IPC分类号：
C22C1/10 | B22F1/16 | B22F10/00 | B22F10/12 | B22F10/18 | B22F10/25 | B22F10/28 | B29C64/153 | B29C64/165 | B29C64/268 | B29C64/314 | B29C71/04 | B33Y10/00 | B33Y40/10 | B33Y70/00 | C22C26/00 | C22C32/00
国民经济行业分类号：
C3516 | C4330 | C4320 | C4090 | C3493 | C3240 | C3140
当前申请(专利权)人：
YAZAKI CORPORATION
原始申请(专利权)人：
YAZAKI CORPORATION
发明人：
RAYCHAUDHURI, SATYABRATA | YAN, YONGAN | GRIGORIAN, LEONID
摘要：
This disclosure relates in general to three dimensional (“3D”) printers having a configuration that prepares a three-dimensional object by using a feedstock comprising a metal or a polymer compound and a carbon coating formed on a surface of the compound. This disclosure also relates to such feedstocks and their preparation methods. This disclosure further relates to 3D composite objects prepared by using such printers and feedstocks. This disclosure also relates to carbon containing photocurable formulations and methods for their preparation. This disclosure further relates to electrically conducting 3D polymer composites prepared by using such carbon containing photocurable formulations.
技术问题语段：
The technical problem addressed in this patent text is the need to improve the materials and processes of 3D printing to create advanced and customized parts that are difficult to manufacture using traditional methods. The text also discusses the challenge of enabling faster 3D printing processes and the use of nanocarbon materials in 3D printing to impart advanced properties and versatility.
技术功效语段：
This patent is about a 3D printer that uses a feedstock with a coating to prepare three-dimensional objects. The coating is made of a metal or a polymer compound and a carbon coating. The feedstock is deposited on a surface and then heated using electromagnetic radiation to bond the feedstock to each other and form a bonded feedstock layer. The coating absorbs the electromagnetic radiation and converts it to heat, which is then transferred to the compound. This results in faster heating and improved mechanical, thermal, and electrical properties of the 3D objects. The patent also describes a method for preparing the feedstock and the use of carbon-containing photocurable formulations for the 3D printer.
权利要求：
1. A method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer comprising:
dispensing a feedstock;
depositing a layer of the feedstock on a surface;
delivering an electromagnetic radiation to selected areas of the feedstock layer; and
preparing a three-dimensional composite object;
wherein the feedstock comprises a metal compound and a coating formed on a surface of the metal compound;
wherein the coating comprises a nanocarbon including a carbon nanotube;
wherein the coating has a thickness; and
wherein the coating absorbs the delivered electromagnetic radiation at a selected area of the feedstock layer, converts the absorbed electromagnetic radiation to heat, and transfers the heat to the metal compound, thereby heating the selected area of the feedstock layer and causing the feedstock to bond to each other and the surface on which it is deposited, and thereby forming a bonded feedstock layer.
2. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, further comprising:
depositing a second layer of the feedstock on a surface of the bonded feedstock layer formed before; and
forming another bonded feedstock layer according to claim 1.
3. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the coating further comprises a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof.
4. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the coating further comprises a non-agglomerated nanocarbon.
5. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the nanocarbon further comprises a graphene, a fullerene, or a combination thereof.
6. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the carbon nanotube comprises a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof.
7. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein:
the nanocarbon further comprises a graphene; and
the graphene comprises a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof.
8. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein:
the coating further comprises a fullerene; and
the fullerene comprises a C60, a C70, a C76, a C78, a C84, or a combination thereof.
9. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the metal compound comprises titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof.
10. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the metal compound comprises a metal particle, a metal wire, a metal tube, a metal sheet, or a combination thereof.
11. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein absorbance of the coating is higher than absorbance of the metal compound.
12. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein absorbance of the coating is at least 50 percent higher than the absorbance of the metal compound.
13. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein absorbance of the coating is at least 100 percent higher than the absorbance of the metal compound.
14. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein absorbance of the coating is at least 500 percent higher than the absorbance of the metal compound.
15. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein absorbance of the coating is at least 800 percent higher than the absorbance of the metal compound.
16. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein a heating rate of the feedstock comprising the metal compound and the coating is higher than a heating rate of a feedstock comprising the metal compound with no coating.
17. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein a heating rate of the feedstock comprising the metal compound and the coating is at least 50 percent higher than a heating rate of a feedstock comprising the metal compound with no coating.
18. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein a heating rate of the feedstock comprising the metal compound and the coating is at least 100 percent higher than a heating rate of a feedstock comprising the metal compound with no coating.
19. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein a heating rate of the feedstock comprising the metal compound and the coating is at least 500 percent higher than a heating rate of a feedstock comprising the metal compound with no coating.
20. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein a heating rate of the feedstock comprising the metal compound and the coating is 800 percent higher than a heating rate of a feedstock comprising the metal compound with no coating.
21. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein a thickness of the coating is configured to substantially absorb electromagnetic radiation, but not to cause defects in the composite object and thereby negatively impact properties of the composite object.
22. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the coating thickness is in the range of 10 nanometers to 100 micrometers.
23. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the coating thickness is in the range of 100 nanometers to 10 micrometers.
24. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the coating thickness is in the range of 1 micrometer to 5 micrometers.
25. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein power of delivered electromagnetic radiation is less than or equivalent to 5,000 watts.
26. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein power of delivered electromagnetic radiation is less than or equivalent to 1,000 watts.
27. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein power of delivered electromagnetic radiation is less than or equivalent to 500 watts.
28. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein power of delivered electromagnetic radiation is less than or equivalent to 100 watts.
29. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the coating is substantially free of any dispersion solvent.
30. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 1, wherein the G/D ratio of nanocarbons in the coating is approximately the same or higher than the G/D ratio of the nanocarbons in their initial state.
31. A method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer, comprising:
dispensing a feedstock comprising a metal compound and a coating thereon;
depositing a layer of the feedstock on a surface; and
delivering electromagnetic radiation to selected areas of the feedstock layer such that the feedstock and the material of the surface on which it is deposited bond together;
wherein the feedstock is prepared by:
dispersing nanocarbons including carbon nanotubes in a solvent to form a slurry without any surfactants, dispersing agents or functional groups, applying the slurry to one or more surfaces of a metal compound, and
allowing the slurry to dry and form a coating on the one or more surfaces of the metal compound;
wherein the amount of the slurry applied to the metal compound is sufficient to result in a dried coating having a thickness in the range of 10 nanometers to 100 micrometers.
32. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 31, wherein the G/D ratio of the nanocarbons in the coating is approximately equal to or higher than the G/D ratio of the nanocarbons prior to dispersion into the solvent.
