interconnection between basal planes 136 and edge planes 134 of numerous sub-particles of the 3D carbon material grown on the fiber. FIGs. 1V-1 Y demonstrate the ability to grow 3D carbon on a 3D fiber structure according to some embodiments, such as 3D carbon growth grown on a 3D carbon fiber.

[0122] In some embodiments, 3D carbon growth on fibers can be achieved by introducing a plurality of fibers into the microwave plasma reactor and using plasma in the microwave reactor to etch the fibers. The etching creates nucleation sites such that when carbon particles and sub-particles are created by hydrocarbon disassociation in the reactor, growth of 3D carbon structures is initiated at these nucleation sites. The direct growth of the 3D carbon structures on the fibers, which themselves are three-dimensional in nature, provides a highly integrated, 3D structure with pores into which resin can permeate. This 3D reinforcement matrix (including the 3D carbon structures integrated with high aspect ratio reinforcing fibers) for a resin composite results in enhanced material properties, such as tensile strength and shear, compared to composites with conventional fibers that have smooth surfaces and which smooth surfaces typically delaminate from the resin matrix.FUNCTIONALIZING CARBON

[0123] In some embodiments, carbon materials, such as 3D carbon materials described herein, can be functionalized to promote adhesion and / or add elements such as oxygen, nitrogen, carbon, silicon, or hardening agents. In some embodiments, the carbon materials can be functionalized in situ - that is, within the same reactor in which the carbon materials are produced. In some embodiments, the carbon materials can be functionalized in postprocessing. For example, the surfaces of fullerenes, graphene, etc. may be functionalized with oxygen- or nitrogen-containing species which form bonds with polymers of the resin matrix, thus improving adhesion and providing strong binding to enhance the strength of composites.

[0124] Embodiments include functionalizing surface treatments for carbon (e.g., CNTs, CNO, graphene, 3D carbon materials such as 3D graphene) utilizing plasma reactors (e.g., microwave plasma reactors) described herein. Various embodiments can include in-34- LYT1P050.P_LYTEP213WOsitu surface treatment during creation of carbon materials that can be combined with a binder or polymer in a composite material. Various embodiments can include surface treatment after creation of the carbon materials while the carbon materials are still within the reactor.

[0125] Graphene is an allotrope of sp2-hybridized carbon arranged in a honeycomb lattice nanostructure possessing a significantly higher mechanical strength than steel. For this reason, many researchers have used graphene in polymer composites, especially polyolefins, in efforts to increase the mechanical properties of the resulting graphene-polymer composites. However, due to the very different physical property of the graphene and polyolefin, it is difficult to achieve a good dispersion of graphene in the polyolefin resin.

[0126] Polyolefins are a family of thermoplastics, a class of polymers that can be repeatedly softened by heating and hardened by cooling, including common examples like polyethylene (PE) and polypropylene (PP) that represent the largest portion of commercial polyolefin. The chemical structure of polyolefins include a sp3-hybridized carbon chains that have a tetrahedral molecular geometry that have a hydrophobic-hydrophobic interaction. However, sp2 hybridized graphene having a planar geometry (and it-it stacking) and sp3 hybridized polyolefin are not compatibilized due to the different nature of their chemical structures.

[0127] 3DG (i.e., three-dimensional graphene) has a structure that may be more compatible with polyolefins. 3DG have a structural morphology that is fundamentally different than 2D graphene. 3DG may be characterized as a carbon nanoparticle. In preferred approaches, as described herein, the carbon nanoparticles has a structural morphology characterized by a plurality of spikes and nodules. The carbon nanoparticle as described herein includes two or more connected multi-walled spherical fullerenes and layers of graphene coating the connected multi-walled spherical fullerenes. Preferably, the multi-walled spherical fullerenes do not contain a core composed of impurity elements other than carbon. The morphology of 3DG is a crumpled 3D structure having a lot of kinks and resembles “broccoli florets”. The floret-type morphology is not a spherical shape.

[0128] Several embodiments describe approaches to 3DG functionalization where compatibility between graphene and polyolefin is a key component. In one embodiment,-35- LYT1P050.P_LYTEP213WOperoxide chemistry is employed with polyolefin to directly functionalize the polyolefin with an anchor group to bridge with graphene. For example, in one approach, polyethylene (PE) is functionalized with a functional group such as m-TMI using peroxide chemistry and is then reacted with graphene oxide (GO) to form m-TMI-grafted PE bound to GO.

[0129] In another embodiment, a surface of three-dimensional graphene oxide (3DGO) may be functionalized with silica particles thereby resulting in a silica-coated 3DGO. In one approach, coating silica on a 3DGO template may include a one pot reaction. In one approach, functional groups may be attached on the surface of a 3DGO to function as an anchor for silica particles. Functional groups may include alkyl, amine, thiol, etc. In exemplary approach, spherical shaped silica may be covalently attached to the surface of 3DGO via a silane linkage to enhance the mechanical properties (e.g., strength, stiffness, etc.) of a polyolefin-silica-graphene composite. In one embodiment, the anisotropic shape of the silica particles enhances the mechanical strength of polyolefin-silica-graphene composite while maintaining flexibility of the composite. The anisotropic shape of the silica particles may include a rod, a bullet, a noodle, etc.GRAFTED 3DG TO POLYOLEFINS

[0130] According to various embodiments described herein, three-dimensional graphene (3DG) is grafted to polyolefin polymers. According to various approaches, strategies include processes to introduce a functional anchor onto the 3DG so that the functional anchor may be present as a nucleophile or electrophile in a chemical reaction between the polyolefin and the graphene itself. Strategic approaches are described that include processes chemically modify one or more of the components of a composite, e.g., 3D graphene, polyolefin, etc. to obtain good compatibilization leading to an enhanced mechanical property of the resulting composite materials. In an exemplary aspect both components 3D graphene and polyolefin are chemically modified to obtain a composite material that has enhanced mechanical properties.

[0131] According to various aspects, at least two methods described herein may be applied to functionalization of graphene and polyolefin. Various processes highlight polyolefins such as polyethylene (PE), polypropylene (PP), etc. In one approach, a method relates to peroxide chemistry. In another approach, a method relates to xanthylation.-36- LYT1P050.P_LYTEP213WODicumyl peroxide is widely used for grafting maleic anhydride onto polyolefins for use as compatibilizers. The general use of peroxides, xanthylation, etc. to functionalize both polyolefin and graphene may be tailored to enhance the mechanical properties of the final polyolefin composite material. Further tailoring of the associative chemistry of graphene and polyolefin can be used to introduce controlled and reversible mechanochemical failure mechanisms.

[0132] More particularly the herein-disclosed polyolefins can be used in failureresistant mechanical structures such as are found in a wide range of commercial applications such as in transportation systems, (e.g., couplings, mounts, manifolds, frames). In some of said transportation systems, the superior mechanical properties of the herein-disclosed polyolefins can be exploited through use of said polyolefins in structures that enclose EV batteries, and / or modules or assemblies or packs enclosing said EV batteries. In some situations, the EV batteries are composed of electrochemical cells, which may be found in pouch formats, or as a can / casing that encloses the electrochemical cell, and / or in the format of a tray to provide a mechanical structure for holding electrochemical cells, and / or in the format of a pan provide a mechanical structure for holding electrochemical cells.

[0133] FIG. 2A depicts a method 200 of functionalization of graphene and polyolefin relating to peroxide chemistry. The following description is a simplification and it should be noted that the 3D graphene 202 may be functionalized multiple times than the one time depicted in the FIGs. For clarity but not meant to be limiting in any way, one functionalization is represented.

[0134] The method 200 depicted in FIG. 2A represents a conceptual framework of covalent grafting graphene to polyolefin. 3D graphene (3DG) 202 is represented here as the circle with the stripe pattern. Table 1 lists several functional chemistries that may be utilized to achieve grafting of polyolefin to 3DG. Part (a) of FIG. 2A depicts the transformation of 3DG 202 into an appropriately chemically-reactive 3DG 204. In one aspect, the chemically-reactive 3DG 204 includes an added functional group 206. The chemically-reactive 3DG may be a functionalized 3DG. In a preferred approach, the conditions i to transform 3DG 202 to a chemically-reactive 3DG 204 includes oxidation of 3DG using ozone activation. The chemically-reactive 3DG 204 is an oxidized 3DG, i.e., a-37- LYT1P050.P_LYTEP213WO3Dgraphene oxide (3DGO). Chemically-reactive 3DG 204 may also be referred to as a functionalized 3DG. Some reagents that may be used for the transformation of 3DG 202 to chemically-reactive 3DG 204 with condition i are listed in Table 1.TABLE 1. Transformation and reagents for achieving desired functionality Transformation of Reagent3DG to functionalized 3DGAminopropyltrimethoxy silane (APTMS) Vinyltrimethoxy silane (VTMS)Ritter reaction (acrylonitrile / sulfuric and acetic acid 3-isopropenyl-a,a-dimethylbenzylisocyanate (TMI)Allyl amine3-(trimethoxysilyl)propyl methacrylate (TMSMA)Transformation of ReagentPolyolefin to functionalizedpolyolefinDicumyl peroxide (DCP)Xanthylation with xanthylamideDCP with 3-isopropenyl-a,a-dimethylbenzyl isocyanate (m-TMI)Transformation of Reagentfunctionalized polyolefin to abonded association of 3DG topolyolefinDifunctional butylacrylateAlkyldiothiol (from xanthylation)Functionalized graphene or graphene oxide

[0135] Part (b) depicts the transformation of a molecular strand of polyolefin 208 (e.g., PE, PP, etc.) into an appropriately functionalized polyolefin 210. In one aspect, a functionalized polyolefin 210 includes added functional groups 212. The notation, ii, describes the conditions to transform polyolefin 208 into functionalized polyolefin 210. A functionalized polyolefin is a chemically-reactive polyolefin. In a preferred approach, the-38- LYT1P050.P_LYTEP213WOpolyolefin 208 has a plurality of hydrocarbon groups 209 that may be functionalized, such as ethylene and propylene groups, olefin monomers, polymerizable hydrocarbon molecules, etc. The polyolefin 208 may be functionalized at the hydrocarbon groups 209 by addition of a functional group 212 thereby transforming the polyolefin 208 into a functionalized polyolefin 210. The functionalization of polyolefin may be designed to enable bond formation of the functional group 212 introduced under conditions ii to the functional group 206 on the chemically-reactive 3DG 204 introduced under conditions i.

[0136] Table 1 lists some reagents such as DCP, m-TMI, etc. that may be used for the transformation of polyolefin to a functionalized polyolefin under conditions ii. In some approaches, the polyolefin may be functionalized with a radical generator, such as dicumyl peroxide, at elevated temperatures, however, usually polyolefins are inert.

[0137] Part (c) depicts the transformation of the functionalized polyolefin to a bonded association of 3DG. For instance, the transformation of a functionalized polyolefin 210 to a 3DG-grafted polyolefin 214 under the conditions iii. The 3DG-grafted polyolefin 214 is shown with a bonded association 216 of the functional group 206 of the chemically-reactive 3DG 204 to the functional group 212 of the functionalized polyolefin 210. Table 1 lists some reagents that may be used for the transformation of a functionalized polyolefin to a bonded association of 3DG under conditions iii.

[0138] According to one embodiment, a polyolefin-graphene composite include a polyolefin having a plurality of hydrocarbon groups, such as ethylene groups, propylene groups, etc. and a plurality of 3DG structures, where each 3DG structure is covalently bonded to one of the plurality of hydrocarbon groups. As illustrated in part (c), a polyolefin-graphene composite may include a 3DG-grafted polyolefin 214 having a plurality of hydrocarbon groups 209 where each chemically-reactive 3DG 204 is covalently bonded to one of the plurality of hydrocarbon groups 209. In some approaches, the functionalized 3DG may be bound to the corresponding hydrocarbon group via a silane functional group. In other approaches, the 3DG may be bound to the corresponding hydrocarbon group via an isocyanate functional group. In preferred approaches, the polyolefin-graphene composite has a uniform distribution of three-dimensional graphene structures along the plurality of hydrocarbon groups of the polyolefin.-39- LYT1P050.P_LYTEP213WO

[0139] According to one embodiment, functionalization of a polyolefin with 3DG may involve a single step. FIG. 2B depicts a method 220 that describes a functionalization pathway of a polyolefin with 3DG in a single step. Method 220 is similar to method 200 depicted in FIG. 2A, however, method 220 includes grafting 3DG onto the polyolefin occurs in one step. Similar to method 200 in FIG. 2A, part (a) of FIG. 2B includes the transformation of 3DG 202 to a chemically-reactive 3DG 204 having an added functional group 206. The transformation of 3DG 202 to chemically-reactive 3DG 204 may occur under conditions i. . In a preferred approach, the conditions i to transform 3DG 202 to a chemically-reactive 3DG 204 includes oxidation of 3DG using ozone activation. The chemically-reactive 3DG 204 is an oxidized 3DG, i.e., a 3Dgraphene oxide (3DGO).

