|Publication number||US20080020193 A1|
|Application number||US 11/491,657|
|Publication date||Jan 24, 2008|
|Filing date||Jul 24, 2006|
|Priority date||Jul 24, 2006|
|Publication number||11491657, 491657, US 2008/0020193 A1, US 2008/020193 A1, US 20080020193 A1, US 20080020193A1, US 2008020193 A1, US 2008020193A1, US-A1-20080020193, US-A1-2008020193, US2008/0020193A1, US2008/020193A1, US20080020193 A1, US20080020193A1, US2008020193 A1, US2008020193A1|
|Inventors||Bor Z. Jang, Aruna Zhamu, Jiusheng Guo, Lulu Song|
|Original Assignee||Jang Bor Z, Aruna Zhamu, Jiusheng Guo, Lulu Song|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (51), Classifications (21)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention is based on the research results of a project supported by the U.S. Department of Energy (DOE) SBIR-STTR Program. The US Government has certain rights on this invention.
The present invention is related to a hybrid composite containing both a nano-filler and a continuous fiber dispersed in a matrix material. The nano-filler comprises nano-scaled graphene plates (NGPs), carbon nano-tubes (CNTs), carbon nano-fibers (CNFs), nano-clay platelets, nano-rods, or any other nanoscale reinforcement with at least an elongate axis. The matrix material comprises a polymer, organic, metal, ceramic, glass, carbon material, or a combination thereof. The nano-filler can be made to be substantially oriented in a preferred direction (e.g., with an elongate axis perpendicular to the continuous fiber).
Advanced composites, containing continuous fibers dispersed in a matrix material, are widely used in aerospace, sports equipment, infrastructure, automotive, and other transportation industries, as both primary and secondary load-bearing structures. These composite materials derive their excellent mechanical strength, stiffness, electrical conductivity, and thermal conductivity from the reinforcement fibers. However, using polymer matrices and carbon or graphite fibers are examples, continuous carbon fiber reinforced polymer composites exhibit these good properties only in the directions parallel to the fiber axial directions. In other words, these composites have excellent in-plane properties and relatively poor thickness-direction and shear properties.
Specifically, the thickness-direction and shear strengths and moduli of continuous carbon fiber reinforced polymer composite laminates are relatively poor. Poor interlaminar shear strengths in turn lead to poor delamination resistance. Incorporation of reinforcements that are oriented in a direction perpendicular to the continuous fiber axis can significantly improve these mechanical properties.
In addition, the longitudinal conductivities (both thermal and electrical) of a carbon fiber are orders of magnitude greater than its corresponding transverse conductivities. Hence, the transverse conductivities of a composite laminate are also much lower than the longitudinal properties. The transverse conductivities of a continuous fiber composite can be significantly improved by incorporating a reinforcement phase perpendicular to the continuous fiber axis. However, the addition of transverse reinforcements such as short (chopped) fibers is known to create processing difficulties. Even with nanoscale fillers like carbon nano-tubes (CNTs) and carbon nano-fibers (CNFs), a small amount of these nano-fillers could dramatically alter the flow properties (e.g., increased viscosity) of a matrix resin. The resulting matrix material, a nano-filler/resin mixture, is typically so viscous that it becomes extremely difficult to disperse continuous fibers in this matrix.
Further specifically, on the one hand, the loading of conductive nano-fillers (e.g., >5 wt. % of CNTs or CNFs) increases the viscosity of the matrix resin to a level that is not conducive to filament winding and other automated composite manufacturing techniques. On the other hand, a low percentage (<5% by wt.) of nano-fillers normally does not provide adequate through-thickness thermal or electrical conductivity to a composite structure for certain engineering applications. A need exists to develop an approach that can resolve these conflicting issues; i.e. a process capable of combining continuous fibers with a matrix that features an adequate proportion of nano-fillers dispersed in a resin or other material with these fillers preferentially oriented along a desired direction for improved transverse or shear properties.