33. The method of preparing a three-dimensional composite object using a three dimensional (“3D”) printer of claim 31, wherein the feedstock metal compound comprises titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof.
技术领域：
[0002]This disclosure relates in general to three dimensional (“3D”) printers having a configuration that prepares a three-dimensional object by using a feedstock comprising a metal or a polymer compound and a carbon coating formed on a surface of the compound. This disclosure also relates to such feedstocks and their preparation methods. This disclosure further relates to 3D composite objects prepared by using such printers and feedstocks. This disclosure also relates to carbon containing photocurable formulations and methods for their preparation. This disclosure further relates to electrically conducting 3D polymer composites prepared by using such carbon containing photocurable formulations.
背景技术：
[0003]3D printing, also known as additive manufacturing, is a technology of building three dimensional (3D) solid objects by depositing layers of materials in a design defined by a computer software using many of the commonly available CAD (computer aided design) packages. This technology can create highly customized complex parts and products that are difficult or impossible to manufacture using traditional technologies.
[0004]There are several major 3D printing technologies differing mainly in the way layers are built to create the final 3D object. Some methods use melting or softening materials to produce the layers. For example, Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) work by respectively sintering or melting metal, plastic, ceramic, or glass powders using irradiative heating. The heating is done by various light sources emitting electromagnetic radiation in ultraviolet (UV), visible, or infrared (IR) range that is absorbed by the powder, and the radiation energy is converted to heat. Typically, the light source is a lamp or a laser. For example, metal powders are typically heated by fiber lasers emitting IR radiation. For example, the popular M 400 SLS 3D printer manufactured by EOS (Germany) uses a Yb-fiber laser rated at about 1 kilowatt power operating at about 1,070 nanometer wavelength. The second group of methods, exemplified by Fused Deposition Modeling (FDM), works by extruding melted plastic filaments or metal wires through an extrusion nozzle. The third group of methods such as stereolithography (SLA) and Digital Light Processing (DLP) are based on curing (solidifying) liquid materials (such as photopolymer resins) with electromagnetic radiation in UV, visible, or IR ranges. Typically, SLA lasers require much less power compared to SLS lasers. For example, the popular Form1+3D printer manufactured by Formlabs (Somerville, Mass.) uses a 0.12 watt laser operating at about 405 nanometer wavelength.
[0005]Current challenges include improving the available 3D printing materials to impart advanced properties and versatility needed for industrial applications, as well as enabling faster 3D printing processes.
[0006]For further disclosures related to the nanocarbon 3D printing materials (including nanocarbon oxides), for example, see the following publications: M. N. dos Santos, C. V. Opelt, S. H. Pezzin, C. A. C. E. da Costa, J. C. Milan, F. H. Lafratta, and L. A. F. Coelho, Nanocomposite of photocurable epoxy-acrylate resin and carbon nanotubes: dynamic-mechanical, thermal and tribological properties, Materials Research, 16 (2), 367-374 (2013); M. Sangermano, E. Borella, A. Priola, M. Messori, R. Taurino, and P. Potschke, Use of single-walled carbon nanotubes as reinforcing fillers in UV-curable epoxy systems. Macromolecular Materials and Engineering, 293(8), 708-713 (2008); Y. F. Zhu, C. Ma, W. Zhang, R. P. Zhang, N. Koratkar, and J. Liang, Alignment of multiwalled carbon nanotubes in bulk epoxy composites via electric field. Journal of Applied Physics, 105(5), 1-6 (2009); M. Martin-Gallego, M. Hernandez, V. Lorenzo, R. Verdejo, M. A. Lopez-Manchado, and M. Sangermano, Cationic photocured epoxy nanocomposites filled with different carbon fillers. Polymer, 53(9), 1831-1838 (2012); M. N. dos Santos, C. V. Opelt, F. H. Lafratta, Lepienski C M, S. H. Pezzin, and L. A. F. Coelho, Thermal and mechanical properties of a nanocomposite of a photocurable epoxy-acrylate resin and multiwalled carbon nanotubes, Materials Science and Engineering A: Structural Materials Properties Microstructure and Processing, 528(13-14), 4318-4324 (2011); F. H. Gojny, M. H. G. Wichmann, U. Kopke, B. Fiedler, and K. Schulte, Carbon nanotube-reinforced epoxy-compo sites: enhanced stiffness and fracture toughness at low nanotube content, Composites Science and Technology, 64(15), 2363-2371 (2004); B. Dong, Z. Yang, Y. Huang, and H. L. Li, Study on tribological properties of multi-walled carbon nanotubes/epoxy resin nanocomposites, Tribology Letters, 20(3-4), 251-254 (2005); S. Ushiba, S. Shoji, K. Masui, P. Kuray, J. Kono, and S. Kawata, 3D microfabrication of single-wall carbon nanotube/polymer composites by two-photon polymerization lithography, Carbon 59, 283-288 (2013). The entire content of each of these publications is incorporated herein by reference.
[0007]A variety of CNT materials (i.e., single-wall, double-wall, and multi-wall CNTs) are commercially available as dry powders and/or suspensions. These CNT materials may be synthesized by variety of CNT synthesis methods. Some examples of the CNT synthesis methods are arc-discharge methods, laser-vaporization methods, and chemical vapor deposition method (CVD). See, for example, following publications: M. Kumar and Y. Ando, Chemical Vapor Deposition of Carbon Nanotubes: A Review on Growth Mechanism and Mass Production, Journal of Nanoscience and Nanotechnology, vol. 10, pp. 3739-3758 (2010); G. L. Hornyak, L. Grigorian, A. C. Dillon, P. A. Parilla, K. M. Jones, and M. J. Heben, A Temperature Window for Chemical Vapor Decomposition Growth of Single-Wall Carbon Nanotubes, Journal of Physical Chemistry B, vol. 106, pp. 2821-2825 (2002); L. Grigorian, G. L. Hornyak, A. C. Dillon, and M. J. Heben, Continuous growth of single-wall carbon nanotubes using chemical vapor deposition, U.S. Pat. No. 7,431,965, Oct. 7, 2008. The entire content of each of these publications is incorporated herein by reference.
[0008]The arc-discharge method employs evaporation of metal-catalyzed graphite electrodes in electric arcs that involve very high (about 4,000° C.) temperatures. The laser-vaporization method employs evaporation of graphite target by lasers in conjunction with high-temperature furnaces. These two methods operate in a batch mode and may therefore be poorly suited to high-volume, low cost production. The CVD method is based on decomposition of carbon-containing gases on supported catalyst and may offer the more efficient, low-cost, and scalable method of producing CNTs. Currently, most commercial CNT materials are manufactured by the CVD method.
