WorldWideScience

Sample records for anchored carbon fiber

  1. Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

    DEFF Research Database (Denmark)

    Kerrouche, Abdelfateh; Boyle, William J.O.; Sun, Tong

    2009-01-01

    Results are reported from a study carried out using a series of Bragg grating based optical fiber sensors written into a very short length (60mm) optical fiber net work and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures...... from the calibrated force applied by the pulling machine and from a conventional resistive strain gauge mounted on the rod itself is obtained. Calculations from strain to shear stress show a relatively uniform stress distribution along the bar anchor used. The results give confidence to results from...... various methods of insitu monitoring of strains on such CFRP rods when used in different engineering structures....

  2. PREPARATION OF TiO2 PHOTOCATALYST ANCHORED ON ACTIVATED CARBON FIBERS AND ITS PHOTODEGRADATION OF METHYLENE BLUE

    Institute of Scientific and Technical Information of China (English)

    Pingfeng Fu; Yong Luan; Xuegang Dai

    2004-01-01

    TiO2 particulate photocatalyst anchored on activated carbon fibers (ACFs) was prepared by a molecular adsorption-deposition method. The TiO2 particles deposited on the carbon fibers formed a coating of about 100 nm in thickness. The photocatalyst prepared was characterized by means of SEM, EDS, XRD and UV-vis adsorption spectroscopy. Anatase-type TiO2 was uniquely developed, and the micrographic structure of ACFs was not damaged during preparation. The roomy space between adjacent carbon fibers could allow UV-light to penetrate into the felt-form photocatalyst to a certain depth, so that a three dimensional environment was formed for the photocatalytic reaction.Such TiO2/ACFs photocatalyst exhibited its photocatalytic reactivity in photodegradation of concentrated methylene blue(MB) solutions. The MB molecules in the bulk solutions was supposed to be condensed around TiO2 particles by adsorption by ACFs. Therefore, the photocatalyst possesses the combined effect of adsorption by activated carbon fibers and photocatalytic reactivity of anatase-type TiO2 on MB photodegradation.

  3. Energy dissipation and high-strain rate dynamic response of E-glass fiber composites with anchored carbon nanotubes

    Science.gov (United States)

    This study explores the mechanical properties of an E-glass fabric composite reinforced with anchored multi-walled carbon nanotubes (CNTs). The CNTs were grown on the E-glass fabric using a floating catalyst chemical vapor deposition procedure. The E-glass fabric with attached CNTs was then incorpor...

  4. Metal-organic framework derived CoSe2 nanoparticles anchored on carbon fibers as bifunctional electrocatalysts for efficient overall water splitting

    Institute of Scientific and Technical Information of China (English)

    Chencheng Sun; Qiuchun Dong; Jun Yang; Ziyang Dai; Jianjian Lin; Peng Chen; Wei Huang

    2016-01-01

    The development of efficient,low-cost,stable,non-noble-metal electrocatalysts for water splitting,particularly those that can catalyze both the hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode,is a challenge.We have developed a facile method for synthesizing CoSe2 nanoparticles uniformly anchored on carbon fiber paper (CoSe2/CF) via pyrolysis and selenization of in situ grown zeolitic imidazolate framework-67 (ZIF-67).CoSe2/CF shows high and stable catalytic activity in both the HER and OER in alkaline solution.At a low cell potential,i.e.,1.63 V,a water electrolyzer equipped with two CoSe2/CF electrodes gave a water-splitting current of 10 mA.cm-2.At a current of 20 mA.cm-2,it can operate without degradation for 30 h.This study not only offers a cost-effective solution for water splitting but also provides a new strategy for developing various catalytic nanostructures by changing the metal-organic framework precursors.

  5. Optical Fiber Grating Sensor for Force Measurement of Anchor Cable

    Institute of Scientific and Technical Information of China (English)

    JIANG Desheng; FU Jinghua; LIU Shengchun; SUI Lingfeng; FU Rong

    2006-01-01

    The development of the sensor suitable for measuring large load stress to the anchor cable becomes an important task in bridge construction and maintenance. Therefore, a new type of optical fiber sensor was developed in the laboratory - optical fiber grating sensor for force measurement of anchor cable (OFBFMAC). No similar report about this kind of sensor has been found up to now in China and other countries. This sensor is proved to be an effective way of monitoring in processes of anchor cable installation, cable cutting, cable force regulation, etc, with the accurate and repeatable measuring results. Its successful application in the tie bar cable force safety monitoring for Wuhan Qingchuan bridge is a new exploration of optical fiber grating sensing technology in bridge tie bar monitoring system.

  6. SILICA SURFACED CARBON FIBERS.

    Science.gov (United States)

    carbon fibers . Several economical and simple processes were developed for obtaining research quantities of silica surfaced carbon filaments. Vat dipping processes were utilized to deposit an oxide such as silica onto the surface and into the micropores of available carbon or graphite base fibers. High performance composite materials were prepared with the surface treated carbon fibers and various resin matrices. The ablative characteristics of these composites were very promising and exhibited fewer limitations than either silica or...treated

  7. Nickel-cobalt layered double hydroxide anchored zinc oxide nanowires grown on carbon fiber cloth for high-performance flexible pseudocapacitive energy storage devices

    KAUST Repository

    Shakir, Imran

    2014-05-01

    Nickel-cobalt layered double hydroxide (Ni-Co LDH) nanoflakes-ZnO nanowires hybrid array has been directly synthesized on a carbon cloth substrate by a facile cost-effective two-step hydrothermal route. As electrode materials for flexible pseudocapacitors, Ni-Co LDH nanoflakes-ZnO nanowires hybrid array exhibits a significantly enhanced specific capacitance of 1927 Fg-1, which is a ∼1.8 time greater than pristine Ni-Co LDH nanoflakes. The synthesized Ni-Co LDH nanoflakes-ZnO nanowires hybrid array shows a maximum energy density of 45.55 Whkg-1 at a power density of 46.15 kWkg -1, which is 35% higher than the pristine Ni-Co LDH nanoflakes electrode. Moreover, Ni-Co LDH nanoflakes-ZnO nanowires hybrid array exhibit excellent excellent rate capability (80.3% capacity retention at 30 Ag -1) and cycling stability (only 3.98% loss after 3000 cycles), due to the significantly improved faradaic redox reaction. © 2014 Elsevier Ltd.

  8. Carbonized asphaltene-based carbon-carbon fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George; Lula, James; Bowen, III, Daniel E.

    2016-12-27

    A method of making a carbon binder-reinforced carbon fiber composite is provided using carbonized asphaltenes as the carbon binder. Combinations of carbon fiber and asphaltenes are also provided, along with the resulting composites and articles of manufacture.

  9. Boron nitride converted carbon fiber

    Science.gov (United States)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  10. Thermoplastic coating of carbon fibers

    Science.gov (United States)

    Edie, D. D.; Lickfield, G. C.; Drews, M. J.; Ellison, M. S.; Gantt, B. W.

    1989-01-01

    A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread cover a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol pct fiber prepregs can be obtained.

  11. Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

    2015-08-04

    Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

  12. Multimetallic Electrodeposition on Carbon Fibers

    Science.gov (United States)

    Böttger-Hiller, F.; Kleiber, J.; Böttger, T.; Lampke, T.

    2016-03-01

    Efficient lightweight design requires intelligent materials that meet versatile functions. One approach is to extend the range of properties of carbon fiber reinforced plastics (CFRP) by plating the fiber component. Electroplating leads to metalized layers on carbon fibers. Herein only cyanide-free electrolytes where used. Until now dendrite-free layers were only obtained using current densities below 1.0 A dm-2. In this work, dendrite-free tin and copper coatings were achieved by pre-metalizing the carbon fiber substrates. Furthermore, applying a combination of two metals with different sized thermal expansion coefficient lead to a bimetallic coating on carbon fiber rovings, which show an actuatory effect.

  13. Carbon Fiber Biocompatibility for Implants

    Directory of Open Access Journals (Sweden)

    Richard Petersen

    2016-01-01

    Full Text Available Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8 and 0.8 mm at 41.6% vs. 19.5% (p < 10−4, respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration.

  14. Novel method for carbon nanofilament growth on carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Johathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM MECH.ENG.; Terani, Mehran [UNM MECH.ENG.; Al - Haik, Marwan [UNM MECH.ENG.; Garcia, Daniel [UNM MECH.ENG.; Taha, Mahmoud R [UNM MECH.ENG.

    2009-01-01

    Fiber reinforced structural composites such as fiber reinforced polymers (FRPs) have proven to be key materials for blast mitigation due to their enhanced mechanical performance. However, there is a need to further increase total energy absorption of the composites in order to retain structural integrity in high energy environments, for example, blast events. Research has shown that composite failure in high energy environments can be traced to their relatively low shear strength attributed to the limited bond strength between the matrix and the fibers. One area of focus for improving the strength of composite materials has been to create 'multi-scale' composites. The most common approach to date is to introduce carbon nanotubes into a more traditional composite consisting of epoxy with embedded micron scale fibers. The inclusion of carbon nanotubes (CNT) clearly toughens different matrices. Depositing CNT in brittle matrix increases stiffness by orders of magnitude. Currently, this approach to create multiscale composites is limited due to the difficulty of dispersing significant amounts of nanotubes. It has repeatedly been reported that phase separation occurs above relatively low weight percent loading (ca. 3%) due to the strong van der Waals forces between CNTs compared with that between CNT and polymer. Hence, the nanotubes tend to segregate and form inclusions. One means to prevent nanotube or nanofilament agglomeration is to anchor one end of the nanostructure, thereby creating a stable multi-phase structure. This is most easily done by literally growing the CNTs directly on micron scale fibers. Recently, CNT were grown on carbon fibers, both polyacrylonitrile- (PAN-) and pitch-based, by hot filament chemical vapor deposition (HFCVD) using H2 and CH4 as precursors. Nickel clusters were electrodeposited on the fiber surfaces to catalyze the growth and uniform CNT coatings were obtained on both the PAN- and pitch-based carbon fibers. Multiwalled CNTs

  15. Carbon Fiber Biocompatibility for Implants

    OpenAIRE

    Richard Petersen

    2016-01-01

    Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-rein...

  16. Carbon Fiber from Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, Anelia [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States); Booth, Samuel [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States)

    2016-09-01

    Carbon fiber (CF), known also as graphite fiber, is a lightweight, strong, and flexible material used in both structural (load-bearing) and non-structural applications (e.g., thermal insulation). The high cost of precursors (the starting material used to make CF, which comes predominately from fossil sources) and manufacturing have kept CF a niche market with applications limited mostly to high-performance structural materials (e.g., aerospace). Alternative precursors to reduce CF cost and dependence on fossil sources have been investigated over the years, including biomass-derived precursors such as rayon, lignin, glycerol, and lignocellulosic sugars. The purpose of this study is to provide a comprehensive overview of CF precursors from biomass and their market potential. We examine the potential CF production from these precursors, the state of technology and applications, and the production cost (when data are available). We discuss their advantages and limitations. We also discuss the physical properties of biomass-based CF, and we compare them to those of polyacrylonitrile (PAN)-based CF. We also discuss manufacturing and end-product considerations for bio-based CF, as well as considerations for plant siting and biomass feedstock logistics, feedstock competition, and risk mitigation strategies. The main contribution of this study is that it provides detailed technical and market information about each bio-based CF precursor in one document while other studies focus on one precursor at a time or a particular topic (e.g., processing). Thus, this publication allows for a comprehensive view of the CF potential from all biomass sources and serves as a reference for both novice and experienced professionals interested in CF production from alternative sources.

  17. Adsorption characteristics of activated carbon hollow fibers

    OpenAIRE

    2009-01-01

    Carbon hollow fibers were prepared with regenerated cellulose or polysulfone hollow fibers by chemical activation using sodium phosphate dibasic followed by the carbonization process. The activation process increases the adsorption properties of fibers which is more prominent for active carbone fibers obtained from the cellulose precursor. Chemical activation with sodium phosphate dibasic produces an active carbon material with both mesopores and micropores.

  18. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  19. Carbon Fiber Technology Facility (CFTF)

    Data.gov (United States)

    Federal Laboratory Consortium — Functionally within the MDF, ORNL operates DOE’s unique Carbon Fiber Technology Facility (CFTF)—a 42,000 ft2 innovative technology facility and works with leading...

  20. Nanotailored Carbon Fibers

    Science.gov (United States)

    2012-04-27

    precursor fiber and also utilize bi- component spinning along with gel spinning, to obtain small diameter fibers. Various processing parameters during...shape of the fiber. In this regard, we have also conducted single component gel spinning using different gelation bath temperatures (100% methanol). SEM...domestic dishwashing detergent, Palmolive antibacterial , 3 wt% detergent and 97% water) for about a week and retested. *** For 5th trial, tungsten

  1. Jilin Chemical Fiber Group Launches Its Largest Carbon Fiber Preject

    Institute of Scientific and Technical Information of China (English)

    Flora

    2011-01-01

    China's carbon fiber precursor production line with 5,000 tons of annual output was put into operation in Jilin Chemical Fiber Group on November 18th this year, creating the maximum production capacity currently in China, for which Jilin Chemical Fiber Group become China's largest carbon fiber precursor production base, The smooth operation of the project has laid a solid foundation for promoting China's carbon fiber industry steady, rapid, and healthy development,

  2. PROGRESS ON ACTIVATED CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Activated carbon fiber is one kind of important adsorption materials. These novel fibrousadsorbents have high specific surface areas or abundant functional groups, which make them havegreater adsorption/desorption rates and larger adsorption capacities than other adsorbents. They canbe prepared as bundle, paper, cloth and felt to meet various technical requirement. They also showreduction property. In this paper the latest progress on the studies of the preparation and adsorptionproperties of activated carbon fibers is reviewed. The application of these materials in drinking waterpurification, environmental control, resource recovery, chemical industry, and in medicine and healthcare is also presented.

  3. Methods of making carbon fiber from asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George; Bowen, III, Daniel E.

    2017-02-28

    Making carbon fiber from asphaltenes obtained through heavy oil upgrading. In more detail, carbon fiber is made from asphaltenes obtained from heavy oil feedstocks undergoing upgrading in a continuous coking reactor.

  4. Advanced Carbon Fiber Nears Broad Automotive Use

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    General Motors and Teijin Limited, a leader in the carbon fiber and composites industry, will co-develop advanced carbon fiber composite technologies for potential high-volume use globally in GM cars, trucks and crossovers.

  5. Automatic Fiber Orientation Detection for Sewed Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Automatic production and precise positioning of carbon fiber reinforced plastics (FRP) require precise detection of the fiber orientations. This paper presents an automatic method for detecting fiber orientations of sewed carbon fibers in the production of FRP. Detection was achieved by appropriate use of regional filling, edge detection operators, autocorrelation methods, and the Hough transformation. Regional filling was used to reduce the influence of the sewed regions, autocorrelation was used to clarify the fiber directions, edge detection operators were used to extract the edge features for the fiber orientations, and the Hough transformation was used to calculate the angles. Results for two kinds of carbon fiber materials show that the method is relatively quick and precise for detecting carbon fiber orientations.

  6. MODIFYING V-14 RUBBER WITH CARBON FIBERS

    Directory of Open Access Journals (Sweden)

    Shadrinov N. V.

    2016-01-01

    Full Text Available The influence of carbon fibers and modified carbon fibers on properties of industrially produced V-14 rubber is examined. The dependences of physical and mechanical properties, hardness, abrasion resistance and resistance in aggressive environment on few amount of filled fiber are established. Structural properties of reinforced elastomeric composites are studied by scanning electron microscopy. Elastomeric layer on the surface of modified carbon fiber, confirmed with high adhesion is identified

  7. Electrical Properties of Carbon Fiber Support Systems

    CERN Document Server

    Cooper, W; Demarteau, M; Fast, J; Hanagaki, K; Johnson, M; Kuykendall, W; Lubatti, H; Matulik, M; Nomerotski, A; Quinn, B; Wang, J

    2005-01-01

    Carbon fiber support structures have become common elements of detector designs for high energy physics experiments. Carbon fiber has many mechanical advantages but it is also characterized by high conductivity, particularly at high frequency, with associated design issues. This paper discusses the elements required for sound electrical performance of silicon detectors employing carbon fiber support elements. Tests on carbon fiber structures are presented indicating that carbon fiber must be regarded as a conductor for the frequency region of 10 to 100 MHz. The general principles of grounding configurations involving carbon fiber structures will be discussed. To illustrate the design requirements, measurements performed with a silicon detector on a carbon fiber support structure at small radius are presented. A grounding scheme employing copper-kapton mesh circuits is described and shown to provide adequate and robust detector performance.

  8. Carbon nanotube fiber spun from wetted ribbon

    Science.gov (United States)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  9. A novel carbon fiber based porous carbon monolith

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Klett, J.W.; Weaver, C.E.

    1995-06-01

    A novel porous carbon material based on carbon fibers has been developed. The material, when activated, develops a significant micro- or mesopore volume dependent upon the carbon fiber type utilized (isotropic pitch or polyacrylonitrile). The materials will find applications in the field of fluid separations or as a catalyst support. Here, the manufacture and characterization of our porous carbon monoliths are described. A novel adsorbent carbon composite material has been developed comprising carbon fibers and a binder. The material, called carbon fiber composite molecular sieve (CFCMS), was developed through a joint research program between Oak Ridge National Laboratory (ORNL) and the University of Kentucky, Center for Applied Energy Research (UKCAER).

  10. Interfacial Studies of Sized Carbon Fiber

    Science.gov (United States)

    Shahrul, S. N.; Hartini, M. N.; Hilmi, E. A.; Nizam, A.

    2010-03-01

    This study was performed to investigate the influence of sizing treatment on carbon fiber in respect of interfacial adhesion in composite materials, Epolam® 2025. Fortafil unsized carbon fiber was used to performed the experiment. The fiber was commercially surface treated and it was a polyacrylonitrile based carbon fiber with 3000 filament per strand. Epicure® 3370 was used as basic sizing chemical and dissolved in two types of solvent, ethanol and acetone for the comparison purpose. The single pull out test has been used to determine the influence of sizing on carbon fiber. The morphology of carbon fiber was observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The apparent interfacial strength IFSS values determined by pull out test for the Epicure® 3370/ethanol sized carbon fiber pointed to a good interfacial behaviour compared to the Epicure® 3370/acetone sized carbon fiber. The Epicure® 3370/ethanol sizing agent was found to be effective in promoting adhesion because of the chemical reactions between the sizing and Epolam® 2025 during the curing process. From this work, it showed that sized carbon fiber using Epicure® 3370 with addition of ethanol give higher mechanical properties of carbon fiber in terms of shear strength and also provided a good adhesion between fiber and matrix compared to the sizing chemical that contain acetone as a solvent.

  11. External reinforcing of fiber concrete constructions by carbon fiber tapes

    OpenAIRE

    S.V. Klyuyev; Yu.V. Guryanov

    2013-01-01

    Strengthening the concrete and reinforced concrete structures with carbon fiber tapes is very actively applied in Europe nowadays. In Russia composites based on carbon fiber have also widely spread recently. The main advantages of these materials for strengthening structures are its high specific strength (strength-weight ratio) and strength-to-density ratio.Experimental studies on strengthening and restoration of the constructions were held. Flexible fiber concrete constructions based on man...

  12. Carbon Fiber Reinforced, Zero CME Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Technical Abstract: This project proposes to develop moisture insensitive, high performance, carbon fiber laminates for future missions. Current space-qualified...

  13. Patterned functional carbon fibers from polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Marcus A [ORNL; Saito, Tomonori [ORNL; Brown, Rebecca H [ORNL; Kumbhar, Amar S [University of North Carolina, Chapel Hill; Naskar, Amit K [ORNL

    2012-01-01

    Patterned, continuous carbon fibers with controlled surface geometry were produced from a novel melt-processible carbon precursor. This portends the use of a unique technique to produce such technologically innovative fibers in large volume for important applications. The novelties of this technique include ease of designing and fabricating fibers with customized surface contour, the ability to manipulate filament diameter from submicron scale to a couple of orders of magnitude larger scale, and the amenable porosity gradient across the carbon wall by diffusion controlled functionalization of precursor. The geometry of fiber cross-section was tailored by using bicomponent melt-spinning with shaped dies and controlling the melt-processing of the precursor polymer. Circular, trilobal, gear-shaped hollow fibers, and solid star-shaped carbon fibers of 0.5 - 20 um diameters, either in self-assembled bundle form, or non-bonded loose filament form, were produced by carbonizing functionalized-polyethylene fibers. Prior to carbonization, melt-spun fibers were converted to a char-forming mass by optimizing the sulfonation on polyethylene macromolecules. The fibers exhibited distinctly ordered carbon morphologies at the outside skin compared to the inner surface or fiber core. Such order in carbon microstructure can be further tuned by altering processing parameters. Partially sulfonated polyethylene-derived hollow carbon fibers exhibit 2-10 fold surface area (50-500 m2/g) compared to the solid fibers (10-25 m2/g) with pore sizes closer to the inside diameter of the filaments larger than the sizes on the outer layer. These specially functionalized carbon fibers hold promise for extraordinary performance improvements when used, for example, as composite reinforcements, catalyst support media, membranes for gas separation, CO2 sorbents, and active electrodes and current collectors for energy storage applications.

