United States of America As Represented by the Administrator of Nasa

National Institute of Aerospace Associates

Jefferson Science Associates, LLC

Jae-Woo Kim

Emilie J Siochi

Godfrey Sauti

Sang Hyouk Choi

Yeonjoon Park

Glen C King

James R Elliott

Peter T Lillehei

Sang-Hyon Chu

Cheol Park

Kristopher E Wise

John M Gardner

John W Connell

Joycelyn S Harrison

Russell A Wincheski

Yi Lin

Michael W Smith

Jin Ho Kang

Diane M Stoakley

Dennis C Working

Sharon E Lowther

Christopher J Stelter

Kevin Carl Jordan

R Roy Whitney

Larry T Taylor

Phillip A Williams

Michael R Funk

Caroline J Campbell

Negin Nazem

Katherine A Fotion

Joycelyn S Harrisson

Sharon Lowther

A cutting mechanism includes electrodes that are utilized to cut or score a non-conductive outer material of a filament or sheet. The electrodes contact a conductive reinforcing material of the filament or sheet to complete an electric circuit. Electric current flows through and heats the conductive material to oxidize or otherwise separate/cut the conductive material and any remaining non-conductive material.

Cutting mechanism for carbon nanotube yarns, tapes, sheets and polymer composites thereof

A method allows for preparation of CNT nanocomposites having improved mechanical, electrical and thermal properties. Structured carbon nanotube forms such as sheet, yarn, and tape are modified with &#x3c0;-conjugated conductive polymers, including polyaniline (PANT), fabricated by in-situ polymerization. The PANI modified CNT nanocomposites are subsequently post-processed to improve mechanical properties by hot press and carbonization.

Polyaniline/carbon nanotube sheet nanocomposites

A method of fabricating (printing) parts utilizing flexible filaments includes anchoring a portion of a flexible filament to a substrate. A length of flexible filament is extended over the substrate while the flexible filament is in tension to thereby avoid buckling of the flexible filament. The flexible filament may comprise a thermoplastic material and fibers or other reinforcing materials whereby composite 3D parts can be fabricated.

Devices and methods for additive manufacturing using flexible filaments

Consolidated carbon nanotube or graphene yarns and woven sheets are consolidated through the formation of a carbon hinder formed from the dehydration of sucrose. The resulting materials, on a macro-scale are lightweight and of a high specific modulus and/or strength. Sucrose is relatively inexpensive and readily available, and the process is therefore cost-effective.

Sucrose treated carbon nanotube and graphene yarns and sheets

A method of fabricating composite articles includes supplying electrical current to an electrically conductive filament. The electrically conductive filament may include a first material that is electrically conductive and a polymer second material. The polymer second material comprises at least one of a thermoplastic polymer and a partially cured thermosetting polymer. The heated filament is deposited according to a predefined pattern in successive layers to adhere the polymer material of the layers together and build up a three dimensional article. The article includes strands of the first material embedded in a substantially continuous polymer matrix of the second material.

Method for the free form fabrication of articles out of electrically conductive filaments using localized heating

A method of controlling an additive fabrication process includes providing a primary substrate and a test substrate. Polymer test material is extruded onto the test substrate utilizing an extrusion head. The extrusion head is moved relative to the test substrate, and a force required to move the extrusion head relative to the test substrate is measured to thereby generate test data. A part is fabricated by extruding polymer material onto the primary substrate utilizing the extrusion head. The test data is utilized to control at least one process parameter associated with extruding polymer material onto the primary substrate.

Adhesion test station in an extrusion apparatus and methods for using the same

A method allows for preparation of CNT nanocomposites having improved mechanical, electrical and thermal properties. Structured carbon nanotube forms such as sheet, yarn, and tape are modified with &#x3c0;-conjugated conductive polymers, including polyaniline (PANI), fabricated by in-situ polymerization. The PANI modified CNT nanocomposites are subsequently post-processed to improve mechanical properties by hot press and carbonization.

Formation of a boron nitride nanotube nanocomposite film by combining a boron nitride nanotube solution with a matrix such as a polymer or a ceramic to form a boron nitride nanotube/polyimide mixture and synthesizing a boron nitride nanotube/polyimide nanocomposite film as an electroactive layer.