[0009]For examples of 3D printers and 3D printing techniques, see: Sachs et al. “Three-Dimensional Printing Techniques” U.S. Pat. No. 5,204,055; Deckard “Apparatus for Producing Parts by Selective Sintering” U.S. Pat. No. 5,597,589; Hopkinson et al. “Method and Apparatus for Combining Particulate Material” U.S. Pat. No. 7,879,282; Liu et al. “Layer Manufacturing of a Multi-Material or Multi-Color 3D Object Using Electrostatic Imaging and Lamination” U.S. Patent Application Publication No. 2002/0145213; Kramer et al. “Systems and Methods for Using Multi-Part Curable Materials” U.S. Patent Application Publication No. 2005/0012247; and Boyd et al. “Method and a System for Solid Freeform Fabrication of a Three-Dimensional Object” U.S. Patent Application Publication No. 2005/0093208. The entire content of each of these patents and patent applications is incorporated herein by reference.
发明内容：
[0010]This disclosure relates in general to three dimensional (“3D”) printers having a configuration that prepares three-dimensional objects by using a feedstock comprising a metal or a polymer compound and a carbon coating formed on a surface of the compound. This disclosure also relates to such feedstocks and their preparation methods. This disclosure further relates to 3D composite objects prepared by using such printers and feedstocks. This disclosure also relates to carbon containing photocurable formulations and methods for their preparation. This disclosure further relates to electrically conducting 3D polymer composites prepared by using such carbon containing photocurable formulations.
[0011]This disclosure relates to a 3D printer that may have a configuration that dispenses a feedstock; deposits a layer of the feedstock on a surface; delivers an electromagnetic radiation to selected areas of the feedstock layer; and prepares a three-dimensional object. The coating may absorb the delivered electromagnetic radiation at a selected area of the feedstock layer, convert the absorbed electromagnetic radiation to heat, and transfer the heat to the metal compound thereby heating the selected area of the feedstock layer, and causing the feedstock to bond to each other, and thereby forming a bonded feedstock layer.
[0012]The 3D printer may further have a configuration that deposits a layer of feedstock on a surface of the bonded feedstock layer formed before; and forms another bonded feedstock layer. Thus, the 3D printer of the instant disclosure may prepare an object layer by layer.
[0013]This disclosure also relates to a feedstock. The feedstock may comprise a compound and a coating formed on a surface of the compound. The compound may be any compound. For example, the compound may be a metal, a glass, a ceramic, a polymer, or a combination thereof. For example, the compound may be a metal.
[0014]This disclosure also relates to carbon containing photocurable formulations and methods for their preparation and to electrically conducting 3D polymer composites prepared by using such carbon containing photocurable formulations. Addition of carbons to photocurable formulations may impart high electrically conductivity and also improve mechanical, thermal, and other properties of 3D-printed polymer objects. For example, carbon containing polymer composites may have higher tensile strength and be less flammable compared to pristine polymer objects.
[0015]The coating may comprise a carbon. The carbon may be any type of carbon. For example, the carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. For example, the coating may comprise a nanocarbon. The nanocarbon may be a non-agglomerated nanocarbon. Examples of the nanocarbon may be a carbon nanotube (CNT), a graphene (GR), a fullerene (FL), or a combination thereof. Examples of the carbon nanotube may be a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. For example, the coating may comprise a graphene. Examples of the graphene may be a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. For example, the coating may comprise a fullerene. Examples the fullerene may be a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0016]For example, the compound may comprise a metal. The metal compound may be any metal. The examples of the metal compound may be titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof. The metal compound may have any shape. For example, the metal compound may comprise a metal particle (e.g. granule), a metal wire, a metal tube, a metal sheet, or a combination thereof.
[0017]The coating may absorb the delivered electromagnetic radiation at a selected area of the feedstock layer, may convert the absorbed electromagnetic radiation to heat, and may then transfer the heat to the compound thereby heating the selected area of the feedstock layer, and causing the feedstock to bond to each other, and thereby forming a bonded feedstock layer.
[0018]The coating has an absorbance of the electromagnetic radiation. The absorbance of the coating may be higher than absorbance of the compound. For example, the absorbance of the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than the absorbance of the compound.
[0019]Because the coating has an absorbance of the electromagnetic radiation higher than that of the compound, heating rate of the feedstock comprising the compound and the coating may be higher than that of a feedstock without the coating. For example, the heating rate of the feedstock comprising the compound and the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than that of a feedstock without the coating.
[0020]The 3D printer of the instant disclosure may emit the electromagnetic radiation at any power suitable to form a bonded feedstock layer. For example, the 3D printer may emit the electromagnetic radiation with power less than or equivalent to 5,000 watts, with power less than or equivalent to 1,000 watts; with power less than or equivalent to 500 watts; or with power less than or equivalent to 100 watts.
[0021]A three-dimensional object prepared by any of the 3D printers disclosed above may be within scope of this instant disclosure.
[0022]This disclosure also relates to a feedstock as disclosed above. This feedstock may be used for preparation of 3D objects by any equipment or method. For example, this feedstock may be used for preparation of 3D objects by any of the 3D printers disclosed above.
[0023]The feedstock may comprise a compound, and a coating formed on a surface of the compound.
[0024]The compound may be any compound. For example, the compound may comprise a metal, a glass, a ceramic, a polymer, or a combination thereof. For example, the compound may comprise a metal. For example, the compound may comprise a polymer.
[0025]The coating may comprise a carbon. The carbon may be any type of carbon. For example, the carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. For example, the coating may comprise a nanocarbon. The nanocarbon may be a non-agglomerated nanocarbon. Examples of the nanocarbon may be a carbon nanotube (CNT), a graphene (GR), a fullerene (FL), or a combination thereof. Examples of the carbon nanotube may be a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. For example, the coating may comprise a graphene. Examples of the graphene may be a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. For example, the coating may comprise a fullerene. Examples the fullerene may be a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0026]For example, the compound may be a metal. The metal may be any metal. The examples of the metal compound may comprise titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof. The metal compound may have any shape. For example, the metal compound may comprise a metal particle (e.g. granule), a metal wire, a metal tube, a metal sheet, or a combination thereof.
[0027]The coating has an absorbance of the electromagnetic radiation. The absorbance of the coating may be higher than absorbance of the compound. For example, the absorbance of the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than the absorbance of the compound.
[0028]Because the coating has an absorbance of the electromagnetic radiation higher than that of the compound, heating rate of the feedstock comprising the compound and the coating may be higher than that of a feedstock without the coating. For example, the heating rate of the feedstock comprising the compound and the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than that of a feedstock without the coating.
[0029]The coating may be sufficiently thick to substantially absorb electromagnetic radiation, but not too thick to cause defects in the composite object and thereby negatively impact properties of the composite object. For example, the coating thickness may be in the range of 10 nanometers to 100 micrometers, in the range of 100 nanometers to 10 micrometers, or in the range of 1 micrometer to 5 micrometers.