  14. Manufacturing of Nanocomposite Carbon Fibers and Composite Cylinders

    Science.gov (United States)

    Tan, Seng; Zhou, Jian-guo

    2013-01-01

    Pitch-based nanocomposite carbon fibers were prepared with various percentages of carbon nanofibers (CNFs), and the fibers were used for manufacturing composite structures. Experimental results show that these nanocomposite carbon fibers exhibit improved structural and electrical conductivity properties as compared to unreinforced carbon fibers. Composite panels fabricated from these nanocomposite carbon fibers and an epoxy system also show the same properties transformed from the fibers. Single-fiber testing per ASTM C1557 standard indicates that the nanocomposite carbon fiber has a tensile modulus of 110% higher, and a tensile strength 17.7% times higher, than the conventional carbon fiber manufactured from pitch. Also, the electrical resistance of the carbon fiber carbonized at 900 C was reduced from 4.8 to 2.2 ohm/cm. The manufacturing of the nanocomposite carbon fiber was based on an extrusion, non-solvent process. The precursor fibers were then carbonized and graphitized. The resultant fibers are continuous.

  15. Photoconductivity of Activated Carbon Fibers

    Science.gov (United States)

    Kuriyama, K.; Dresselhaus, M. S.

    1990-08-01

    The photoconductivity is measured on a high-surface-area disordered carbon material, namely activated carbon fibers, to investigate their electronic properties. Measurements of decay time, recombination kinetics and temperature dependence of the photoconductivity generally reflect the electronic properties of a material. The material studied in this paper is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000--2000m{sup 2}/g. Our preliminary thermopower measurements suggest that this carbon material is a p-type semiconductor with an amorphous-like microstructure. The intrinsic electrical conductivity, on the order of 20S/cm at room temperature, increases with increasing temperature in the range 30--290K. In contrast with the intrinsic conductivity, the photoconductivity in vacuum decreases with increasing temperature. The recombination kinetics changes from a monomolecular process at room temperature to a biomolecular process at low temperatures. The observed decay time of the photoconductivity is {approx equal}0.3sec. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The intrinsic carrier density and the activation energy for conduction are estimated to be {approx equal}10{sup 21}/cm{sup 3} and {approx equal}20meV, respectively. The majority of the induced photocarriers and of the intrinsic carriers are trapped, resulting in the long decay time of the photoconductivity and the positive temperature dependence of the conductivity.

  16. The Transport Properties of Activated Carbon Fibers

    Science.gov (United States)

    di Vittorio, S. L.; Dresselhaus, M. S.; Endo, M.; Issi, J-P.; Piraux, L.

    1990-07-01

    The transport properties of activated isotropic pitch-based carbon fibers with surface area 1000 m{sup 2}/g have been investigated. We report preliminary results on the electrical conductivity, the magnetoresistance, the thermal conductivity and the thermopower of these fibers as a function of temperature. Comparisons are made to transport properties of other disordered carbons.

  17. Patterned functional carbon fibers from polyethylene.

    Science.gov (United States)

    Hunt, Marcus A; Saito, Tomonori; Brown, Rebecca H; Kumbhar, Amar S; Naskar, Amit K

    2012-05-08

    Carbon fibers having unique morphologies, from hollow circular to gear-shaped, are produced from a novel melt-processable precursor and method. The resulting carbon fiber exhibits microstructural and topological properties that are dependent on processing conditions, rendering them highly amenable to myriad applications.

  18. Coating of carbon fibers -- The strength of the fibers

    Energy Technology Data Exchange (ETDEWEB)

    Helmer, T. [Alusingen GmbH, Singen (Germany); Peterlik, H.; Kromp, K. [Univ. Wien, Vienna (Austria). Inst. fuer Festkoerperphysik

    1995-01-01

    The 6k carbon fiber Torayca T800H was coated with pyrolytic carbon by a CVD process. Fiber bundles were tested and evaluated. By this procedure, the whole distribution of the failure probability with respect to the fiber strength is obtained in a single experiment. The 50% strength of the fiber bundle, i.e., the strength at which 50% of the fibers in the bundle are broken, is inversely proportional to the square root of the thickness of the coating. By relating the strength to the defect size according to linear-elastic fracture mechanics (LEFM), the probability density function of the defects was derived. It is Weibull-shaped for the uncoated fiber and shows an increasing bimodal shape for the increasing coating thicknesses.

  19. Characterization of electrospun lignin based carbon fibers

    Science.gov (United States)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-01

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 - 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  20. Experimental analysis of reinforced concrete beams strengthened in bending with carbon fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    M. M. VIEIRA

    Full Text Available The use of carbon fiber reinforced polymer (CFRP has been widely used for the reinforcement of concrete structures due to its practicality and versatility in application, low weight, high tensile strength and corrosion resistance. Some construction companies use CFRP in flexural strengthening of reinforced concrete beams, but without anchor systems. Therefore, the aim of this study is analyze, through an experimental program, the structural behavior of reinforced concrete beams flexural strengthened by CFRP without anchor fibers, varying steel reinforcement and the amount of carbon fibers reinforcement layers. Thus, two groups of reinforced concrete beams were produced with the same geometric feature but with different steel reinforcement. Each group had five beams: one that is not reinforced with CFRP (reference and other reinforced with two, three, four and five layers of carbon fibers. Beams were designed using a computational routine developed in MAPLE software and subsequently tested in 4-point points flexural test up to collapse. Experimental tests have confirmed the effectiveness of the reinforcement, ratifying that beams collapse at higher loads and lower deformation as the amount of fibers in the reinforcing layers increased. However, the increase in the number of layers did not provide a significant increase in the performance of strengthened beams, indicating that it was not possible to take full advantage of strengthening applied due to the occurrence of premature failure mode in the strengthened beams for pullout of the cover that could have been avoided through the use of a suitable anchoring system for CFRP.

  1. The point-defect of carbon nanotubes anchoring Au nanoparticles

    DEFF Research Database (Denmark)

    Lv, Y. A.; Cui, Y. H.; Li, X. N.

    2010-01-01

    The understanding of the interaction between Au and carbon nanotubes (CNTs) is very important since Au/CNTs composites have wide applications in many fields. In this study, we investigated the dispersion of Au nanoparticles on the CNTs by transmission electron microscopy and the bonding mechanism...... of states, charge transfer and frontier molecular orbitals. (C) 2010 Elsevier B.V. All rights reserved....

  2. Carbon Fiber Reinforced Polymer for Cable Structures—A Review

    Directory of Open Access Journals (Sweden)

    Yue Liu

    2015-10-01

    Full Text Available Carbon Fiber Reinforced Polymer (CFRP is an advanced composite material with the advantages of high strength, lightweight, no corrosion and excellent fatigue resistance. Therefore, unidirectional CFRP has great potential for cables and to replace steel cables in cable structures. However, CFRP is a typical orthotropic material and its strength and modulus perpendicular to the fiber direction are much lower than those in the fiber direction, which brings a challenge for anchoring CFRP cables. This paper presents an overview of application of CFRP cables in cable structures, including historical review, state of the art and prospects for the future. After introducing properties of carbon fibers, mechanical characteristics and structural forms of CFRP cables, existing CFRP cable structures in the world (all of them are cable bridges are reviewed. Especially, their CFRP cable anchorages are presented in detail. New applications for CFRP cables, i.e., cable roofs and cable facades, are also presented, including the introduction of a prototype CFRP cable roof and the conceptual design of a novel structure—CFRP Continuous Band Winding System. In addition, other challenges that impede widespread application of CFRP cable structures are briefly introduced.

  3. Heat Treated Carbon Fiber Material Selection Database

    Science.gov (United States)

    Effinger, M.; Patel, B.; Koenig, J.

    2008-01-01

    Carbon fibers are used in a variety high temperature applications and materials. However, one limiting factor in their transition into additional applications is an understanding of their functional properties during component processing and function. The requirements on the fibers are governed by the nature of the materials and the environments in which they will be used. The current carbon fiber vendor literature is geared toward the polymeric composite industry and not the ceramic composite industry. Thus, selection of carbon fibers is difficult, since their properties change as a function of heat treatment, processing or component operational temperature, which ever is greatest. To enable proper decisions to be made, a program was established wherein multiple fibers were selected and heat treated at different temperatures. The fibers were then examined for their physical and mechanical properties which are reported herein.

  4. Wettability of a Single Carbon Fiber.

    Science.gov (United States)

    Qiu, Si; Fuentes, Carlos A; Zhang, Dongxing; Van Vuure, Aart Willem; Seveno, David

    2016-09-27

    Wettability as determined from contact angle measurements is a suitable parameter for characterizing the physical bonding of a polymer matrix and reinforcing fibers, but it is very challenging to measure the capillary force exerted by a probe liquid on a fiber accurately for very fine fibers such as single carbon fibers. Herein, we propose an innovative method for measuring dynamic contact angles with a tensiometer, considering both the intrinsic variability of the carbon fiber diameter and the extremely small amplitude of the capillary forces, allowing the measurement of reliable dynamic contact angles over a large range of contact line velocities. The analysis of the contact angle dynamics by the molecular-kinetic theory permits us to check the relevancy of the measured contact angles and to obtain the static contact angle value, improving the prospect of employing tensiometry to better understand the wetting behavior of carbon fibers.

  5. Residual stress in high modulus carbon fibers

    Science.gov (United States)

    Chen, K. J.; Diefendorf, R. J.

    1982-01-01

    The modulus and residual strain in carbon fibers are measured by successively electrochemically milling away the fiber surface. Electrochemical etching is found to remove the carbon fiber surface very uniformly, in contrast to air and wet oxidation. The precision of fiber diameter measurements is improved by using a laser diffraction technique instead of optical methods. More precise diameter measurements reveal that past correlations of diameter and fiber modulus are largely measurement artifact. The moduli of most carbon fibers decrease after the outer layers of the fibers are removed. Owing to experimental difficulties, the moduli and strengths of the fibers at their centers are not determined, and moduli are estimated on the basis of microstructure. The calculated residual stresses are found to be insensitive to these moduli estimates as well as the exact form of regression equation used to describe the moduli and residual strain distributions. Axial compressive residual stresses are found to be very high for some higher modulus carbon fibers. It is pointed out that the compressive stress makes the fibers insensitive to surface flaws when loaded in tension but it may initiate failure by buckling when loaded in compression.

  6. FIBER ORIENTATION IN INJECTION MOLDED LONG CARBON FIBER THERMOPLASTIC COMPOSITES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin; Nguyen, Ba Nghiep; Mathur, Raj N.; Sharma, Bhisham; Sangid, Michael D.; Costa, Franco; Jin, Xiaoshi; Tucker III, Charles L.; Fifield, Leonard S.

    2015-03-23

    A set of edge-gated and center-gated plaques were injection molded with long carbon fiber-reinforced thermoplastic composites, and the fiber orientation was measured at different locations of the plaques. Autodesk Simulation Moldflow Insight (ASMI) software was used to simulate the injection molding of these plaques and to predict the fiber orientation, using the anisotropic rotary diffusion and the reduced strain closure models. The phenomenological parameters of the orientation models were carefully identified by fitting to the measured orientation data. The fiber orientation predictions show very good agreement with the experimental data.

  7. Carbon fiber content measurement in composite

    Science.gov (United States)

    Wang, Qiushi

    Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40°C min--1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and

  8. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  9. Carbon fiber resin matrix interphase: effect of carbon fiber surface treatment on composite performance

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, S.; Megerdigian, C.; Papalia, R.

    1985-04-01

    Carbon fibers are supplied by various manufacturers with a predetermined level of surface treatment and matrix compatible sizings. Surface treatment of the carbon fiber increases the active oxygen content, the polarity and the total free surface energy of the fiber surface. This study is directed toward determining the effect of varying carbon fiber surface treatment on the composite performance of thermoset matrix resins. The effect of varying fiber surface treatment on performance of a promising proprietary sizing is also presented. 6 references, 11 figures.

  10. Carbon fiber composite molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Rogers, M.R.; Williams, A.M.

    1996-06-01

    The removal of CO{sub 2} is of significance in several energy applications. The combustion of fossil fuels, such as coal or natural gas, releases large volumes of CO{sub 2} to the environment. Several options exist to reduce CO{sub 2} emissions, including substitution of nuclear power for fossil fuels, increasing the efficiency of fossil plants and capturing the CO{sub 2} prior to emission to the environment. All of these techniques have the attractive feature of limiting the amount of CO{sub 2} emitted to the atmosphere, but each has economic, technical, or societal limitations. In the production of natural gas, the feed stream from the well frequently contains contaminants and diluents which must be removed before the gas can enter the pipeline distribution system. Notable amongst these diluent gasses is CO{sub 2}, which has no calorific value. Currently, the pipeline specification calls for <2 mol % CO{sub 2} in the gas. Gas separation is thus a relevant technology in the field of energy production. A novel separation system based on a parametric swing process has been developed that utilizes the unique combination of properties exhibited by our carbon fiber composite molecular sieve (CFCMS).

  11. Characterization of electrospun lignin based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri [School of Engineering, Thornbrough Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada); Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada)

    2015-05-22

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 – 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  12. Microstructure of carbon fiber preform and distribution of pyrolytic carbon by chemical vapor infiltration

    Institute of Scientific and Technical Information of China (English)

    陈建勋; 黄伯云

    2004-01-01

    The carbon/carbon composites were made by chemical vapor infiltration(CVI) with needled felt preform. The distribution of the pyrolytic carbon in the carbon fiber preform was studied by polarized light microscope(PLM) and scanning electronic microscope(SEM). The experimental results indicate that the amount of pyrolytic carbon deposited on the surface of chopped carbon fiber is more than that on the surface of long carbon fiber. The reason is the different porosity between the layer of chopped carbon fiber and long carbon fiber. The carbon precursor gas which passes through the part of chopped carbon fibers decomposes and deposits on the surface of chopped carbon fiber. The pyrolytic carbon on the surface of long carbon fibers is produced by the carbon precursor gas diffusing from the chopped fiber and the Z-d fiber. Uniform pore distribution and porosity in preform are necessary for producing C/C composites with high properties.

  13. Carbon Fiber Damage in Accelerator Beam

    CERN Document Server

    Sapinski, M; Guerrero, A; Koopman, J; Métral, E

    2009-01-01

    Carbon fibers are commonly used as moving targets in Beam Wire Scanners. Because of their thermomechanical properties they are very resistant to particle beams. Their strength deteriorates with time due to radiation damage and low-cycle thermal fatigue. In case of high intensity beams this process can accelerate and in extreme cases the fiber is damaged during a single scan. In this work a model describing the fiber temperature, thermionic emission and sublimation is discussed. Results are compared with fiber damage test performed on SPS beam in November 2008. In conclusions the limits of Wire Scanner operation on high intensity beams are drawn.

  14. ELECTRODEPOSITION OF POLYMERS ON CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    HE Jiasong; WU Renjie

    1983-01-01

    Styrene-co-maleic anhydride, vinyl acetate-co-maleic anhydride, methyl methacrylate-co-maleic anhydride copolymers were deposited on the surface of carbon fibers by an electrodeposition technique.The anion-free radical mechanism of this process and the physical adhesion to the surface were preliminarily confirmed. The adhesion at fiber-resin matrix interface in carbon fiber reinforced plastics was improved by the electrodeposited polymer interlayer and the shear failure occurred mainly in the matrix.Interlaminar shear strength of the unidirectional carbon fiber reinforced epoxy composite is increased from about 600 kg/cm2 to 1000 kg/cm2 by electrodeposition of polymers and the strength loss of the composite which has been immersed in boiling water for 100 hrs is decreased.

  15. Thermophysical ESEM Characterization of Carbon Fibers

    Science.gov (United States)

    Sue, Jiwoong; Ochoa, Ozden O.; Effinger, Michael R.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    Coefficients of thermal expansion (CTE) of carbon fibers create residual stresses in aggressive manufacturing and service environments. In this effort, environmental scanning electron microscope (ESEM) is used for in situ observations of a carbon fiber cross-section up to 1000 C in order to evaluate the much neglected transverse CTE. The perimeter of fiber cross-section is calculated with the Scion image processing program from images that were taken at every 100 C increments. CTE values are calculated by linear regression of the strain data based on the perimeter changes. Furthermore, through SEM, WDS and TEM observations, we are in the process of bringing an interactive rationale between CTE, crystallinity and surface roughness of carbon fibers.

  16. Solid phase extraction of uranium(VI) onto benzoylthiourea-anchored activated carbon.

    Science.gov (United States)

    Zhao, Yongsheng; Liu, Chunxia; Feng, Miao; Chen, Zhen; Li, Shuqiong; Tian, Gan; Wang, Li; Huang, Jingbo; Li, Shoujian

    2010-04-15

    A new solid phase extractant selective for uranium(VI) based on benzoylthiourea anchored to activated carbon was developed via hydroxylation, amidation and reaction with benzoyl isothiocyanate in sequence. Fourier transform infrared spectroscopy and total element analysis proved that benzoylthiourea had been successfully grafted to the surface of the activated carbon, with a loading capacity of 1.2 mmol benzoylthiourea per gram of activated carbon. The parameters that affect the uranium(VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, adsorbent dose and temperature, have been investigated. Results have been analyzed by Langmuir and Freundlich isotherm; the former was more suitable to describe the sorption process. The maximum sorption capacity (82 mg/g) for uranium(VI) was obtained at experimental conditions. The rate constant for the uranium sorption by the as-synthesized extractant was 0.441 min(-1) from the first order rate equation. Thermodynamic parameters (DeltaH(0)=-46.2 kJ/mol; DeltaS(0)=-98.0 J/mol K; DeltaG(0)=-17.5 kJ/mol) showed the adsorption of an exothermic process and spontaneous nature, respectively. Additional studies indicated that the benzoylthiourea-anchored activated carbon (BT-AC) selectively sorbed uranyl ions in the presence of competing ions, Na(+), Co(2+), Sr(2+), Cs(+) and La(3+).

  17. Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete

    OpenAIRE

    Weimin Song; Jian Yin

    2016-01-01

    Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%,...

  18. Solid catalytic growth mechanism of micro-coiled carbon fibers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Micro-coiled carbon fibers were prepared by catalytic pyrolysisof acetylene with nano-sized nickel powder catalyst using the substrate method. The morphology of micro-coiled carbon fibers was observed through field emission scanning electron microscopy. It was found that the fiber and coil diameter of the obtained micro-coiled carbon fibers is about 500—600 nm and 4—5 μm, respectively. Most of the micro-coiled carbon fibers obtained were regular double carbon coils, but a few irregular ones were also observed. On the basis of the experimental observation, a solid catalytic growth mechanism of micro-coiled carbon fibers was proposed.

  19. Thermoplastic coated carbon fibers for textile preforms

    Science.gov (United States)

    Allen, L. E.; Edie, D. D.; Lickfield, G. C.; Mccollum, J. R.

    1988-01-01

    A continuous process for producing prepreg from carbon fiber and thermoplastic matrix is described. After the tow has been spread using a pneumatic device, the process utilizes a fluidized bed to apply thermoplastic powder to the bundle. Finally, direct electrical heating of the coated fiber tow melts the polymer on the individual fibers, creating a uniform and extremely flexible prepreg. The efficiency of the process was evaluated during initial trials in which a thermoplastic polyimide, LaRC-TPI, was applied to T-300, 3K (3000 filament) carbon fiber tow. The physical properties of unidirectional composite specimens fabricated from this prepreg were measured, and the matrix uniformity and void content of the samples was determined. The results of these evaluations are detailed and discussed.

  20. Coating silicon carbide on carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yuqing; Wang Zuoming; Liu Min; Zhou Benlian; Shi Changxu (Inst. of Metal Research, Shenyang (China))

    1992-01-01

    The deposition of an SiC coating on the surface of carbon fibers improves their oxidation resistance and lowers their reactivity with metals at high temperature. Attention is presently given to the case of CVD SiC deposition with a view to the effects of coating thickness, deposition, and crystal structure. The presence of H(+) and other ions during CVD, as well as of free Si, is noted to decrease fiber strength. 10 refs.