[0140] Part (b) of FIG. 2B illustrates a second part of method 220 that includes the transformation of a polyolefin to a bonded 3DG polyolefin in a single step. A polyolefin 218 transforms into a functionalized polyolefin 224 in the presence of a chemically-reactive 3DG 204. A polyolefin 218 undergoes a covalent bond formation 226 with an anchoring group 222 during the compounding process and subsequently bonds with chemically-reactive 3DG 204 to form polyolefin bonded to 3DG 224. This concept may be applied to examples where grafting the polyolefin is achieved in the compounding step of the thermoplastic.

[0141] FIG. 2C illustrates a method 250 that is one example of method 200. A basic peroxide, such as dicumyl peroxide (DCP), mediates functionalization of a neutral polyolefin such as polyethylene by turning polyethylene into a radical species, and the radical will then react with vinyl groups to form a chemical bond. For example, the radicalized polyethylene reacts with the vinyl silane grafted on the 3DGO. This bring 3DGO in direct contact with the polyethylene for further strength enhancement. The transformation of grafting of vinyl silane-functionalized graphene to polyethylene occurs through radical / peroxide chemistry. In other approaches, the reaction may include a compounder under compounding conditions for polyethylene with 3DGO. Other functionalizations are possible, including but not limited to functionalization with various vinyl and allyl groups.

[0142] FIG. 2D illustrates two examples of method 200. Method 260 illustrates polypropylene grafted with m-TMI with a peroxide to form a covalent bond, which then-40- LYT1P050.P_LYTEP213WOreacts with hydroxyl groups present on graphene oxide (3DGO) to form a urethane during the compounding process. PP-m-TMI (polypropylene functionalized with m-TMI) acts as a compatibilizer between polyolefin and graphene. The use of peroxide to introduce functional groups on polyolefin may be conducted either in solution or neat during the melt-blending process without solvent.

[0143] The use of radicals has drawbacks, including chain-scission from tertiary radicals which have the effect of reducing the molecular weight of the polyolefin and therefore negatively impacting the mechanical properties of the final composite material. One approach includes a promising method for functionalizing polyolefins is through radical amides. In one approach, xanthylation of polyolefins may be used for graphene grafting to polyolefins. In one example, xanthylation of polypropylene may include light-mediated H-radical abstraction on polypropylene. After xanthylation of polypropylene, a thiol-Michael addition onto acrylamide functionalized 3DG may be achieved through amino-propyltrimethoxysilane functionalization of graphene followed by amidation of the primary amine with acryloyl chloride.

[0144] Briefly the process for forming a structure of 3DG grafted polyolefin includes mixing the polyolefin pellets (e.g., PE, PP, etc.) as a hot mold using two mixers. The functionalized 3DG is added to the mixture and mixed at 120 °C to 140 °C. The mixture may be poured into molds to form a desired shape.

[0145] According to one embodiment, the polyolefin has a chemical formula (CH2CHR)nand the polyolefin-graphene composite has a chemical formula (CH(3DG)CHR)n, where a mechanical strength the polyolefin-graphene composite is greater than a mechanical strength of the polyolefin. In various approaches, the functionalized graphene in the polyolefin composite may be detected via a series of analyses, including but not limited the following. The composite may be analyzed by first stripping off polyolefin using a chlorinated solvent at a high temperature followed by washing off any residual polyolefin from the composite to isolate the functionalized 3DG. The composition of the composite may be assessed by gravimetric analysis, elemental analysis and thermogravimetric analysis. The morphology of the functionalized 3DG may be assessed using microscopic images after isolation. The functionalized 3DG in the-41- LYT1P050.P_LYTEP213WOpolyolefin composite may be reverse-engineered using generally well-known methods for better understanding of the structure of the composite.SILICA / 3DG HYBRID COMPOUNDS

[0146] There is a persistent challenge of balancing stiffness and ductility in polyolefin materials, a trade-off that typically forces engineers to sacrifice one property for the other. Silica is an effective strength enhancing additive; however, tensile strength properties of a polyolefin composite that has silica may be compromised and thus adversely impact strength. By using a hybrid filler system of covalently bonded oxidized 3D graphene and shape-anisotropic silica, a composite may retain flexibility while achieving elevated mechanical strength. Moreover, it has been desirable to lower the general range of graphene loading. For example, in one approach, the graphene loading may be in a range of 3.5 wt.% to 2 wt.% or less. These improvements would reduce material consumption, lowers production costs, and extends product lifespan.

[0147] Researchers and manufacturers have encountered the challenge of simultaneously enhancing stiffness and ductility in polyolefin materials. Early attempts often involved blending multiple polymer types (i.e., thermoplastic polyolefins - a blend of polymers), but these methods frequently ended up sacrificing one property for the other. Over time, advanced fillers such as carbon nanotubes, layered silicates, and graphitic materials were explored to create interlinked networks that help carry stress while still allowing some chain mobility.

[0148] Various embodiments described herein address a critical challenge in polymer engineering — namely, achieving both high stiffness and ductility in polyolefin materials, which is a balance typically difficult to attain. In one embodiment, functionalizing and / or associating graphene with an additive may lead to a chemically functionalized graphene that may lead to improved mechanical properties. In one approach, inorganic substances, such as silica nanoparticles were considered for functionalizing 3DG. As described herein, one embodiment includes in situ silica synthesis where a surface of graphene is coated with a silica layer. Another embodiment includes a separate silica synthesis where silica nanoparticles are synthesized separately and distributed onto the graphene surface.-42- LYT1P050.P_LYTEP213WO

[0149] FIG. 3 illustrates two embodiments for associating silica nanoparticles onto a surface of oxidized 3DG (3DGO). The SEM images show varying magnifications of a silica-graphene hybrid compound having silica nanoparticles added in the approaches described herein. Part (a) illustrates in situ synthesis of silica nanoparticles on the surface of 3DGO. As described further below, TEOS, a silica precursor, is added to graphene oxide so that silica nanoparticles grow from the surface of the graphene oxide. The characteristic flakey morphology of the 3DGO becomes coated with a silica layer. The in situ process allows the weight ratio of graphene to silica to be varied (e.g., preferably more silica and less graphene).

[0150] Part (b) illustrates synthesis of silica nanoparticles separately from the graphene followed by addition of the synthesized silica nanoparticles to the oxidized 3DG (3DGO). In one example, as shown in the SEM images, spherical silica nanoparticles are evenly distributed on the graphene surface. The size of the silica nanoparticles may be tuned. The weight ratio of the graphene to silica may be varied (e.g., preferably more silica and less graphene).IN SITU SILICA NANOPARTICLE SYNTHESIS

[0151] By utilizing covalently bonded oxidized 3D graphene (3DGO) alongside shape-anisotropic silica, the composite more effectively disperses stresses throughout the polymer matrix. 3D graphene forms a stable, stress-bearing network, while shape-anisotropic silica offers additional load-bearing capacity and preserves ductility by aligning with the polymer chains. This synergy resolves the common stiffness-ductility trade-off and opens avenues for more robust yet flexible plastic components.

[0152] In one embodiment, in situ silica synthesis includes the surface of ozone-treated 3DG (e.g., 3DGO) functionalized with silica nanoparticles. Ozone treatment of 3DG oxidizes 3DG to become a 3D graphene oxide (3DGO). The oxidized groups on 3DG act as an anchor for chemical reactions to add functional groups to the GO. In one approach, silica nanoparticles are coupled on the surface of 3DGO. In one approach, some of the silica nanoparticles are coupled to hydroxyl groups on the surface of the 3DGO. In another approach, the surface of 3DG is coated with a layer of silica nanoparticles. As described herein, silica nanoparticles are shown to be evenly distributed on the graphene surface. The-43- LYT1P050.P_LYTEP213WOsilica particle size may be tuned. A weight ratio of silica to graphene may be varied so that less graphene is needed to form the silica-decorated graphene. In some approaches, a weight ratio of graphene to silica is preferably in a range of greater than about 0.1 to about 15. In some approaches, a weight ratio of graphene to silica in the graphene-silica compound is less than 0.90, less than 0.70, less than 0.50, less than 0.40 less than 0.30, less than 0.20, less than 0.15, about 0.10, less than 0.10, etc.

[0153] In one approach, silica nanoparticles are directly condensed onto the graphene oxide surface. In one example, as illustrated in part (a) of FIG.4, method 1 describes direct silica condensation with a silica such as TEOS. A separately prepared silica precursor mixture, e.g., TEOS, is added to an ozone-treated 3DG (e.g., 3DGO) dispersion thereby resulting in silane groups being condensed on the hydroxyl groups on the graphene surface under basic conditions (e.g., NFUOH) in a solvent of ethanol and water. A silica coating is formed on the surface of the graphene characterized by silica nanoparticles formed on the graphene via available hydroxyl groups.

[0154] According to one embodiment, some of the silica nanoparticles are associated with the surface of the oxidized three-dimensional graphene via a coupling agent. In a preferred approach, the coupling agent is an amino-functionalized silane. In one example, an amino-functionalized silane, e.g., APTES, may be condensed on graphene surface in a two-step process. In one example, as illustrated in part (b), method 2 describes silane coupling followed by silica condensation. Amino-functionalized silane (e.g., APTES) having a dangling primary amine group is reacted with ozone-treated 3DG (3DGO) via condensing onto available hydroxyl groups. A separately prepared silica mixture, e.g., TEOS, is added to the silane-functionalized 3DGO. Silica nanoparticles condense onto silane groups as well as unreacted hydroxyl groups. Method 2 utilizes a coupling agents, such as APTES, between the graphene hydroxyl group and the silica nanoparticles. The presence of a coupling agent allows silica nanoparticles to be tethered off the surface of the graphene and allows better incorporation of silica as indicated by the two silica nanoparticles formed on the hydroxyl group using method 2 compared to the single silica nanoparticle formed on the hydroxyl group using method 1.

[0155] According to one embodiment, a silica-graphene hybrid compound enhances mechanical strength to a polyolefin-graphene composite material. Mechanical strength of-44- LYT1P050.P_LYTEP213WOpolyolefin composite material may be assessed measuring the flexural modulus, e.g., bending modulus, of the material. Flexural modulus is a material property that describes the material’s stiffness and resistance to bending, measured as the ratio of stress to strain in flexural deformation. Flexural modulus quantifies the composite material’s resistance to bending when a force is applied perpendicular to the long edge of the material.

[0156] In a preferred approach, a mechanical strength of a polyolefin-silica-graphene composite is greater than a mechanical strength of a polyolefin without the silica-graphene hybrid compound by at least 10% as measured by FM. FIG. 5 is a plot of flexural modulus of each polyolefin sample formed with the silica-graphene hybrid compounds generated using method 1 or method 2 in FIG. 4. Table 2 lists the properties of each sample tested for flexural modulus (FM). All formulations contained 2 wt% of calculated ozone-treated 3DG (3DGO) amount relative to the total formulation. The samples were processed at 225 °C for about 24 hours. Compared to neat PP (polypropylene), the addition of both 3DGO and 3DGO-SiO2 did not lead to improved FM. In the sample that included 3DGO-APTES-SiO2, FM improved by 16.6% compared to neat PP and 13.6% compared to both PP / 3DGO and PP / 3DGO-SiO2.TABLE 2: Properties of formulations 3DGO-SiO2compared to 3DGO-APTES-SiO2Sample APTES Flexural StandardModulus Deviation(psi) (psi)Neat PP No 203,723 7,6872 wt% 3DGO No 209,033 1,5353DGO-SiO2No 209,021 1,6333DGO-ASiO2Yes 237,559 2,756

[0157] In one embodiment, a scaled up production (5X) of a 3DGO-ASiO2hybrid compound has a higher yield compared to a smaller scale production of 3DGO-ASiO2. For example, comparing formation of a 3DGO-ASiO2compound using a larger 5X scale to a 3DGO-ASiO2compound formed using smaller scale (as shown above in Table 2), the yield from the 5X scaled up formulation is about 5X the yield of the silica-graphene compound formed using the smaller scale (37.0 g versus 7.9 g). Moreover, the scaled up formulation-45- LYT1P050.P_LYTEP213WOhas a preferred slightly less graphene per silica (9.2% graphene / 81.9% silica) compared to the standard formulation (12.5% graphene / 74% silica). FIG. 6 depicts scanning electron micrograph (SEM) images of the silica-graphene compound formed using standard formulation in part (a), and silica-graphene compound formed with a 5X scaled up formulation in part (b). For both formulations, the silica particles are evenly distributed on the oxidized graphene surface of both samples. However, the silica particle size of the silica-graphene compound in scaled up formulation has silica nanoparticles that are about 2X smaller (70-80 nm diameter) (part (b)) compared to the nanoparticles formed in the silica-graphene compound using a smaller scale formulation (150-250 nm diameter) (part (a)).