Generally, the advantages of nanoscale reinforcements in polymer matrices are fourfold: (1) when nanoscale fillers are finely dispersed in the matrix, the tremendous surface area developed could contribute to both polymer chain confinement and load transfer effects, leading to higher glass transition temperature, stiffness, and strength; (2) nanoscale fillers provide an extraordinarily zigzagging, tortuous path that leads to enhanced resistance to micro-cracking; (3) nanoscale fillers can also enhance the electrical and thermal conductivities; and (4) carbon-based nanoscale fillers have excellent thermal protection properties and, when incorporated in a matrix material, could eliminate the need for a thermal protective layer—for instance, in missile and rocket applications.
Fabrication of carbon nanotubes (CNTs) is expensive, particularly for the purifying process required to make them useful in applications. Instead of trying to discover lower cost processes for CNTs, we have been seeking to develop an alternative nanoscale carbon material with comparable properties that can be produced cost-effectively and in larger quantities. This development work has led to the discovery of processes for producing a new class of nano material herein referred to as nanoscale graphene plates (NGP) [Jang, et al., “Nano-scaled Graphene Plates,” U.S. Pat. No. 7,071,258 (Jul. 4, 2006) and “Process for Producing Nano-scaled Graphene Plates,” U.S. patent pending, Ser. No. 10/858,814 (Jun. 3, 2004)]. An NGP is a nanoscale platelet composed of one or more layers of graphene plane. In a graphene plane, carbon atoms occupy a 2-D hexagonal lattice. These carbon atoms are bonded together through strong covalent bonds lying on this plane. In the c-axis direction, several graphene planes may be weakly bonded together primarily through van der Waals forces. An NGP may be viewed as a flattened sheet of a CNT. Although NGP and CNT are geometrically different in architecture, preliminary calculations have indicated very similar mechanical properties (in-plane stiffness and strength) and thermal and electrical conductivities (Table 1).
Estimated physical constants of CNTs and NGPs.
~1 TPa (in-plane)
5–50 μΩ cm
50 μΩ cm (in plane)
Up to 1,500 W m−1 K−1
3,000 W m−1 K−1 (in-plane)
6–30 W m−1 K−1 (c-axis)
22 × 106 EMU/g (⊥ to
22 × 106 EMU/g (⊥ to the
0.5 × 106 EMU/g (|| to
0.5 × 106 EMU/g (|| to the
−1 × 10−6 K−1 (in-plane)
29 × 10−6 K−1 (c-axis)
>700° C. (in air);
450–650° C. (in air)
2800° C. (in vacuum)
Typically 100–500 m2/g
Up to 1,500 m2/g
NGP-reinforced composites are also expected to exhibit similar properties compared to CNT-reinforced composites. When the NGP-resin mixture, a nanocomposite, is incorporated as a matrix for forming a continuous fiber reinforced composite, the resulting hybrid composite (containing both the NGP and the continuous fiber as reinforcement phases) is expected to have improved mechanical and physical properties compared to the conventional fiber composite (containing only continuous fiber, no NGP). A need exists for incorporating both NGPs and continuous fibers in a matrix material to make a hybrid composite. Further, as indicated earlier, the loading of nano-fillers (e.g., CNTs and CNFs) increases the viscosity of the matrix resin to a level that is not conducive to subsequent filament winding and other automated composite manufacturing techniques. A need exists to develop a process that is capable of combining both continuous fibers and CNTs, CNFs, other nano-rods, or nano-platelets with a matrix material to make a hybrid composite. Preferably, such a process can be automated.