[0030]A three-dimensional object prepared by using any of the feedstocks disclosed above may be within scope of this instant disclosure.
[0031]The instant disclosure also relates to a method of preparation (“preparation method”). For example, the preparation method may be preparation of a suspension of a carbon in a solvent (“method of preparation of a carbon suspension”). For example, the method may comprise processing a conditioned mixture at a high shear rate and thereby preparing a carbon suspension. In this preparation method, the conditioned mixture may be prepared by a method comprising processing a solution at a low shear rate. The low shear rate may be lower than 200,000 s−1. The high shear rate may be equivalent to or higher than 200,000 s-1.
[0032]In this method, first, the conditioned mixture may be prepared. The conditioned mixture may be prepared by processing a solution at a shear rate lower than 200,000 s−1. In this method, second, a carbon suspension is prepared by processing the conditioned mixture at a shear rate higher than 200,000 s−1. After this high shear processing, a carbon suspension comprising substantially non-agglomerated carbons may be obtained.
[0033]The solution may comprise a carbon and a solvent. The solution may be substantially free of any dispersing agent. The carbon may be substantially free of functional groups that can facilitate dispersion of the carbon in the solution.
[0034]The carbon may be any carbon disclosed above. For example, the carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. For example, the coating may comprise a nanocarbon. The nanocarbon may be a non-agglomerated nanocarbon. Examples of the nanocarbon may be a carbon nanotube (CNT), a graphene (GR), a fullerene (FL), or a combination thereof. Examples of the carbon nanotube may be a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. For example, the coating may comprise a graphene. Examples of the graphene may be a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. For example, the coating may comprise a fullerene. Examples the fullerene may be a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0035]In this method, the solvent may be any solvent. For example, the solvent may comprise water, an acid, a base, an aromatic solvent, an alcohol, an aromatic solvent, benzene, halogenated benzene, xylene, toluene, a dichlorobenzene, dimethylformamide, formamide and its derivatives, N-methylpyrrolidinone, dichloroethane, dibromoethane, carbon disulfide, pyridine, or a combination thereof.
[0036]In this method, the conditioned mixture may substantially be free of any dispersing agent.
[0037]The preparation method may further comprise depositing the carbon suspension on a surface of a metal compound.
[0038]The metal compound may comprise any metal. For example, the metal compound may comprise titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof. The metal compound may have any structural form or shape. For example, the metal compound comprises a metal particle, a metal wire, a metal tube, a metal sheet, or a combination thereof.
[0039]The preparation method may further comprise removing the solvent; thereby forming a coating on a surface of the metal compound; and thereby preparing a feedstock. The solvent may be removed until the feedstock is substantially free of solvent. The solvent may be removed by any technique. For example, the solvent may be removed by evaporation, centrifugation, using drying agents (e.g. absorbents or adsorbents), or a combination thereof.
[0040]The coating has a thickness. The coating thickness may be in the range of 10 nanometers to 100 micrometers; the range of 100 nanometers to 10 micrometers; or in the range of 1 micrometer to 5 micrometers.
[0041]After the removal of the solvent, the coating may essentially comprise the carbon.
[0042]Any three-dimensional composite object prepared by using any of the carbon suspension prepared by any of the method disclosed above may be within the scope of the instant disclosure.
[0043]The instant disclosure also relates to a carbon containing photocurable formulation. This formulation may comprise a carbon; a photocurable resin; and a photoinitiator (i.e. photo-catalyst). The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 100 ohmcm, or lower than or equivalent to 10 ohmcm, or lower than or equivalent to 1 ohmcm, or lower than or equivalent to 0.1 ohmcm.
[0044]The carbon containing photocurable formulation may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. The carbon may comprise a nanocarbon. The carbon may comprise a non-agglomerated nanocarbon. The nanocarbon may comprise a carbon nanotube, a graphene, a fullerene, or a combination thereof. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The graphene may comprise a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. The fullerene may comprise a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0045]The photocurable resin may comprise a photocurable monomer, a photocurable oligomer, a photocurable polymer, or a combination thereof. The photocurable resin may comprise a monomer, oligomer, or a polymer of a hydrocarbon. The hydrocarbon may be any hydrocarbon. For example, the hydrocarbon may be an acrylate, a methacrylate, an epoxy, a urethane, an ester, a silicone, a styrene, or a combination thereof. For example, the hydrocarbon may comprise a monofunctional hydrocarbon, a difunctional hydrocarbon, a trifunctional hydrocarbon, a multifunctional hydrocarbon, or a combination thereof.
[0046]The carbon containing photocurable formulation may have a viscosity. The viscosity of the carbon containing photocurable formulation is in the range of 1 millipascalsecond to 1,000 millipascalsecond at about 25° C.; or in the range of 10 millipascalsecond to 300 millipascalsecond at about 25° C.; or in the range of 50 millipascalsecond to 150 millipascalsecond at about 25° C.
[0047]The carbon containing photocurable formulation may comprise a carbon nanotube. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 1 ohmcm.
[0048]Any three-dimensional polymer composite object prepared by using any of the carbon containing photocurable formulations disclosed above is within the scope of the instant disclosure.
[0049]The instant disclosure also relates to a method of preparation of a carbon containing photocurable formulation. The method may comprise processing a conditioned photocurable mixture at a high shear rate and thereby preparing a carbon containing photocurable formulation. The conditioned photocurable mixture may be prepared by a method comprising processing a photocurable mixture at a low shear rate. The photocurable mixture may comprise a carbon, a photocurable resin, and a photoinitiator. The high shear rate may be equivalent to or higher than 200,000 s−1; or equivalent to or higher than 500,000 s−1; or equivalent to or higher than 1,000,000 s−1; or equivalent to or higher than 10,000,000 s−1. The low shear rate may be lower than 200,000 s−1.
[0050]The conditioned photocurable mixture may be substantially free of any dispersing agent. The photocurable mixture may be substantially free of any dispersing agent.
[0051]The carbon may substantially be free of functional groups that can facilitate dispersion of the carbon compound in the mixture.
[0052]The carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. The nanocarbon may comprise a carbon nanotube, a graphene, a fullerene, or a combination thereof. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The graphene may comprise a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. The fullerene may comprise a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0053]The photocurable resin may comprise a photocurable monomer, a photocurable oligomer, a photocurable polymer, or a combination thereof.
[0054]The photocurable resin may comprise a monomer, oligomer or a polymer of an acrylate, a methacrylate, an epoxy, a urethane, an ester, a silicone, a vinyl alcohol, a vinyl acetate, an alkene, a glycerol, a glycol, a ketone, or a combination thereof.