[0158] Ozone-treated 3DG (3DGO) has a flaky morphology that is characterized by a plurality of edges and nodules that expose the surface of the GO to functionalization. Commercial GO, on the other hand, is characterized by a morphology of planar sheets. The SEM images shown in FIG. 7 illustrate differences in silica-graphene compounds formed with 3DGO and commercial GO at various magnifications. The upper row images in part (a) show the silica-decorated ozone-treated 3DG (3DGO-SiO2) having a flakey morphology of 3DGO (5000x magnification) with silica nanoparticles distributed on the flakey 3DGO. The lower row images in part (b) show the silica-decorated commercial GO (Comm-GO-SiO2), having the characteristic morphology of planar sheets with the silica nanoparticles distributed on the surface of the sheets. In both cases, the silica functionalization does not include an amino-functionalized saline APTES. Both silica-graphene hybrid compounds have silica nanoparticles that are similar size. However, the 3DGO compositions show large portions of bare graphene surface. The total yield of hybrid compounds is slightly larger in the 3DGO preparation compared to the commercial GO (2.3 g vs 1.6 g).

[0159] According to one approach, a process mediated by an amino-functionalized silane coupling agent produces silica-graphene compounds having a more even distribution of silica particles on the surface of 3DGO. In one approach, including a coupling agent such as APTES before adding the silica precursor allows the silica particles to become evenly distributed on the surface of the flakey-characterized 3DGO. FIG. 8 illustrates the effect of including APTES in the process of forming silica-decorated GO hybrid-46- LYT1P050.P_LYTEP213WOcompounds (as described in part (b) of FIG. 3) that results in better silica condensation on 3DG0 compared to Comm-GO. The SEM images in the upper row of part (a) show the 3DGO-ASiO2 hybrid compound having an even distribution of silica nanoparticles on the 3DGO surface. The SEM images in the lower row of part (b) illustrate the Comm-GO-ASiO2 hybrid compound showing the planar nanoplatelets of GO sparsely covered with silica nanoparticles.

[0160] Some differences between 3DGO and commercial GO include silica particle size in the hybrid compound. The silica particle size is significantly larger in the 3DGO-ASiO2 hybrid compound compared to the Comm-GO- ASiO2 hybrid compound (150-250 nm vs 20-30 nm). Moreover, the process of including the amino-functionalized silane results in a greater total yield hybrid compound in the 3DGO composites compared to the Comm-GO composites (7.9 g vs 5.8 g). Preferably, hybrid compounds formed with 3DGO have a significant decrease in graphene to silica ratio that highlights a more efficient condensation of silica particles on the graphene surface (3DGO-ASiO2:12.5% graphene / 74.0% silica vs Comm-GO-ASiO2: 15.7% graphene / 68.2% silica).

[0161] According to one approach, including an amine-functionalized silane coupling agent in the process of forming a silica-decorated GO improves the flexural modulus (FM) of polyolefin composite material formed with silica-decorated GO. Samples of polypropylene (PP) and commercial GO (Comm-GO) composite material were tested for mechanical strength by measuring flexural modulus as illustrated in FIG. 9A. All formulations contained an amount of 2 wt.% calculated graphene and the formulations were processed at 180 °C for about 24 hours. Table 3 summarizes the results of FIG. 8 A that illustrate the increase of FM of a composite material having silica-commercial GO that was mediated with APTES (Comm-GO-ASiO2) compared to a composite material having the silica-commercial GO that was formed without the coupling agent (APTES) (Comm-GO-SiO2). Compared to neat PP, commercial GO without silica (Comm-GO) and silica condensed on commercial GO (Comm-GO-SiO2) showed marginal improvement in FM by 1.5% and 2.2%, respectively. The PP composite having commercial GO condensed with silica nanoparticles via the silane coupling agent APTES (Comm-GO-ASiO2) demonstrated an enhanced FM by 9.9% compared to neat PP.-47- LYT1P050.P_LYTEP213WOTABLE 3. Effect of APTES on preparation of silica-decorated commercial GO Sample APTES Flexural Standardmodulus deviation(psi) (psi)Neat PP No 239,484 1,104Comm-GO No 242,969 2,548Comm-GO-SiO2 No 244,848 2,270Comm-GO-ASiO2Yes 258,281 4,306

[0162] According to one approach, polyolefin-silica-3DGO composite material has enhanced mechanical strength compared to polyolefin material without silica and 3DG. Moreover, polyolefin-silica-3DGO composite material has increased mechanical strength compared to polyolefin-silica-comm-GO composite material thereby indicating that composite material with 3DGO has enhanced strength compared to polyolefin composite material with conventional commercial GO. In an exemplary approach, polyolefin composite material formed with 3DGO decorated with silica nanoparticles in the presence of an amino-functionalized silane coupling agent such as APTES perform better than polyolefin composites formed with a commercial GO in a similar process.

[0163] FIG. 9B illustrates the enhanced FM of composites formed with Comm-GO compared to composites formed with 3DGO, where the silica hybrid compounds were formed in the presence of the coupling agent APTES, an amino-functionalized silane. Compared to neat PP, a PP-Comm-GO-ASiO2 composite material has an 11.9% improvement in FM over neat PP, whereas a PP-3DGO-ASiO2 composite material has a greater degree of improvement in FM over neat PP by 16.35%. The improvement may be maintained at a similar level when processed at a lower temperature of 180 °C compared to 225 °C.

[0164] In one approach, the amount of silica precursor, e.g., TEOS, correlates to the amount of silica nanoparticles formed on the surface of GO. A greater amount of silica precursor added relative to GO results in a higher silica content in the silica-graphene composite. For example, a higher ratio 20:1 TEOS: GO in the formulation results a sample having higher silica content in the silica-3DGO hybrid compound. FIG. 10 depicts SEM-48- LYT1P050.P_LYTEP213WOimages of composites formed with a 20: 1 TEOS:3DGO in the upper row part (a) compared to 5:1 TEOS:3DGO in the lower row part (b). As evident in the images representing varying magnification of the samples, there are noticeably less silica nanoparticles on the graphene surface in the composite formed with less silica (5:1) (part (b)).

[0165] In preferred approaches, a higher ratio of silica precursor to the graphene in preparation of the silica-graphene compound results in a lower ratio of graphene to silica thereby reducing the amount of graphene in the formed silica-graphene compounds. It is preferable to obtain silica-graphene compounds that have a reduced amount of graphene while maintaining the benefits of the presence of graphene in order to lower costs. As shown in the images of part (a), the silica-graphene compound formed with a 20:1 TEOS:3DGO results in a silica-graphene compound having a less graphene per silica present (9.2% graphene / 81.9% silica) compared to 5:1 TEOS:GO (46.2% graphene / 39.9% silica) as shown in part (b).

[0166] Increasing the amount of silica precursor per graphene (TEOS:GO) improves mechanical strength of the resulting composite formed with the silica-graphene hybrid compound. FIG. 11 depicts the plot of FM of the PP composites of FIG. 9. The PP composite that includes silica-graphene hybrid compound formed with 20:1 TEOS:3DGO demonstrated a remarkable improvement in FM of 16.4% over the PP composite formed with 5:1 TEOS:3DGO. The PP composite formed with 5:1 TEOS:GO demonstrated only a 4.6% improvement in FM compared to neat PP. The significant improvement in FM enhancement for composites having a silica-graphene hybrid compound formed with a higher TEOS:3DGO ratio may reflect the contribution of SiO2 nanoparticles in the silica-graphene compound having a greater impact in strengthening the mechanical properties in the PP composite. Without wishing to be bound by any theory, it is believed that a greater amount of silica precursor during formation of the silica-graphene hybrid compounds results in better coverage of the graphene surface with more SiO2 nanoparticles.

[0167] Formation of silica-decorated graphene hybrid compounds demonstrate minimal differences whether an acid catalyst or a base catalyst is used to form the hybrid compounds. FIG. 12 illustrates SEM images of varying magnifications of silica-graphene hybrid compounds formed using an acid catalyst in the upper row part (a) compared to silica-graphene hybrid compounds formed using a base catalyst in the lower row part (b).-49- LYT1P050.P_LYTEP213WOExamples of acid catalysts include acetic acid, etc. and examples of base catalysts include ammonia (NH4OH), etc. Silica particles are evenly distributed on the graphene surface of both compounds. The silica particle size is similar for both compounds, about 150-250 nm in diameter. The total yield of compound is the same (7.9 g with an acid catalyst and 6.8 g with a base catalyst). The ratio of graphene / silica is about the same for both compounds (12.5% graphene / 74% silica with an acid catalyst and 11.8% graphene / 75.1 silica with a base catalyst).

[0168] The type of catalyst used for forming a silica-graphene hybrid compound may affect the mechanical strength of a PP composite having silica-graphene hybrid compounds. As shown in the plot of FIG. 13, the flexural modulus (FM) of a PP composite having the silica-graphene hybrid compound (SDGO-ASiCh) formed with an acid catalyst (shown in part (a) of FIG. 12) is slightly higher than the FM of a PP composite having the silica-graphene hybrid compound (3DGO-ASiO2) formed using a base catalyst (shown in part (b) of FIG. 12) . The slight difference may result from the acid catalyst predominately leading to the condensation of silanol groups onto graphene oxide. Moreover, a protonated amino group may have a more favorable electrostatic interaction with the silica surface. Examples of acid catalysts include acetic acid, any known acid catalyst used in silane condensation reactions. Example of base catalysts include ammonia (NH4OH) and any known base catalysts known to be used in silane condensation reactions.SEPARATE SYNTHESIS OF SILICA NANOPARTICLES: SHAPE ANISOTROPIC SILICA

[0169] According to one embodiment, synthesis of silica nanoparticles separate from the graphene followed by distribution of the formed silica nanoparticles allows the silica nanoparticle size to be tuned according to an application. In one approach, silica nanoparticles may be tuned to an anisotropic shape to enable improved flexibility of a resultant polyolefin-silica-graphene composite. Spherical nanoparticles provide stiffness and mechanical strength to the resulting polyolefin-silica-graphene composite, as reflected in the significant enhancement of FM values; however, polyolefin-silica-graphene composites have less flexibility. The addition of a stiff inorganic compound (e.g., silica) causes the polymer matrix to be severely impacted. In various approaches, the shape of the-50- LYT1P050.P_LYTEP213WOsilica nanoparticles being spheres, bullets, rods, noodles, etc. may be tuned to enhance the flexibility of a polyolefin-silica-graphene composite while maintaining desired stiffness and mechanical strength of the polyolefin-silica-graphene composite material.

