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CN-121986068-A - Novel composition of particles, powders, pellets or wires coated with discrete carbon nanotube coating

CN121986068ACN 121986068 ACN121986068 ACN 121986068ACN-121986068-A

Abstract

The present invention relates to a novel composition for producing particles, powders or wires having a discrete carbon nanotube coating, wherein the coating has a selected porosity range and the discrete carbon nanotubes have a selected surface modification to improve wetting of the material or flow through the pores of the carbon nanotube coating. The coating has less than about 20 mass% carbon nanotube bundles or ropes having a size greater than about 5 microns, thereby improving the performance of the printed component. The composition may include a coating having a thickness of about 5 nanometers to about 5000 nanometers on particles or polymer chains having a diameter of less than about 5000 microns, wherein the coating includes discrete carbon nanotubes and/or surface modifications of the discrete carbon nanotubes.

Inventors

  • Clive P. Bosniak
  • Steven Lord
  • Olga S. Ivanova
  • Tanner Flake

Assignees

  • 麦可纳诺有限责任公司

Dates

Publication Date
20260505
Application Date
20240415
Priority Date
20240412

Claims (20)

  1. 1. A composition for coated particles comprising: A coating having a thickness of about 5 nanometers to about 5000 nanometers on particles having a diameter of less than about 5000 micrometers, wherein the particles comprise a powder, a pellet, or a polymer wire, wherein the coating comprises discrete carbon nanotubes.
  2. 2. The composition of claim 1, wherein the particles are selected from the group consisting of organic polymers and inorganic substances.
  3. 3. The composition of claim 2, wherein the organic polymer is selected from elastomers having glass transition temperatures below about 25 ℃.
  4. 4. The composition of claim 2, wherein the organic polymer is selected from polymers having a glass transition temperature greater than about 25 ℃.
  5. 5. The composition of claim 2 wherein the inorganic material is selected from the group consisting of ceramics, cements, silicates, metals, metal oxides, metal salts, and mixtures thereof.
  6. 6. The composition of claim 1, wherein the coating has a porosity of about 0.05 to about 0.95.
  7. 7. The composition of claim 1, wherein the discrete carbon nanotubes are selected from single-walled, double-walled, or multi-walled carbon nanotubes and mixtures thereof.
  8. 8. The composition of claim 1, further comprising a carbonaceous material selected from the group consisting of carbon black, carbon fiber, graphite, graphene, reduced graphene, carbon nanorods, and graphene oxide.
  9. 9. The composition of claim 7, wherein the pattern of aspect ratios of the discrete carbon nanotubes is a unimodal distribution.
  10. 10. The composition of claim 7, wherein the pattern of aspect ratios of the discrete carbon nanotubes is at least a bimodal distribution.
  11. 11. The composition of claim 7, wherein the carbon nanotubes have a length greater than about 0.2 microns.
  12. 12. The composition of claim 7, wherein the discrete carbon nanotubes are dispersed, wherein the mass of the discrete carbon nanotubes present in the form of entangled bundles or ropes of carbon nanotubes having a size greater than about 5 microns in at least one dimension is less than about 20% of the coating mass.
  13. 13. The composition of claim 7, wherein the ratio of discrete carbon nanotubes to carbonaceous material selected from the group consisting of carbon black, carbon fibers, graphite, graphene, reduced graphene, and graphene oxide is in the range of about 1:99 to about 99:1 by weight.
  14. 14. A composition for making particles comprising: a coating having a thickness of about 5 nanometers to about 2000 nanometers on particles having a diameter of less than about 1000 microns, wherein the coating is selected from the group consisting of discrete carbon nanotubes further comprising a surface modification of the discrete carbon nanotubes.
  15. 15. The composition of claim 14, wherein the surface modification is attached to the surface of the discrete carbon nanotubes by covalent bonding, ionic bonding, or hydrogen bonding.
  16. 16. The composition of claim 14, wherein the discrete carbon nanotubes further comprise a surface modification selected from the group consisting of molecules containing oxygen, silicon, titanium, zirconium, sulfur, phosphorus, or nitrogen, or any mixture thereof.
  17. 17. The composition of claim 15, wherein the discrete carbon nanotubes further comprise a surface modification selected from the group consisting of anionic, cationic, nonionic, and zwitterionic surfactants, polyvinyl alcohols, copolymers of polyvinyl alcohols and polyvinyl acetates, polyvinylpyrrolidone and copolymers thereof, carboxymethyl cellulose, carboxypropyl cellulose, carboxymethyl propyl cellulose, hydroxyethyl cellulose, polyetherimides, polyethers, starches, and mixtures thereof.
  18. 18. The composition of claim 14, wherein the surface modified hansen solubility parameter dispersion parameter value differs from the hansen solubility parameter dispersion parameter value of the particle by within about 2J 0.5 m -1.5 .
  19. 19. The composition of claim 14, wherein the surface modification is miscible with the polymer comprising the particles.
  20. 20. The composition of claim 14, wherein there is at least some chemical interaction between the composition of particles and the surface modification.