  1. CARBON FIBER COMPOSITES IN HIGH VOLUME

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Charles David [ORNL; Das, Sujit [ORNL; Jeon, Dr. Saeil [Volvo Trucks North America

    2014-01-01

    Vehicle lightweighting represents one of several design approaches that automotive and heavy truck manufacturers are currently evaluating to improve fuel economy, lower emissions, and improve freight efficiency (tons-miles per gallon of fuel). With changes in fuel efficiency and environmental regulations in the area of transportation, the next decade will likely see considerable vehicle lightweighting throughout the ground transportation industry. Greater use of carbon fiber composites and light metals is a key component of that strategy. This paper examines the competition between candidate materials for lightweighting of heavy vehicles and passenger cars. A 53-component, 25 % mass reduction, body-in-white cost analysis is presented for each material class, highlighting the potential cost penalty for each kilogram of mass reduction and then comparing the various material options. Lastly, as the cost of carbon fiber is a major component of the elevated cost of carbon fiber composites, a brief look at the factors that influence that cost is presented.

  2. Hybrid solar cell on a carbon fiber

    Science.gov (United States)

    Grynko, Dmytro A.; Fedoryak, Alexander N.; Smertenko, Petro S.; Dimitriev, Oleg P.; Ogurtsov, Nikolay A.; Pud, Alexander A.

    2016-05-01

    In this work, a method to assemble nanoscale hybrid solar cells in the form of a brush of radially oriented CdS nanowire crystals around a single carbon fiber is demonstrated for the first time. A solar cell was assembled on a carbon fiber with a diameter of ~5-10 μm which served as a core electrode; inorganic CdS nanowire crystals and organic dye or polymer layers were successively deposited on the carbon fiber as active components resulting in a core-shell photovoltaic structure. Polymer, dye-sensitized, and inverted solar cells have been prepared and compared with their analogues made on the flat indium-tin oxide electrode.

  3. Coating for gasifiable carbon-graphite fibers

    Science.gov (United States)

    Harper-Tervet, Jan (Inventor); Dowler, Warren L. (Inventor); Yen, Shiao-Ping S. (Inventor); Mueller, William A. (Inventor)

    1982-01-01

    A thin, uniform, firmly adherent coating of metal gasification catalyst is applied to a carbon-graphite fiber by first coating the fiber with a film-forming polymer containing functional moieties capable of reaction with the catalytic metal ions. Multivalent metal cations such as calcium cross-link the polymer such as a polyacrylic acid to insolubilize the film by forming catalytic metal macro-salt links between adjacent polymer chains. The coated fibers are used as reinforcement for resin composites and will gasify upon combustion without evolving conductive airborne fragments.

  4. Improvement of carbon fiber surface properties using electron beam irradiation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Carbon fiber-reinforced advance composites have been used for struetural applications, mainly on account of their mechanical properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between its components, which are carbon fiber and polymeric matrix. The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite. EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests. Experimental results showed that EB irradiation improved the tensile strength of carbon fiber samples. The maximum value in tensile strength was reached using doses of about 250kGy. After breakage, the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated carbon fibers were evaluated. SEM micrographs showed modifications on the carbon fiber surface.

  5. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sujit Das, Josh Warren, Devin West, Susan M. Schexnayder

    2016-05-01

    This analysis identifies key opportunities in the carbon fiber supply chain where resources and investments can help advance the clean energy economy. The report focuses on four application areas — wind energy, aerospace, automotive, and pressure vessels — that top the list of industries using carbon fiber and carbon fiber reinforced polymers. For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components.

  6. Studies on copper coating on carbon fibers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The weak interface bonding of metal matrix reinforced by carbon fibers is the central problem of fabricating such composites. Depositing copper coating on carbon fibers is regarded as a feasible method to solve the problem. In this paper, copper coating has been deposited on the fibers through both electroless deposition and electroplating methods. Two kinds of complexing agents and two stabilizing agents are taken during the electroless plating process. The solution is stable, and little extraneous component is absorbed on the surface. After adding additive agents and increasing the concentration of H2SO4 to the acid cupric sulfate electrolyte, the "black core" during usual electroplating process is avoided. The quality of copper coating is analyzed using SEM and XRD, etc.

  7. Multifunctional Carbon Nanotube Fiber Composites

    Science.gov (United States)

    2007-11-02

    coagulant. The second process (patent pending) is novel in that it directly results polymer-free nanotube fibers without using a super acid spinning...chemical and electrochemical stability, hydrophobicity and viscosity . The generic structure, chemical name and abbreviations for the most common ions...modification procedure involved the electrochemical infiltration of small amounts of the polypyrrole/p-toluene sulphonate (PPy/PTS) conducting polymer

  8. Formation of thick dielectrophoretic carbon nanotube fibers

    Energy Technology Data Exchange (ETDEWEB)

    Plaado, Margo; Mononen, Robert Matias; Lohmus, Ruenno; Kink, Ilmar; Saal, Kristjan, E-mail: saal@fi.tartu.ee [Institute of Physics, University of Tartu, and Estonian Nanotechnology Competence Centre, 142 Riia Street, 51014 Tartu (Estonia)

    2011-07-29

    The aim of this work was to study the formation process of dielectrophoretic (DEP) carbon nanotube fibers (CNT-fibers) and characterize the fiber properties relevant to their technological applications. The fiber diameter was shown to increase when applied voltage was increased (up to 350 V{sub pp}) and when retraction speed was decreased (down from 400 {mu}m s{sup -1}) in accordance with theoretical expectations. This paper represents the first demonstration of the formation of thick DEP CNT-fibers (up to {approx} 0.4 mm). This is an intriguing result, as it expands the diversity of possible applications of the fibers and facilitates their characterization by analytical methods that require large quantities of the material. The performance of these thick fibers was as follows: a density of {approx} 0.35 g cm{sup -3}, a tensile strength of {approx} 15 MPa, a Young's modulus of {approx} 1 GPa, and an electrical resistivity of {approx} 70 m{Omega} cm.

  9. Effect of Anodization on the Graphitization of PANbased Carbon Fibers of PAN-based Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    HE Dongmei; YAO Yinghua; XU Shihai; CAI Qingyun

    2011-01-01

    One-step pretreatment,anodization,is used to activate the polyacrylonitrile (PAN)-based carbon fibers instead of the routine two-step pretreatment,sensitization with SnCl2 and activation with PdCl2 The effect of the anodization pretreatment on the graphitization of PAN-based carbon fibers is investigated as a function of Ni-P catalyst.The PAN-based carbon fibers are anodized in H3PO4 electrolyte resulting in the formation of active sites,which thereby facilitates the following electroless Ni-P coating.Carbon fibers in the presence and absence of Ni-P coatings are heat treated and the structural changes are characterized by X-ray diffraction and Raman spectroscopy,both of which indicate that the graphitization of PAN-based carbon fibers are accelerated by both the anodization treatment and the catalysts Ni-E Using the anodized carbon fibers,the routine two-step pretreatment,sensitization and activation,is not needed.

  10. Surface Anchoring of Nematic Phase on Carbon Nanotubes: Nanostructure of Ultra-High Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ogale, Amod A

    2012-04-27

    Nuclear energy is a dependable and economical source of electricity. Because fuel supply sources are available domestically, nuclear energy can be a strong domestic industry that can reduce dependence on foreign energy sources. Commercial nuclear power plants have extensive security measures to protect the facility from intruders [1]. However, additional research efforts are needed to increase the inherent process safety of nuclear energy plants to protect the public in the event of a reactor malfunction. The next generation nuclear plant (NGNP) is envisioned to utilize a very high temperature reactor (VHTR) design with an operating temperature of 650-1000°C [2]. One of the most important safety design requirements for this reactor is that it must be inherently safe, i.e., the reactor must shut down safely in the event that the coolant flow is interrupted [2]. This next-generation Gen IV reactor must operate in an inherently safe mode where the off-normal temperatures may reach 1500°C due to coolant-flow interruption. Metallic alloys used currently in reactor internals will melt at such temperatures. Structural materials that will not melt at such ultra-high temperatures are carbon/graphtic fibers and carbon-matrix composites. Graphite does not have a measurable melting point; it is known to sublime starting about 3300°C. However, neutron radiation-damage effects on carbon fibers are poorly understood. Therefore, the goal of this project is to obtain a fundamental understanding of the role of nanotexture on the properties of resulting carbon fibers and their neutron-damage characteristics. Although polygranular graphite has been used in nuclear environment for almost fifty years, it is not suitable for structural applications because it do not possess adequate strength, stiffness, or toughness that is required of structural components such as reaction control-rods, upper plenum shroud, and lower core-support plate [2,3]. For structural purposes, composites

  11. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  12. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  13. Carbon Fiber Foam Composites and Methods for Making the Same

    Science.gov (United States)

    Leseman, Zayd Chad (Inventor); Atwater, Mark Andrew (Inventor); Phillips, Jonathan (Inventor)

    2014-01-01

    Exemplary embodiments provide methods and apparatus of forming fibrous carbon foams (FCFs). In one embodiment, FCFs can be formed by flowing a fuel rich gas mixture over a catalytic material and components to be encapsulated in a mold to form composite carbon fibers, each composite carbon fiber having a carbon phase grown to encapsulate the component in situ. The composite carbon fibers can be intertwined with one another to form FCFs having a geometry according to the mold.

  14. Plasma electrolytic polishing of metalized carbon fibers

    Directory of Open Access Journals (Sweden)

    Falko Böttger-Hiller

    2016-02-01

    Full Text Available Efficient lightweight structures require intelligent materials that meet versatile functions. Especially, carbon-fiber-reinforced polymers (CFRPs are gaining relevance. Their increasing use aims at reducing energy consumption in many applications. CFRPs are generally very light in weight, while at the same time being extremely stiff and strong (specific strength: CFRPs: 1.3 Nm kg–1, steel: 0.27 Nm kg–1; specific stiffness: CFRPs: 100 Nm kg–1, steel: 25 Nm kg–1. To increase performance and especially functionality of CFRPs, the integration of microelectronic components into CFRP parts is aspired. The functionalization by sensors, actuators and electronics can enable a high lightweight factor and a new level of failure-safety. The integration of microelectronic components for this purpose requires a working procedure to provide electrical contacts for a reliable connection to energy supply and data interfaces. To overcome this challenge, metalized carbon fibers are used. Metalized fibers are, similar to the usual reinforcing fibers, able to be soldered and therefore easy to incorporate into CFRPs. Unfortunately, metalized fibers have to be pre-treated by flux-agents. Until now, there is no flux which is suitable for mass production without destroying the polymer of the CFRP. The process of plasma electrolytic polishing (PeP could be an option, but is so far not available for copper. Thus, in this study, plasma electrolytic polishing is transferred to copper and its alloys. To achieve this, electrolytic parameters as well as the electrical setup are adapted. It can be observed that the gloss and roughness can be adjusted by means of this procedure. Finally, plasma electrolytic polishing is used to treat thin copper layers on carbon fibers.

  15. Quasi-Carbon Fibers and the Composites

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The aim of this report is to study the properties of quasi-carbon fibers (QCF) prepared from the PAN fiber precursor by pyrolysis at a temperature between 400℃ and 1200℃. The resistivity of QCF with different heat-treated temperature (HTT) was investigated by a Hall-35 testing system,and the flexural properties of the result composites (QCFC) are also discussed. In addition, the scanning electronic microscope (SEM) was utilized to observe the surface morphology of QCF and the fracture section of QCFC obtained from flexural testing.

  16. Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres

    Science.gov (United States)

    Kyoungjin An, Alicia; Lee, Eui-Jong; Guo, Jiaxin; Jeong, Sanghyun; Lee, Jung-Gil; Ghaffour, Noreddine

    2017-01-01

    To ascertain membrane distillation (MD) as an emerging desalination technology to meet the global water challenge, development of membranes with ideal material properties is crucial. Functionalized carbon nanotubes (CNTs) were anchored to nanofibres of electrospun membranes. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer membrane, resulting in well-aligned CNTs inside crystalline fibres with superhydrophobicity. Consideration for the chemical/physical properties of the CNT composite membranes and calculation of their theoretical fluxes revealed the mechanism of MD: CNTs facilitated the repulsive force for Knudsen and molecular diffusions, reduced the boundary-layer effect in viscous flow, and assisted surface diffusion, allowing for fast vapor transport with anti-wetting. This study shows that the role of CNTs and an optimal composite ratio can be used to reduce the gap between theoretical and experimental approaches to desalination.

  17. Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres

    KAUST Repository

    An, Alicia Kyoungjin

    2017-01-30

    To ascertain membrane distillation (MD) as an emerging desalination technology to meet the global water challenge, development of membranes with ideal material properties is crucial. Functionalized carbon nanotubes (CNTs) were anchored to nanofibres of electrospun membranes. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer membrane, resulting in well-aligned CNTs inside crystalline fibres with superhydrophobicity. Consideration for the chemical/physical properties of the CNT composite membranes and calculation of their theoretical fluxes revealed the mechanism of MD: CNTs facilitated the repulsive force for Knudsen and molecular diffusions, reduced the boundary-layer effect in viscous flow, and assisted surface diffusion, allowing for fast vapor transport with anti-wetting. This study shows that the role of CNTs and an optimal composite ratio can be used to reduce the gap between theoretical and experimental approaches to desalination.

  18. Organometallic Complexes Anchored to Conductive Carbon for Electrocatalytic Oxidation of Methane at Low Temperature.

    Science.gov (United States)

    Joglekar, Madhura; Nguyen, Vinh; Pylypenko, Svitlana; Ngo, Chilan; Li, Quanning; O'Reilly, Matthew E; Gray, Tristan S; Hubbard, William A; Gunnoe, T Brent; Herring, Andrew M; Trewyn, Brian G

    2016-01-13

    Low-temperature direct methane fuel cells (DMEFCs) offer the opportunity to substantially improve the efficiency of energy production from natural gas. This study focuses on the development of well-defined platinum organometallic complexes covalently anchored to ordered mesoporous carbon (OMC) for electrochemical oxidation of methane in a proton exchange membrane fuel cell at 80 °C. A maximum normalized power of 403 μW/mg Pt was obtained, which was 5 times higher than the power obtained from a modern commercial catalyst and 2 orders of magnitude greater than that from a Pt black catalyst. The observed differences in catalytic activities for oxidation of methane are linked to the chemistry of the tethered catalysts, determined by X-ray photoelectron spectroscopy. The chemistry/activity relationships demonstrate a tangible path for the design of electrocatalytic systems for C-H bond activation that afford superior performance in DMEFC for potential commercial applications.

  19. Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres

    Science.gov (United States)

    Kyoungjin An, Alicia; Lee, Eui-Jong; Guo, Jiaxin; Jeong, Sanghyun; Lee, Jung-Gil; Ghaffour, Noreddine

    2017-01-01

    To ascertain membrane distillation (MD) as an emerging desalination technology to meet the global water challenge, development of membranes with ideal material properties is crucial. Functionalized carbon nanotubes (CNTs) were anchored to nanofibres of electrospun membranes. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer membrane, resulting in well-aligned CNTs inside crystalline fibres with superhydrophobicity. Consideration for the chemical/physical properties of the CNT composite membranes and calculation of their theoretical fluxes revealed the mechanism of MD: CNTs facilitated the repulsive force for Knudsen and molecular diffusions, reduced the boundary-layer effect in viscous flow, and assisted surface diffusion, allowing for fast vapor transport with anti-wetting. This study shows that the role of CNTs and an optimal composite ratio can be used to reduce the gap between theoretical and experimental approaches to desalination. PMID:28134288

  20. Carbon fiber composite molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Rogers, M.R. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Monolithic adsorbents based on isotropic pitch fibers have been developed jointly by ORNL and the University of Kentucky, Center for Applied Energy Research. The monoliths are attractive for gas separation and storage applications because of their unique combination of physical properties and microporous structure. Currently at ORNL the monoliths are produced in billets that are 10 cm in diameter and 25 cm in length. The monolithic adsorbent material is being considered for guard bed applications on a natural gas (NG) powered device. In order for the material to be successful in this application, one must attain a uniform activation to modest micropore volumes throughout the large monoliths currently being produced. Here the authors report the results of a study directed toward attaining uniform activation in these billets.

  1. Carbon Fiber Damage in Particle Beam

    CERN Document Server

    Dehning, B; Kroyer, T; Meyer, M; Sapinski, M

    2011-01-01

    Carbon fibers are commonly used as moving targets in beam wire scanners. The heating of the fiber due to energy loss of the particles travelling through is simulated with Geant4. The heating induced by the beam electromagnetic field is estimated with ANSYS. The heat transfer and sublimation processes are modelled. Due to the model nonlinearity, a numerical approach based on discretization of the wire movement is used to solve it for particular beams. Radiation damage to the fiber is estimated with SRIM. The model is tested with available SPS and LEP data and a dedicated damage test on the SPS beam is performed followed by a post-mortem analysis of the wire remnants. Predictions for the LHC beams are made.

  2. Fabrication of Microscale Carbon Nanotube Fibers

    Directory of Open Access Journals (Sweden)

    Gengzhi Sun

    2012-01-01

    Full Text Available Carbon nanotubes (CNTs have excellent mechanical, chemical, and electronic properties, but realizing these excellences in practical applications needs to assemble individual CNTs into larger-scale products. Recently, CNT fibers demonstrate the potential of retaining CNT's superior properties at macroscale level. High-performance CNT fibers have been widely obtained by several fabrication approaches. Here in this paper, we review several key spinning techniques including surfactant-based coagulation spinning, liquid-crystal-based solution spinning, spinning from vertical-aligned CNT arrays, and spinning from CNT aerogel. The method, principle, limitations, and recent progress of each technique have been addressed, and the fiber properties and their dependences on spinning parameters are also discussed.

  3. Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

    OpenAIRE

    Yunzhou Shi; Biao Wang

    2014-01-01

    Carbon fiber (CF)/cellulose (CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show ...

  4. Carbon nanotube and graphene nanoribbon-coated conductive Kevlar fibers.

    Science.gov (United States)

    Xiang, Changsheng; Lu, Wei; Zhu, Yu; Sun, Zhengzong; Yan, Zheng; Hwang, Chi-Chau; Tour, James M

    2012-01-01

    Conductive carbon material-coated Kevlar fibers were fabricated through layer-by-layer spray coating. Polyurethane was used as the interlayer between the Kevlar fiber and carbon materials to bind the carbon materials to the Kevlar fiber. Strongly adhering single-walled carbon nanotube coatings yielded a durable conductivity of 65 S/cm without significant mechanical degradation. In addition, the properties remained stable after bending or water washing cycles. The coated fibers were analyzed using scanning electron microcopy and a knot test. The as-produced fiber had a knot efficiency of 23%, which is more than four times higher than that of carbon fibers. The spray-coating of graphene nanoribbons onto Kevlar fibers was also investigated. These flexible coated-Kevlar fibers have the potential to be used for conductive wires in wearable electronics and battery-heated armors.

  5. Carbon fiber-reinforced carbon as a potential implant material.

    Science.gov (United States)

    Adams, D; Williams, D F; Hill, J

    1978-01-01

    A carbon fiber-reinforced carbon is being evaluated as a promising implant material. In a unidirectional composite, high strengths (1200 MN/m2 longitudinal flexural strength) and high modulus (140 GN/m2 flexural modulus) may be obtained with an interlaminar shear strength of 18 MN/m2. Alternatively, layers of fibers may be laid in two directions to give more isotopic properties. The compatibility of the material with bone has been studied by implanting specimens in holes drilled in rat femora. For a period of up to 8 weeks, a thin layer of fibrous tissue bridged the gap between bone and implant; but this tissue mineralizes and by 10 weeks, bone can be observed adjacent to the implant, giving firm fixation. Potential applications include endosseous dental implants where a greater strength in the neck than that provided by unreinforced carbon would be advantageous.

  6. Mechanical Properties of Heat-treated Carbon Fibers

    Science.gov (United States)

    Effinger, Michael R.; Patel, Bhavesh; Koenig, John; Cuneo, Jaques; Neveux, Michael G.; Demos, Chrystoph G.

    2004-01-01

    Carbon fibers are selected for ceramic matrix composites (CMC) are based on their as-fabricated properties or on "that is what we have always done" technical culture while citing cost and availability when there are others with similar cost and availability. However, the information is not available for proper selection of carbon fibers since heat-treated properties are not known for the fibers on the market currently. Heat-treating changes the fiber's properties. Therefore, an effort was undertaken to establish fiber properties on 19 different types of fibers from six different manufactures for both PAN and pitch fibers. Heat-treating has been done at three different temperatures.

  7. Property and Shape Modulation of Carbon Fibers Using Lasers.

    Science.gov (United States)

    Blaker, Jonny J; Anthony, David B; Tang, Guang; Shamsuddin, Siti-Ros; Kalinka, Gerhard; Weinrich, Malte; Abdolvand, Amin; Shaffer, Milo S P; Bismarck, Alexander

    2016-06-29

    An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes.