[0055]The carbon containing photocurable formulation has a viscosity, wherein the viscosity of the carbon containing photocurable formulation may in the range of 1 millipascalsecond to 1,000 millipascalsecond at about 25° C.; or in the range of 10 millipascalsecond to 300 millipascalsecond at about 25° C.; or in the range of 50 millipascalsecond to 150 millipascalsecond at about 25° C.
[0056]The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 100 ohmcm; or lower than or equivalent to 10 ohmcm; or lower than or equivalent to 1 ohmcm; or lower than or equivalent to 0.1 ohmcm.
[0057]In this preparation method the carbon may comprise a carbon nanotube. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 1 ohmcm.
[0058]Any three-dimensional polymer composite object prepared by using any of the carbon containing photocurable formulation disclosed above, which may be prepared by any of the methods suitable for preparation of such formulations may be within the scope of the instant disclosure.
[0059]Any combination of the above feedstocks; methods of preparation of such feedstocks; carbon containing photocurable formulations; methods of preparation of such formulations; 3D printers; 3D printers that use such feedstocks and/or such formulations; 3D objects; methods of preparation of such 3D objects by using such 3D printers, feedstocks and formulations may be within the scope of the instant disclosure.
[0060]These, as well as other components, steps, features, objects, benefits, and advantages, will now become clear from a review of the following detailed description of illustrative embodiments, the accompanying drawings, and the exemplary features.
具体实施方式：
[0070]Illustrative embodiments are now described. Other embodiments may be used in addition or instead. Details that may be apparent or unnecessary may be omitted to save space or for a more effective presentation. Some embodiments may be practiced with additional components or steps and/or without all of the components or steps that are described.
[0071]In this disclosure, the word “form” may mean “deposit”, “coat”, “dispose”, “laminate”, “apply”, “place”, “provide”, “position”, “manufacture” or the like. In this disclosure, the phrase “any combination thereof” or “a combination thereof” may mean “a mixture thereof”, “a composite thereof”, “an alloy thereof”, or the like. In this disclosure, the indefinite article “a” and phrases “one or more” and “at least one” are synonymous and mean “at least one”.
[0072]This disclosure relates in general to three dimensional (“3D”) printers having a configuration that prepares three-dimensional objects by using a feedstock comprising a metal or a polymer compound and a carbon coating formed on a surface of the compound. This disclosure also relates to such feedstocks and their preparation methods. This disclosure further relates to 3D composite objects prepared by using such printers and feedstocks. This disclosure also relates to carbon containing photocurable formulations and methods for their preparation. This disclosure further relates to electrically conducting 3D polymer composites prepared by using such carbon containing photocurable formulations.
[0073]Addition of carbons and, in particular, nanocarbons, such as carbon nanotubes (CNT), graphenes (GR), fullerenes (FL), and their mixtures in various proportions and combinations, to metal, plastic, ceramic, glass, polymer, and other 3D printing materials may lead to formation of nanocarbon composites with increased electrical conductivity, increased thermal conductivity, increased mechanical strength, and other improvements in properties.
[0074]Addition of nanocarbons also may lead to increased absorption of incident light in wide frequency range (e.g., UV, visible, IR) thereby improving the efficiency of irradiative heating of the feedstock and photochemical reactions. This may lead to higher rates and increased throughput of 3D printing processes, thereby making 3D printed parts more competitive on the market.
[0075]A major challenge in these tasks is ensuring high degree of dispersion of carbon in the carbon composite materials since only well-dispersed carbons impart useful properties. Typically, carbon agglomeration results in underutilized potential of the composite material and degraded properties of product.
[0076]Another challenge is preventing structural or other damage to carbons in the process of fabrication of nanocarbon composites. Damaged carbons may exhibit inferior properties when incorporated in composite materials.
[0077]The feedstock of the instant disclosure may provide several advantages to the 3D printing of objects. For example, three dimensional objects may be printed at higher throughputs by using the feedstocks of the instant disclosure. The production costs of such article may thereby be decreased while production rates are increased. The use of these feedstocks may also decrease the power requirements of the 3D printers, thereby decreasing the prices of such printers.
[0078]The feedstocks of the instant disclosure may also provide materials with improved properties for 3D printing technologies. These improvements may include (but not limited to) higher electrical and thermal conductivity, better mechanical and thermal properties.
[0079]This disclosure relates to a 3D printer that may have a configuration that dispenses a feedstock; deposits a layer of the feedstock on a surface; delivers an electromagnetic radiation to selected areas of the feedstock layer; and prepares a three-dimensional object. The coating may absorb the delivered electromagnetic radiation at a selected area of the feedstock layer, convert the absorbed electromagnetic radiation to heat, and transfer the heat to the metal compound thereby heating the selected area of the feedstock layer, and causing the feedstock to bond to each other, and thereby forming a bonded feedstock layer.
[0080]The deposition of the first layer may happen on any surface. For example, this surface may be a surface of another object.
[0081]The 3D printer may further have a configuration that deposits a layer of feedstock on a surface of the bonded feedstock layer formed before; and forms another bonded feedstock layer. Thus, the 3D printer of the instant disclosure may prepare an object layer by layer.
[0082]This disclosure also relates to a feedstock. The feedstock may comprise a compound and a coating formed on a surface of the compound. The compound may comprise any compound. For example, the compound may comprise a metal, a glass, a ceramic, a polymer, or a combination thereof. For example, the compound may be a metal. For example, the compound may be a polymer.
[0083]The coating may comprise a carbon. The carbon may be any type of carbon. For example, the carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof.
[0084]For example, the coating may comprise a nanocarbon. The nanocarbon may be a non-agglomerated nanocarbon. Examples of the nanocarbon may be a carbon nanotube (CNT), a graphene (GR), a fullerene (FL), or a combination thereof. Examples of the carbon nanotube may be a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof.
[0085]For example, the coating may comprise a graphene. Examples of the graphene may be a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof.
[0086]For example, the coating may comprise a fullerene. Examples the fullerene may be a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0087]For example, the compound may be a metal compound. The metal compound may be any metal. The examples of the metal compound may be titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof.
[0088]The metal compound may have any shape. For example, the metal compound may comprise a metal particle (e.g. granule), a metal wire, a metal tube, a metal sheet, or a combination thereof.
[0089]The coating may absorb the delivered electromagnetic radiation at a selected area of the feedstock layer, may convert the absorbed electromagnetic radiation to heat, and may then transfer the heat to the compound thereby heating the selected area of the feedstock layer, and causing the feedstock to bond to each other, and thereby forming a bonded feedstock layer.
[0090]The coating has an absorbance of the electromagnetic radiation. The absorbance of the coating may be higher than absorbance of the compound. For example, the absorbance of the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than the absorbance of the compound.