[0170] According to one approach, the shape of a silica nanoparticle may be tuned to have an aspect ratio (length / width) greater than one (aspect ratio > 1) by modifying the Stober method used to form spherical silica nanoparticles. In one approach, anisotropic silica particles may be prepared using a modified Stober method. The modified Stober method including forming anisotropic silica particles from a mixture of pentanol, polyvinylpyrrolidone (PVP), sodium citrate, and modifying the amount of the silica component (e.g., TEOS). Table 4 lists the relative amounts of each component in the synthesis formulation of the modified Stober method. In one approach, the precursor of silica is contained in an emulsified droplet and the silica is grown outward in a controlled manner. In various approaches, varying the amount of the silica component of the synthesis formulation (e.g., TEOS) while maintaining the amounts of the other ingredients of the formulation during formation of silica nanoparticles leads to different shapes. Thus, a desired shape of a silica nanoparticle may be defined by a predefined amount of silica component (e.g., TEOS) in the synthesis formulation. It was surprising, however, that a formulation having a defined amount of TEOS generates a population of nanoparticles having uniform shape. Moreover, the formulation having a defined amount of TEOS generates a population of nanoparticles having a uniform size where the size of the nanoparticle is measured in terms of length, width, diameter, etc. The shape of the silica nanoparticles may be formed to a desired aspect ratio and the plurality of silica nanoparticles have a uniform size and shape.TABLE 4. Synthesis Formulation of Silica Nanoparticles Using Modified Stober method Component SiO2 bullet SiO2 rod SiO2 noodle TEOS (g) 5 20 40 EtOH (mL) 53 53 77 NH4OH (g) 12.9 12.9 6.22 Water (mL) 15 15 21.6 Pentanol (mL) 532 532 771-51- LYT1P050.P_LYTEP213WOpolyvinylpyrollidone (40K) (g) 53 53 77.1 0.18 M sodium citrate (mL) 2.6 2.6 5.1

[0171] FIG. 14 includes SEM images of preparations of shape anisotropic silica nanoparticles. Part (a) includes images at various magnifications of one example of forming bullet-shaped silica nanoparticles using a modified Stober method. There is uniformity between the shapes of the bullet-shaped nanoparticles. A bullet-shaped silica nanoparticle may be defined as a particle having an aspect ratio (LAV) in a range of 1<LAV < 5, where the length is the longest dimension and the width is the shortest dimension. Each end of a bullet-shaped nanoparticle has a shape that is different than the shape of the opposite end. For example, one end may have a flat, blunt, etc. shape and the opposite end may have a circular curvature shape, such as a conical shape. The average dimensions (length, width) of the plurality of bullet-shaped silica nanoparticles depicted in the images of part (a) are about 500 nm wide and 800 nm long that calculates to an aspect ratio of about 1.6.

[0172] Part (b) of FIG. 14 includes SEM images of different magnifications of rodshaped silica nanoparticles. A rod-shaped silica nanoparticle may be defined as a particle having an aspect ratio (LAV) in a range of 5<LAV < 20 where the length is the longest dimension, and the width is the shortest dimension. A rod-shaped may be defined as a particle having a middle part connecting two ends where the middle part has a cylindrical shape, and both ends have a circular curvature. In one approach, the circular curvature of the ends may be a conical shape. There is uniformity between the shapes of the rod-shaped nanoparticles. The average dimensions (length, width) of the plurality of rod-shaped silica nanoparticles depicted in the images of part (a) are about 200 nm wide and 3.5 pm long that calculates to an aspect ratio of about 17.5.

[0173] The SEM images of varying magnifications depicted in FIG. 15 compare silica-graphene hybrid compounds having shape anisotropic silica nanoparticles. Part (a) illustrates silica-graphene hybrid compounds having bullet-shaped silica nanoparticles.3DGO has been decorated with bullet-shaped silica (SiO2) nanoparticles (formed with APTES) and designated 3DGO-ASiO2 bullets. The bullet-shaped silica nanoparticles are nestled in the voids of the 3DGO structure. Staining of elements carbon (C), oxygen (O),-52- LYT1P050.P_LYTEP213WOand silicon (Si) in the images (not shown) demonstrates that Si and O is concentrated at bullet-shaped silica and staining of carbon throughout the composite depicted in the image. Table 5 lists the relative mass% of each element according to the staining depicted in the images. TGA analysis shows the silica-graphene compound having about equal amounts of graphene and silica: 46.2% graphene and 44.5% silica (a graphene to silica ratio of about 1).

[0174] Part (b) of FIG. 15 illustrates a silica-graphene hybrid compound having rodshaped silica nanoparticles. 3DGO has been decorated with rod-shaped silica (SiO2) nanoparticles (formed with APTES) and designated 3DGO-ASiO2 rods. The rod-shaped silica nanoparticles are positioned on the surface of 3DG and through the network of the 3DGO structure. Staining of the elements in the images of the compound (not shown) indicate Si and O is concentrated at rod-shaped silica and staining of carbon throughout the composite depicted in the image. Table 5 lists the relative mass% of each element according to the staining depicted in the images. TGA analysis shows the compound includes a graphene to silica ratio that is about 0.57, having 31.1% graphene and 54.4% silica. The bullet-shaped silica nanoparticles in part (a) are evenly distributed on the flaky surface of the 3DGO, however, the number of bullet-shaped nanoparticles is less visible than the rod-shaped nanoparticles distributed on the 3DGO in part (b).

[0175] Part (c) of FIG. 15 illustrates a silica-graphene compound having noodleshaped silica nanoparticles. The noodle-shaped silica nanoparticles have a strand-like morphology. It was surprising to form a silica nanoparticle that had an unexpected shape like a strand-like nanoparticle. Without wishing to be bound by any theory, it is believed that increasing the silica component (e.g., TEOS) of the synthesis formulation would jeopardize the growth of silica in the emulsified droplets. In the example of forming noodle-shaped silica nanoparticles, the nanoparticles are formed as a strand at high amounts of TEOS (Table 4). Noodle-shaped silica nanoparticles have an aspect ratio greater than 40. The small width dimension of the noodle-shaped silica nanoparticles cause the nanoparticles to have less rigidity compared to the rod-shaped nanoparticles and thus tend to curl around features on the surface of the graphene.-53- LYT1P050.P_LYTEP213WOTABLE 5. Percent mass of elements in 3DGO-AS1O2 composites with bullet-shaped nanoparticles and rod-shaped nanoparticlesBullet-shape Rod-shape Element(keV) Mass% (keV) Mass% Carbon (C K) 0.277 87.76 0.277 59.37 Oxygen (O K) 0.525 9.59 0.525 24.28 Silicon (Si K) 1.739 2.65 1.739 26.34 TOTAL 100.00 100.0

[0176] The Thermogravimetric Analysis (TGA) of silica-graphene hybrid compounds allows a determination of the amount of silica is present in the silica-graphene hybrid. The final mass at 1000 °C resulting from the TGA analysis of a silica-graphene compound determines the composition of silica. The TGA of the silica-graphene hybrid compounds formed with silica rods and silica bullets is depicted in the plot of FIG. 16. The silica-graphene compound having silica rods (•) lost more weight than the compound having silica bullets. The decrease in weight around 350 °C in the silica rods compound is likely due to the oxidation of polyvinylpyrollidone (PVP) in the compound. Without wishing to be bound by any theory, the physical structure of silica rods are more porous than silica bullets, and thus demonstrate a greater loss of mass. Reference TGA analysis of silica spheres compared to silica rods has shown that silica rods lose more weight compared to silica spheres with increasing temperature.

[0177] Polyethylene (PE) composites with each 3DGO-ASiO2 anisotropic shape may be characterized as having differences in strength and flexibility. Strength of the composites may be measured in terms of flexural modulus (FM). Flexibility of the composites may be measured using Elongation at Break that determines the extent a material can be elongated and absorb more impact without breaking. A material having higher elongation at break are more flexible. In preferred approaches, a flexibility of the polyolefin-silica-graphene composite having rod-shaped silica nanoparticles is greater than-54- LYT1P050.P_LYTEP213WOa flexibility of a polyolefin without a silica-graphene hybrid compound as measured by elongation at break.

[0178] FIG. 17 is a plot of FM and elongation results of the PE composites. Table 5 lists the values of % improvement of FM of the PE composite material relative to neat PE. All samples included PE with 2 wt.% graphene loading. Silica spheres, silica bullets, and silica noodles (listed in Table 6, not shown on FIG. 16) demonstrated comparable mechanical results. FM of composites having silica spheres, silica bullets, and silica noodles demonstrated a 13.9%, 11.7%, and 11.3% improvement, respectively, in FM compared to neat PE. The composites having rod-shaped silica nanoparticles, however, demonstrated a remarkable FM that resulted in a 19.5% improvement over neat PE composite.

[0179] The composites having silica spheres, silica bullets, and silica rods were also tested for % elongation as shown in FIG. 16 and Table 6. The smaller aspect ratio of spheres and bullets may correlate to a slight increase the % elongation at break of the composite compared to neat PE. The composite having rod-shaped silica nanoparticles (aspect ratio about 17.5) demonstrated a larger increase of % elongation compared to the PE composites having the smaller aspect ratio shapes. The PE composite having rod-shaped silica nanoparticles has a mechanical properties characteristics of full tensile elongation with nearly 20% improvement in FM.TABLE 6: Flexural modulus of composites having anisotropic shaped silica nanoparticles Sample Flexural modulus % Improvement over % Elongation at (psi) neat PP breakNeat PE 81,955 - - Spherical SiO2 93,156 13.9 841Bullet-shaped SiO2 91,516 11.7 838 Noodle-shaped SiO2 92,602 11.3 - Rod-shaped SiO2 97,934 19.5 843

[0180] The rod-shaped silica nanoparticles in a polyolefin-silica-graphene composite may align generally in the direction of the injection molding of the polymer matrix. Thus,-55- LYT1P050.P_LYTEP213WOfor elongation at break, the tensile strain that may be applied parallel to the direction of the polymer matrix thereby demonstrating the polyolefin-silica-graphene composite has increased flexibility relative to neat polyolefin material and polyolefin-silica-graphene composites that have smaller aspect ratio silica nanoparticles. Evidence of the alignment of rod-shaped silica nanoparticles generally in the direction of injection Stober method molding is illustrated in the SEM images of FIG. 18 that depict different magnifications of a polyolefin-silica-graphene composite under strain. The images illustrate the alignment of the rod-shaped silica nanoparticles in the direction of tensile strain induced by the elongation at break testing.

[0181] In addition to the foregoing, the present disclosure relates to polymer composite materials for additive manufacturing applications, and more particularly to polyamide-based composites incorporating three-dimensional graphene and carbon fiber reinforcement for use in fused deposition modeling and related extrusion-based fabrication processes.

[0182] Polyamide materials, including various nylon grades such as nylon 12, nylon 6, and nylon 11, present significant challenges in additive manufacturing due to their inherent hygroscopic nature, which causes moisture absorption from the environment and leads to dimensional instability, reduced mechanical properties, and processing difficulties during extrusion. Additionally, existing carbon fiber-reinforced polyamide systems suffer from compromised interfacial adhesion between the fibers and the polymer matrix, resulting in suboptimal load transfer and reduced composite performance. The incorporation of reinforcing fillers can also negatively impact flow characteristics during processing, creating difficulties in achieving consistent extrusion and layer adhesion. Furthermore, the fundamental incompatibility between hydrophilic polyamide matrices and hydrophobic reinforcing agents limits achievable improvements in composite performance.

[0183] The present disclosure addresses these challenges through a polyamide-graphene composite that incorporates three-dimensional graphene (3DG) along with carbon fibers dispersed within a polyamide matrix. The three-dimensional graphene, being innately hydrophobic, increases the surface hydrophobicity of the polyamide matrix, thereby reducing its hygroscopic nature and improving processability without requiring extensive drying procedures prior to processing. The combination of carbon fibers with-56- LYT1P050.P_LYTEP213WOappropriate sizing agents and uniformly dispersed three-dimensional graphene provides enhanced mechanical strength while maintaining the flow characteristics necessary for consistent extrusion in fused deposition modeling applications.

[0184] The present disclosure further provides a composite system wherein the three-dimensional graphene is dispersed at the interface between the carbon fibers and the polyamide matrix, cooperatively enhancing interfacial adhesion and load transfer. The carbon fibers may include epoxy-based, polyurethane-based, or polyamide-compatible sizing agents that increase dispersibility within the polyamide matrix, while the three-dimensional graphene may be present in amounts 0.01 - 5 wt% to achieve both improved mechanical strength and improved printability relative to carbon fiber-reinforced polyamides without the three-dimensional graphene. The composite may be configured as a filament for fused deposition modeling, enabling applications in additive manufacturing where both high performance and consistent processability are required.

[0185] FIG. 19 illustrates a comparison table 1900 summarizing three different composite material approaches for polymer reinforcement, in accordance with one embodiment. As an option, the comparison table 1900 may be implemented in the context of any one or more of the embodiments set forth in any previous and / or subsequent Figures and / or description thereof. Of course, however, the comparison table 1900 may be implemented in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0186] As shown, the comparison table 1900 includes rows for component categories and columns for three distinct material systems: covalent graphene-polyolefin grafting, anisotropic silica-graphene hybrids, and 3DG-infused CF-reinforced nylon. The comparison table 1900 identifies the polymer matrix for the covalent graphene-polyolefin grafting as polyolefin, including polyethylene (PE) and polypropylene (PP). In some embodiments, the polyethylene may include high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) as alternative polymer matrix materials for graphene composite formation. The polypropylene may be blended with graphene and silica nanoparticles to form composite materials in various configurations.