The present invention provides a process that is capable of producing a hybrid composite that contains both nano-fillers (e.g., NGPs, CNTs, CNFs, or a combination thereof) and continuous fibers as reinforcement phases dispersed in a matrix material. The nano-fillers can be oriented in a direction that is non-parallel to the longitudinal axis direction of the continuous fiber (e.g., preferably perpendicular to the continuous fiber axis). The process begins with spreading a continuous fiber tow separate continuous filaments from each other and then incorporating nano-fillers in a continuous fiber tow with individual nano-fillers embedded in the interstitial spaces between continuous filaments. The resulting hybrid fiber tow is then impregnated with a resin to produce a resin-pre-impregnated hybrid tow or hybrid towpreg. This wet hybrid towpreg can then go through a filament winding, fiber placement, prepregging, or pultrusion process for making a composite structure.
Alternatively, the hybrid fiber tow can be woven, braided, knitted, or stitched into a textile-structured preform, which is then impregnated with a resin.
The process may involve incorporating continuous fibers, nano-fillers, and a matrix-making material in a powder form concurrently to form a matrix-forming powder-impregnated hybrid fiber tow, a dry hybrid towpreg. The dry hybrid towpreg can then go through a filament winding, fiber placement, weaving, braiding, knitting, or stitching to form a structured preform, which is then converted to become a hybrid composite structure by heating and consolidating the matrix-forming material to become the solid matrix material.
The present invention also provides hybrid fiber tows, hybrid fiber towpregs, and resulting hybrid fiber composites that can be composed of a wide range of fibers, fillers, and matrix materials.
The versatility of the invented process opens up a window of many application opportunities for hybrid composites containing continuous fibers and nano-fillers such as NGPs, CNTs, and CNFs.
The conventional approach to fabricating composite materials containing both continuous fibers and fillers (such as nanoscale fillers, short fibers, etc.) typically involves mixing the fillers with a resin first, followed by impregnating the continuous fiber tows with the resin/filler mixture. It is now well-recognized that a small amount of nano-fillers like carbon nano-tubes (CNTs) and carbon nano-fibers (CNFs) could dramatically increase the viscosity of a matrix resin. The resulting nano-filler/resin mixture is typically so viscous that it becomes extremely difficult to disperse continuous fibers in this matrix. Hence, it is also commonly believed that only a small amount of nano-fillers can be incorporated in a hybrid composite.
Furthermore, the prior-art sequence of mixing nano-fillers with a resin and then impregnating continuous fibers with the nano-filler/resin mixture tends to produce a hybrid composite with fillers oriented along the continuous fiber axis. Such an orientation does not improve thickness-direction properties and shear properties of a composite laminate with continuous fibers lying on a laminar plane.
Contrary to what composite materials experts would or might expect, we have developed an approach that enables the fabrication of hybrid composites containing a high proportion of nano-fillers with a preferential orientation that is substantially perpendicular to the continuous fiber axis (
This process also enables impregnation of continuous fiber/nano-filler preform shape with a ceramic, glass, or carbon matrix via a specialized technique like chemical vapor infiltration to produce corresponding hybrid composites, which otherwise would be difficult to obtain.
As an example to illustrate this process, a fluidized-bed powder impregnation or coating process (
Electrostatic charges may be imparted to nano-fillers to facilitate attraction of nano-fillers to the carbon fiber tow. This is analogous to the conventional towpreg production operation by which micron-scaled thermoplastic powder particles, serving as a precursor to the composite matrix, are incorporated into a continuous fiber tow [e.g., J. D. Muzzy, et al., U.S. Pat. No. 5,094,883, Mar. 10, 1992]. No nanoscale filler was involved in this earlier process.
In one embodiment of the present invention, a matrix-forming material (e.g., thermoplastic powder particles 20 in
In the presently invented hybridfiber tow approach, the continuous hybrid fiber tow may be directed to enter a resin bath for impregnation with a matrix resin in a filament-winding, prepreg-forming, pultrusion, or fiber placing operation (
Alternatively, the hybrid fiber tow may be subjected to weaving, winding, braiding, stitching, knitting, freeform fabrication, and/or other textile-forming procedures to produce a dry composite preform, which is then impregnated with a matrix material to obtain a composite structure. With a polymer matrix, the preform can be impregnated through resin transfer molding, reaction injection molding, vacuum-assisted transfer molding, pressure-assisted liquid resin impregnation, etc. For a metal matrix, the preform can be impregnated through microwave-assisted infiltration, liquid metal impregnation, etc. For a glass or ceramic matrix, the preform can be impregnated through chemical vapor deposition or chemical vapor infiltration. A resin-impregnated preform can be subjected to a heat treatment (pyrolization) that converts a polymer into a carbonaceous matrix.