[0091]Because the coating has an absorbance of the electromagnetic radiation higher than that of the compound, heating rate of the feedstock comprising the compound and the coating may be higher than that of a feedstock without the coating. For example, the heating rate of the feedstock comprising the compound and the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than that of a feedstock without the coating.
[0092]The coating may be sufficiently thick to substantially absorb electromagnetic radiation, but not too thick to cause defects in the composite object and thereby negatively impact properties of the composite object. For example, the coating thickness may be in the range of 10 nanometers to 100 micrometers, in the range of 100 nanometers to 10 micrometers, or in the range of 1 micrometer to 5 micrometers.
[0093]The 3D printer of the instant disclosure may emit the electromagnetic radiation at any power suitable to form a bonded feedstock layer. Lowest emission power that forms a bonded feedstock layer may be preferred since manufacturing cost of the 3D printers and/or operating costs of such printers may thereby be decreased. For example, the 3D printer may emit the electromagnetic radiation with power less than or equivalent to 5,000 watts, with power less than or equivalent to 1,000 watts; with power less than or equivalent to 500 watts; or with power less than or equivalent to 100 watts.
[0094]Any three-dimensional object prepared by any of the 3D printers disclosed above may be within scope of this instant disclosure.
[0095]This disclosure also relates to a feedstock as disclosed above. This feedstock may be used in preparation of 3D objects by any equipment or method. For example, this feedstock may be used in preparation of 3D objects by any of the 3D printers disclosed above.
[0096]The feedstock may comprise a compound, and a coating formed on a surface of the compound.
[0097]The compound may be any compound. For example, the compound may comprise a metal, a glass, a ceramic, a polymer, or a combination thereof. For example, the compound may comprise a metal. For example, the compound may comprise a polymer.
[0098]The coating may comprise a carbon. The carbon may be any type of carbon. For example, the carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof.
[0099]For example, the coating may comprise a nanocarbon. The nanocarbon may be a non-agglomerated nanocarbon. Examples of the nanocarbon may be a carbon nanotube (CNT), a graphene (GR), a fullerene (FL), or a combination thereof. Examples of the carbon nanotube may be a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof.
[0100]For example, the coating may comprise a graphene. Examples of the graphene may be a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof.
[0101]For example, the coating may comprise a fullerene. Examples the fullerene may be a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0102]For example, the compound may be a metal. The metal compound may comprise any metal. The examples of the metal may comprise titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof.
[0103]The metal compound may have any shape. For example, the metal compound may comprise a metal particle (e.g. granule), a metal wire, a metal tube, a metal sheet, or a combination thereof.
[0104]The coating may have an absorbance of the electromagnetic radiation. The absorbance of the coating may be higher than absorbance of the compound. For example, the absorbance of the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than the absorbance of the compound.
[0105]Because the coating has an absorbance of the electromagnetic radiation higher than that of the compound, heating rate of the feedstock comprising the compound and the coating may be higher than that of a feedstock without the coating. For example, the heating rate of the feedstock comprising the compound and the coating may be at least 50 percent, at least 100 percent, at least 500 percent, or at least 800 percent higher than that of a feedstock without the coating.
[0106]The coating may be sufficiently thick to substantially absorb electromagnetic radiation, but not too thick to cause defects in the composite object and thereby negatively impact properties of the composite object. For example, the coating thickness may be in the range of 10 nanometers to 100 micrometers, in the range of 100 nanometers to 10 micrometers, or in the range of 1 micrometer to 5 micrometers.
[0107]Any three-dimensional object prepared by using any of the feedstocks disclosed above may be within scope of this instant disclosure.
[0108]The instant disclosure also relates to a method of preparation (“preparation method”). For example, the preparation method may be preparation of a suspension of a carbon in a solvent (“method of preparation of a carbon suspension”). For example, the method may comprise processing a conditioned mixture at a high shear rate and thereby preparing a carbon suspension. In this preparation method, the conditioned mixture may be prepared by a method comprising processing a solution at a low shear rate. The low shear rate may be lower than 200,000 s−1. The high shear rate may be equivalent to or higher than 200,000 s−1.
[0109]In this method, first, the conditioned mixture may be prepared. The conditioned mixture may be prepared by processing a solution at a shear rate lower than 200,000 s−1. The low shear rate processing of the solution may be achieved by using any low shear mixing equipment. Such mixing equipment is disclosed, for example, in a publication by Deutsch et al. “Mix or Match: Choose the Best Mixers Every Time: The choice is wide—from a variety of agitators, to devices that homogenize, emulsify, or disintegrate solids” Chemical Engineering, volume 105, issue 8 (August, 1998): page 70. The entire content of this publication is incorporated herein by reference.
[0110]In this method, second, a carbon suspension is prepared by processing the conditioned mixture at a shear rate higher than 200,000 s−1. Examples of the high shear rate equipment may be rotor-stators, colloid mills, homogenizers and microfluidizers, as disclosed in Deutsch publication. Microfluidizer high shear fluid processors manufactured by Microfluidics Corporation (Westwood, Mass.) may be suitable for high shear processing of the conditioned mixture. Such microfluidizers may process the conditioned mixture at a shear rate higher than 1,000,000 s−1. After this high shear processing, a carbon suspension comprising substantially non-agglomerated carbons may be obtained.
[0111]The solution may comprise a carbon and a solvent. The solution may be substantially free of any dispersing agent. The carbon may be substantially free of functional groups that can facilitate dispersion of the carbon compound in the solution.
[0112]The carbon may be any carbon disclosed above. For example, the carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. For example, the coating may comprise a nanocarbon. The nanocarbon may be a non-agglomerated nanocarbon. Examples of the nanocarbon may be a carbon nanotube (CNT), a graphene (GR), a fullerene (FL), or a combination thereof. Examples of the carbon nanotube may be a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. For example, the coating may comprise a graphene. Examples of the graphene may be a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. For example, the coating may comprise a fullerene. Examples the fullerene may be a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0113]In this method, the solvent may be any solvent. For example, the solvent may comprise water, an acid, a base, an aromatic solvent, an alcohol, an aromatic solvent, benzene, halogenated benzene, xylene, toluene, a dichlorobenzene, dimethylformamide, formamide and its derivatives, N-methylpyrrolidinone, dichloroethane, dibromoethane, carbon disulfide, pyridine, or a combination thereof.
[0114]In this method, the conditioned mixture may substantially be free of any dispersing agent.
[0115]The preparation method may further comprise depositing the carbon suspension on a surface of a metal compound.
[0116]The metal compound may comprise any metal. For example, the metal compound may comprise titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, aluminum, indium, gallium, tin, silver, gold, platinum, lead, bismuth, steel, bronze, brass, or a combination thereof.