  8. Carbon Fibers: Reexamination of the Critical Low-Temperature (200-300C) Stabilization of Polyacrylonitrile,

    Science.gov (United States)

    CARBON FIBERS , SYNTHESIS(CHEMISTRY)), (*ACRYLONITRILE POLYMERS, CARBON FIBERS ), SHEETS, CARBON, FILMS, OXIDATION, THERMAL ANALYSIS, CHEMICAL BONDS, INFRARED SPECTRA, MOLECULAR STRUCTURE, HEAT TREATMENT

  9. Waste polyvinylchloride derived pitch as a precursor to develop carbon fibers and activated carbon fibers.

    Science.gov (United States)

    Qiao, W M; Yoon, S H; Mochida, I; Yang, J H

    2007-01-01

    Polyvinylchloride (PVC) was successfully recycled through the solvent extraction from waste pipe with an extraction yield of ca. 86%. The extracted PVC was pyrolyzed by a two-stage process (260 and 410 degrees C) to obtain free-chlorine PVC based pitch through an effective removal of chlorine from PVC during the heat-treatment. As-prepared pitch (softening point: 220 degrees C) was spun, stabilized, carbonized into carbon fibers (CFs), and further activated into activated carbon fibers (ACFs) in a flow of CO2. As-prepared CFs show comparable mechanical properties to commercial CFs, whose maximum tensile strength and modulus are 862 MPa and 62 GPa, respectively. The resultant ACFs exhibit a high surface area of 1200 m2/g, narrow pore size distribution and a low oxygen content of 3%. The study provides an effective insight to recycle PVC from waste PVC and develop a carbon precursor for high performance carbon materials such as CFs and ACFs.

  10. Synergistic effect of a new wedge-bond-type anchor for CFRP tendons

    Institute of Scientific and Technical Information of China (English)

    谢桂华; 刘荣桂; 陈蓓; 李明君; 石天罡

    2015-01-01

    In order to improve the anchoring force of anchors for carbon fiber reinforced polymer (CFRP) tendons further, a new wedge-bond-type anchor for CFRP tendons was developed. The increment in anchoring force induced by the clamping segment of anchor was studied. Taking the deformation of all parts in clamping segment in the transverse direction into consideration, the calculation formula for the increment of anchoring force was proposed based on the linear elastic hypotheses. The proposed model is verified by experiments and conclusions are drawn that the anchoring force is influenced mainly by the inclination angle of clamping pieces, the length of clamping part and the thickness of bonding medium. Especially, the thickness of bonding medium should be lowered in design to improve the synergistic effect of anchors.

  11. Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Weimin Song

    2016-08-01

    Full Text Available Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF and carbon fiber (CF was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC, carbon fiber reinforced concrete (CFRC and hybrid fiber reinforced concrete (HFRC were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored.

  12. Rapid Development of Carbon Fiber Industry in Jilin

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In recent years, Jilin Carbon Fiber Industrial Zone in Liaoning Province has seen a rapid development, forming a complete industrial chain from precursor to carbonization, and then to products. Along with the promotion of a large number of carbon fiber in

  13. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Among the...

  14. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Included among...

  15. Designed amyloid fibers as materials for selective carbon dioxide capture.

    Science.gov (United States)

    Li, Dan; Furukawa, Hiroyasu; Deng, Hexiang; Liu, Cong; Yaghi, Omar M; Eisenberg, David S

    2014-01-07

    New materials capable of binding carbon dioxide are essential for addressing climate change. Here, we demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide via carbamate formation. Thermodynamic and kinetic capture-and-release tests show the carbamate formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence of water, in both a natural amyloid and designed amyloids having increased carbon dioxide capacity. Heating to 100 °C regenerates the material. These results demonstrate the potential of amyloid fibers for environmental carbon dioxide capture.

  16. Alumina Coating on Carbon Fibers by Sol-Gel Method

    OpenAIRE

    2006-01-01

    Alumina precursor film was coated on carbon fibers by a sol-gel method using aluminum alkoxide solution. The optimum coating condition for the concentration of alumina alkoxide and silane coupling agent was determined to uniformly coat alumina precursor on carbon fibers. Alumina precursor converted to alumina ceramics by heating at 750℃. SEM and EPMA showed that alumina ceramics was uniformly coated on carbon fibers. The thickness of alumina layer increased with increasing coating times. The ...

  17. Electron beam irradiation-enhanced wettability of carbon fibers.

    Science.gov (United States)

    Kim, Bo-Hye; Lee, Dong Hun; Yang, Kap Seung; Lee, Byung-Cheol; Kim, Yoong Ahm; Endo, Morinobu

    2011-02-01

    A simple but controllable way of altering the surface nature of carbon fibers, without sacrificing their intrinsic mechanical properties, is demonstrated using electron beam irradiation. Such treatment leads to physically improved roughness as well as chemically introduced hydrophilic oxygen-containing functional groups on the surface of carbon fibers that are essential for assuring an efficient stress transfer from carbon fibers to a polymer matrix.

  18. Surface oxidized mesoporous carbons derived from porous silicon as dual polysulfide confinement and anchoring cathodes in lithium sulfur batteries

    Science.gov (United States)

    Carter, Rachel; Ejorh, Dennis; Share, Keith; Cohn, Adam P.; Douglas, Anna; Muralidharan, Nitin; Tovar, Trenton M.; Pint, Cary L.

    2016-10-01

    Despite widespread focus on porous carbons for lithium-sulfur battery cathode materials, electrode design to preserve mass-specific performance and sustained extended cycling stability remains a challenge. Here, we demonstrate electrochemically etched porous silicon as a sacrificial template to produce a new class of functional mesoporous carbons optimized for dual chemical and physical confinement of soluble polysulfides in lithium-sulfur battery cathodes. Melt infiltration loading of sulfur at 60 wt% enables initial discharge capacity of 1350 mAh/gsulfur at rates of 0.1 C - approaching theoretical capacity of 1675 mAh/gsulfur. Cycling performance measured at 0.2 C indicates 81% capacity retention measured over 100 cycles with 830 mAh/gsulfur capacity. Unlike other carbons, this template combines structural properties necessary for sulfur containment and polysulfide confinement to achieve high specific capacity, but also boasts surface-bound oxygen-containing functional groups that are able to chemically anchor the soluble Li2Sn species on the interior of the mesoporous carbon to sustain cycling performance. In turn, this elucidates a scalable and competitive material framework that is capable, without the addition of additional membranes or inactive anchoring materials, of providing the simultaneous anchoring and confinement effects necessary to overcome performance limitations in lithium sulfur batteries.

  19. The dynamic response of carbon fiber-filled polymer composites

    OpenAIRE

    Patterson B.; Orler E.B.; Furmanski J.; Rigg P.A.; Scharff R.J.; Stahl D.B.; Sheffield S.A.; Gustavsen R.L.; Dattelbaum D.M.; Coe J.D.

    2012-01-01

    The dynamic (shock) responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE) composite to 18.6 GPa in the through-thickness direction,...

  20. Voltammetric detection of biological molecules using chopped carbon fiber.

    Science.gov (United States)

    Sugawara, Kazuharu; Yugami, Asako; Kojima, Akira

    2010-01-01

    Voltammetric detection of biological molecules was carried out using chopped carbon fibers produced from carbon fiber reinforced plastics that are biocompatible and inexpensive. Because chopped carbon fibers normally are covered with a sizing agent, they are difficult to use as an electrode. However, when the surface of a chopped carbon fiber was treated with ethanol and hydrochloric acid, it became conductive. To evaluate the functioning of chopped carbon fibers, voltammetric measurements of [Fe(CN)(6)](3-) were carried out. Redoxes of FAD, ascorbic acid and NADH as biomolecules were recorded using cyclic voltammetry. The sizing agents used to bundle the fibers were epoxy, polyamide and polyurethane resins. The peak currents were the greatest when using the chopped carbon fibers that were created with epoxy resins. When the electrode response of the chopped carbon fibers was compared with that of a glassy carbon electrode, the peak currents and the reversibility of the electrode reaction were sufficient. Therefore, the chopped carbon fibers will be useful as disposable electrodes for the sensing of biomolecules.

  1. Continuous nanoscale carbon fibers with superior mechanical strength.

    Science.gov (United States)

    Liu, Jie; Yue, Zhongren; Fong, Hao

    2009-03-01

    Continuous nanoscale carbon fibers can be developed by stabilization and carbonization of highly aligned and extensively stretched electrospun polyacrylonitrile copolymer nanofiber precursor under optimal tension. These carbon fibers, with diameters of tens of nanometers, are expected to possess a superior mechanical strength that is unlikely to be achieved through conventional approaches. This is because i) the innovative precursor, with a fiber diameter approximately 100 times smaller than that of conventional counterparts, possesses an extremely high degree of macromolecular orientation and a significantly reduced amount of structural imperfections, and ii) the ultrasmall fiber diameter also effectively prevents the formation of structural inhomogeneity, particularly sheath/core structures during stabilization and carbonization.

  2. Polarization dependence of laser interaction with carbon fibers and CFRP.

    Science.gov (United States)

    Freitag, Christian; Weber, Rudolf; Graf, Thomas

    2014-01-27

    A key factor for laser materials processing is the absorptivity of the material at the laser wavelength, which determines the fraction of the laser energy that is coupled into the material. Based on the Fresnel equations, a theoretical model is used to determine the absorptivity for carbon fiber fabrics and carbon fiber reinforced plastics (CFRP). The surface of each carbon fiber is considered as multiple layers of concentric cylinders of graphite. With this the optical properties of carbon fibers and their composites can be estimated from the well-known optical properties of graphite.

  3. On the nature of interface of carbon nanotube coated carbon fibers with different polymers

    Science.gov (United States)

    Singh Bedi, Harpreet; Padhee, Srikant S.; Agnihotri, Prabhat K.

    2016-07-01

    Experimental investigations are carried out to analyse the wetting behaviour of carbon nanotube (CNT) coated carbon fiber to determine their suitability to process carbon nanotube coated carbon fiber/polymer multiscale composites for structural applications. To overcome the problem of agglomeration, CNTs are grown directly on the surface of carbon fibers as well as fabric using thermal chemical vapour deposition (CVD) technique. The term multiscale is used because different reinforcement mechanisms operate at the scale of long fibers and CNTs which are of few micrometers in length. The load carrying capacity of these multiscale composites critically depends on the efficiency and extent of load transfer from low strength matrix to high strength fiber which in turn depends on the interfacial strength between CNT coated carbon fiber and polymer matrix. A systematic analysis of wetting behaviour of CNT coated carbon fiber with epoxy and polyester matrix is carried out in this study. It is shown that CNT coated carbon fibers as well as fabric show better wettability with epoxy matrix as compared to polyester matrix. This results in stronger interface of CNT coated carbon fiber with epoxy as compared to polyester in multiscale composite system. A similar observation is made in nanoindentation testing of single fiber multiscale composites processed with epoxy and polyester matrix. In addition, it is observed that wettability, interfacial strength and average properties of CNT coated carbon fiber/polymer composites are a function of CNT density on the surface of carbon fibers.

  4. Reinforcement of RC structure by carbon fibers

    Directory of Open Access Journals (Sweden)

    Kissi B.

    2016-01-01

    Full Text Available In recent years, rehabilitation has been the subject of extensive research due to the increased spending on building maintenance work and restoration of built works. In all cases, it is essential to carry out methods of reinforcement or maintenance of structural elements, following an inspection analysis and methodology of a correct diagnosis. This research focuses on the calculation of the necessary reinforcement sections of carbon fiber for structural elements with reinforced concrete in order to improve their load bearing capacity and rigidity. The different results obtained reveal a considerable gain in resistance and deformation capacity of reinforced sections without significant increase in the weight of the rehabilitated elements.

  5. Deformation Resistance Effect of PAN-based Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    ZHENG Lixia; LI Zhuoqiu; SONG Xianhui; LU Yong

    2009-01-01

    The deformation resistance effect of polyacrylonitrile(PAN)-based carbon fibers was investigated,and the variatipn law of electrical resistivity under tensile stress was analyzed.The results show that the gauge factor(fractional change in resistance per unit strain)of PAN-based carbon fibers is 1.38,which is lower than that of the commonly-used resistance strain gauge.These may due to that the electrical resistivity of carbon fibers decreases under tensile stress.In addition when the carbon fibers are stretched,the change of its resistance is caused by fiber physical dimension and the change of electric resistivity,and mainly caused by the change of physical dimension.The mechanical properties of carbon fiber monofilament were also measured.

  6. Biodegradation of pitch-based high performance carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, T. (Yamaguchi Univ., Yamaguchi, (Japan). Faculty of Education)

    1992-09-10

    Although carbon fibers are widely used in various purposes because of their excellent mechanical properties, their behavior under biodegradation by microorganisms has not been elucidated. To elucidate the process of biodegradation of carbon fibers is important for understanding thoroughly the durability and the functionality of the fibers. In this article, a study has been made on biodegradation of pitch-based high performance carbon fibers by microorganisms. The fiber which was degraded has been examined with a scanning electron microscope. Aspergillus flavus has broken surface areas of high performance carbon fibers in 60 days and the fibril structure under the surface layer of the fiber has been exfoliated by degradation. The fibrils on the second layer have been 100-110nm wide. The fibrils have been in line nearly parallel to the fiber axis. The above carbon fibers are carbon type, but in case of graphite type high performance carbon fibers, its broken areas have not been shown and they have shown much stronger resistance against microbial attacks. 11 refs., 8 figs., 2 tabs.

  7. Characterization of carbon fibers and fiber-matrix adhesion in composites

    Science.gov (United States)

    Wightman, J. P.; Devilbiss, T. A.

    1985-01-01

    The effect of fiber/matrix interactions on the mechanical properties of thermoplastic carbon fiber composites was determined. The experimental approach was a multi-faceted one involving the following areas: characterization of the surface of carbon fibers using X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS) and scanning transmission electron microcopy (STEM); determination of the functional groups on carbon fiber surfaces using an elemental tagging scheme - derivatization; determination of the polar and dispersion contribution to the surface energy of carbon fibers by measuring wetting forces in a series of liquids having known polar and dispersion components; and study of the interaction of thermoplastic polymers with carbon surfaces by solution adsorption, STEM and fiber critical length.

  8. Friction and wear behavior of carbon fiber reinforced brake materials

    Institute of Scientific and Technical Information of China (English)

    Du-qing CHENG; Xue-tao WANG; Jian ZHU; Dong-bua QIU; Xiu-wei CHENG; Qing-feng GUAN

    2009-01-01

    A new composite brake material was fabri-cated with metallic powders, barium sulphate and modified phenolic resin as the matrix and carbon fiber as the reinforced material. The friction, wear and fade character-istics of this composite were determined using a D-MS friction material testing machine. The surface structure of carbon fiber reinforced friction materials was analyzed by scanning electronic microscopy (SEM). Glass fiber-reinforced and asbestos fiber-reinforced composites with the same matrix were also fabricated for comparison. The carbon fiber-reinforced friction materials (CFRFM) shows lower wear rate than those of glass fiber- and asbestos fiber-reinforced composites in the temperature range of 100℃-300℃. It is interesting that the frictional coefficient of the carbon fiber-reinforced friction materials increases as frictional temperature increases from 100℃ to 300℃, while the frictional coefficients of the other two composites decrease during the increasing temperatures. Based on the SEM observation, the wear mechanism of CFRFM at low temperatures included fiber thinning and pull-out. At high temperature, the phenolic matrix was degraded and more pull-out enhanced fiber was demonstrated. The properties of carbon fiber may be the main reason that the CFRFM possess excellent tribological performances.

  9. Interlaminar fracture in carbon fiber/thermoplastic composites

    Science.gov (United States)

    Hinkley, J. A.; Bascom, W. D.; Allred, R. E.

    1990-01-01

    The surfaces of commercial carbon fibers are generally chemically cleaned or oxidized and then coated with an oligomeric sizing to optimize their adhesion to epoxy matrix resins. Evidence from fractography, from embedded fiber testing and from fracture energies suggests that these standard treatments are relatively ineffective for thermoplastic matrices. This evidence is reviewed and model thermoplastic composites (polyphenylene oxide/high strain carbon fibers) are used to demonstrate how differences in adhesion can lead to a twofold change in interlaminar fracture toughness. The potential for improved adhesion via plasma modification of fiber surfaces is discussed. Finally, a surprising case of fiber-catalyzed resin degradation is described.

  10. Characterization and Oxidation Behavior of Rayon-Derived Carbon Fibers

    Science.gov (United States)

    Jacobson, Nathan; Hull, David

    2010-01-01

    Rayon-derived fibers are the central constituent of reinforced carbon/ carbon (RCC) composites. Optical, scanning electron, and transmission electron microscopy were used to characterize the as-fabricated fibers and the fibers after oxidation. Oxidation rates were measured with weight loss techniques in air and oxygen. The as-received fibers are approximately 10 micron in diameter and characterized by grooves or crenulations around the edges. Below 800 C, in the reaction-controlled region, preferential attack began in the crenulations and appeared to occur down fissures in the fibers.

  11. High efficient preparation of carbon nanotube-grafted carbon fibers with the improved tensile strength

    Science.gov (United States)

    Fan, Wenxin; Wang, Yanxiang; Wang, Chengguo; Chen, Jiqiang; Wang, Qifen; Yuan, Yan; Niu, Fangxu

    2016-02-01

    An innovative technique has been developed to obtain the uniform catalyst coating on continuously moving carbon fibers. Carbon nanotube (CNT)-grafted carbon fibers with significantly improved tensile strength have been succeeded to produce by using chemical vapor deposition (CVD) when compared to the tensile strength of untreated carbon fibers. The critical requirements for preparation of CNT-grafted carbon fibers with high tensile strength have been found, mainly including (i) the obtainment of uniform coating of catalyst particles with small particle size, (ii) the low catalyst-induced and mechano-chemical degradation of carbon fibers, and (iii) the high catalyst activity which could facilitate the healing and strengthening of carbon fibers during the growth of CNTs. The optimum growth temperature was found to be about 500 °C, and the optimum catalyst is Ni due to its highest activity, there is a pronounced increase of 10% in tensile strength of carbon fibers after CNT growth at 500 °C by using Ni catalyst. Based on the observation from HRTEM images, a healing and crosslink model of neighboring carbon crystals by CNTs has been formulated to reveal the main reason that causes an increase in tensile strength of carbon fibers after the growth of CNTs. Such results have provided the theoretical and experimental foundation for the large-scale preparation of CNT-grafted carbon fibers with the improved tensile strength, significantly promoting the development of CNT-grafted carbon fiber reinforced polymer composites.

  12. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  13. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  14. Computational modeling of ring textures in mesophase carbon fibers

    Directory of Open Access Journals (Sweden)

    de Andrade Lima Luiz Rogério Pinho

    2003-01-01

    Full Text Available Carbon fibers are widely used in many industrial applications due the fact of their excellent properties. Carbonaceous mesophases are liquid crystalline precursor materials that can be spun into high performance carbon fibers using the melt spinning process, which is a flow cascade consisting of pressure driven flow-converging die flow-free surface extensional spinline flow that modifies the precursor molecular orientation structure. Carbon fiber property optimization requires a better understanding of the principles that control the structure development during the fiber formation processes and the rheological processing properties. This paper presents the elastic and continuum theory of liquid crystalsand computer simulations of structure formation for pressure-driven flow of carbonaceous liquid crystalline precursors used in the industrial carbon fiber spinning process. The simulations results capture the formation of characteristic fiber macro-textures and provide new knowledge on the role of viscous and elastic effects in the spinning process.

  15. All-round joining method with carbon fiber reinforced interface

    Science.gov (United States)

    Miwa, Noriyoshi; Tanaka, Kazunori; Kamiya, Yoshiko; Nishi, Yoshitake

    2008-08-01

    Carbon fiber reinforced polymer (CFRP) has been recently applied to not only wing, but also fan blades of turbo fan engines. To prevent impact force, leading edge of titanium was often mounted on the CFRP fan blades with adhesive force. In order to enhance the joining strength, a joining method with carbon fiber reinforced interface has been developed. By using nickel-coated carbon fibers, a joining sample with carbon fiber-reinforced interface between CFRP and CFRM has been successfully developed. The joining sample with nickel-coated carbon fiber interface exhibits the high tensile strength, which was about 10 times higher than that with conventional adhesion. On the other hand, Al-welding methods to steel, Cu and Ti with carbon fiber reinforced interface have been successfully developed to lighten the parts of machines of racing car and airplane. Carbon fibers in felt are covered with metals to protect the interfacial reaction. The first step of the welding method is that the Al coated felt is contacted and wrapped with molten aluminum solidified under gravity pressure, whereas the second step is that the felt with double layer of Ni and Al is contacted and wrapped with molten steel (Cu or Ti) solidified under gravity pressure. Tensile strength of Al-Fe (Cu or Ti) welded sample with carbon fiber reinforced interface is higher than those of Al-Fe (Cu or Ti) welded sample.