The nanoscale filler that can be used in the presently invented hybrid fiber tow, towpreg, or composite can be a nanoscale graphene plate, non-graphite platelet, carbon nano-tube, nano-rod, carbon nano-fiber, non-carbon nano-fiber, or a combination thereof. These entities all have one thing in common—they have at least on elongate axis. For instance, CNTs have one elongate axis (in the tube axial direction) and platelets have two elongate axes (in the length and width direction). The resulting hybrid composite can easily have nano-fillers that are present at a loading of greater than 5% by weight based on the total weight of nano-fillers plus the matrix material. The nano-fillers in many cases exceed 15% by weight. A majority of these nano-fillers have an elongate axis oriented at an angle of at least 45 degrees with respect to the continuous fiber axis. If improved transverse thermal or electrical conductivities are desired, carbon-based nano-fillers are preferred.
The NGPs obtained in our facilities typically have a platelet thickness of 1-100 nm and length and width of 0.1-10 μm. These rigid two-dimensional platelets appear to be conducive to fitting into inter-filament interstices. The nanoscale graphene plate or non-graphite platelet that has a length or width smaller than 500 nm is particularly well-suited to the present application. The flexibility of both the CNT and the CNF afforded to by their large length-to-diameter ratios makes these one-dimensional structures tend to assume curved or coiled shapes and should make it more difficult to be incorporated in a hybrid composite. However, surprisingly, the presently invented process is capable of incorporating CNTs and CNFs into the inter-filament spaces.
A fluidized-bed powder impregnation apparatus, schematically shown in
The fluidized bed powder coating apparatus are well-known in the art. For instance, these apparatus were successfully used to prepare a towpreg that is composed of reinforcing filaments coated with matrix-forming resin powder as a precursor to a plastic matrix composite [J. Lamanche, et al., U.S. Pat. No. 3,703,396 (Nov. 21, 1972)]. A key component in the system is a tow spreader. Spreading of the filaments can be achieved by vibrating the graphite fiber tow in air pulsating at a frequency and intensity sufficient to couple the energy of the pulsating medium to the graphite tow [e.g., S. Iyer, et al., U.S. Pat. No. 5,042,122 (Aug. 27, 1991)]. Spreading may also be facilitated or promoted by using air currents or electrostatic charges of the same polarity.
An optional filament re-merger or compactor may be used to facilitate the merging of separated filaments, along with the embedded nano-fillers, into a more compact fiber tow. This filament re-merging step can occur before, during, and after the resin impregnation step. Resin impregnation can be part of a filament-winding, prepreg-forming, fiber-placing, or pultrusion process.
The continuous filament can be a polymer fiber, ceramic fiber, carbon fiber, graphite fiber, glass fiber, or a combination thereof. In the hybrid fiber tow, the nano-fillers are preferably oriented in a direction substantially non-parallel to the continuous filament axial direction and further preferably perpendicular to the filament axis.