[0117]The metal compound may have any structural form or shape. For example, the metal compound may comprise a metal particle, a metal wire, a metal tube, a metal sheet, or a combination thereof.
[0118]The preparation method may further comprise removing the solvent; thereby forming a coating on a surface of the metal compound; and thereby preparing a feedstock. The solvent may be removed until the feedstock is substantially free of solvent. The solvent may be removed by any technique. For example, the solvent may be removed by evaporation, centrifugation, using drying agents (e.g. absorbents or adsorbents), or a combination thereof.
[0119]The coating has a thickness. The coating thickness may be in the range of 10 nanometers to 100 micrometers; the range of 100 nanometers to 10 micrometers; or in the range of 1 micrometer to 5 micrometers.
[0120]After the removal of the solvent, the coating may essentially comprise the carbon.
[0121]Any three-dimensional composite object prepared by using the carbon suspension prepared by the method disclosed above may be within the scope of the instant disclosure.
[0122]The instant disclosure also relates to a carbon containing photocurable formulation. This formulation may comprise a carbon; a photocurable resin; and a photoinitiator (i.e. photo-catalyst). The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 100 ohmcm, or lower than or equivalent to 10 ohmcm, or lower than or equivalent to 1 ohmcm, or lower than or equivalent to 0.1 ohmcm.
[0123]The carbon containing photocurable formulation may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. The carbon may comprise a nanocarbon. The carbon may comprise a non-agglomerated nanocarbon. The nanocarbon may comprise a carbon nanotube, a graphene, a fullerene, or a combination thereof. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The graphene may comprise a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. The fullerene may comprise a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0124]The photocurable resin may comprise a photocurable monomer, a photocurable oligomer, a photocurable polymer, or a combination thereof. The photocurable resin may comprise a monomer, oligomer, or a polymer of a hydrocarbon. The hydrocarbon may be any hydrocarbon. For example, the hydrocarbon may be an acrylate, a methacrylate, an epoxy, a urethane, an ester, a silicone, a styrene, or a combination thereof. For example, the hydrocarbon may comprise a monofunctional hydrocarbon, a difunctional hydrocarbon, a trifunctional hydrocarbon, a multifunctional hydrocarbon, or a combination thereof.
[0125]The carbon containing photocurable formulation has a viscosity. The viscosity of the carbon containing photocurable formulation is in the range of 1 millipascalsecond to 1,000 millipascalsecond at about 25° C.; or in the range of 10 millipascalsecond to 300 millipascalsecond at about 25° C.; or in the range of 50 millipascalsecond to 150 millipascalsecond at about 25° C.
[0126]The carbon containing photocurable formulation may comprise a carbon nanotube, and wherein the carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof; wherein the carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 1 ohmcm.
[0127]Any three-dimensional polymer composite object prepared by using any of the carbon containing photocurable formulations disclosed above is within the scope of the instant disclosure.
[0128]The instant disclosure also relates to a method of preparation of a carbon containing photocurable formulation. The method may comprise processing a conditioned photocurable mixture at a high shear rate and thereby preparing a carbon containing photocurable formulation. The conditioned photocurable mixture may be prepared by a method comprising processing a photocurable mixture at a low shear rate. The photocurable mixture may comprise a carbon, a photocurable resin, and a photoinitiator. The high shear rate may be equivalent to or higher than 200,000 s−1; or equivalent to or higher than 500,000 s−1; or equivalent to or higher than 1,000,000 s−1; or equivalent to or higher than 10,000,000 s−1. The low shear rate may be lower than 200,000 s−1.
[0129]The conditioned photocurable mixture may substantially be free of any dispersing agent. The photocurable mixture may be substantially free of any dispersing agent.
[0130]The carbon may substantially be free of functional groups that can facilitate dispersion of the carbon compound in the mixture.
[0131]The carbon may comprise a nanocarbon, a pyrolytic carbon, a graphite, an activated carbon, an amorphous carbon, a carbon fiber, or a combination thereof. The nanocarbon may comprise a carbon nanotube, a graphene, a fullerene, or a combination thereof. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The graphene may comprise a single layer graphene, a double layer graphene, a multilayer graphene, a graphene strip, or a combination thereof. The fullerene may comprise a C60, a C70, a C76, a C78, a C84, or a combination thereof.
[0132]The photocurable resin may comprise a monomer, oligomer or a polymer of an acrylate, a methacrylate, an epoxy, a urethane, an ester, a silicone, a vinyl alcohol, a vinyl acetate, an alkene, a glycerol, a glycol, a ketone, or a combination thereof.
[0133]The carbon containing photocurable formulation has a viscosity, wherein the viscosity of the carbon containing photocurable formulation may in the range of 1 millipascalsecond to 1,000 millipascalsecond at about 25° C.; or in the range of 10 millipascalsecond to 300 millipascalsecond at about 25° C.; or in the range of 50 millipascalsecond to 150 millipascalsecond at about 25° C.
[0134]The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 100 ohmcm; or lower than or equivalent to 10 ohmcm; or lower than or equivalent to 1 ohmcm; or lower than or equivalent to 0.1 ohmcm.
[0135]In this preparation method the carbon may comprise a carbon nanotube. The carbon nanotube may comprise a single-wall carbon nanotube, a double-wall carbon nanotube, a multi-wall carbon nanotube, or a combination thereof. The carbon containing photocurable formulation, when cured, may yield a polymer composite with an electrical resistivity lower than or equivalent to 1 ohmcm.
[0136]Any three-dimensional polymer composite object prepared by using any of the carbon containing photocurable formulation disclosed above, which may be prepared by any of the methods suitable for preparation of such formulations may be within the scope of the instant disclosure.
[0137]As disclosed above, the CNT materials may be synthesized by variety of CNT synthesis methods. The CNT formation and growth may stop during the synthesis. The CNT formation and growth may stop due to decreased catalyst activity when the catalyst's surface is covered with an amorphous carbon layer. Or, the CNT formation and growth may be stopped after a pre-determined period of synthesis. At this process stage, the CNTs are “as-synthesized CNTs”.
[0138]The as-synthesized CNTs may be processed before they are used. For example, the as-synthesized CNTs may be incorporated into a liquid or mixed with a liquid. This incorporation may be done, for example, to dissolve impurities (e.g. non-CNT material), to provide a CNT suspension, or a combination thereof. Examples of impurities may be non-CNT carbons (e.g., amorphous carbon), inorganic catalysts, catalyst supports, or a combination thereof.