  16. Surface State of Carbon Fibers Modified by Electrochemical Oxidation

    Institute of Scientific and Technical Information of China (English)

    Yunxia GUO; Jie LIU; Jieying LIANG

    2005-01-01

    Surface of polyacrylonitrile (PAN)-based carbon fibers was modified by electrochemical oxidation. The modification effect on carbon fibers surface was explored using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Results showed that on the modified surface of carbon fibers, the carbon contents decreased by 9.7% and the oxygen and nitrogen contents increased by 53.8% and 7.5 times, respectively. The surface roughness and the hydroxyl and carbonyl contents also increased. The surface orientation index was reduced by 1.5%which decreased tensile strength of carbon fibers by 8.1%, and the microcrystalline dimension also decreased which increased the active sites of carbon fiber surface by 78%. The physical and chemical properties of carbon fibers surface were modified through the electrochemical oxidative method, which improved the cohesiveness between the fibers and resin matrix and increased the interlaminar shear strength (ILSS) of carbon fibers reinforced epoxy composite (CFRP) over 20%.

  17. Increased sensitivity in fiber-based spectroscopy using carbon-coated fiber.

    Science.gov (United States)

    Sudirman, Aziza; Norin, Lars; Margulis, Walter

    2012-12-17

    Carbon-coated optical fibers are used here for reducing the luminescence background created by the primary-coating and thus increase the sensitivity of fiber-based spectroscopy systems. The 2-3 orders of magnitude signal-to-noise ratio improvement with standard telecom fibers is sufficient to allow for their use as Raman probes in the identification of organic solvents.

  18. Preliminary experimental study of a carbon fiber array cathode

    Science.gov (United States)

    Li, An-kun; Fan, Yu-wei

    2016-08-01

    The preliminary experimental results of a carbon fiber array cathode for the magnetically insulated transmission line oscillator (MILO) operations are reported. When the diode voltage and diode current were 480 kV and 44 kA, respectively, high-power microwaves with a peak power of about 3 GW and a pulse duration of about 60 ns were obtained in a MILO device with the carbon fiber array cathode. The preliminary experimental results show that the shot-to-shot reproducibility of the diode current and the microwave power is stable until 700 shots. No obvious damage or deterioration can be observed in the carbon fiber surface morphology after 700 shots. Moreover, the cathode performance has no observable deterioration after 700 shots. In conclusion, the maintain-free lifetime of the carbon fiber array cathode is more than 700 shots. In this way, this carbon fiber array cathode offers a potential replacement for the existing velvet cathode.

  19. DSC Study on the Polyacrylonitrile Precursors for Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    Wangxi ZHANG; Musen LI

    2005-01-01

    Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers displayed double separated peaks and these fibers were of high quality because of their process stability during their conversion to carbon fibers of high performance. Some fabrication processes, such as spinning, drawing, could not apparently change the DSC features of a PAN precursor fiber. It was concluded that the thermal properties of a PAN precursor fiber was mainly determined from its comonomer content type and compositions.

  20. Smart Cellulose Fibers Coated with Carbon Nanotube Networks

    OpenAIRE

    Haisong Qi; Jianwen Liu; Edith Mäder

    2014-01-01

    Smart multi-walled carbon nanotube (MWCNT)-coated cellulose fibers with a unique sensing ability were manufactured by a simple dip coating process. The formation of electrically-conducting MWCNT networks on cellulose mono- and multi-filament fiber surfaces was confirmed by electrical resistance measurements and visualized by scanning electron microscopy. The interaction between MWCNT networks and cellulose fiber was investigated by Raman spectroscopy. The piezoresistivity of these fibers fo...

  1. Carbon nanotube reinforced polyacrylonitrile and poly(etherketone) fibers

    Science.gov (United States)

    Jain, Rahul

    The graphitic nature, continuous structure, and high mechanical properties of carbon nanotubes (CNTs) make them good candidate for reinforcing polymer fiber. The different types of CNTs including single-wall carbon nanotubes (SWNTs), few-wall carbon nanotubes (FWNTs), and multi-wall carbon nanotubes (MWNTs), and carbon nanofibers (CNFs) differ in terms of their diameter and number of graphitic walls. The desire has been to increase the concentration of CNTs as much as possible to make next generation multi-functional materials. The work in this thesis is mainly focused on MWNT and CNF reinforced polyacrylonitrile (PAN) composite fibers, and SWNT, FWNT, and MWNT reinforced poly(etherketone) (PEK) composite fibers. To the best of our knowledge, this is the first study to report the spinning of 20% MWNT or 30% CNF reinforced polymer fiber spun using conventional fiber spinning. Also, this is the first study to report the PEK/CNT composite fibers. The fibers were characterized for their thermal, tensile, mechanical, and dynamic mechanical properties. The fiber structure and morphology was studied using WAXD and SEM. The effect of two-stage heat drawing, sonication time for CNF dispersion, fiber drying temperature, and molecular weight of PAN was also studied. Other challenges associated with processing high concentrations of solutions for making composite fibers have been identified and reported. The effect of CNT diameter and concentration on fiber spinnability and electrical conductivity of composite fiber have also been studied. This work suggests that CNT diameter controls the maximum possible concentration of CNTs in a composite fiber. The results show that by properly choosing the type of CNT, length of CNTs, dispersion of CNTs, fiber spinning method, fiber draw ratio, and type of polymer, one can get electrically conducting fibers with wide range of conductivities for different applications. The PEK based control and composite fibers possess high thermal

  2. RADIATION EFFECTS ON EPOXY CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E

    2008-05-30

    Carbon fiber-reinforced bisphenol-A epoxy matrix composite was evaluated for gamma radiation resistance. The composite was exposed to total gamma doses of 50, 100, and 200 Mrad. Irradiated and baseline samples were tested for tensile strength, hardness and evaluated using FTIR (Fourier transform infrared) spectroscopy and DSC (differential scanning calorimetry) for structural changes. Scanning electron microscopy was used to evaluate microstructural behavior. Mechanical testing of the composite bars revealed no apparent change in modulus, strain to failure, or fracture strength after exposures. However, testing of only the epoxy matrix revealed changes in hardness, thermal properties, and FTIR results with increasing gamma irradiation. The results suggest the epoxy within the composite can be affected by exposure to gamma irradiation.

  3. Graphene quantum dots derived from carbon fibers.

    Science.gov (United States)

    Peng, Juan; Gao, Wei; Gupta, Bipin Kumar; Liu, Zheng; Romero-Aburto, Rebeca; Ge, Liehui; Song, Li; Alemany, Lawrence B; Zhan, Xiaobo; Gao, Guanhui; Vithayathil, Sajna Antony; Kaipparettu, Benny Abraham; Marti, Angel A; Hayashi, Takuya; Zhu, Jun-Jie; Ajayan, Pulickel M

    2012-02-08

    Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1-4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1-3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications.

  4. Controlled chemical stabilization of polyvinyl precursor fiber, and high strength carbon fiber produced therefrom

    Science.gov (United States)

    Naskar, Amit K.

    2016-12-27

    Method for the preparation of carbon fiber, which comprises: (i) immersing functionalized polyvinyl precursor fiber into a liquid solution having a boiling point of at least 60.degree. C.; (ii) heating the liquid solution to a first temperature of at least 25.degree. C. at which the functionalized precursor fiber engages in an elimination-addition equilibrium while a tension of at least 0.1 MPa is applied to the fiber; (iii) gradually raising the first temperature to a final temperature that is at least 20.degree. C. above the first temperature and up to the boiling point of the liquid solution for sufficient time to convert the functionalized precursor fiber to a pre-carbonized fiber; and (iv) subjecting the pre-carbonized fiber produced according to step (iii) to high temperature carbonization conditions to produce the final carbon fiber. Articles and devices containing the fibers, including woven and non-woven mats or paper forms of the fibers, are also described.

  5. Carbon nanotubes on carbon fibers: Synthesis, structures and properties

    Science.gov (United States)

    Zhang, Qiuhong

    The interface between carbon fibers (CFs) and the resin matrix in traditional high performance composites is characterized by a large discontinuity in mechanical, electrical, and thermal properties which can cause inefficient energy transfer. Due to the exceptional properties of carbon nanotubes (CNTs), their growth at the surface of carbon fibers is a promising approach to controlling interfacial interactions and achieving the enhanced bulk properties. However, the reactive conditions used to grow carbon nanotubes also have the potential to introduce defects that can degrade the mechanical properties of the carbon fiber (CF) substrate. In this study, using thermal chemical vapor deposition (CVD) method, high density multi-wall carbon nanotubes have been successfully synthesized directly on PAN-based CF surface without significantly compromising tensile properties. The influence of CVD growth conditions on the single CF tensile properties and carbon nanotube (CNT) morphology was investigated. The experimental results revealed that under high temperature growth conditions, the tensile strength of CF was greatly decreased at the beginning of CNT growth process with the largest decrease observed for sized CFs. However, the tensile strength of unsized CFs with CNT was approximately the same as the initial CF at lower growth temperature. The interfacial shear strength of CNT coated CF (CNT/CF) in epoxy was studied by means of the single-fiber fragmentation test. Results of the test indicate an improvement in interfacial shear strength with the addition of a CNT coating. This improvement can most likely be attributed to an increase in the interphase yield strength as well as an improvement in interfacial adhesion due to the presence of the nanotubes. CNT/CF also offers promise as stress and strain sensors in CF reinforced composite materials. This study investigates fundamental mechanical and electrical properties of CNT/CF using nanoindentation method by designed

  6. Aligning carbon fibers in micro-extruded composite ink

    Science.gov (United States)

    Mahajan, Chaitanya G.

    Direct write processes include a wide range of additive manufacturing techniques with the ability to fabricate structures directly onto planar and non-planar surfaces. Most additive manufacturing techniques use unreinforced polymers to produce parts. By adding carbon fiber as a reinforcing material, properties such as mechanical strength, electrical conductivity, and thermal conductivity can be enhanced. Carbon fibers can be long and continuous, or short and discontinuous. The strength of carbon fiber composite parts is greatly increased when the fibers are preferentially aligned. This research focuses on increasing the strength of additively manufactured parts reinforced using discontinuous carbon fibers that have been aligned during the micro extrusion process. A design of experiments (DOE) approach was used to identify significant process parameters affecting fiber alignment. Factors such as the length of carbon fibers, nozzle diameter, fiber loading fraction, air pressure, translational speed and standoff distance were considered. A two dimensional Fast Fourier Transform (2D FFT) was used to quantify the degree of fiber alignment in the extruded composite inks. ImageJ software supported by an oval profile plugin was used with micrographs of printed samples to obtain the carbon fiber alignment values. The optimal value for the factors was derived by identifying the significant main and interaction effects. Based on the results of the DOE, tensile test samples were printed with fibers aligned parallel and perpendicular to the tensile axis. A standard test method for tensile properties of plastic revealed that the extruded parts with fibers aligned along the tensile axis were better in tensile strength and modulus.

  7. The preparation, properties and application of carbon fibers for SPME.

    Science.gov (United States)

    Gierak, A; Seredych, M; Bartnicki, A

    2006-07-15

    The conditions of preparation of new types of carbon fibers for solid phase micro extraction (SPME) prepared by methylene chloride pyrolysis (at 600 degrees C) on the quartz fiber (100 microm) as well as by supporting synthetic active carbon (prepared especially for this purposes) supported in a special epoxide-acrylic polymer is described. The properties of such carbon fibers for SPME were defined by determination of the partition coefficient of the tested substances (i.e., benzene, toluene, xylenes, trichloromethane and tetrachloromethane) and by the microscopic investigations with the application of the optical and scanning electron microscope. The obtained carbon SPME fibers were applied to the analysis of some volatile organic compounds from its aqueous matrix. During chromatographic GC test, at the investigated SPME carbon fibers, we obtained different but mostly high partition coefficients for the determined compounds (Kfs from 120 for trichloromethane up to 11,500 for tetrachloromethane). Owing to the high partition coefficients of the studied substances obtained on carbon fibers, it was possible to do the analysis of organic substances occurring in trace amounts in different matrices. In this paper, we present the analysis of BTX contents in the petrol analyzed with the application carbonized with CH(2)Cl(2) SPME fiber (C1NM) and a headspace over the petrol sample (concentration of each BTX approximately g/dm(3)).

  8. Activated Carbon Fibers For Gas Storage

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, Timothy D [ORNL; Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL

    2017-01-01

    The advantages of Activated Carbon Fibers (ACF) over Granular Activated Carbon (GAC) are reviewed and their relationship to ACF structure and texture are discussed. These advantages make ACF very attractive for gas storage applications. Both adsorbed natural gas (ANG) and hydrogen gas adsorption performance are discussed. The predicted and actual structure and performance of lignin-derived ACF is reviewed. The manufacture and performance of ACF derived monolith for potential automotive natural gas (NG) storage applications is reported Future trends for ACF for gas storage are considered to be positive. The recent improvements in NG extraction coupled with the widespread availability of NG wells means a relatively inexpensive and abundant NG supply in the foreseeable future. This has rekindled interest in NG powered vehicles. The advantages and benefit of ANG compared to compressed NG offer the promise of accelerated use of ANG as a commuter vehicle fuel. It is to be hoped the current cost hurdle of ACF can be overcome opening ANG applications that take advantage of the favorable properties of ACF versus GAC. Lastly, suggestions are made regarding the direction of future work.

  9. A single carbon fiber microelectrode with branching carbon nanotubes for bioelectrochemical processes.

    Science.gov (United States)

    Zhao, Xueyan; Lu, Xin; Tze, William T Y; Wang, Ping

    2010-06-15

    Carbon fiber electrodes are greatly promising for microelectronic applications including high performance biosensors, miniaturized transmitters, and energy storage and generation devices. For biosensor applications, one drawback of using carbon fiber microelectrodes, especially single fiber electrodes, is the weak electronic signals, a consequence of low surface area of fibers, which ultimately limit the sensitivity of the sensors. In this paper, we report a novel single fiber microelectrode with branched carbon nanotubes for enhanced sensing performance. The fiber microelectrode was prepared from carbonization of cellulose fibers. Upon introduction of carbon nanotubes, the carbon fibers exhibited a significant increase in the specific surface area from carbon nanotubes enhanced the redox reactions on surfaces of the electrode by reducing the oxidation potential of NAD(H) from 0.8 to 0.55 V. The single carbon fiber with branched nanotubes was also examined for the detection of glycerol, and the results showed linear responding signals in a concentration range of 40-250 microM. These results are comparable to the properties of fossil-based carbon materials, and thus our cellulose-based carbon electrodes provide a potentially sustainable alternative in bioelectrochemical applications.

  10. [Carbon fiber-reinforced plastics as implant materials].

    Science.gov (United States)

    Bader, R; Steinhauser, E; Rechl, H; Siebels, W; Mittelmeier, W; Gradinger, R

    2003-01-01

    Carbon fiber-reinforced plastics have been used clinically as an implant material for different applications for over 20 years.A review of technical basics of the composite materials (carbon fibers and matrix systems), fields of application,advantages (e.g., postoperative visualization without distortion in computed and magnetic resonance tomography), and disadvantages with use as an implant material is given. The question of the biocompatibility of carbon fiber-reinforced plastics is discussed on the basis of experimental and clinical studies. Selected implant systems made of carbon composite materials for treatments in orthopedic surgery such as joint replacement, tumor surgery, and spinal operations are presented and assessed. Present applications for carbon fiber reinforced plastics are seen in the field of spinal surgery, both as cages for interbody fusion and vertebral body replacement.

  11. Increasing the Tensile Property of Unidirectional Carbon/Carbon Composites by Grafting Carbon Nanotubes onto Carbon Fibers by Electrophoretic Deposition

    Institute of Scientific and Technical Information of China (English)

    Qiang Song; Kezhi Li; Hejun Li; Qiangang Fu

    2013-01-01

    Although in-situ growing carbon nanotubes (CNTs) on carbon fibers could greatly increase the matrix-dominated mechanical properties of carbon/carbon composites (C/Cs),it always decreased the tensile strength of carbon fibers.In this work,CNTs were introduced into unidirectional carbon fiber (CF) preforms by electrophoretic deposition (EPD) and they were used to reinforce C/Cs.Effects of the content of CNTs introduced by EPD on tensile property of unidirectional C/Cs were investigated.Results demonstrated that EPD could be used as a simple and efficient method to fabricate carbon nanotube reinforced C/Cs (CNT-C/Cs) with excellent tensile strength,which pays a meaningful way to maximize the global performance of CNT-C/Cs.

  12. High-resolution NMR spectra of n-alkanes penetrating into carbon fibers and of protons in carbon fibers.

    Science.gov (United States)

    Yamazaki, Yuya; Kobayashi, Nobuaki; Nikki, Kunio; Kuwahara, Daisuke

    2008-08-01

    We present a simple NMR method for microscopically exploring the local environment in carbon fibers. The method utilizes n-alkanes as probe molecules, where the n-alkanes penetrate carbon fibers of interest. The high-resolution (1)H NMR spectra for a mixture of a carbon fiber and n-alkanes acquired by this method show a shift of the resonance line, which is due to the local structure of the fiber. The utility of this method is discussed on the basis of the (1)H NMR spectra obtained. In addition, the (1)H distribution and the local motion in the structure of the carbon fiber are revealed in view of the (1)H NMR spectra.

  13. Global Carbon Fiber Composites. Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Warren, Joshua A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); West, Devin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schexnayder, Susan M. [Univ. of Tennessee, Knoxville, TN (United States)

    2016-05-01

    The objective of this study is to identify key opportunities in the carbon fiber (CF) supply chain where resources and investments can help advance the clean energy economy. The report focuses on four application areas—wind energy, aerospace, automotive, and pressure vessels—that top the list of industries using CF and carbon fiber reinforced polymers (CFRP) and are particularly relevant to the mission of U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE EERE). For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components.

  14. Electrical Conductivity of the Carbon Fiber Conductive Concrete

    Institute of Scientific and Technical Information of China (English)

    HOU Zuofu; LI Zhuoqiu; WANG Jianjun

    2007-01-01

    This paper discussed two methods to enhance the electrical conductivity of the carbon fiber(CF) electrically conductive concrete. The increase in the content of stone and the amount of water used to dissolve the methylcellulose and marinate the carbon fibers can decrease the electrical resistivity of the electrically conductive concrete effectively. Based on these two methods, the minimum CF content of the CF electrically conductive concrete for deicing or snow-melting application and the optimal ratio of the amount of water to dissolve the methylcellulose and marinate the carbon fibers were obtained.

  15. Characteristics of Resistivity-temperature for Carbon Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The resistance response to temperature change of carbon fiber reinforced cement-based composites (CFRC) is reported, which shows some outstanding phenomena of positive temperature coefficient (PTC) of resistance and negative temperature coefficient (NTC) of resistance during the temperature rising.The influences of carbon fiber, cement-based matrix and thermal cycles on the characteristics of temperature-resistivity for the system were also discussed.Because of the special characteristics for temperature resistivity, carbon fiber cement based composites can be useful in structure with the function of alarm for fire.

  16. Carbon Fiber and Tungsten Disulfide Nanoscale Architectures for Armor Applications

    Science.gov (United States)

    2012-06-01

    carbon nanotubes are usually only microns in length, it is possible to spin the fibers into a yarn that maintains much of the theoretical strength of the...4 a. Carbon Nanotubes and Nanofibers ..........................................4 b. Tungsten Disulfide...7 II. CARBON NANOFIBER AND WS2 NANOPARTICLE SYNTHESIS AND CHARACTERIZATION METHODS

  17. Oxidation of Carbon Fibers in Water Vapor Studied

    Science.gov (United States)

    Opila, Elizabeth J.

    2003-01-01

    T-300 carbon fibers (BP Amoco Chemicals, Greenville, SC) are a common reinforcement for silicon carbide composite materials, and carbon-fiber-reinforced silicon carbide composites (C/SiC) are proposed for use in space propulsion applications. It has been shown that the time to failure for C/SiC in stressed oxidation tests is directly correlated with the fiber oxidation rate (ref. 1). To date, most of the testing of these fibers and composites has been conducted in oxygen or air environments; however, many components for space propulsion, such as turbopumps, combustors, and thrusters, are expected to operate in hydrogen and water vapor (H2/H2O) environments with very low oxygen contents. The oxidation rate of carbon fibers in conditions representative of space propulsion environments is, therefore, critical for predicting component lifetimes for real applications. This report describes experimental results that demonstrate that, under some conditions, lower oxidation rates of carbon fibers are observed in water vapor and H2/H2O environments than are found in oxygen or air. At the NASA Glenn Research Center, the weight loss of the fibers was studied as a function of water pressure, temperature, and gas velocity. The rate of carbon fiber oxidation was determined, and the reaction mechanism was identified.