In summary, the process for producing a hybrid fiber tow comprises (a) spreading a continuous fiber tow into multiple, separated filaments that define interstitial spaces between the filaments; (b) exposing the separated filaments to a fluid medium or fluidized medium containing nanoscale fillers under a flow condition for a duration of time sufficient to cause the nanoscale fillers to stay in the interstitial spaces; and (c) moving the separated filaments with the interstitial nanoscale fillers away from the medium to produce the hybrid fiber tow. The step of exposing can comprise moving the separated filaments through a fluidized bed comprising a fluidized medium that contains the nanoscale particles suspended in the medium, as illustrated in
Alternatively, the step of exposing comprises moving the separated filaments through a fluid medium that contains the nanoscale particles suspended in a liquid or solution. In other words, the fluidized-bed powder coater device shown in
Further alternatively, as schematically shown in
The fluid medium (e.g., in
In another embodiment of the present invention, in addition to the aforementioned steps (a), (b), and (c), the process further comprises (d) reeling the continuous fiber tow from a roller or spool prior to the fiber tow spreading step; (e) impregnating the hybrid fiber tow with a matrix material to form a matrix-impregnated hybrid fiber tow; (f) subjecting the matrix-impregnated hybrid tow to a shape-forming operation to form a composite shape; and (g) consolidating the composite shape through heating, curing, and/or cooling the matrix material to form a hybrid composite structure. The shape-forming operation can comprise a filament winding, fiber placement, prepreg-forming, pultrusion, freeform fabrication step, or a combination thereof. Freeform fabrication involved computerized deposition of a material point-by-point and layer-by-layer. The process is also commonly referred to as rapid prototyping.
In yet another embodiment of the present invention, the process comprises, in addition to aforementioned steps (a), (b), and (c), the following steps: (d) reeling the continuous fiber tow from a roller or spool prior to the fiber tow spreading step; (e) subjecting the hybrid fiber tow to a shape-forming operation to form a composite preform; (f) impregnating the preform with a matrix material; and (g) consolidating the matrix-impregnated preform through heating, curing, and/or cooling the matrix material to form a hybrid composite structure. The shape-forming operation can comprise a step of filament winding, fiber placement, freeform fabrication, weaving, braiding, stitching, knitting, or a combination thereof.
In still another embodiment of the present invention, the process comprises, in addition to the aforementioned steps (a), (b), and (c), the following steps: (d) reeling the continuous fiber tow from a roller or spool prior to the fiber tow spreading step; (e) subjecting the hybrid fiber towpreg to a shape-forming operation to form a composite shape; and (f) consolidating the composite shape through heating, curing, and/or cooling the matrix-forming material to form a hybrid composite structure. The shape-forming operation can include a step of filament winding, fiber placement, prepreg-forming, freeform fabrication, weaving, braiding, stitching, knitting, or a combination thereof.
In all of the aforementioned versions of the invented process, the step of consolidating can comprise melting a matrix material, cooling or solidifying a matrix material, curing a resin, polymerizing or cross-linking a resin precursor, converting an organic or polymeric material to a carbonaceous material, chemical vapor infiltration, or a combination thereof.