[0187] The comparison table 1900 identifies the polymer matrix for the anisotropic silica-graphene hybrids as polyolefin (PE / PP), and the polymer matrix for the 3DG-infused-57- LYT1P050.P_LYTEP213WOCF-reinforced nylon as polyamide. The polyamide matrix may comprise at least one of nylon 12, nylon 6, nylon 11, nylon 6 / 6, nylon 6 / 12, polyetherimide (PEI), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polycarbonate, or polyphenylene sulfide (PPS), and / or similar compounds. In one embodiment, the comparison table 1900 demonstrates the evolution from polyolefin-based systems to polyamide-based systems, where the polyamide materials provide enhanced thermal and mechanical properties suitable for additive manufacturing applications.

[0188] The comparison table 1900 indicates that the covalent graphene-poly olefin grafting and the anisotropic silica-graphene hybrids have no reinforcing fiber, while the 3DG-infused CF-reinforced nylon includes carbon fibers as the reinforcing fiber. The carbon fibers may comprise a sizing agent on a surface thereof to enhance interfacial adhesion with the polymer matrix. In various embodiments, the sizing agent may comprise an epoxy -based sizing, a polyurethane-based sizing, or a polyamide-compatible sizing. The epoxy-based sizing on the carbon fibers adjusts the hydrophilicity of the carbon fiber surface, making the carbon fibers more miscible and dispersible within the hydrophilic polyamide matrix.

[0189] Additionally, the comparison table 1900 shows that the covalent graphene-polyolefin grafting uses oxidized three-dimensional graphene (3DGO) as the reinforcing additive, where the oxidized 3DG forms covalent bonds with the polymer backbone with the help of a radical initiator such as dicumyl peroxide (DCP) at elevated temperature during the compounding process. The anisotropic silica-graphene hybrids use silica nanoparticles as the reinforcing additive, and the 3DG-infused CF-reinforced nylon uses 3D graphene as the reinforcing additive. For the anisotropic silica-graphene hybrids, the silica nanoparticles may be coupled to the three-dimensional graphene oxide surface via a silane linkage, where a silane coupling agent such as 3-aminopropyltriethoxysilane (APTES) bonds to the graphene oxide surface and the silica nanoparticles condense onto the silane groups as well as unreacted hydroxyl groups.

[0190] In various embodiments, the covalent graphene-polyolefin grafting system utilizes a radical-mediated bonding mechanism to achieve direct chemical linkage between the oxidized three-dimensional graphene and the polyolefin matrix. A radical initiator such as dicumyl peroxide (DCP) generates radical species on the polyolefin backbone at-58- LYT1P050.P_LYTEP213WOelevated temperatures during the compounding process, enabling the formation of covalent bonds between the functionalized oxidized 3DG and the polyethylene or polypropylene chains. This radical-initiated grafting approach provides enhanced load transfer between the graphene reinforcement and the polymer matrix compared to systems relying solely on physical dispersion or non-covalent interactions.

[0191] The silica nanoparticles may have shape-anisotropic morphologies including spherical, bullet-shaped, rod-shaped, or noodle-shaped configurations. Rod-shaped silica with an aspect ratio of about 17 may provide approximately 10-30% improvement in flexural modulus while maintaining full elongation at 0.1-3 wt% graphene loading. In some embodiments, the silica may be formed as a continuous coating on the graphene oxide surface through in-situ synthesis where tetraethyl orthosilicate (TEOS) silica precursor is added to graphene oxide to grow silica directly from the surface, rather than attaching preformed silica nanoparticles. The TEOS to graphene oxide weight ratio may range from 10:1 to 10:1, where different ratios affect the mechanical properties and elongation characteristics of the resulting composite.

[0192] Further, the three-dimensional graphene may be oxidized via ozone treatment in a fluidized bed to form graphene oxide (3DGO) with hydroxyl, epoxy, carbonyl, and carboxyl functional groups on the surface. The composite may include functional groups attached to the graphene oxide / silica hybrid surface, including alkyl groups (such as octyl C8 or Cl 8 chains), amine groups, or thiol groups to improve compatibility with the polymer matrix. In some embodiments, the three-dimensional graphene produced in a microwave reactor may be oxidized via ozone treatment in a fluidized bed column to form graphene oxide (3DGO) with hydroxyl, epoxy, carbonyl, and carboxyl functional groups on the surface. Additionally, the functional groups attached to the graphene oxide / silica hybrid surface may provide varying degrees of flexural modulus improvement depending on the specific chemistry, where octyl group functionalization may provide approximately 9-14% improvement, amine group functionalization may provide approximately 8-22% improvement, and thiol group functionalization may provide approximately 11-30% improvement in flexural modulus while maintaining elongation properties.

[0193] The comparison table 1900 specifies the bonding mechanism as covalent bonding for the covalent graphene-poly olefin grafting, silane linkage coupling for the-59- LYT1P050.P_LYTEP213WOanisotropic silica-graphene hybrids, and uniform dispersion within matrix for the 3DG-infused CF-reinforced nylon. In one embodiment, the graphene oxide may be functionalized with 3-isopropenyl-a,a-dimethylbenzylisocyanate (TMI) via urethane linkage to help exfoliation of GO sheets in organic solvents and potentially bond to polymer chains at elevated temperatures. In some embodiments, the graphene oxide may be functionalized with octadecylamine (18-carbon alkyl chains) via amide bond formation to lower the polarity and increase hydrophobicity for better compatibility with polyolefin matrices.

[0194] The comparison table 1900 identifies the coupling agent as silane or isocyanate functional groups for the covalent graphene-polyolefin grafting, amino-functionalized silane for the anisotropic silica-graphene hybrids, and epoxy sizing on carbon fibers for the 3DG-infused CF-reinforced nylon. The composite may include maleic anhydride grafted polyethylene (MA-g-PE or MAPE) or maleic anhydride grafted polypropylene (MAPP) as a coupling agent to enhance interfacial bonding between the polymer matrix and fillers. In various embodiments, these coupling agents may facilitate load transfer between the reinforcing components and the polymer matrix.

[0195] Still yet, the comparison table 1900 indicates that the application for the covalent graphene-polyolefin grafting is injection molding, the application for the anisotropic silica-graphene hybrids is injection molding, and the application for the 3DG-infused CF-reinforced nylon is 3D printing filament.

[0196] Taking a step back, the comparison table 1900 demonstrates a resolution to challenges in the prior art relating to compatibility between graphene and polymer matrices. The sp2-hybridized carbon structure of graphene with its planar geometry and it-it stacking interactions differs fundamentally from the sp3 -hybridized tetrahedral geometry of polyolefins, creating compatibility challenges. The evolution from covalent grafting approaches to silica-mediated coupling and finally to carbon fiber-reinforced polyamide systems with 3D graphene dispersion represents a variety of approaches to addressing interfacial adhesion and mechanical property enhancement.

[0197] The comparison table 1900 further demonstrates that the transition from polyolefin-based injection molding applications to polyamide-based 3D printing filament applications addresses the growing demand for high-performance additive manufacturing-60- LYT1P050.P_LYTEP213WOmaterials. The incorporation of carbon fibers with appropriate sizing agents in combination with 3D graphene provides a composite system that balances mechanical reinforcement with processability requirements for fused deposition modeling.

[0198] In various embodiments, the polymer matrix may be modified to include blends of polyolefins and polyamides to achieve intermediate properties between the systems shown in the comparison table 1900. For example, the silica nanoparticle morphology may be tailored based on the specific mechanical property requirements, where spherical silica, bullet-shaped silica, noodle-shaped silica, and rod-shaped silica each may cause improvement in flexural modulus. For example, the silica nanoparticle morphology may be tailored based on the specific mechanical property requirements, where spherical silica provides approximately 13.7% improvement in flexural modulus, bullet-shaped silica provides approximately 11.7% improvement, noodle-shaped silica provides approximately 13.0% improvement, and rod-shaped silica provides approximately 19.5% improvement. The rod-shaped silica nanoparticles with an aspect ratio of approximately 17 demonstrate the highest flexural modulus improvement while maintaining full elongation properties at 2 wt% graphene loading.

[0199] In various embodiments, the functional groups on the graphene oxide / silica hybrid surface may be selected based on the polymer matrix chemistry, where alkyl groups provide hydrophobic interactions with polyolefins, amine groups may react with maleic anhydride grafted polymers, and thiol groups may interact with carboxylic acid group present on oxidized 3DG to form a thioester, which can interact with free thiol groups via transesterification during the deformation process to achieve both high flexural modulus and elongation. The weight ratio of silica to graphene may be varied to optimize the balance between mechanical reinforcement and composite processability.

[0200] In various embodiments, the 3DG-infused CF-reinforced nylon system shown in the comparison table 1900 may incorporate elements from the other approaches, such as silane-functionalized graphene or maleic anhydride coupling agents, to further enhance interfacial adhesion between the carbon fibers, 3D graphene, and polyamide matrix. The carbon fiber sizing chemistry may be selected to complement the surface chemistry of the 3D graphene, creating synergistic reinforcement effects within the composite structure.-61- LYT1P050.P_LYTEP213WO

[0201] Table 7, shown below, provides a comprehensive summary of other possibilities and ranges associated with each component of the 3DG-infused CF-reinforced nylon system, including the polyamide matrix, carbon fibers, three-dimensional graphene, composite properties, applications, and performance benefits. The table demonstrates the breadth of material selections, dimensional parameters, and functional characteristics that may be implemented within the polyamide-graphene composite system for additive manufacturing applications.TABLE 7: POLYAMIDE-GRAPHENE COMPOSITE COMPONENT POSSIBILITIES AND RANGESComponent Aspect Possibilities / RangesPolyamide Material Type Nylon 12, Nylon 6, Nylon 11, Nylon 6 / 6, Nylon 6 / 12, Matrix Polyetherimide (PEI), Polyether ether ketone (PEEK),Polyetherketoneketone (PEKK), Polycarbonate, Polyphenylene sulfide (PPS)Hydrophilicity Inherently hydrophilic; hygroscopic nature reduced by presence of 3D grapheneSurface Increased by presence of three-dimensional graphene HydrophobicityCarbon Fiber Type Chopped carbon fibers, Continuous carbon fibers FibersDiameter About 5 pm to about 10 pmLength (Short About 0.01 mm to about 1 mmFibers)Length (Long About 3 mm to about 6 mm (for industrial 3D printers Fibers) with larger nozzle sizes)Loading About 5 wt% to about 40 wt% of the composite AmountSizing Agent Epoxy-based sizing, Polyurethane-based sizing, Type Polyamide-compatible sizingSizing Adjusts hydrophilicity of carbon fiber surface; increases Function dispersibility within hydrophilic polyamide matrix Three- Graphene Type Three-dimensional graphene (3DG); non-oxidized DimensionalGraphene(3DG)Structural Plurality of spikes and nodules; promotes mechanicalMorphology interlocking with polyamide matrix-62- LYT1P050.P_LYTEP213WOComponent Aspect Possibilities / RangesLoading About 0.1 wt% to about 5 wt% of the composite Amount(Range)Dispersion Uniformly dispersed within polyamide matrix; dispersed at interface between carbon fibers and polyamide matrix Growth May be grown directly on a surface of the carbon fibers MethodChemical Innately hydrophobic; increases surface hydrophobicity Nature of polyamide matrixComposite Mechanical Greater than mechanical strength of polyamide without Properties Strength 3DG by at least 10%Hygroscopic Reduced by presence of 3D graphene; limits moisture Nature absorptionProcessability Improved; reduced need for pre-drying procedures Interfacial Cooperatively enhanced by sizing agent on carbon Adhesion fibers and 3D grapheneApplication Manufacturing Additive manufacturing; fused deposition modeling Method (FDM)Product Form Filament for fused deposition modeling Processing Compounding — > Spooling into filament — > 3D printing StepsNozzle Standard nozzles (short fibers: 0.01-1 mm); Industrial Compatibility large nozzles (long fibers: 3-6 mm)Target Aerospace components, Automotive components, High- Applications performance structural partsPerformance Printability Improved relative to carbon fiber-reinforced polyamide Benefits without 3DGDimensional Enhanced across varying humidity conditions StabilityExtrusion Consistent; reduced nozzle clogging and uneven Behavior material flowLayer Improved due to cooperative enhancement of interfacial Adhesion adhesionPre-Drying Reduced or eliminated compared to conventional nylonRequirements filaments

[0202] FIG. 20 illustrates a polyamide-graphene composite 2000 showing the structural arrangement of reinforcing components within a polymer matrix, in accordance with one embodiment. As an option, the polyamide-graphene composite 2000 may be implemented in the context of any one or more of the embodiments set forth in any previous and / or subsequent Figures and / or description thereof. Of course, however, the polyamide--63- LYT1P050.P_LYTEP213WOgraphene composite 2000 may be implemented in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0203] As shown, the polyamide-graphene composite 2000 includes a polyamide matrix 2002, a plurality of carbon fibers 2004 dispersed within the polyamide matrix 2002, and a plurality of three-dimensional graphene (3DG) 2006. The polyamide matrix 2002 forms the continuous phase of the composite material. The polyamide matrix 2002 may comprise at least one of nylon 12, nylon 6, nylon 11, nylon 6 / 6, nylon 6 / 12, polyetherimide (PEI), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polycarbonate, or polyphenylene sulfide (PPS), as described previously with reference to the comparison table 1900.