[0139]The liquid mixture at this process stage may comprise a liquid and an as-synthesized nanocarbon (“the nanocarbon slurry”). The liquid may comprise any liquid. For example, the liquid may comprise water, or mixtures thereof. The solvent may comprise any solvent. For example, the solvent may comprise a hydrocarbon solvent such as alcohol, ketone, ester, ether, alkane, alkene, aromatic hydrocarbons (such as benzene and various derivatives), or mixtures thereof. The nanocarbon slurry may further comprise an acid, a base, a suspension agent, or a combination thereof.
[0140]In one example, the CVD process may involve passing a hydrocarbon vapor through a reactor at a sufficiently high temperature, varying in the range of 600° C. to 1200° C., and in presence of a catalyst to decompose the hydrocarbon. In one example, the catalyst may comprise metals and/or metal oxides (e.g., Fe, Co, Ni, Mo, their oxides, and a combination thereof). The catalyst may be nanoparticles of such metals and/or metal oxides. In one example, support material may comprise alumina, silica, magnesium oxide, and a combination thereof. The CNTs may form and grow on catalyst particles in the reactor and may be collected upon cooling the system to a room temperature. These CNTs collected directly from the reactor and not yet treated in any way are the as-synthesized CNTs. The as-synthesized CNTs may comprise at least 50 wt % inorganic impurities including the catalyst and the support material, which may need to be removed to produce a material comprising CNTs with desired properties.
[0141]In one example, the as-synthesized CNTs may be purified by being immersed in acids (such as H2SO4, HNO3, HCl, and a combination thereof) and refluxed for a period varying in the range of 1 hour to 24 hours resulting in significantly decreased amount of impurities (down to a few wt % of impurities). The purified CNT material may be thoroughly washed to remove any residual acid and then dried in a convection oven at a temperature varying in the range of 20° C. to 150° C. for a period varying in the range of 1 hour to 48 hours.
[0142]The as-synthesized and purified CNTs may easily be dispersed in the liquid since they may not be substantially agglomerated. However, upon being wetted and subsequently dried, the CNT material may be converted into an agglomerated and tangled mat comprising irregular clusters of individual CNTs, as shown in FIG. 1. This post-drying transition may occur due to high amount of the CNTs' atomically smooth surface and attendant large surface energy. This condition may make the conformation of straight individual CNTs energetically unstable and susceptible to deformation and agglomeration.
[0143]The instability may greatly be enhanced by introducing a liquid between individual CNTs and then evaporating the liquid. In other words, wetting and then drying CNTs may induce severe agglomeration due to attraction forces exerted by liquids in intimate contact with the CNT surface. Upon drying, CNTs may coalesce into large bundles (including tens to hundreds of CNTs in cross section), which then form a highly tangled structure, as shown in FIG. 1 by way of example. These agglomerated structures may not exhibit many of the remarkable properties expected of individual, well-dispersed and/or isolated CNTs.
[0144]Commercially available CNT materials are typically those of the purified and dried grade, marketed either as a powder obtained after drying, or as a CNT suspension produced by re-dispersing the dry purified powder in either an aqueous or organic solvent. The commercially available purified grades of the CNT materials (“the commercial CNTs”) may undergo at least one wetting and drying cycle before they are supplied to a user. The commercial CNTs may thereby have agglomerated structures.
[0145]It may then be difficult to disperse this agglomerated structure down to the level of individual CNTs that may be required for many applications. To accomplish this task, commercially available grades of CNT materials may have to be subjected to vigorous harsh treatments that may consume a lot of energy and inflict considerable collateral damage upon the CNT material (e.g., by destroying some CNTs, creating defects in CNT walls, and/or cutting CNTs into shorter segments) resulting in degraded nanocarbon material properties.
[0146]In one example, this disclosure relates to a method comprising using the as-synthesized CNTs, the non-agglomerated and/or non-damaged CNTs, the CNT slurry, or the combination thereof in preparation of the nanocarbon composites. The drying-induced agglomeration and entanglement, as well as damage during processing of agglomerated CNT may thereby be avoided. For example, the purified CNTs may be kept in a suspension or, at least, as the nanocarbon slurry (the “purified CNT slurry”). In other words, the as-synthesized CNT materials may be purified by refluxing in acids but then never be allowed to dry before reaching the customer, instead being kept as the purified CNT slurry. The customer may either use the purified CNT slurry or, if necessary, exchange the liquid with another liquid and process the CNT slurry as desired, allowing it to dry only at the final step of their process. This arrangement would significantly facilitate dispersion and prevent damaging of CNT materials resulting in improvement of product properties and performance.
[0147]The process of dispersing the purified CNT slurry material down to the level of individual CNTs may be accomplished through any of mixing, sonicating, or homogenizing techniques, or a combination thereof. As compared to the current commercial CNT materials, the dispersion of the purified CNT slurry material may require much less effort and inflict much less damage to CNTs in the process of achieving the desired degree of dispersion. The same considerations may apply to other types of nanocarbon materials. Higher degree of dispersion and reduced damage to nanocarbon structure may result in improved properties. The dispersion process may be carried out in either aqueous or organic solvents. Examples of aqueous or organic solvents may comprise water, toluene, alcohol, carbon disulfide, dichlorobenzene, other benzene derivatives, aromatic solvents, dimethylformamide, N-methylpyrrolidinone, pyridine, and mixtures thereof.
[0148]The purified CNT slurry may comprise a liquid and a CNT. The CNT may comprise less than 80 wt %, less than 50 wt %, or less than 10 wt % of the CNT slurry. Presence of sufficient number of liquid molecules in intimate contact with CNTs stabilizes the system and prevents CNT agglomeration.
[0149]A convenient method to evaluate the degree of agglomeration of CNTs incorporated into composite materials may be through examination of scanning electron microscopy (SEM) and/or transmission electron microscopy (TEM) images. The CNT agglomerates are readily visible in SEM and/or TEM images at magnifications 1,000 or 30,000 times and less, depending on agglomerate size. The non-agglomerated CNTs are much smaller in size and may be seen in SEM and/or TEM images at magnifications 40,000 or 80,000 times and higher.
[0150]The damage to CNTs caused by a harsh dispersion process may be evaluated by measuring Raman spectroscopy, in particular, using the intensity ratio of the so-called G-band and D-band. The G-bands that are typically detected at about 1,580 cm 1 (within +20 cm-1) are due to the non-defective graphitic CNT structure of, while the D-bands (at about 1,350 cm-1 within +20 cm 1) are predominantly due to structural defects, as disclosed by M. S. Dresselhaus, A. Jorio, A. G. Souza Filho and R. Saito, Defect characterization in graphene and carbon nanotubes using Raman spectroscopy, Phil. Trans. Royal Society A, vol. 368, pp. 5355-5377 (2010). The content of this publication is incorporated herein by reference.
[0151]The intensity ratio of the G-band to the D-band (i.e., the G/D ra