  18. Interactions between the glass fiber coating and oxidized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ku-Herrera, J.J., E-mail: jesuskuh@live.com.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Nistal, A. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Cauich-Rodríguez, J.V. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Rubio, F.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Bartolo-Pérez, P. [Departamento de Física Aplicada, Cinvestav, Unidad Mérida, C.P., 97310 Mérida, Yucatán (Mexico)

    2015-03-01

    Graphical abstract: - Highlights: • Oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto E-glass fibers. • The role of the fiber coating on the deposition of MWCNTs on the fibers is studied. • A rather homogeneous deposition of MWCNTs is achieved if the coating is maintained. • Multiple oxygen-containing groups were found in the analysis of the fiber coating. • Evidence of chemical interaction between MWCNTs and the fiber coating was found. - Abstract: Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as “sizing”), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

  19. The Tensile Behavior of High-Strength Carbon Fibers.

    Science.gov (United States)

    Langston, Tye

    2016-08-01

    Carbon fibers exhibit exceptional properties such as high stiffness and specific strength, making them excellent reinforcements for composite materials. However, it is difficult to directly measure their tensile properties and estimates are often obtained by tensioning fiber bundles or composites. While these macro scale tests are informative for composite design, their results differ from that of direct testing of individual fibers. Furthermore, carbon filament strength also depends on other variables, including the test length, actual fiber diameter, and material flaw distribution. Single fiber tensile testing was performed on high-strength carbon fibers to determine the load and strain at failure. Scanning electron microscopy was also conducted to evaluate the fiber surface morphology and precisely measure each fiber's diameter. Fiber strength was found to depend on the test gage length and in an effort to better understand the overall expected performance of these fibers at various lengths, statistical weak link scaling was performed. In addition, the true Young's modulus was also determined by taking the system compliance into account. It was found that all properties (tensile strength, strain to failure, and Young's modulus) matched very well with the manufacturers' reported values at 20 mm gage lengths, but deviated significantly at other lengths.

  20. STUDY OF DEPENDENCE OF POLYETHYLENE AND CARBON FIBERS COMPOSITES PROPERNIES ON SURFACE CHARACTERISTICS OF FIBER AND TYPE OF SAMPLES

    Directory of Open Access Journals (Sweden)

    Petukhova E. S.

    2015-06-01

    Full Text Available PE2NT11 and chopped carbon fibers and PE2NT11 and modified carbon fibers composites were investigated. It was shown that the mechanical properties depend on the surface characteristics of fibers. It was found that laboratory and tube samples have some difference in mechanical properties that connected with specific distribution of fibers in samples

  1. STUDY OF DEPENDENCE OF POLYETHYLENE AND CARBON FIBERS COMPOSITES PROPERNIES ON SURFACE CHARACTERISTICS OF FIBER AND TYPE OF SAMPLES

    OpenAIRE

    Petukhova E. S.

    2015-01-01

    PE2NT11 and chopped carbon fibers and PE2NT11 and modified carbon fibers composites were investigated. It was shown that the mechanical properties depend on the surface characteristics of fibers. It was found that laboratory and tube samples have some difference in mechanical properties that connected with specific distribution of fibers in samples

  2. Autonomic healing of carbon fiber/epoxy interfaces.

    Science.gov (United States)

    Jones, Amanda R; Cintora, Alicia; White, Scott R; Sottos, Nancy R

    2014-05-14

    A maximum of 91% recovery of interfacial shear strength (IFSS) is achieved for carbon fiber/epoxy interfaces functionalized with capsules containing reactive epoxy resin and ethyl phenyl acetate (EPA). We find a binder is necessary to improve the retention of capsules on the carbon fiber surface. Two different methods for applying the binder to the carbon fiber surface are investigated. Healing efficiency is assessed by recovery of IFSS of a single functionalized fiber embedded in a microdroplet of epoxy. Debonding of the fiber/matrix interface ruptures the capsules, releasing resin and EPA solvent into the crack plane. The solvent swells the matrix, initiating transport of residual amine functionality from the matrix for further curing with the epoxy resin delivered to the crack plane. The two binder protocols produce comparable results, both yielding higher recovery of IFSS than samples prepared without a binder.

  3. Influence of Carbon Fiber Contents on the Temperature Sensibility of CFRC Road Material

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The relationship between the electrical resistivity of carbon fiber reinforced concrete(CFRC) containing different carbon fiber contents and temperature was studied.it is found that carbon fiber contents influence greatly on the temperature sensibility of CFRC road material.Only with a certain amount of carbon fiber can CFRC show a sensitive and stable temperature sensibility.

  4. The surface properties of carbon fibers and their adhesion to organic polymers

    Science.gov (United States)

    Bascom, W. D.; Drzal, L. T.

    1987-01-01

    The state of knowledge of the surface properties of carbon fibers is reviewed, with emphasis on fiber/matrix adhesion in carbon fiber reinforced plastics. Subjects treated include carbon fiber structure and chemistry, techniques for the study of the fiber surface, polymer/fiber bond strength and its measurement, variations in polymer properties in the interphase, and the influence of fiber matrix adhesion on composite mechanical properties. Critical issues are summarized and search recommendations are made.

  5. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Warren, Josh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); West, Devin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schexnayder, Susan M. [Univ. of Tennessee, Knoxville, TN (United States)

    2016-05-01

    This study identifies key opportunities in the carbon fiber supply chain where the United States Department of Energy's Office of Energy Efficiency and Renewable Energy resources and investments can help the United States achieve or maintain a competitive advantage. The report focuses on four application areas--wind energy, aerospace, automotive, and pressure vessels--that top the list of industries using carbon fiber and carbon fiber reinforced polymers and are also particularly relevant to EERE's mission. For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components, all contributing to a competitiveness assessment that addresses the United States' role in future industry growth. This report was prepared by researchers at Oak Ridge National Laboratory and the University of Tennessee for the Clean Energy Manufacturing Analysis Center.

  6. Experimental Study on Electric Properties of Carbon Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the phenomenon that the physical properties have a great effect on the electric capability of carbon fiber reinforced concrete, the author researched the relationship between DC resistance of carbon fiber reinforced concrete and curing age using the two-probe method. Then the effect of insulative area,location and quantity on DC resistance of carbon fiber reinforced concrete was investigated at different curing age with analysis of hydration. The results suggest that DC resistance increases greatly with its curing age, which illustrates the relationship like Gaussian curve. In every curing ages the electric capability of carbon fiber reinforced concrete weakenes with the increase of insulative area. In same curing ages, section and insulative area, the more the quantity of insulation, the stronger the conductibility. The insulative location in optimal position can only result in optimal conductibility.

  7. Effect of carbon fiber on calcium phosphate bone cement

    Institute of Scientific and Technical Information of China (English)

    戴红莲; 王欣宇; 黄健; 闫玉华; 李世普

    2004-01-01

    The calcium phosphate cement (α-TCP/TTCP) was reinforced with oxidation-treated carbon fibers. The effect of aspect ratio and content of carbon fiber on the compression strength and bending strength of the hardened body was discussed. The results show that the reinforcing effect is optimal as the aspect ratio is 375 and the additive amount is 0.3% (mass fraction). Under this condition, the compressive strength is increased by 55% (maximum 63.46 MPa), and the bending strength is nearly increased by 100% (maximum 11.95 MPa), respectively. However, if the additive quantity and aspect ratio are too high, the effect of the carbon fibers is limited because it can not be dispersed uniformly in the hardened body. The biological evaluation indicates that the calcium phosphate cement reinforced by carbon fibers has good biocompatibility.

  8. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Uicab, O. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Yazdani-Pedram, M. [Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, S. Livingstone 1007, Independencia, Santiago (Chile); Toro, P. [Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Beauchef 850, Santiago (Chile); Gamboa, F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, Km. 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán (Mexico); Mazo, M.A.; Nistal, A.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain)

    2016-11-01

    Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO{sub 3}/H{sub 2}SO{sub 4} reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  9. Carbon-fiber composite molecular sieves for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G.; Fei, Y.Q. [Univ. of Kentucky Center for Applied Energy Research, Lexington, KY (United States)

    1995-08-01

    The progress of research in the development of novel, rigid, monolithic adsorbent carbon fiber composites is described. Carbon fiber composites are produced at ORNL and activated at the CAER using steam or CO{sub 2} under different conditions, with the aims of producing a uniform degree of activation through the material, and of closely controlling pore structure and adsorptive properties The principal focus of the work to date has been to produce materials with narrow porosity for use in gas separations.

  10. Chronic in vivo stability assessment of carbon fiber microelectrode arrays

    Science.gov (United States)

    Patel, Paras R.; Zhang, Huanan; Robbins, Matthew T.; Nofar, Justin B.; Marshall, Shaun P.; Kobylarek, Michael J.; Kozai, Takashi D. Y.; Kotov, Nicholas A.; Chestek, Cynthia A.

    2016-12-01

    Objective. Individual carbon fiber microelectrodes can record unit activity in both acute and semi-chronic (∼1 month) implants. Additionally, new methods have been developed to insert a 16 channel array of carbon fiber microelectrodes. Before assessing the in vivo long-term viability of these arrays, accelerated soak tests were carried out to determine the most stable site coating material. Next, a multi-animal, multi-month, chronic implantation study was carried out with carbon fiber microelectrode arrays and silicon electrodes. Approach. Carbon fibers were first functionalized with one of two different formulations of PEDOT and subjected to accelerated aging in a heated water bath. After determining the best PEDOT formula to use, carbon fiber arrays were chronically implanted in rat motor cortex. Some rodents were also implanted with a single silicon electrode, while others received both. At the end of the study a subset of animals were perfused and the brain tissue sliced. Tissue sections were stained for astrocytes, microglia, and neurons. The local reactive responses were assessed using qualitative and quantitative methods. Main results. Electrophysiology recordings showed the carbon fibers detecting unit activity for at least 3 months with average amplitudes of ∼200 μV. Histology analysis showed the carbon fiber arrays with a minimal to non-existent glial scarring response with no adverse effects on neuronal density. Silicon electrodes showed large glial scarring that impacted neuronal counts. Significance. This study has validated the use of carbon fiber microelectrode arrays as a chronic neural recording technology. These electrodes have demonstrated the ability to detect single units with high amplitude over 3 months, and show the potential to record for even longer periods. In addition, the minimal reactive response should hold stable indefinitely, as any response by the immune system may reach a steady state after 12 weeks.

  11. Nanowire modified carbon fibers for enhanced electrical energy storage

    Science.gov (United States)

    Shuvo, Mohammad Arif Ishtiaque; (Bill) Tseng, Tzu-Liang; Ashiqur Rahaman Khan, Md.; Karim, Hasanul; Morton, Philip; Delfin, Diego; Lin, Yirong

    2013-09-01

    The study of electrochemical super-capacitors has become one of the most attractive topics in both academia and industry as energy storage devices because of their high power density, long life cycles, and high charge/discharge efficiency. Recently, there has been increasing interest in the development of multifunctional structural energy storage devices such as structural super-capacitors for applications in aerospace, automobiles, and portable electronics. These multifunctional structural super-capacitors provide structures combining energy storage and load bearing functionalities, leading to material systems with reduced volume and/or weight. Due to their superior materials properties, carbon fiber composites have been widely used in structural applications for aerospace and automotive industries. Besides, carbon fiber has good electrical conductivity which will provide lower equivalent series resistance; therefore, it can be an excellent candidate for structural energy storage applications. Hence, this paper is focused on performing a pilot study for using nanowire/carbon fiber hybrids as building materials for structural energy storage materials; aiming at enhancing the charge/discharge rate and energy density. This hybrid material combines the high specific surface area of carbon fiber and pseudo-capacitive effect of metal oxide nanowires, which were grown hydrothermally in an aligned fashion on carbon fibers. The aligned nanowire array could provide a higher specific surface area that leads to high electrode-electrolyte contact area thus fast ion diffusion rates. Scanning Electron Microscopy and X-Ray Diffraction measurements are used for the initial characterization of this nanowire/carbon fiber hybrid material system. Electrochemical testing is performed using a potentio-galvanostat. The results show that gold sputtered nanowire carbon fiber hybrid provides 65.9% higher energy density than bare carbon fiber cloth as super-capacitor.

  12. Ultrafine microporous and mesoporous activated carbon fibers from alkali lignin

    OpenAIRE

    2013-01-01

    A facile and sustainable approach has been successfully devised to fabricate ultrafine (100-500 nm) highly porous activated carbon fibers (ACFs) by electrospinning of aqueous solutions of predominantly alkali lignin (low sulfonate content) followed by simultaneous carbonization and activation at 850 °C under N2. Incorporating a polyethylene oxide (PEO) carrier with only up to one ninth of lignin not only enabled efficient electrospinning into fibers but also retained fibrous structures during...

  13. ADSORPTION OF DYES ON ACTIVATED CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    ChenShuixia; WuChangqing; 等

    1998-01-01

    The adsorption behavior of dyes on a variety of sisal based activated carbon fibers (SACF) has been studied in this paper. The results show that this kind of ACF has excellent adsorption capacities for some organic (dye) molecules.SACF can remove nearly all methylene blue,crystal violet,bromophenol blue and Eriochrome blue black R from water after static adsorption for 24h. at 30℃. The adsorption amounts can reach more than 400mg/g when adding 50 mg SACF into 50 ml dye solution.Under the same conditions,the adsorption amounts of xylenol orange fluorescein and Eriochrome black T wree lower.On the other hand,the adsorption amounts change along with the characteristics of adsorbents.The SACFs activated above 840℃,which have higher specific surface areas and wider pore radii,have higher adsorption amounts for the dyes.The researching results also show that the adsorption rates of dyes onto SACFs decrease by the order of methylene blue,Eriochrome blue black R and crystal violet.

  14. Tensile Properties of Polyimide Composites Incorporating Carbon Nanotubes-Grafted and Polyimide-Coated Carbon Fibers

    Science.gov (United States)

    Naito, Kimiyoshi

    2014-09-01

    The tensile properties and fracture behavior of polyimide composite bundles incorporating carbon nanotubes-grafted (CNT-grafted) and polyimide-coated (PI-coated) high-tensile-strength polyacrylonitrile (PAN)-based (T1000GB), and high-modulus pitch-based (K13D) carbon fibers were investigated. The CNT were grown on the surface of the carbon fibers by chemical vapor deposition. The pyromellitic dianhydride/4,4'-oxydianiline PI nanolayer coating was deposited on the surface of the carbon fiber by high-temperature vapor deposition polymerization. The results clearly demonstrate that CNT grafting and PI coating were effective for improving the Weibull modulus of T1000GB PAN-based and K13D pitch-based carbon fiber bundle composites. In addition, the average tensile strength of the PI-coated T1000GB carbon fiber bundle composites was also higher than that of the as-received carbon fiber bundle composites, while the average tensile strength of the CNT-grafted T1000GB, K13D, and the PI-coated K13D carbon fiber bundle composites was similar to that of the as-received carbon fiber bundle composites.

  15. Carbon fiber enhanced bioelectricity generation in soil microbial fuel cells.

    Science.gov (United States)

    Li, Xiaojing; Wang, Xin; Zhao, Qian; Wan, Lili; Li, Yongtao; Zhou, Qixing

    2016-11-15

    The soil microbial fuel cell (MFC) is a promising biotechnology for the bioelectricity recovery as well as the remediation of organics contaminated soil. However, the electricity production and the remediation efficiency of soil MFC are seriously limited by the tremendous internal resistance of soil. Conductive carbon fiber was mixed with petroleum hydrocarbons contaminated soil and significantly enhanced the performance of soil MFC. The maximum current density, the maximum power density and the accumulated charge output of MFC mixed carbon fiber (MC) were 10, 22 and 16 times as high as those of closed circuit control due to the carbon fiber productively assisted the anode to collect the electron. The internal resistance of MC reduced by 58%, 83% of which owed to the charge transfer resistance, resulting in a high efficiency of electron transfer from soil to anode. The degradation rates of total petroleum hydrocarbons enhanced by 100% and 329% compared to closed and opened circuit controls without the carbon fiber respectively. The effective range of remediation and the bioelectricity recovery was extended from 6 to 20cm with the same area of air-cathode. The mixed carbon fiber apparently enhanced the bioelectricity generation and the remediation efficiency of soil MFC by means of promoting the electron transfer rate from soil to anode. The use of conductively functional materials (e.g. carbon fiber) is very meaningful for the remediation and bioelectricity recovery in the bioelectrochemical remediation.

  16. Carbon fiber reinforced thermoplastic composites for future automotive applications

    Science.gov (United States)

    Friedrich, K.

    2016-05-01

    After a brief introduction to polymer composite properties and markets, the state of the art activities in the field of manufacturing of advanced composites for automotive applications are elucidated. These include (a) long fiber reinforced thermoplastics (LFT) for secondary automotive components, and (b) continuous carbon fiber reinforced thermosetting composites for car body applications. It is followed by future possibilities of carbon fiber reinforced thermoplastic composites for e.g. (i) crash elements, (ii) racing car seats, and (iii) production and recycling of automotive fenders.

  17. CARBONIZED STARCH MICROCELLULAR FOAM-CELLULOSE FIBER COMPOSITE STRUCTURES

    Directory of Open Access Journals (Sweden)

    Andrew R. Rutledge

    2008-11-01

    Full Text Available The production of microporous carbon foams from renewable starch microcellular foam-fiber (SMCF-Fiber composites is described. Carbon foams are used in applications such as thermal insulation, battery electrodes, filters, fuel cells, and medical devices. SMCF-Fiber compos-ites were created from an aquagel. The water in the aquagel was exchanged with ethanol and then dried and carbonized. Higher amylose content starches and fiber contents of up to 4% improved the processability of the foam. The SMCF structure revealed agglomerates of swollen starch granules connected by a web of starch with pores in the 50-200 nanometer range. Heating the SMCF-fiber in a nitrogen atmosphere to temperatures between 350-700˚C produced carbon foams with a three-dimensional closed cell foam structure with cell diameters around 50 microns and pore walls around 1-3 microns. The stress versus strain compression data for carbonized samples displayed a linear elastic region and a plateau indicative of brittle crushing, typical of an elastic-brittle foam. The carbon foam products from these renew-able precursors are promising carbon structures with moderate strength and low density.

  18. Synthesis of subnanometer-diameter vertically aligned single-walled carbon nanotubes with copper-anchored cobalt catalysts

    Science.gov (United States)

    Cui, Kehang; Kumamoto, Akihito; Xiang, Rong; An, Hua; Wang, Benjamin; Inoue, Taiki; Chiashi, Shohei; Ikuhara, Yuichi; Maruyama, Shigeo

    2016-01-01

    We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high-quality SWNTs are expected to pave the way to replace silicon for next-generation optoelectronic and photovoltaic devices.We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high

  19. Carbon fiber dispersion models used for risk analysis calculations

    Science.gov (United States)

    1979-01-01

    For evaluating the downwind, ground level exposure contours from carbon fiber dispersion, two fiber release scenarios were chosen. The first is the fire and explosion release in which all of the fibers are released instantaneously. This model applies to accident scenarios where an explosion follows a short-duration fire in the aftermath of the accident. The second is the plume release scenario in which the total mass of fibers is released into the fire plume. This model applies to aircraft accidents where only a fire results. These models are described in detail.

  20. The Carbon Nanotube Fibers for Optoelectric Conversion and Energy Storage

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo

    2014-01-01

    Full Text Available This review summarizes recent studies on carbon nanotube (CNT fibers for weavable device of optoelectric conversion and energy storage. The intrinsic properties of individual CNTs make the CNT fibers ideal candidates for optoelectric conversion and energy storage. Many potential applications such as solar cell, supercapacitor, and lithium ion battery have been envisaged. The recent advancement in CNT fibers for optoelectric conversion and energy storage and the current challenge including low energy conversion efficiency and low stability and future direction of the energy fiber have been finally summarized in this paper.

  1. Influence of carbon nanotubes coatings onto carbon fiber by oxidative treatments combined with electrophoretic deposition on interfacial properties of carbon fiber composite

    Science.gov (United States)

    Deng, Chao; Jiang, Jianjun; Liu, Fa; Fang, Liangchao; Wang, Junbiao; Li, Dejia; Wu, Jianjun

    2015-12-01

    To improve the interfacial performance of carbon fiber (CF) and epoxy resin, carbon nanotubes (CNTs) coatings were utilized to achieve this purpose through coating onto CF by the treatment with hydrogen peroxide and concentrated nitric acid combined with electrophoretic deposition (EPD) process. The influence of electrophoretically deposited CNTs coatings on the surface properties of CFs were investigated by Fourier transform infrared spectrometer, atomic force microscopy, scanning electron microscopy and dynamic contact angle analysis. The results indicated that the deposition of carbon nanotubes introduced some polar groups to carbon fiber surfaces, enhanced surface roughness and changed surface morphologies of carbon fibers. Surface wettability of carbon fibers may be significantly improved by increasing surface free energy of the fibers due to the deposition of CNTs. The thickness and density of the coatings increases with the introduction of pretreatment of the CF during the EPD process. Short beam shear test was performed to examine the effect of carbon fiber functionalization on mechanical properties of the carbon fiber/epoxy resin composites. The interfacial adhesion of CNTs/CF reinforced epoxy composites showed obvious enhancement of interlaminar shear strength by 60.2% and scanning electron microscope photographs showed that the failure mode of composites was changed after the carbon fibers were coated with CNTs.