Methods of manufacturing energy conversion materials fabricated with boron nitride nanotubes (BNNTs) and BNNT polymer composites

A method of fabricating composite structures comprising carbon nanotubes. The method including providing a nanotube starting material, forming the composite structure with the nanotube starting material and monitoring at least a magnetic or Raman property of the composite structure while forming the composite structure.

Magnetic and Raman based method for process control during fabrication of carbon nanotube based structures

Nanotube filaments comprising carbon, boron and nitrogen of the general formula BCN, having high-aspect ratio and high-crystallinity produced by a pressurized vapor/condenser method and a process of production. The process comprises thermally exciting a boron-containing target in a chamber containing a carbon source and nitrogen at a pressure which is elevated above atmospheric pressure.

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Consolidated carbon nanotube or graphene yarns and woven sheets are consolidated through the formation of a carbon binder formed from the dehydration of sucrose. The resulting materials, on a macro-scale are lightweight and of a high specific modulus and/or strength. Sucrose is relatively inexpensive and readily available, and the process is therefore cost-effective.

Methods for forming holey carbon allotropes and graphene nanomeshes are provided by the various embodiments. The various embodiments may be applicable to a variety of carbon allotropes, such as graphene, graphene oxide, reduced graphene oxide, thermal exfoliated graphene, graphene nanoribbons, graphite, exfoliated graphite, expanded graphite, carbon nanotubes (e.g., single-walled carbon nanotubes, double-walled carbon nanotubes, few-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), carbon nanofibers, carbon fibers, carbon black, amorphous carbon, fullerenes, etc. The methods may produce holey carbon allotropes without the use of solvents, catalysts, flammable gas, additional chemical agents, or electrolysis to produce the pores (e.g., holes, etc.) in the carbon allotropes. In an embodiment, a carbon allotrope may be heated at a working window temperature for a working period of time to create holes in the carbon allotrope.

Single-step, solvent-free, catalyst-free preparation of holey carbon allotropes

A novel method to develop highly conductive functional materials which can effectively shield various electromagnetic effects (EMEs) and harmful radiations. Metallized nanotube polymer composites (MNPC) are composed of a lightweight polymer matrix, superstrong nanotubes (NT), and functional nanoparticle inclusions. MNPC is prepared by supercritical fluid infusion of various metal precursors (Au, Pt, Fe, and Ni salts), incorporated simultaneously or sequentially, into a solid NT-polymer composite followed by thermal reduction. The infused metal precursor tends to diffuse toward the nanotube surface preferentially as well as the surfaces of the NT-polymer matrix, and is reduced to form nanometer-scale metal particles or metal coatings. The conductivity of the MNPC increases with the metallization, which provides better shielding capabilities against various EMEs and radiations by reflecting and absorbing EM waves more efficiently. Furthermore, the supercritical fluid infusion process aids to improve the toughness of the composite films significantly regardless of the existence of metal.

Metallized nanotube polymer composite (MNPC) and methods for making same

Metal and semiconductor nanoshells, particularly transition metal nanoshells, are fabricated using dendrimer molecules. Metallic colloids, metallic ions or semiconductors are attached to amine groups on the dendrimer surface in stabilized solution for the surface seeding method and the surface seedless method, respectively. Subsequently, the process is repeated with additional metallic ions or semiconductor, a stabilizer, and NaBHto increase the wall thickness of the metallic or semiconductor lining on the dendrimer surface. Metallic or semiconductor ions are automatically reduced on the metallic or semiconductor nanoparticles causing the formation of hollow metallic or semiconductor nanoparticles. The void size of the formed hollow nanoparticles depends on the dendrimer generation. The thickness of the metallic or semiconductor thin film around the dendrimer depends on the repetition times and the size of initial metallic or semiconductor seeds.

Fabrication of metallic hollow nanoparticles

A new fabrication method for nanovoids-imbedded bismuth telluride (Bi&#x2014;Te) material with low dimensional (quantum-dots, quantum-wires, or quantum-wells) structure was conceived during the development of advanced thermoelectric (TE) materials. Bismuth telluride is currently the best-known candidate material for solid-state TE cooling devices because it possesses the highest TE figure of merit at room temperature. The innovative process described here allows nanometer-scale voids to be incorporated in Bi&#x2014;Te material. The final nanovoid structure such as void size, size distribution, void location, etc. can be also controlled under various process conditions.

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Newport News, VA, United States of America

Jae-Woo Kim