[0204] The carbon fibers 2004 are shown as elongated cylindrical (i.e. rod) structures dispersed within the polyamide matrix 2002, with some carbon fibers 2004 oriented in different directions to illustrate their distribution throughout the polyamide-graphene composite 2000. In some embodiments, the carbon fibers 2004 may have a diameter in a range of about 5 pm to about 10 pm. The carbon fibers 2004 may have a length in a range of about 0.01 mm to about 1 mm for applications where shorter fibers may be desired to maintain flow characteristics during processing.

[0205] Additionally, the carbon fibers 2004 may have a length in a range of about 3 mm to about 6 mm for applications utilizing larger nozzle sizes on industrial 3D printers. In some embodiments, the carbon fibers 2004 may be chopped carbon fibers that provide reinforcement while maintaining processability for extrusion-based manufacturing. In other embodiments, the carbon fibers 2004 may be continuous carbon fibers for applications requiring maximum tensile strength along the fiber direction. The carbon fibers 2004 may be present in an amount of about 5 wt% to about 40 wt% of the polyamide-graphene composite 2000.

[0206] The carbon fibers 2004 may comprise a sizing agent on a surface thereof to enhance interfacial adhesion with the polyamide matrix 2002. The sizing agent may comprise an epoxy-based sizing, a polyurethane-based sizing, or a polyamide-compatible sizing. The epoxy-based sizing increases dispersibility of the carbon fibers 2004 within the polyamide matrix 2002 by adjusting the hydrophilicity of the carbon fiber surface, making the carbon fibers 2004 more miscible within the hydrophilic polyamide matrix 2002.-64- LYT1P050.P_LYTEP213WO

[0207] Additionally, the 3D graphene 2006 is represented as particles of varying sizes distributed throughout the polyamide matrix 2002. The 3D graphene 2006 particles are positioned both at the interface between the carbon fibers 2004 and the polyamide matrix 2002 as well as within the bulk of the polyamide matrix 2002. In various embodiments, the plurality of 3D graphene 2006 may be uniformly dispersed within the polyamide matrix 2002, and the 3D graphene 2006 may be dispersed at an interface between the carbon fibers 2004 and the polyamide matrix 2002.

[0208] The 3D graphene 2006 may have a structural morphology characterized by a plurality of spikes and nodules, and the structural morphology may promote mechanical interlocking with the polyamide matrix 2002. In some embodiments, the 3D graphene 2006 may be grown directly on a surface of the carbon fibers 2004 to enhance interfacial bonding between the reinforcing components. The 3D graphene 2006 may be present in an amount of about 0.01 wt% to about 5 wt% of the polyamide-graphene composite 2000, where graphene loading ranges from 0.1 wt% to 5 wt% may increase mechanical property improvements depending on the specific application requirements.

[0209] In one particular embodiment, the 3D graphene 2006 may be present in an amount of about 0.05 - 5 wt% of the polyamide-graphene composite 2000, and the carbon fibers 2004 may comprise an epoxy-based sizing, and the polyamide-graphene composite 2000 may exhibit both improved mechanical strength and improved printability relative to a carbon fiber-reinforced polyamide without the 3D graphene 2006. The graphene nanoplatelets forming the 3D graphene 2006 may have a thickness in the range of 2-8 nm to 15 nm and a diameter of approximately up to 25 pm, where thinner platelets provide better dispersion and improved tensile and flexural properties within the polyamide matrix 2002.

[0210] In various embodiments, the graphene nanoplatelets may have a surface area ranging from 50-80 m2 / g to 120-150 m2 / g, where higher surface area correlates with improved mechanical property enhancement in the polyamide-graphene composite 2000. A mechanical strength of the polyamide-graphene composite 2000 may be greater than a mechanical strength of a polyamide without the 3D graphene 2006. Additionally, the polyamide-graphene composite 2000 may exhibit improved thermal stability with-65- LYT1P050.P_LYTEP213WOdegradation temperature increased and temperature at 50% weight loss increased compared to neat polymer.

[0211] The sizing agent on the carbon fibers 2004 and the 3D graphene 2006 cooperatively enhance interfacial adhesion between the carbon fibers 2004 and the polyamide matrix 2002, and the polyamide-graphene composite 2000 may exhibit improved processability for fused deposition modeling relative to a carbon fiber-reinforced polyamide without the 3D graphene 2006. For example, the polyamide-graphene composite 2000 may exhibit heterogeneous nucleation effects from the 3D graphene 2006 filler, increasing crystallization temperature (such as within the range of 2.7°C to 4.8°C) and improving crystallinity of the polyamide matrix 2002.

[0212] As further shown in FIG. 20, the polyamide-graphene composite 2000 may be configured for additive manufacturing. In some embodiments, the polyamide-graphene composite 2000 may be in the form of a filament for fused deposition modeling. The polyamide-graphene composite 2000 may be formed into test specimens by injection molding.

[0213] The polyamide-graphene composite 2000 demonstrates a resolution to challenges in the prior art relating to achieving both mechanical reinforcement and processability in additive manufacturing materials. The combination of the carbon fibers 2004 with appropriate sizing agents and the uniformly dispersed 3D graphene 2006 provides enhanced load transfer while maintaining the flow characteristics required for consistent extrusion in fused deposition modeling applications.

[0214] The polyamide-graphene composite 2000 further demonstrates that the incorporation of the 3D graphene 2006 at the interface between the carbon fibers 2004 and the polyamide matrix 2002 addresses interfacial adhesion challenges that limit performance in conventional carbon fiber-reinforced polyamide systems. The cooperative enhancement provided by the sizing agent and the 3D graphene 2006 enables improved mechanical properties without compromising the processability requirements for filamentbased additive manufacturing.

[0215] It is to be appreciated that other alterations are envisioned. For example, in various embodiments, the polyamide-graphene composite 2000 may include wood fiber as an alternative or additional filler material, where wood fiber content up to 30-40 wt% may-66- LYT1P050.P_LYTEP213WOimprove stress and modulus properties when combined with appropriate coupling agents. Additionally, the polyamide-graphene composite 2000 may include calcium carbonate (CaCCh) nanoparticles as an alternative filler material, where such particle may improve impact strength and modulus.

[0216] In various embodiments, the silica to graphene weight ratio in hybrid filler configurations may be varied to optimize mechanical properties, with ratios ranging from 1:1 to 4:1 TEOS to GO. Additionally, in other embodiments, the carbon fibers 2004 may be modified with different sizing chemistries to complement the surface characteristics of the 3D graphene 2006, where the selection of sizing agent may be based on the specific polyamide grade used in the polyamide matrix 2002. The rod-shaped silica particles, when incorporated as an additional filler, may align with the pulling direction during tensile testing, as observed in SEM images of elongated tensile coupons, contributing to improved mechanical properties in the polyamide-graphene composite 2000.

[0217] FIG. 21 illustrates a comparison diagram 2100 showing the difference in moisture absorption characteristics between polyamide materials with and without three-dimensional graphene reinforcement, in accordance with one embodiment. As an option, the comparison diagram 2100 may be implemented in the context of any one or more of the embodiments set forth in any previous and / or subsequent Figures and / or description thereof. Of course, however, the comparison diagram 2100 may be implemented in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0218] As shown, the comparison diagram 2100 is divided into two side-by-side sections showing cross-sectional views of two material configurations: a nylon matrix 2102 and a nylon matrix with 3D graphene 2104. The nylon matrix 2102 is labeled as hydrophilic and shows a textured surface with numerous water droplets of varying sizes distributed throughout and on the surface of the material, indicating the hygroscopic nature of the nylon matrix 2102. The nylon matrix 2102 represents polyamide materials such as nylon 12, nylon 6, nylon 11, nylon 6 / 6, and nylon 6 / 12 that inherently attract and absorb moisture from the surrounding environment due to the presence of amide groups in the polymer backbone.-67- LYT1P050.P_LYTEP213WO

[0219] In contrast, the nylon matrix with 3D graphene 2104 is labeled as having reduced hygroscopic nature and displays a similar textured base material but with a distinct hexagonal graphene structure visible on the upper portion of the cross-section. The nylon matrix with 3D graphene 2104 shows smaller and fewer water droplets compared to the nylon matrix 2102, demonstrating the effect of the 3D graphene 2006 in reducing the water absorption characteristics of the material.

[0220] As described previously with reference to FIG. 20, a surface hydrophobicity of the polyamide matrix 2002 is increased by the presence of the three-dimensional graphene. The 3D graphene 2006, being innately hydrophobic due to its sp2-hybridized carbon structure with planar geometry and it-it stacking interactions, imparts hydrophobic characteristics to the polyamide matrix 2002 when uniformly dispersed throughout the composite material. The increased surface hydrophobicity reduces a hygroscopic nature of the polyamide matrix 2002, thereby limiting the moisture absorption that causes dimensional instability, reduced mechanical properties, and processing difficulties during extrusion in fused deposition modeling applications.

[0221] The comparison diagram 2100 demonstrates that the incorporation of the 3D graphene 2006 into the polyamide matrix 2002 addresses processability challenges associated with conventional polyamide materials. The reduced hygroscopic nature of the nylon matrix with 3D graphene 2104 enables users to process the polyamide-graphene composite 2000 without extensive pre-drying procedures that are typically required for hygroscopic polyamide materials. In some embodiments, the amino-functionalized graphene oxide / silica hybrid may be combined with maleic anhydride grafted polyethylene (PE-g-MA) to create reactive compatibility between the filler and polymer matrix, further enhancing interfacial adhesion and moisture resistance.

[0222] With continued reference to FIG. 21, the silica nanoparticles that may be incorporated into the polyamide-graphene composite 2000 are synthesized using pentanol, polyvinylpyrrolidone (PVP), and sodium citrate with varying amounts of TEOS (5g for bullets, 20g for rods, 40g for noodles) to control particle morphology. The GO-ASiO2 composite may have a BET surface area of approximately 72.45 m2 / g for noodle-shaped silica morphology, with carbon content of approximately 71% by elemental analysis. The polyamide-graphene composite 2000 may exhibit improved storage modulus, with-68- LYT1P050.P_LYTEP213WOincreases of up to 54% at 5 wt% graphene loading compared to neat polymer, as measured by dynamic mechanical analysis.

[0223] In various embodiments, the polyamide-graphene composite 2000 may be configured for use in automotive components, home appliances, aerospace applications, building materials, furniture, and / or sports equipment. The reduced hygroscopic nature demonstrated in the comparison diagram 2100 enables the polyamide-graphene composite 2000 to maintain consistent mechanical properties and dimensional stability across varying humidity conditions encountered in these applications.

[0224] The comparison diagram 2100 demonstrates a resolution to challenges in the prior art relating to moisture sensitivity in polyamide-based additive manufacturing materials. The hygroscopic nature of conventional polyamide materials requires extensive drying procedures before processing and controlled storage conditions to prevent moisture absorption, adding complexity and cost to manufacturing operations. The incorporation of the 3D graphene 2006 into the polyamide matrix 2002 provides a material-level solution that reduces moisture sensitivity without requiring additional processing steps or specialized storage conditions.

[0225] The comparison diagram 2100 further demonstrates that the hydrophobic characteristics imparted by the 3D graphene 2006 complement the mechanical reinforcement provided by the carbon fibers 2004 in the polyamide-graphene composite 2000. The combination of reduced hygroscopic behavior and enhanced mechanical properties enables the polyamide-graphene composite 2000 to meet performance requirements for demanding applications while maintaining the processability characteristics required for fused deposition modeling.