  2. Mechanical properties of carbon fiber composites for environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, R.; Grulke, E. [Univ. of Kentucky, Lexington, KY (United States)

    1996-10-01

    Activated carbon fiber composites show great promise as fixed-bed catalytic reactors for use in environmental applications such as flue gas clean-up and ground water decontamination. A novel manufacturing process produces low density composites from chopped carbon fibers and binders. These composites have high permeability, can be activated to have high surface area, and have many potential environmental applications. This paper reports the mechanical and flow properties of these low density composites. Three point flexural strength tests were used to measure composite yield strength and flexural moduli. Composites containing over 10 pph binder had an adequate yield strength of about 200 psi at activations up to 40% weight loss. The composites were anisotropic, having along-fiber to cross-fiber yield strength ratios between 1.2 and 2.0. The friction factor for flow through the composites can be correlated using the fiber Reynolds number, and is affected by the composite bulk density.

  3. Multiscale carbon nanotube-carbon fiber reinforcement for advanced epoxy composites.

    Science.gov (United States)

    Bekyarova, E; Thostenson, E T; Yu, A; Kim, H; Gao, J; Tang, J; Hahn, H T; Chou, T-W; Itkis, M E; Haddon, R C

    2007-03-27

    We report an approach to the development of advanced structural composites based on engineered multiscale carbon nanotube-carbon fiber reinforcement. Electrophoresis was utilized for the selective deposition of multi- and single-walled carbon nanotubes (CNTs) on woven carbon fabric. The CNT-coated carbon fabric panels were subsequently infiltrated with epoxy resin using vacuum-assisted resin transfer molding (VARTM) to fabricate multiscale hybrid composites in which the nanotubes were completely integrated into the fiber bundles and reinforced the matrix-rich regions. The carbon nanotube/carbon fabric/epoxy composites showed approximately 30% enhancement of the interlaminar shear strength as compared to that of carbon fiber/epoxy composites without carbon nanotubes and demonstrate significantly improved out-of-plane electrical conductivity.

  4. SURFACE MORPHOLOGY OF CARBON FIBER POLYMER COMPOSITES AFTER LASER STRUCTURING

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Chen, Jian [ORNL; Jones, Jonaaron F. [University of Tennessee (UT); Alexandra, Hackett [University of Tennessee (UT); Jellison Jr, Gerald Earle [ORNL; Daniel, Claus [ORNL; Warren, Charles David [ORNL; Rehkopf, Jackie D. [Plasan Carbon Composites

    2015-01-01

    The increasing use of Carbon Fiber Polymer Composite (CFPC) as a lightweight material in automotive and aerospace industries requires the control of surface morphology. In this study, the composites surface was prepared by ablating the resin in the top fiber layer of the composite using an Nd:YAG laser. The CFPC specimens with T700S carbon fiber and Prepreg - T83 resin (epoxy) were supplied by Plasan Carbon Composites, Inc. as 4 ply thick, 0/90o plaques. The effect of laser fluence, scanning speed, and wavelength was investigated to remove resin without an excessive damage of the fibers. In addition, resin ablation due to the power variation created by a laser interference technique is presented. Optical property measurements, optical micrographs, 3D imaging, and high-resolution optical profiler images were used to study the effect of the laser processing on the surface morphology.

  5. Resistance Responses of Carbon Fiber Cement to Cycled Compressive Stresses

    Institute of Scientific and Technical Information of China (English)

    SHUI Zhonghe; LI Chao; LIAO Weidong

    2005-01-01

    The stress-resistance relationship of carbon fiber cement was studicd. Attention has been paid to explore the improvement of the stress-resistance sensitivity under cycled stress restriction. The prismy carbon fiber cement sensors were pre-fabricated. The factors such as contents of carbon fibers, silica fume, dispersant and the w/ c were taken into account. The electrical resistance variations with the dynamic and static loads were simulated using a strain-controlled test machine. The test results show that there is an optimal fiber content, with which the compression-sensitivity achieves a high level. The addition of silica fume can improve the sensitivity. Urder the optimal test conditions, the measured resistances can greatly correspond with the changes of the load.

  6. Adsorption Properties of Lignin-derived Activated Carbon Fibers (LACF)

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gallego, Nidia C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Thibaud-Erkey, Catherine [United Technologies Research Center (UTRC), East Hartford, CT (United States); Karra, Reddy [United Technologies Research Center (UTRC), East Hartford, CT (United States)

    2016-04-01

    The object of this CRADA project between Oak Ridge National Laboratory (ORNL) and United Technologies Research Center (UTRC) is the characterization of lignin-derived activated carbon fibers (LACF) and determination of their adsorption properties for volatile organic compounds (VOC). Carbon fibers from lignin raw materials were manufactured at Oak Ridge National Laboratory (ORNL) using the technology previously developed at ORNL. These fibers were physically activated at ORNL using various activation conditions, and their surface area and pore-size distribution were characterized by gas adsorption. Based on these properties, ORNL did down-select five differently activated LACF materials that were delivered to UTRC for measurement of VOC adsorption properties. UTRC used standard techniques based on breakthrough curves to measure and determine the adsorption properties of indoor air pollutants (IAP) - namely formaldehyde and carbon dioxide - and to verify the extent of saturated fiber regenerability by thermal treatments. The results are summarized as follows: (1) ORNL demonstrated that physical activation of lignin-derived carbon fibers can be tailored to obtain LACF with surface areas and pore size distributions matching the properties of activated carbon fibers obtained from more expensive, fossil-fuel precursors; (2) UTRC investigated the LACF potential for use in air cleaning applications currently pursued by UTRC, such as building ventilation, and demonstrated their regenerability for CO2 and formaldehyde, (3) Both partners agree that LACF have potential for possible use in air cleaning applications.

  7. Hansen solubility parameters for a carbon fiber/epoxy composite

    DEFF Research Database (Denmark)

    Launay, Helene; Hansen, Charles M.; Almdal, Kristoffer

    2007-01-01

    In this study, the physical affinity between an epoxy matrix and oxidized, unsized carbon fibers has been evaluated using Hansen solubility (cohesion) parameters (HSP). A strong physical compatibility has been shown, since their respective HSP are close. The use of a glassy carbon substrate...

  8. Effect of plasma surface treatment of recycled carbon fiber on carbon fiber-reinforced plastics (CFRP) interfacial properties

    Science.gov (United States)

    Lee, Hooseok; Ohsawa, Isamu; Takahashi, Jun

    2015-02-01

    We studied the effects of plasma surface treatment of recycled carbon fiber on adhesion of the fiber to polymers after various treatment times. Conventional surface treatment methods have been attempted for recycled carbon fiber, but most require very long processing times, which may increase cost. Hence, in this study, plasma processing was performed for 0.5 s or less. Surface functionalization was quantified by X-ray photoelectron spectroscopy. O/C increased from approximately 11% to 25%. The micro-droplet test of adhesion properties and the mechanical properties of CFRP were also investigated.

  9. [Raman spectra of carbon fibers during electrochemical treatment].

    Science.gov (United States)

    Zhang, Min; Zhu, Bo; Wang, Cheng-guo; Wei, Han-xing

    2010-01-01

    Laser Raman spectroscopy was employed to characterize the microstructure variations of polyacrylonitrile-based carbon fibers during electrochemical treatment, and the characteristics of first-order Raman spectra of carbon fibers with different treatment time were investigated in the present paper. The results indicate that the Raman spectra of the carbon fibers can be fitted into four bands, named as D (or D1) band, G band, D2 band and D3 band, respectively. The Raman parameters to characterize surface microstructure variations of carbon fibers mainly include R(I(D2)) / I(G), area ratio of D band and G band), I(D2) / I(G) (area ratio of D2 band and G band), I(D3) / I(G) (area ratio of D3 band and G band), and I(D(S))/ I(G) (area ratio of all the disordered structure and G band). The peak separation between D band and G band becomes large after electrochemical treatment. R increases, which indicates that the surface disordered degree of carbon fibers increases. I(D3) / I(G) increases, which is caused by organic molecules, fragments or functional groups; decreases which is caused by the break of the aliphatic structures. With increasing treatment time, I(D(S)) / I(G) increases continuously, and the change trend of l(D(S)) / I(G) is consistent with that of R value, which can be used to comprehensively explain the variation of the surface structure of carbon fibers. So, the variety rules of the structure of carbon fibers can be investigated by laser Raman spectroscopy during electrochemical treatment.

  10. Effect of plasma surface treatment of recycled carbon fiber on carbon fiber-reinforced plastics (CFRP) interfacial properties

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hooseok, E-mail: hooseok.lee@gmail.com; Ohsawa, Isamu; Takahashi, Jun

    2015-02-15

    Highlights: • Plasma treatment was used to improve the adhesion property between the recycled CF and polymer matrix. • In order to evaluate the adhesion between plasma treated recycled CF and polymer, micro droplet test was conducted. • The interfacial shear strength and the interfacial adhesion of recycled carbon fiber increased. - Abstract: We studied the effects of plasma surface treatment of recycled carbon fiber on adhesion of the fiber to polymers after various treatment times. Conventional surface treatment methods have been attempted for recycled carbon fiber, but most require very long processing times, which may increase cost. Hence, in this study, plasma processing was performed for 0.5 s or less. Surface functionalization was quantified by X-ray photoelectron spectroscopy. O/C increased from approximately 11% to 25%. The micro-droplet test of adhesion properties and the mechanical properties of CFRP were also investigated.

  11. [Raman spectra of PAN-based carbon fibers during graphitization].

    Science.gov (United States)

    Li, Dong-Feng; Wang, Hao-Jing; Wang, Xin-Kui

    2007-11-01

    Laser Raman spectroscopy was employed to characterize the structure of PAN-based carbon fibers during graphitization (2 000-3 000 degrees C), and the spectra of the surface and the cross section of the fibers were compared. The results show that the Raman spectra of the fibers after graphitization can be separated as three bands (D, G and D'). The degree of disorder of the fibers can be measured by Raman spectra parameter, such as the full-widths at half maximum (FWHM) of D and G bands, Raman shift of G band, and the integrated intensity ratio in the form of R(I(D) I(G)). Further investigation demonstrated that the FWHM of D and G bands, Raman shift of G band and the value of R decrease with increasing heat treatment temperature (HTT). The D band can be seen and the value of R is 0.19 even after being heat treated at 3 000 V, indicting that the fibers still have disordered carbons. In addition, the value of R is linearly related to the reciprocal of the basal plane length of the crystallites (L(a)). The spectra of the surface and the cross-section of the fibers after graphitization show obvious difference. So the degree of graphitization and preferred orientation of carbon fibers can be quantitatively characterized by laser Raman spectroscopy.

  12. Use of Carbon Fiber Composite Molecular Sieves for Air Separation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Frederick S [ORNL; Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Burchell, Timothy D [ORNL

    2005-09-01

    A novel adsorbent material, 'carbon fiber composite molecular sieve' (CFCMS), has been developed by the Oak Ridge National Laboratory. Its features include high surface area, large pore volume, and a rigid, permeable carbon structure that exhibits significant electrical conductivity. The unique combination of high adsorptive capacity, permeability, good mechanical properties, and electrical conductivity represents an enabling technology for the development of novel gas separation and purification systems. In this context, it is proposed that a fast-cycle air separation process that exploits a kinetic separation of oxygen and nitrogen should be possible using a CFCMS material coupled with electrical swing adsorption (ESA). The adsorption of O{sub 2}, N{sub 2}, and CO{sub 2} on activated carbon fibers was investigated using static and dynamic techniques. Molecular sieving effects in the activated carbon fiber were highlighted by the adsorption of CO{sub 2}, a more sensitive probe molecule for the presence of microporosity in adsorbents. The kinetic studies revealed that O2 was more rapidly adsorbed on the carbon fiber than N{sub 2}, and with higher uptake under equilibrium conditions, providing the fiber contained a high proportion of very narrow micropores. The work indicated that CFCMS is capable of separating O{sub 2} and N{sub 2} from air on the basis of the different diffusion rates of the two molecules in the micropore network of the activated carbon fibers comprising the composite material. In response to recent enquires from several potential users of CFCMS materials, attention has been given to the development of a viable continuous process for the commercial production of CFCMS material. As part of this effort, work was implemented on characterizing the performance of lignin-based activated carbon fiber, a potentially lower cost fiber than the pitch-based fibers used for CFCMS production to date. Similarly, to address engineering issues

  13. Hydrous ruthenium oxide nanoparticles anchored to graphene and carbon nanotube hybrid foam for supercapacitors.

    Science.gov (United States)

    Wang, Wei; Guo, Shirui; Lee, Ilkeun; Ahmed, Kazi; Zhong, Jiebin; Favors, Zachary; Zaera, Francisco; Ozkan, Mihrimah; Ozkan, Cengiz S

    2014-03-25

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g(-1), areal capacitance: 1.11 F cm(-2)) which leads to an exceptionally high energy density of 39.28 Wh kg(-1) and power density of 128.01 kW kg(-1). The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.

  14. Hydrous ruthenium oxide nanoparticles anchored to graphene and carbon nanotube hybrid foam for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei [Univ. of California, Riverside, CA (United States); Guo, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lee, I. [Univ. of California, Riverside, CA (United States); Ahmed, K. [Univ. of California, Riverside, CA (United States); Zhong, J. [Univ. of California, Riverside, CA (United States); Favors, Z. [Univ. of California, Riverside, CA (United States); Zaera, F. [Univ. of California, Riverside, CA (United States); Ozkan, M. [Univ. of California, Riverside, CA (United States); Ozkan, C. S [Univ. of California, Riverside, CA (United States)

    2014-03-25

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO₂) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO₂ nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g⁻¹, areal capacitance: 1.11 F cm⁻²) which leads to an exceptionally high energy density of 39.28 Wh kg⁻¹ and power density of 128.01 kW kg⁻¹. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.

  15. Processes for preparing carbon fibers using gaseous sulfur trioxide

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Bryan E.; Lysenko, Zenon; Bernius, Mark T.; Hukkanen, Eric J.

    2016-01-05

    Disclosed herein are processes for preparing carbonized polymers, such as carbon fibers, comprising: sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 gas to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of said solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C.

  16. The dynamic response of carbon fiber-filled polymer composites

    Directory of Open Access Journals (Sweden)

    Patterson B.

    2012-08-01

    Full Text Available The dynamic (shock responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE composite to 18.6 GPa in the through-thickness direction, in which the shock propagates normal to the fibers. The data are best represented by a linear Rankine-Hugoniot fit: Us = 2.87 + 1.17 ×up(ρ0 = 1.536g/cm3. The shock wave structures were found to be highly heterogeneous, both due to the anisotropic nature of the fiber-epoxy microstructure, and the high degree of void volume. Plate impact experiments were also performed on a carbon fiber-filled phenolic (CP composite to much higher shock input pressures, exceeding the reactants-to-products transition common to polymers. The CP was found to be stiffer than the filament-wound CE in the unreacted Hugoniot regime, and transformed to products near the shock-driven reaction threshold on the principal Hugoniot previously shown for the phenolic binder itself. [19] On-going research is focused on interrogating the direction-dependent dyanamic response and dynamic failure strength (spall for the CE composite in the TT and 0∘ (fiber directions.

  17. Influence of deposited CNTs on the surface of carbon fiber by ultrasonically assisted electrophoretic deposition

    Science.gov (United States)

    Jiang, J. J.; Liu, F.; Deng, C.; Fang, L. C.; Li, D. J.

    2015-07-01

    The surface property of carbon fiber directly affects the interface performance between carbon fiber and matrix. To improve the surface property of carbon fiber, we proposed a simple method to prepare carbon nanotubes /carbon fiber hybrid fiber via ultrasonically assisted electrophoretic deposition (EPD). Surface morphologies and surface functional group of carbon fibers were examined by atomic force microscopy (AFM), scanning electron microscopy (SEM) and fourier transform infrared spectrometer (FTIR), respectively. The results show that the deposition of carbon nanotubes changed the surface morphologies of carbon fibers and introduced polar groups (C=O and C-O) to carbon fiber surface. Comparing the results with EPD-only, ultrasonically assisted EPD increased the uniformity of carbon nanotubes coatings whereas only sparse and not uniformly deposition formed without ultrasonic.

  18. Strain measurements on concrete beam and carbon fiber cable with distributed optical fiber Bragg grating sensors

    Science.gov (United States)

    Nellen, Philipp M.; Bronnimann, Rolf; Sennhauser, Urs J.; Askins, Charles G.; Putnam, Martin A.

    1996-09-01

    We report on civil engineering applications of wavelength multiplexed optical fiber Bragg grating arrays directly produced on the draw tower for testing and surveying advanced structures and materials such as carbon fiber reinforced concrete elements and prestressing cables. We equipped a 6 by 0.9 by 0.5 m concrete beam, which was reinforced with carbon fiber reinforced epoxy laminates, and a 7-m long prestressing carbon fiber cable made of seven twisted strands, with optical fiber Bragg grating sensors. Static strains up to 8000 micrometers/m and dynamic strains up to 1200 micrometers/m were measured with a Michelson interferometer used as Fourier spectrometer with a resolution of about 10 micrometers/m for all sensors. Comparative measurements with electrical resistance strain gauges were in good agreement with the fiber optical results. We installed the fiber sensors in two different arrangements: some Bragg grating array elements measured local strain while others were applied in an extensometric configuration to measure moderate strain over a base length of 0.1 to 1 m.

  19. Femtosecond laser-induced surface structures on carbon fibers.

    Science.gov (United States)

    Sajzew, Roman; Schröder, Jan; Kunz, Clemens; Engel, Sebastian; Müller, Frank A; Gräf, Stephan

    2015-12-15

    The influence of different polarization states during the generation of periodic nanostructures on the surface of carbon fibers was investigated using a femtosecond laser with a pulse duration τ=300  fs, a wavelength λ=1025  nm, and a peak fluence F=4  J/cm². It was shown that linear polarization results in a well-aligned periodic pattern with different orders of magnitude concerning their period and an alignment parallel and perpendicular to fiber direction, respectively. For circular polarization, both types of uniform laser-induced periodic surface structures (LIPSS) patterns appear simultaneously with different dominance in dependence on the position at the fiber surface. Their orientation was explained by the polarization-dependent absorptivity and the geometrical anisotropy of the carbon fibers.

  20. Mechanical properties of carbon fiber composites for environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, R.; Grulke, E.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States)

    1996-12-31

    Activated carbon fiber composites show great promise as fixed-bed catalytic reactors for use in environmental applications such as flue gas clean-up and ground water decontamination. A novel manufacturing process produces low density composites from chopped carbon fibers and binders. These composites have high permeability, can be activated to have high surface area, and have many potential environmental applications. This paper reports the mechanical and flow properties of these low density composites. Three point flexural strength tests were used to measure composite yield strength and flexural moduli. Composites containing over 10 pph binder had an adequate yield strength of about 200 psi at activations up to 40% weight loss. The composites were anisotropic, having along-fiber to cross-fiber yield strength ratios between 1.2 and 2.0. The pressure drop of air through the composites correlated with the gas velocity, and showed a dependence on sample density.

  1. Surface characteristics of carbon fibers modified by direct oxyfluorination.

    Science.gov (United States)

    Seo, Min-Kang; Park, Soo-Jin

    2009-02-01

    The effect of oxyfluorinated conditions on the surface characteristics of carbon fibers was investigated. Infrared (IR) spectroscopy results indicated that the oxyfluorinated carbon fibers showed carboxyl/ester groups (CO) at 1632 cm(-1) and hydroxyl groups (OH) at 3450 cm(-1) and had a higher OH peak intensity than that of the fluorinated ones. X-ray photoelectron spectroscopy (XPS) results for the fibers also showed that oxyfluorination introduced a much higher oxygen concentration onto the fiber surfaces than fluorination with F(2) only. Additionally, contact-angle results showed that the surface was better wetted by following oxyfluorination and that the polarity of the surface was increased by increasing the oxyfluorination temperature.

  2. Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

    Institute of Scientific and Technical Information of China (English)

    Yunzhou Shi; Biao Wang

    2014-01-01

    Carbon fiber (CF)/cellulose (CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modi-fication. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers, the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization, it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also, through four-probe method, the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties.

  3. Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    2014-02-01

    Full Text Available Carbon fiber (CF/cellulose (CLS composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers, the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization, it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also, through four-probe method, the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties.