Description

Novel composition of particles, powders, pellets or wires coated with discrete carbon nanotube coating Technical Field The present disclosure relates generally to novel compositions for producing additive manufacturing and molding feedstock laser sintered particles, powders, or wires with discrete carbon nanotube coatings, wherein the coatings have selected porosity and thickness ranges, and selected surface modifications to improve sintering, wetting, or flow of material through the pores of the carbon nanotube coating. In addition, the carbon nanotube coating comprises less than about 20% of the coating mass of carbon nanotubes in the form of highly entangled bundles or ropes of carbon nanotubes, wherein the bundles or ropes of carbon nanotubes have a size in at least one dimension greater than about 5 microns. Background Additive Manufacturing (AM) is a set of techniques for building three-dimensional objects by processing materials in a layer-by-layer manner. The materials are typically, but are not limited to, crosslinkable monomers or oligomers, thermoplastics, metals, ceramics, silicates, cements, and biological tissues. AM technology typically uses computers, 3D modeling software (computer aided design—cad), hardware devices, and feedstock materials. After generating the CAD model of the part, the AM hardware transforms the data from the CAD file and deposits material (liquid, powder, sheet or other form) in a layer-by-layer fashion to make the 3D object. The term AM encompasses many technologies and is synonymous with 3D printing, rapid prototyping, direct digital manufacturing, layered manufacturing and additive manufacturing. The material molding process is a set of techniques for reproducing the positive shape of the female mold geometry by filling the mold cavity with a material conforming to the shape of the mold to form a three-dimensional object. The materials are typically, but are not limited to, crosslinkable monomers or oligomers, thermoplastics, metals, ceramic slurries, cements, and hydrogels. Carbon Nanotubes (CNTs) can be classified into single-walled, double-walled, and multi-walled according to the number of walls. Each wall of the CNT may be further divided into chiral or achiral forms. Some carbon atoms of the CNT may be substituted with nitrogen atoms. Some walls may contain ston-wiles (Stone-Wales) defects, which are defined as heptagon-pentagon pairs. Currently, CNTs are manufactured on a large scale by chemical vapor deposition reactors, but this method produces aggregated carbon nanotube bundles or ropes, which have very limited commercial use due to poor properties as reinforcing fillers in the aggregated state. The use of CNTs as reinforcing agents or fillers or conductive fillers in polymer composites is a field where CNTs are considered to have significant application value if they are prepared in discrete carbon nanotubes. However, the utilization of CNTs in these applications is hampered by the general inability to reliably produce discrete or individualized CNTs. Various methods have been developed to debundle or unwind CNTs in different media. For example, the CNT can be greatly shortened by a strong oxidation means and then dispersed as individual nanotubes in a dilute solution. However, these tubes have low aspect ratios and are not suitable for high strength composites. The CNTs may also be dispersed as individual tubes in a very dilute solution by sonication in the presence of a surfactant. Exemplary surfactants for dispersing CNTs in an aqueous solution include, for example, sodium dodecyl sulfate or cetyltrimethylammonium bromide. In some cases, solutions of individualized CNTs can be prepared from polymer-wrapped carbon nanotubes. Individualized single-walled CNT solutions have also been prepared using polysaccharides, polypeptides, water-soluble polymers, nucleic acids, DNA, polynucleotides, polyimides, and polyvinylpyrrolidone in very dilute solutions, but these dilute solutions are expensive to use and are not suitable for mass production and additive manufacturing. Numerous materials such as, but not limited to, crosslinkable monomers and oligomers crosslinked by means such as irradiation or heating, thermosetting and thermoplastic powders, thermoplastic pellets, sizing rubbers, filaments and metal injection molding materials, hot melt plastic inks have been used for molding operations and AM, however, conventional molding and AM materials still have many limitations in terms of properties such as electrical conductivity, thermal conductivity, impact strength, and deformation during processing required for rigidity, tear, thermal deformation resistance, laser marking, rigidity, electromagnetic radiation shielding or electrostatic management, and the like. There is a need for particle coatings of discrete carbon nanotubes. Drawings Fig. 1 is an electron micrograph of a dried coating of discrete oxidized multiwall carbon nanotubes showing the porosity of the