[0226] In various embodiments, the degree of hydrophobicity modification in the nylon matrix with 3D graphene 2104 may be tailored by adjusting the loading level of the 3D graphene 2006 within the polyamide matrix 2002, where higher graphene concentrations provide greater reduction in moisture absorption while maintaining uniform dispersion throughout the composite structure. The surface chemistry of the 3D graphene 2006 may be modified through functionalization with alkyl groups, amine groups, or thiol groups to further tune the hydrophobic characteristics and compatibility with the polyamide matrix 2002.-69- LYT1P050.P_LYTEP213WO

[0227] In various embodiments, the nylon matrix with 3D graphene 2104 may incorporate additional functional additives such as antioxidants, UV stabilizers, or flame retardants to enhance performance in specific application environments while maintaining the reduced hygroscopic characteristics provided by the 3D graphene 2006. The polyamide-graphene composite 2000 may be formulated with different polyamide grades including polyetherimide (PEI), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polycarbonate, or polyphenylene sulfide (PPS) to achieve specific thermal, mechanical, and / or chemical resistance properties for targeted applications.

[0228] In various embodiments, the comparison diagram 2100 may represent composites where the 3D graphene 2006 is present at low concentrations (such as 0.1 wt% or even lower) to achieve measurable reductions in hygroscopic behavior while minimizing impact on material cost and / or processing characteristics. The carbon fibers 2004 with epoxy-based sizing may cooperate with the 3D graphene 2006 to create a synergistic effect where the sizing agent enhances fiber-matrix adhesion while the graphene provides both mechanical reinforcement and / or hydrophobicity modification throughout the polyamide matrix 2002.ADDITIONAL EMBODIMENTS

[0229] In various embodiments, the carbon fibers may have a length in a range of about 1 mm to about 6 mm for applications utilizing larger nozzle sizes on industrial 3D printers. The larger nozzle sizes on industrial 3D printers may accommodate longer carbon fibers, where the really large nozzles get up to three to six millimeters. The selection of carbon fiber length may be based on a balance between mechanical reinforcement and printability requirements for the specific additive manufacturing application.

[0230] In various embodiments, different types of three-dimensional graphene may be used depending on the polymer matrix and application context. For polyolefin-based systems such as polyethylene and polypropylene, oxidized three-dimensional graphene (3DGO) may be employed to facilitate covalent bonding and silane linkage coupling with the polymer matrix. For polyamide-based systems such as nylon, non-oxidized three-dimensional graphene (3DG) may be employed, where the innate hydrophobicity of the non-oxidized graphene increases the surface hydrophobicity of the polyamide matrix and-70- LYT1P050.P_LYTEP213WOreduces its hygroscopic nature. The selection of oxidized or non-oxidized three-dimensional graphene may be based on the desired interaction characteristics with the specific polymer matrix, where oxidized graphene provides reactive functional groups for chemical bonding in polyolefin systems and non-oxidized graphene provides hydrophobic interactions in polyamide systems.

[0231] In various embodiments, the polyamide-graphene composite may be processed by compounding the polyamide matrix with the carbon fibers and the three-dimensional graphene, followed by spooling the compounded material into a filament, and subsequently printing the filament using a 3D printer. The application entails compounding it first, then spooling into a filament, and then printing it using a 3d printer. This processing method differs from injection molding processes used for polyolefin-graphene composites, where the material is extruded and injection molded rather than formed into a filament for additive manufacturing.

[0232] In various embodiments, the epoxy sizing on the carbon fibers adjusts the hydrophilicity of the carbon fiber surface, making the carbon fibers more miscible and dispersible within the hydrophilic polyamide matrix. The sizing chemistry may be selected to complement the surface characteristics of the three-dimensional graphene, where the combination of appropriately sized carbon fibers and uniformly dispersed three-dimensional graphene achieves optimal dispersion and interfacial adhesion within the composite. In some embodiments, alternative sizing chemistries such as polyurethane-based sizing or polyamide-compatible sizing may be employed based on the specific polyamide grade and processing conditions to further enhance fiber-matrix compatibility.

[0233] In various embodiments, the three-dimensional graphene, being innately hydrophobic, increases the surface hydrophobicity of the polyamide matrix, thereby reducing the hygroscopic nature of the polyamide. The reduced hygroscopic behavior improves the usability and processability of the composite, enabling users to process the polyamide-graphene composite without extensive pre-drying procedures that are typically required for hygroscopic polyamide materials. In some embodiments, the polyamide-graphene composite may be stored under ambient conditions and loaded directly into a 3D printer with minimal pre-drying, reducing production cycle time and eliminating the need for desiccant chamber operation prior to fused deposition modeling.-71- LYT1P050.P_LYTEP213WO

[0234] In various embodiments, the polyamide-graphene composite represents an alternative from polyolefin-based graphene composite systems. The anisotropic silica-graphene hybrids system is different from the 3DG-infused CF-reinforced nylon system in that the anisotropic silica-graphene hybrids system is based on polyolefin, such as polyethylene and polypropylene, but the 3DG-infused CF-reinforced nylon system is based on a totally different matrix system, nylon. Also, the strengthening additive that is used in the anisotropic silica-graphene hybrids system, which is silica nanoparticles, is replaced by carbon fibers in the 3DG-infused CF-reinforced nylon system. The transition from silica nanoparticles as a strengthening additive in polyolefin systems to carbon fibers in polyamide systems provides different reinforcement mechanisms suited to the respective polymer matrix chemistries.

[0235] In various embodiments, the three-dimensional graphene in the polyamide-graphene composite does not require silane linkage coupling to silica nanoparticles as used in polyolefin-based systems. The silicon nanoparticles are not included in the polyamide-graphene composite, and the oxidized designation is removed. The interaction between the three-dimensional graphene and the polyamide matrix may occur through hydrophobichydrophobic interactions and mechanical interlocking rather than through silane-mediated chemical bonding.

[0236] In various embodiments, the polyamide-graphene composite may exhibit improved processability compared to conventional carbon fiber-reinforced polyamide materials. The reduced moisture sensitivity provided by the three-dimensional graphene enables users to process the composite without extensive pre-drying procedures, thereby simplifying manufacturing workflows and reducing preparation time. The decreased hygroscopic nature of the composite may enable more consistent extrusion behavior during fused deposition modeling, reducing the nozzle clogging, uneven material flow, and surface defects that can occur with moisture-laden polyamide filaments.

[0237] In various embodiments, the carbon fiber length may be selected based on the specific 3D printing application requirements. Very short fibers may be used to reinforce but still ensure printing well and printing quickly for high flow rate applications, while longer fibers (such as up to three to six millimeters) may be used with larger nozzle sizes-72- LYT1P050.P_LYTEP213WOon industrial 3D printers. The carbon fiber length selection may involve balancing mechanical reinforcement with flow characteristics during extrusion.

[0238] In various embodiments, the polyamide-graphene composite may be configured for high flow nylon filament applications where short carbon fibers are used to provide reinforcement while maintaining the ability to print well and print quickly. The short fiber configuration may be particularly suited for applications requiring rapid deposition rates and fine feature resolution in the printed parts.USE CASE SCENARIO

[0239] By way of a use-case scenario, and in various embodiments, a manufacturer of automotive components implements a polyolefin-graphene composite for producing lightweight structural parts using injection molding. The manufacturer receives pellets of the polyolefin-graphene composite comprising polyethylene or polypropylene as the polymer matrix with oxidized three-dimensional graphene covalently bonded to the hydrocarbon groups of the polyolefin via silane or isocyanate functional groups. During the injection molding process, the covalent bonding between the oxidized three-dimensional graphene and the polyolefin matrix provides enhanced load transfer throughout the composite structure, enabling the manufacturer to produce automotive brackets, mounts, and housings with improved mechanical strength relative to unfilled polyolefin materials. The resulting injection molded components exhibit enhanced stiffness suitable for under-hood applications, improved thermal stability for components exposed to engine heat, and consistent mechanical performance across production batches due to the uniform distribution of the covalently bonded graphene throughout the polyolefin matrix.

[0240] By way of another use-case scenario, and in various embodiments, a consumer products manufacturer implements a silica-graphene hybrid compound in a polyolefin matrix for producing durable household goods and sporting equipment using injection molding. The manufacturer receives compounded pellets comprising polyethylene or polypropylene reinforced with oxidized three-dimensional graphene coupled to shape-anisotropic silica nanoparticles via silane linkage. The rod-shaped silica nanoparticles align with the polymer flow direction during injection molding, providing improvement in-73- LYT1P050.P_LYTEP213WOflexural modulus while maintaining full elongation properties that prevent brittle failure during impact loading. Unlike conventional filled polyolefin systems that sacrifice ductility for stiffness, the manufacturer is able to produce products such as tool handles, protective cases, and recreational equipment that exhibit both enhanced rigidity and impact resistance. The resulting injection molded components demonstrate improved durability under repeated loading cycles, reduced material consumption due to the ability to achieve target stiffness with thinner wall sections, and extended product lifespan that reduces replacement frequency and associated costs for end users.

[0241] By way of another use-case scenario, and in various embodiments, an additive manufacturing facility operator implements the polyamide-graphene composite as a filament material for producing high-performance aerospace components using fused deposition modeling. The operator receives spools of the polyamide-graphene composite filament comprising nylon 12 as the polyamide matrix, chopped carbon fibers with epoxybased sizing, and three-dimensional graphene uniformly dispersed throughout the composite. Unlike conventional nylon filaments that require extensive drying in a desiccant chamber for 4-8 hours prior to printing due to their hygroscopic nature, the operator is able to load the polyamide-graphene composite filament directly into the 3D printer with minimal pre-drying because the three-dimensional graphene has increased the surface hydrophobicity of the polyamide matrix, thereby reducing moisture absorption during storage under ambient conditions. During the fused deposition modeling process, the carbon fibers with their epoxy-based sizing cooperate with the three-dimensional graphene dispersed at the interface between the carbon fibers and the polyamide matrix to provide consistent extrusion behavior without nozzle clogging or uneven material flow, enabling the operator to produce aerospace brackets with improved mechanical strength exceeding that of carbon fiber-reinforced polyamide without the three-dimensional graphene. The resulting printed components exhibit enhanced dimensional stability across varying humidity conditions encountered in aerospace applications, reduced surface defects from moisture-related hydrolysis during high-temperature processing, and improved layer adhesion due to the cooperative enhancement of interfacial adhesion provided by the sizing agent and the three-dimensional graphene throughout the polyamide matrix. The elimination of extensive pre-drying procedures reduces production cycle time, lowers-74- LYT1P050.P_LYTEP213WOenergy consumption associated with desiccant chamber operation, and enables more flexible manufacturing workflows where filament spools may be stored under ambient conditions without degradation of printability or final part quality.IMPROVEMENTS OVER EXISTING SYSTEMS

[0242] The present disclosure addresses significant challenges in polymer composite materials that have long limited the performance and processability of graphene-reinforced polymer systems across multiple application domains. Prior art solutions have struggled to achieve effective compatibilization between graphene and polymer matrices due to the fundamental structural differences between sp2-hybridized graphene with its planar geometry and it-it stacking interactions and sp3-hybridized polymer chains with tetrahedral geometry. Conventional approaches to incorporating graphene into polyolefin matrices such as polyethylene and polypropylene have been limited by poor dispersion, agglomeration of graphene particles, and weak interfacial adhesion that fails to provide efficient load transfer between the reinforcing graphene and the polymer matrix. Additionally, prior art polyamide-based systems suffer from the inherent hygroscopic nature of polyamide materials, which causes moisture absorption from the environment leading to dimensional instability, reduced mechanical properties, and processing difficulties during extrusion-based fabrication processes such as fused deposition modeling. Conventional carbon fiber-reinforced polyamide systems suffer from compromised interfacial adhesion between the fibers and the polymer matrix, resulting in suboptimal load transfer and reduced composite performance. Furthermore, existing reinforcement strategies that rely solely on fiber addition fail to address the fundamental compatibility challenges between hydrophilic polyamide matrices and hydrophobic reinforcing agents, requiring extensive drying procedures prior to processing and careful storage conditions to prevent moisture-related degradation. These conventional systems frequently exhibit inconsistent extrusion behavior due to poor fiber-matrix compatibility, resulting in nozzle clogging, uneven material flow, and surface defects in printed parts.