As examples to illustrate the utility value of the developed hybrid composites, we obtained the thermal conductivity values of a series of hybrid composites containing continuous graphite fibers (approximately 60% by volume of the total composite) and NGP/epoxy matrix materials (with several NGP weight fractions based on the total NGP/epoxy weight) or CNT/epoxy matrices. As shown in
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7832983||May 1, 2007||Nov 16, 2010||Goodrich Corporation||Nacelles and nacelle components containing nanoreinforced carbon fiber composite material|
|US8096353 *||Aug 26, 2008||Jan 17, 2012||Schlumberger Technology Corporation||Oilfield nanocomposites|
|US8158217 *||Jan 3, 2007||Apr 17, 2012||Applied Nanostructured Solutions, Llc||CNT-infused fiber and method therefor|
|US8168291||Nov 23, 2010||May 1, 2012||Applied Nanostructured Solutions, Llc||Ceramic composite materials containing carbon nanotube-infused fiber materials and methods for production thereof|
|US8325079||Apr 23, 2010||Dec 4, 2012||Applied Nanostructured Solutions, Llc||CNT-based signature control material|
|US8420258 *||Feb 25, 2009||Apr 16, 2013||Ronald Anthony Rojeski||High capacity electrodes|
|US8481214||Oct 13, 2010||Jul 9, 2013||Catalyst Power Technologies||Electrodes including support filament with collar stop|
|US8545938||Oct 3, 2011||Oct 1, 2013||United Technologies Corporation||Method of fabricating a ceramic component|
|US8545963||Dec 14, 2010||Oct 1, 2013||Applied Nanostructured Solutions, Llc||Flame-resistant composite materials and articles containing carbon nanotube-infused fiber materials|
|US8561934||Aug 28, 2009||Oct 22, 2013||Teresa M. Kruckenberg||Lightning strike protection|
|US8580342||Feb 26, 2010||Nov 12, 2013||Applied Nanostructured Solutions, Llc||Low temperature CNT growth using gas-preheat method|
|US8585934||Feb 17, 2010||Nov 19, 2013||Applied Nanostructured Solutions, Llc||Composites comprising carbon nanotubes on fiber|
|US8601965||Nov 23, 2010||Dec 10, 2013||Applied Nanostructured Solutions, Llc||CNT-tailored composite sea-based structures|
|US8652683||Nov 6, 2012||Feb 18, 2014||Catalyst Power Technologies, Inc.||High capacity electrodes|
|US8658310||Nov 6, 2012||Feb 25, 2014||Catalyst Power Technologies, Inc.||High capacity electrodes|
|US8662449||Nov 23, 2010||Mar 4, 2014||Applied Nanostructured Solutions, Llc||CNT-tailored composite air-based structures|
|US8664573||Apr 26, 2010||Mar 4, 2014||Applied Nanostructured Solutions, Llc||CNT-based resistive heating for deicing composite structures|
|US8665581||Mar 2, 2011||Mar 4, 2014||Applied Nanostructured Solutions, Llc||Spiral wound electrical devices containing carbon nanotube-infused electrode materials and methods and apparatuses for production thereof|
|US8752279||Apr 8, 2011||Jun 17, 2014||Goodrich Corporation||Methods of protecting an aircraft component from ice formation|
|US8780526||May 26, 2011||Jul 15, 2014||Applied Nanostructured Solutions, Llc||Electrical devices containing carbon nanotube-infused fibers and methods for production thereof|
|US8784937||Sep 12, 2011||Jul 22, 2014||Applied Nanostructured Solutions, Llc||Glass substrates having carbon nanotubes grown thereon and methods for production thereof|
|US8787001||Mar 2, 2011||Jul 22, 2014||Applied Nanostructured Solutions, Llc||Electrical devices containing carbon nanotube-infused fibers and methods for production thereof|
|US8808580 *||Apr 19, 2011||Aug 19, 2014||Arkema France||Thermoplastic and/or elastomeric composite based on carbon nanotubes and graphenes|
|US8815341||Sep 13, 2011||Aug 26, 2014||Applied Nanostructured Solutions, Llc||Carbon fiber substrates having carbon nanotubes grown thereon and processes for production thereof|
|US8900661||Oct 3, 2011||Dec 2, 2014||United Technologies Corporation||Method of filling porosity of ceramic component|
|US8945688||Jan 3, 2011||Feb 3, 2015||General Electric Company||Process of forming a material having nano-particles and a material having nano-particles|