[0243] The disclosed polymer composite systems overcome these deficiencies through novel approaches that address the compatibility and performance challenges at multiple levels. In polyolefin-based systems, the covalent bonding of oxidized three-dimensional-75- LYT1P050.P_LYTEP213WOgraphene to hydrocarbon groups of the polyolefin via silane or isocyanate functional groups provides a direct chemical linkage that overcomes the inherent incompatibility between graphene and polyolefin structures, enabling uniform distribution of graphene throughout the polymer matrix and efficient load transfer that enhances mechanical strength. The silica- graphene hybrid approach further advances composite performance by coupling shape-anisotropic silica nanoparticles to the oxidized three-dimensional graphene surface via silane linkage, where rod-shaped silica nanoparticles provide improvement in flexural modulus while maintaining full elongation properties that prevent brittle failure. This silica-graphene hybrid system resolves the persistent challenge of balancing stiffness and ductility in polyolefin materials, a trade-off that typically forces engineers to sacrifice one property for the other. The polyamide-graphene composite incorporating three-dimensional graphene along with carbon fibers dispersed within a polyamide matrix addresses the unique challenges of additive manufacturing applications. The three-dimensional graphene, being innately hydrophobic due to its sp2-hybridized carbon structure, increases the surface hydrophobicity of the polyamide matrix, thereby reducing its hygroscopic nature and improving processability without requiring extensive pre-drying procedures. The combination of carbon fibers with appropriate sizing agents and uniformly dispersed three-dimensional graphene provides enhanced mechanical strength while maintaining the flow characteristics necessary for consistent extrusion in fused deposition modeling applications. Furthermore, the three-dimensional graphene dispersed at the interface between the carbon fibers and the polyamide matrix cooperatively enhances interfacial adhesion and load transfer, addressing the critical pain point of poor fiber-matrix compatibility in existing solutions. This innovative approach achieves mechanical strength improvements of at least 10% over carbon fiber- reinforced polyamides without the three-dimensional graphene, while simultaneously enabling improved printability and reduced moisture sensitivity that have plagued prior art systems.SYSTEM IMPLEMENTATION EMBODIMENTS

[0244] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and-76- LYT1P050.P_LYTEP213WOscope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

[0245] It should be understood that the arrangement of components illustrated in the Figures described are exemplary and that other arrangements are possible. It should also be understood that the various system components (and means) defined by the claims, described below, and illustrated in the various block diagrams represent logical components in some systems configured according to the subject matter disclosed herein.

[0246] For example, one or more of these system components (and means) may be realized, in whole or in part, by at least some of the components illustrated in the arrangements illustrated in the described Figures. In addition, while at least one of these components are implemented at least partially as an electronic hardware component, and therefore constitutes a machine, the other components may be implemented in software that when included in an execution environment constitutes a machine, hardware, or a combination of software and hardware.

[0247] More particularly, at least one component defined by the claims is implemented at least partially as an electronic hardware component, such as an instruction execution machine (e.g., a processor-based or processor-containing machine) and / or as specialized circuits or circuitry (e.g., discreet logic gates interconnected to perform a specialized function). Other components may be implemented in software, hardware, or a combination of software and hardware. Moreover, some or all of these other components may be combined, some may be omitted altogether, and additional components may be added while still achieving the functionality described herein. Thus, the subject matter described herein may be embodied in many different variations, and all such variations are contemplated to be within the scope of what is claimed.

[0248] In the description above, the subject matter is described with reference to acts and symbolic representations of operations that are performed by one or more devices, unless indicated otherwise. As such, it will be understood that such acts and operations, which are at times referred to as being computer-executed, include the manipulation by the processor of data in a structured form. This manipulation transforms the data or maintains it at locations in the memory system of the computer, which reconfigures or otherwise alters the operation of the device in a manner well understood by those skilled in the art.-77- LYT1P050.P_LYTEP213WOThe data is maintained at physical locations of the memory as data structures that have particular properties defined by the format of the data. However, while the subject matter is being described in the foregoing context, it is not meant to be limiting as those of skill in the art will appreciate that various of the acts and operations described hereinafter may also be implemented in hardware.

[0249] To facilitate an understanding of the subject matter described herein, many aspects are described in terms of sequences of actions. The description herein of any sequence of actions is not intended to imply that the specific order described for performing that sequence must be followed. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[0250] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the subject matter (particularly in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation, as the scope of protection sought is defined by the claims as set forth hereinafter together with any equivalents thereof entitled to. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illustrate the subject matter and does not pose a limitation on the scope of the subject matter unless otherwise claimed. The use of the term “based on” and other like phrases indicating a condition for bringing about a result, both in the claims and in the written description, is not intended to foreclose any other conditions that bring about that result. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention as claimed.

[0251] The aspects described herein included the one or more modes known to the inventor for carrying out the claimed subject matter. Of course, variations of those aspects will become apparent to those of ordinary skill in the art upon reading the foregoing-78- LYT1P050.P_LYTEP213WOdescription. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the claimed subject matter to be practiced otherwise than as specifically described herein. Accordingly, this claimed subject matter includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

-79- LYT1P050.P_LYTEP213WOCLAIMSWhat is claimed is:

1. A polyolefin-graphene composite, comprising:a polyolefin having a plurality of hydrocarbon groups; anda plurality of oxidized three-dimensional graphene (3DG0), wherein each oxidized three-dimensional graphene is covalently bonded to one of the plurality of hydrocarbon groups.

2. The polyolefin-graphene composite as recited in claim 1, wherein the polyolefin is selected from the group consisting of: polypropylene and polyethylene.

3. The polyolefin-graphene composite as recited in claim 1, wherein each oxidized three-dimensional graphene is bound to the corresponding hydrocarbon group via a silane functional group.

4. The polyolefin-graphene composite as recited in claim 3, wherein each oxidized three-dimensional graphene is bound to the corresponding hydrocarbon group via an isocyanate functional group.

5. The polyolefin-graphene composite as recited in claim 1, where the polyolefin- graphene composite has a uniform distribution of the plurality of oxidized three- dimensional graphene bound to the plurality of hydrocarbon groups of the polyolefin.

6. The polyolefin-graphene composite as recited in claim 1, wherein the polyolefin has a chemical formula (CH2CHR)n and the polyolefin-graphene composite has a chemical formula (CH(3DG)CHR)n, wherein a mechanical strength the polyolefin-graphene composite is greater than a mechanical strength of the polyolefin.-80- LYT1P050.P_LYTEP213WO7. The polyolefin-graphene composite as recited in claim 1, wherein each oxidized three-dimensional graphene is a carbon nanoparticle.

8. The polyolefin-graphene composite as recited in claim 7, herein the carbon nanoparticle has a structural morphology characterized by a plurality of spikes and nodules.

9. The polyolefin-graphene composite as recited in claim 7, wherein the carbon nanoparticle includes two or more connected multi-walled spherical or cylindrical fullerenes and layers of graphene coating the connected multi-walled spherical fullerenes.

10. The polyolefin-graphene composite as recited in claim 9, wherein the multiwalled spherical or cylindrical fullerenes do not contain a core composed of impurity elements other than carbon.

11. A silica-graphene hybrid compound, comprising:oxidized three-dimensional graphene (3DGO); anda plurality of silica nanoparticles coupled to a surface of the oxidized three- dimensional graphene.

12. The silica-graphene hybrid compound as recited in claim 11, wherein some of the silica nanoparticles are coupled to hydroxyl groups on the surface of the oxidized three-dimensional graphene.

13. The silica-graphene hybrid compound as recited in claim 11, wherein the plurality of silica nanoparticles are evenly distributed on the surface of the oxidized three- dimensional graphene.

14. The silica-graphene hybrid compound as recited in claim 11, wherein a weight ratio of graphene to silica is in a range of about 0.1 to about 15.-81- LYT1P050.P_LYTEP213WO15. The silica-graphene hybrid compound as recited in claim 11, wherein some of the silica nanoparticles are associated with the surface of the oxidized three- dimensional graphene via a coupling agent.

16. The silica-graphene hybrid compound as recited in claim 15, wherein the coupling agent is an amino-functionalized silane.

17. A polyolefin-graphene composite formed from the silica-graphene hybrid compound described in claim 11, wherein a mechanical strength of the polyolefin- graphene composite is greater than a mechanical strength of a polyolefin without the silica-graphene hybrid compound by at least 10%.

18. The polyolefin-graphene composite as recited in claim 17, wherein a shape of the plurality of silica nanoparticles is a rod-shaped nanoparticle.

19. The polyolefin-graphene composite as recited in claim 18, wherein the rod-shaped nanoparticle has an aspect ratio (LAV) in a range of 5 < LAV < 20.

20. The polyolefin-graphene composite as recited in claim 18, wherein a flexibility of the polyolefin-graphene composite is greater than a flexibility of a polyolefin without a silica-graphene hybrid compound.

21. A polyamide-graphene composite, comprising:a polyamide matrix;a plurality of carbon fibers dispersed within the polyamide matrix; and a plurality of three-dimensional graphene (3DG).

22. The polyamide-graphene composite as recited in claim 21 , wherein a surface hydrophobicity of the polyamide matrix is increased by the presence of the three-dimensional graphene.-82- LYT1P050.P_LYTEP213WO23. The polyamide-graphene composite as recited in claim 21 , wherein the three-dimensional graphene has a structural morphology characterized by a plurality of spikes and nodules, and wherein the structural morphology promotes mechanical interlocking with the polyamide matrix.

24. The polyamide-graphene composite as recited in claim 21 , wherein the three-dimensional graphene is present in an amount within a range of 0.05 - 5 wt% of the composite, and wherein the carbon fibers comprise an epoxy -based sizing, and wherein the composite exhibits both improved mechanical strength and improved printability relative to a carbon fiber-reinforced polyamide without the three-dimensional graphene.

25. The polyamide-graphene composite as recited in claim 21 , wherein the polyamide matrix comprises at least one of nylon 12, nylon 6, nylon 11, nylon 6 / 6, nylon 6 / 12, poly etherimide (PEI), poly ether ether ketone (PEEK), poly etherketoneketone (PEKK), polycarbonate, or polyphenylene sulfide (PPS).

26. The polyamide-graphene composite as recited in claim 21 , wherein the plurality of three-dimensional graphene is uniformly dispersed within the polyamide matrix.

27. The polyamide-graphene composite as recited in claim 21 , wherein the carbon fibers have a diameter in a range of about 5 pm to about 10 pm.

28. The polyamide-graphene composite as recited in claim 21 , wherein the carbon fibers have a length in a range of about 0.01 mm to about 1 mm.

29. The polyamide-graphene composite as recited in claim 28, wherein the carbon fibers have a length in a range of about 3 mm to about 6 mm.

30. The polyamide-graphene composite as recited in claim 21 , wherein the carbon fibers are chopped carbon fibers.-83- LYT1P050.P_LYTEP213WO31. The polyamide-graphene composite as recited in claim 21 , wherein the carbon fibers are continuous carbon fibers.

32. The polyamide-graphene composite as recited in claim 21 , wherein the carbon fibers comprise a sizing agent on a surface thereof.

33. The polyamide-graphene composite as recited in claim 32, wherein the sizing agent comprises an epoxy-based sizing, a polyurethane-based sizing, or a polyamide-compatible sizing.

34. The polyamide-graphene composite as recited in claim 21 , wherein the three-dimensional graphene is grown directly on a surface of the carbon fibers.

35. The polyamide-graphene composite as recited in claim 21 , wherein the carbon fibers are present in an amount of about 5 wt% to about 40 wt% of the composite.

36. The polyamide-graphene composite as recited in claim 21 , wherein the three-dimensional graphene is present in an amount of about 0.1 wt% to about 5 wt% of the composite.

37. The polyamide-graphene composite as recited in claim 21 , wherein a mechanical strength of the polyamide-graphene composite is greater than a mechanical strength of a polyamide without the three-dimensional graphene.

38. The polyamide-graphene composite as recited in claim 21 , wherein the composite is configured for additive manufacturing.

39. The polyamide-graphene composite as recited in claim 38, wherein the composite is in the form of a filament for fused deposition modeling.-84- LYT1P050.P_LYTEP213WO40. The polyamide-graphene composite as recited in claim 22, wherein the increased surface hydrophobicity reduces a hygroscopic nature of the polyamide matrix.

41. The polyamide-graphene composite as recited in claim 21 , wherein the three-dimensional graphene is dispersed at an interface between the carbon fibers and the polyamide matrix.

42. The polyamide-graphene composite as recited in claim 33, wherein the epoxybased sizing increases dispersibility of the carbon fibers within the polyamide matrix.

43. The polyamide-graphene composite as recited in claim 32, wherein the sizing agent on the carbon fibers and the three-dimensional graphene cooperatively enhance interfacial adhesion between the carbon fibers and the polyamide matrix, and wherein the composite exhibits improved processability for fused deposition modeling relative to a carbon fiber-reinforced polyamide without the three-dimensional graphene.

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