|US8951631||Nov 2, 2009||Feb 10, 2015||Applied Nanostructured Solutions, Llc||CNT-infused metal fiber materials and process therefor|
|US8951632||Nov 2, 2009||Feb 10, 2015||Applied Nanostructured Solutions, Llc||CNT-infused carbon fiber materials and process therefor|
|US8962130||Mar 9, 2007||Feb 24, 2015||Rohr, Inc.||Low density lightning strike protection for use in airplanes|
|US8969225||Jul 29, 2010||Mar 3, 2015||Applied Nano Structured Soultions, LLC||Incorporation of nanoparticles in composite fibers|
|US8999453 *||Feb 1, 2011||Apr 7, 2015||Applied Nanostructured Solutions, Llc||Carbon nanotube-infused fiber materials containing parallel-aligned carbon nanotubes, methods for production thereof, and composite materials derived therefrom|
|US9005755||Jun 5, 2012||Apr 14, 2015||Applied Nanostructured Solutions, Llc||CNS-infused carbon nanomaterials and process therefor|
|US9012021 *||Mar 26, 2008||Apr 21, 2015||Xerox Corporation||Composition of matter for composite plastic contact elements featuring controlled conduction pathways, and related manufacturing processes|
|US9017854||Aug 29, 2011||Apr 28, 2015||Applied Nanostructured Solutions, Llc||Structural energy storage assemblies and methods for production thereof|
|US9085464||Mar 7, 2012||Jul 21, 2015||Applied Nanostructured Solutions, Llc||Resistance measurement system and method of using the same|
|US9111658||Apr 13, 2012||Aug 18, 2015||Applied Nanostructured Solutions, Llc||CNS-shielded wires|
|US20100192851 *||Aug 5, 2010||Lockheed Martin Corporation||Cnt-infused glass fiber materials and process therefor|
|US20110168083 *||Feb 26, 2010||Jul 14, 2011||Lockheed Martin Corporation||Cnt-infused ceramic fiber materials and process therefor|
|US20110168089 *||Jul 14, 2011||Lockheed Martin Corporation||Cnt-infused carbon fiber materials and process therefor|
|US20110186775 *||Aug 4, 2011||Applied Nanostructured Solutions, Llc.||Carbon nanotube-infused fiber materials containing parallel-aligned carbon nanotubes, methods for production thereof, and composite materials derived therefrom|
|US20110260116 *||Oct 27, 2011||Arkema France||Thermoplastic and/or elastomeric composite based on carbon nanotubes and graphenes|
|US20120065300 *||Nov 16, 2011||Mar 15, 2012||Applied Nanostructured Solutions, Llc.||Cnt-infused fiber and method therefor|
|US20120189846 *||Jul 26, 2012||Lockheed Martin Corporation||Cnt-infused ceramic fiber materials and process therefor|
|US20130171441 *||Jan 3, 2012||Jul 4, 2013||Lockheed Martin Corporation||Structural composite materials with high strain capability|
|US20150037530 *||Aug 5, 2013||Feb 5, 2015||Aruna Zhamu||Impregnated continuous graphitic fiber tows and composites containing same|
|EP2112192A2 *||Feb 27, 2009||Oct 28, 2009||Xerox Corporation||Composite elements with controlled electrical conduction|
|EP2329936A1 *||Dec 1, 2009||Jun 8, 2011||Siemens Aktiengesellschaft||Fibre-reinforced material|
|WO2009108731A2 *||Feb 25, 2009||Sep 3, 2009||Ronald Anthony Rojeski||High capacity electrodes|
|WO2012037265A2 *||Sep 14, 2011||Mar 22, 2012||3M Innovative Properties Company||Fiber-reinforced nanoparticle-loaded thermoset polymer composite wires and cables, and methods|
|WO2012124935A2 *||Mar 9, 2012||Sep 20, 2012||Iucf-Hyu (Industry-University Cooperation Foundation Hanyang University)||Hybrid polymer composite fiber including graphene and carbon nanotube, and method for manufacturing same|
|WO2013092307A1 *||Dec 11, 2012||Jun 27, 2013||Dsm Ip Assets B.V.||Sliding element for use in an engine or chain transmission apparatus|
|Cooperative Classification||Y10T428/249924, D04H3/12, D04C1/12, B29C70/20, D02J1/18, B29B15/12, D04H3/04, B29C70/025, B29B15/125, B29K2105/162, D06B1/04|
|European Classification||D04H3/04, D04H3/12, D02J1/18, B29C70/20, B29C70/02A4, B29B15/10B, D04C1/12, D06B1/04|