  4. Field Sensing Characteristic Research of Carbon Fiber Smart Material

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaoyu; Lü Yong; CHEN Jianzhong; LI Zhuoqiu

    2015-01-01

    In order to research the field sensing characteristic of the carbon fiber smart material, the Tikhonov regularization principle and the modiifed Newton-Raphson(MNR) algorithm were adopted to solve the inverse problem of the electrical resistance tomography (ERT). An ERT system of carbon fiber smart material was developed. Field sensing characteristic was researched with the experiment. The experimental results show that the speciifc resistance distribution of carbon ifber smart material is highly consistent with the distribution of structural strain. High resistance zone responds to high strain area, and the speciifc resistance distribution of carbon ifber smart material relfects the distribution of sample strain in covering area. Monitoring by carbon ifber smart material on complicated strain status in sample ifeld domain is realized through theoretical and experimental study.

  5. Shear strengthening of pre-damaged reinforced concrete beams with carbon fiber reinforced polymer sheet strips

    Institute of Scientific and Technical Information of China (English)

    Feras ALZOUBI; ZHANG Qi; LI Zheng-liang

    2007-01-01

    This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete (RC) beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer (CFRP) sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with side-bonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in ACI-440 and fib European code were compared with the experimental results.

  6. Study on Microwave Dielectric Property of Carbon Black and Short Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    WU Hong-huan; ZHU Dong-mei; LUO Fa; ZHOU Wan-cheng; WANG Xiao-yan

    2006-01-01

    Carbon black and carbon fibers of different lengths were introduced in different matrices at different ratios to explore their microwave dielectric properties under 8.2 GHz-12.4 GHz. It is found that the actual dielectric constants of the samples containing carbon black are in a two-order function of the contents of carbon black ((з)′,(з)″=Av2+Bv+C) and the complex dielectric constants show an obvious frequency response. Of the added fibers of different lengths, the 4 mm-long one could well disperse in the matrices having not only good frequency response, but also larger real parts, imaginary parts and loss values. The imaginary parts and the loss values (tanδ) of the samples with 4 mm-long carbon fibers added increase linearly with the contents of fiber increasing. So it is practicable to adjust the dielectric parameters of the material in a wide range by changing the added amount of carbon black, and the carbon fiber or altering the lengths of the carbon fiber added.

  7. Fabrication optimisation of carbon fiber electrode with Taguchi method.

    Science.gov (United States)

    Cheng, Ching-Ching; Young, Ming-Shing; Chuang, Chang-Lin; Chang, Ching-Chang

    2003-07-01

    In this study, we describe an optimised procedure for fabricating carbon fiber electrodes using Taguchi quality engineering method (TQEM). The preliminary results show a S/N ratio improvement from 22 to 30 db (decibel). The optimised parameter was tested by using a glass micropipette (0.3 mm outer/2.5 mm inner length of carbon fiber) dipped into PBS solution under 2.9 V triangle-wave electrochemical processing for 15 s, followed by coating treatment of micropipette on 2.6 V DC for 45 s in 5% Nafion solution. It is thus shown that Taguchi process optimisation can improve cost, manufacture time and quality of carbon fiber electrodes.

  8. Puncture-Healing Thermoplastic Resin Carbon-Fiber-Reinforced Composites

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

    2015-01-01

    A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

  9. Residual stress measurement in carbon coatings of optical fibers from the fiber bending curvature and coating thickness difference

    Science.gov (United States)

    Shiue, Sham-Tsong; Lin, Hung-Chien; Shen, Ting-Ying; Ouyang, Hao

    2005-06-01

    The residual stress measurement in carbon coatings of optical fibers is theoretically and experimentally investigated. A simple formula used to measure the residual stresses in the thin film deposited on a cylindrical substrate with the bending curvature is proposed. During a temperature drop, the carbon-coated optical fiber is bent due to the nonuniform deposition of coating materials. The axial residual stresses in carbon coatings of optical fibers can be measured from the fiber bending curvature and coating thickness difference. Furthermore, if Young's modulus of carbon coatings is known, the thermal expansion coefficient of carbon coatings can be determined.

  10. Effect of carbon nanotubes upon emissions from cutting and sanding carbon fiber-epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Heitbrink, William A. [LMK OSH Consulting LLC (United States); Lo, Li-Ming, E-mail: LLo@cdc.gov [Centers for Disease Control and Prevention (CDC), Division of Applied Research and Technology, National Institute for Occupational Safety and Health (NIOSH) (United States)

    2015-08-15

    Carbon nanotubes (CNTs) are being incorporated into structural composites to enhance material strength. During fabrication or repair activities, machining nanocomposites may release CNTs into the workplace air. An experimental study was conducted to evaluate the emissions generated by cutting and sanding on three types of epoxy-composite panels: Panel A containing graphite fibers, Panel B containing graphite fibers and carbon-based mat, and Panel C containing graphite fibers, carbon-based mat, and multi-walled CNTs. Aerosol sampling was conducted with direct-reading instruments, and filter samples were collected for measuring elemental carbon (EC) and fiber concentrations. Our study results showed that cutting Panel C with a band saw did not generate detectable emissions of fibers inspected by transmission electron microscopy but did increase the particle mass, number, and EC emission concentrations by 20–80 % compared to Panels A and B. Sanding operation performed on two Panel C resulted in fiber emission rates of 1.9 × 10{sup 8} and 2.8 × 10{sup 6} fibers per second (f/s), while no free aerosol fibers were detected from sanding Panels A and B containing no CNTs. These free CNT fibers may be a health concern. However, the analysis of particle and EC concentrations from these same samples cannot clearly indicate the presence of CNTs, because extraneous aerosol generation from machining the composite epoxy material increased the mass concentrations of the EC.

  11. Carbon-Nanotube Fibers for Wearable Devices and Smart Textiles.

    Science.gov (United States)

    Di, Jiangtao; Zhang, Xiaohua; Yong, Zhenzhong; Zhang, Yongyi; Li, Da; Li, Ru; Li, Qingwen

    2016-12-01

    Carbon-nanotube (CNT) fibers integrate such properties as high mechanical strength, extraordinary structural flexibility, high thermal and electrical conductivities, novel corrosion and oxidation resistivities, and high surface area, which makes them a very promising candidate for next-generation smart textiles and wearable devices. A brief review of the preparation of CNT fibers and recently developed CNT-fiber-based flexible and functional devices, which include artificial muscles, electrochemical double-layer capacitors, lithium-ion batteries, solar cells, and memristors, is presented.

  12. Interfacial Properties Modification of Carbon Fiber/ Polyarylacetylene Composites

    Institute of Scientific and Technical Information of China (English)

    FU Hong-jun; MA Chong-qi; KUANG Nai-hang; LUAN Shi-lin

    2007-01-01

    This work was dedicated to performing surface oxidation and coating treatments on carbon fibers (CF) and investigating the changes of fiber surface properties after these treatments, including surface composition, relative volume of functional groups, and surface topography with X-ray photoelectron spectroscopy (XPS) and atom force microscopy (AFM) technology. The results show that,after oxidation treatments, interfacial properties between CF and non-polar polyarylacetylene (PAA) resin are remarkably modified by removing weak surface layers and increasing fiber surface roughness. Coating treatment by high char phenolic resin solution after oxidation makes interface of CF/PAA composites to be upgraded and the interfacial properties further bettered.

  13. Dark pulse generation in fiber lasers incorporating carbon nanotubes.

    Science.gov (United States)

    Liu, H H; Chow, K K

    2014-12-01

    We demonstrate the generation of dark pulses from carbon nanotube (CNT) incorporated erbium-doped fiber ring lasers with net anomalous dispersion. A side-polished fiber coated with CNT layer by optically-driven deposition method is embedded into the laser in order to enhance the birefringence and nonlinearity of the laser cavity. The dual-wavelength domain-wall dark pulses are obtained from the developed CNT-incorporated fiber laser at a relatively low pump threshold of 50.6 mW. Dark pulses repeated at the fifth-order harmonic of the fundamental cavity frequency are observed by adjusting the intra-cavity polarization state.

  14. Carbon fiber composite characterization in adverse thermal environments.

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Vasquez, Sylvia; Brown, Alexander L.; Hubbard, Joshua A.; Ramirez, Ciro J.; Dodd, Amanda B.

    2011-05-01

    The behavior of carbon fiber aircraft composites was studied in adverse thermal environments. The effects of resin composition and fiber orientation were measured in two test configurations: 102 by 127 millimeter (mm) test coupons were irradiated at approximately 22.5 kW/m{sup 2} to measure thermal response, and 102 by 254 mm test coupons were irradiated at approximately 30.7 kW/m{sup 2} to characterize piloted flame spread in the vertically upward direction. Carbon-fiber composite materials with epoxy and bismaleimide resins, and uni-directional and woven fiber orientations, were tested. Bismaleimide samples produced less smoke, and were more resistant to flame spread, as expected for high temperature thermoset resins with characteristically lower heat release rates. All materials lost approximately 20-25% of their mass regardless of resin type, fiber orientation, or test configuration. Woven fiber composites displayed localized smoke jetting whereas uni-directional composites developed cracks parallel to the fibers from which smoke and flames emanated. Swelling and delamination were observed with volumetric expansion on the order of 100% to 200%. The purpose of this work was to provide validation data for SNL's foundational thermal and combustion modeling capabilities.

  15. Removal of Ozone by Carbon Nanotubes/Quartz Fiber Film.

    Science.gov (United States)

    Yang, Shen; Nie, Jingqi; Wei, Fei; Yang, Xudong

    2016-09-01

    Ozone is recognized as a harmful gaseous pollutant, which can lead to severe human health problems. In this study, carbon nanotubes (CNTs) were tested as a new approach for ozone removal. The CNTs/quartz fiber film was fabricated through growth of CNTs upon pure quartz fiber using chemical vapor deposition method. Ozone conversion efficiency of the CNTs/quartz fiber film was tested for 10 h and compared with that of quartz film, activated carbon (AC), and a potassium iodide (KI) solution under the same conditions. The pressure resistance of these materials under different airflow rates was also measured. The results showed that the CNTs/quartz fiber film had better ozone conversion efficiency but also higher pressure resistance than AC and the KI solution of the same weight. The ozone removal performance of the CNTs/quartz fiber film was comparable with AC at 20 times more weight. The CNTs played a dominant role in ozone removal by the CNTs/quartz fiber film. Its high ozone conversion efficiency, lightweight and free-standing properties make the CNTs/quartz fiber film applicable to ozone removal. Further investigation should be focused on reducing pressure resistance and studying the CNT mechanism for removing ozone.

  16. Interlaminar and ductile characteristics of carbon fibers-reinforced plastics produced by nanoscaled electroless nickel plating on carbon fiber surfaces.

    Science.gov (United States)

    Park, Soo-Jin; Jang, Yu-Sin; Rhee, Kyong-Yop

    2002-01-15

    In this work, a new method based on nanoscaled Ni-P alloy coating on carbon fiber surfaces is proposed for the improvement of interfacial properties between fibers and epoxy matrix in a composite system. Fiber surfaces and the mechanical interfacial properties of composites were characterized by atomic absorption spectrophotometer (AAS), scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), interlaminar shear strength (ILSS), and impact strength. Experimental results showed that the O(1s)/C(1s) ratio or Ni and P amounts had been increased as the electroless nickel plating proceeded; the ILSS had also been slightly improved. The impact properties were significantly improved in the presence of Ni-P alloy on carbon fiber surfaces, increasing the ductility of the composites. This was probably due to the effect of substituted Ni-P alloy, leading to an increase of the resistance to the deformation and the crack initiation of the epoxy system.

  17. Compression Molding of CFRTP Used with Carbon Fiber Extracted from CFRP Waste

    Science.gov (United States)

    Kimura, Teruo; Ino, Haruhiro; Nishida, Yuichi; Aoyama, Naoki; Shibata, Katsuji

    This study investigated a compression molding method of carbon fiber reinforced thermoplastics (CFRTP) made of carbon fiber extracted from CFRP waste. The short carbon fibers were mixed with polyester fibers using a papermaking method to make the preform sheet of compression molding. The waste obtained from a textile water jet loom was used as a matrix material. The setting speed of each fiber during the papermaking process was regulated by using a dispersing agent to obtain the good dispersion of each fiber. Laminated preform sheets combined with polyester fibers and carbon fibers were compressed with heating at 300°C and then the polyester fiber was melted as a matrix material. It was cleared from the experimental results that the mechanical properties of molded CFRTP largely depends on both the fiber dispersion and the content of carbon fiber in the preform.

  18. Effect of anodic surface treatment on PAN-based carbon fiber and its relationship to the fracture toughness of the carbon fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites...... in the fiber surface nature and the mechanical interfacial properties between the carbon fiber and epoxy resin matrix of the resulting composites, i.e., the fracture toughness. We suggest that good wetting plays an important role in improving the degree of adhesion at interfaces between fibers and matrices...

  19. Raman Spectroscopy for the Nondestructive Testing of Carbon Fiber

    Directory of Open Access Journals (Sweden)

    Glenn Washer

    2008-01-01

    Full Text Available The goal of this research is to evaluate the potential of Raman spectroscopy as a method of condition assessment for carbon fiber composite materials used in high performance situations such as composite overwrapped pressure vessels (COPVs. There are currently limited nondestructive evaluation (NDE technologies to evaluate these composite materials in situ. Variations in elastic strain in the composite material can manifest from degradation or damage, and as such could provide a tool for condition assessment. The characterization of active Raman bands and the strain sensitivity of these bands for commercially available carbon fibers are reported.

  20. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

    Science.gov (United States)

    Rodríguez-Uicab, O.; Avilés, F.; Gonzalez-Chi, P. I.; Canché-Escamilla, G.; Duarte-Aranda, S.; Yazdani-Pedram, M.; Toro, P.; Gamboa, F.; Mazo, M. A.; Nistal, A.; Rubio, J.

    2016-11-01

    Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating ("sizing"), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  1. Real time sensing of structural glass fiber reinforced composites by using embedded PVA - carbon nanotube fibers

    Directory of Open Access Journals (Sweden)

    Marioli-Riga Z.

    2010-06-01

    Full Text Available Polyvinyl alcohol - carbon nanotube (PVA-CNT fibers had been embedded to glass fiber reinforced polymers (GFRP for the structural health monitoring of the composite material. The addition of the conductive PVA-CNT fiber to the nonconductive GFRP material aimed to enhance its sensing ability by means of the electrical resistance measurement method. The test specimen’s response to mechanical load and the in situ PVA-CNT fiber’s electrical resistance measurements were correlated for sensing and damage monitoring purposes. The embedded PVA-CNT fiber worked as a sensor in GFRP coupons in tensile loadings. Sensing ability of the PVA-CNT fibers was also demonstrated on an integral composite structure. PVA-CNT fiber near the fracture area of the structure recorded very high values when essential damage occurred to the structure. A finite element model of the same structure was developed to predict axial strains at locations of the integral composite structure where the fibers were embedded. The predicted FEA strains were correlated with the experimental measurements from the PVA-CNT fibers. Calculated and experimental values were in good agreement, thus enabling PVA-CNT fibers to be used as strain sensors.

  2. Preparation of PAN/phenolic-based carbon/carbon composites with flexible towpreg carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)], E-mail: liwei5168@hnu.cn; Chen Zhenhua; Li Jin; Chen Xianhong; Xuan Hao; Wang Xiaoyi [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

    2008-06-25

    Carbon/carbon composites made with flexible towpreg carbon fiber as reinforcement and phenolic resins as matrix precursor were impregnated with pitch during re-carbonization process. The structural characteristics of the composites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), three-point bending tests, Archimedes' method and water adsorption. Results showed that the density of the carbon/carbon composites increases from 1.45 to 1.54 g/cm{sup 3} with the cycles of pitch impregnated and re-carbonization. Open porosity measurement indicated that the increase of porosity resulted from the decomposition of phenolic resin matrix, and the open porosity of the composite gradually decreased after the impregnation and re-carbonization process. These composites also exhibited an improvement in flexural strength with increasing number of densification cycles. From SEM morphological observation, it was concluded that few cracks appeared in the surfaces and a few smaller pores with a diameter <1 {mu}m could be observed.

  3. PREPARATION OF ACTIVATED CARBON FIBER AND THEIR XENON ADSORPTION PROPERTIES (Ⅲ)-ADSORPTION ON MODIFIED ACTIVATED CARBON FIBER

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Structures of a series of activated carbon fibers were modified by impregnating them withorganic and inorganic materials such as Methylene blue(Mb)、 p-nitrophenol (PNP)、 NaCl or byoxidizing with KMnO4 or HNO3. The influence of pore filling or chemical treatment on their xenonadsorption properties was studied. The experimental results show that Mb and PNP filling ofactivated carbon fibers result in the decrease of xenon adsorption capacities of these treated ACFs,which is due to the decrease of their surface area and micro-pore volume. However, the adsorptioncapacity increases greatly with oxidizing treatment of activated carbon fibers by 7mol/L HNO3.

  4. Smart Cellulose Fibers Coated with Carbon Nanotube Networks

    Directory of Open Access Journals (Sweden)

    Haisong Qi

    2014-11-01

    Full Text Available Smart multi-walled carbon nanotube (MWCNT-coated cellulose fibers with a unique sensing ability were manufactured by a simple dip coating process. The formation of electrically-conducting MWCNT networks on cellulose mono- and multi-filament fiber surfaces was confirmed by electrical resistance measurements and visualized by scanning electron microscopy. The interaction between MWCNT networks and cellulose fiber was investigated by Raman spectroscopy. The piezoresistivity of these fibers for strain sensing was investigated. The MWCNT-coated cellulose fibers exhibited a unique linear strain-dependent electrical resistance change up to 18% strain, with good reversibility and repeatability. In addition, the sensing behavior of these fibers to volatile molecules (including vapors of methanol, ethanol, acetone, chloroform and tetrahydrofuran was investigated. The results revealed a rapid response, high sensitivity and good reproducibility for these chemical vapors. Besides, they showed good selectivity to different vapors. It is suggested that the intrinsic physical and chemical features of cellulose fiber, well-formed MWCNT networks and favorable MWCNT-cellulose interaction caused the unique and excellent sensing ability of the MWCNT-coated cellulose fibers, which have the potential to be used as smart materials.

  5. Carbon-fiber composite molecular sieves for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F. [Univ. of Kentucky, Lexington, KY (United States)

    1996-08-01

    This report describes continuing work on the activation and characterization of formed carbon fiber composites. The composites are produced at the Oak Ridge National Laboratory (ORNL) and activated at the Center for Applied Energy Research (CAER) using steam, CO{sub 2}, or O{sub 2} at different conditions of temperature and time, and with different furnace configurations. The general aims of the project are to produce uniformly activated samples with controlled pore structures for specialist applications such as gas separation and water treatment. In previous work the authors reported that composites produced from isotropic pitch fibers weighing up to 25g can be uniformly activated through the appropriate choice of reaction conditions and furnace configurations. They have now succeeded in uniformly activating composites of dimensions up to 12 x 7 x 6 cm, or up to about 166 gram - a scale-up factor of about six. Part of the work has involved the installation of a new furnace that can accommodate larger composites. Efforts were made to achieve uniform activation in both steam and CO{sub 2}. The authors have also succeeded in producing materials with very uniform and narrow pore size distributions by using a novel method involving low temperature oxygen chemisorption in combination with heat treatment in N{sub 2} at high temperatures. Work has also started on the activation of PAN based carbon fibers and fiber composites with the aim of producing composites with wide pore structures for use as catalyst supports. So far activation of the PAN fiber composites supplied by ORNL has been difficult which is attributed to the low reactivity of the PAN fibers. As a result, studies are now being made of the activation of the PAN fibers to investigate the optimum carbonization and activation conditions for PAN based fibers.

  6. Permeability characterization of stitched carbon fiber preforms by fiber optic sensors

    Directory of Open Access Journals (Sweden)

    V. Antonucci

    2011-12-01

    Full Text Available The in-plane and through thickness permeability of unidirectional stitched carbon fiber preforms have been determined through vacuum infusion tests. The impregnation of various dry preforms with different stitching characteristics has been monitored by fiber optic sensors that have been stitched together with the dry tow to manufacture the dry preform. The experimental infusion times have been fitted by a numerical procedure based on Finite Element (FE processing simulations. A good agreement between the numerical and experimental infusion times has been found demonstrating the potentiality of the fiber sensor system as suitable tool to evaluate impregnation times and permeability characteristics.

  7. Rapid Fabrication of Carbide Matrix/Carbon Fiber Composites

    Science.gov (United States)

    Williams, Brian E.; Bernander, Robert E.

    2007-01-01

    Composites of zirconium carbide matrix material reinforced with carbon fibers can be fabricated relatively rapidly in a process that includes a melt infiltration step. Heretofore, these and other ceramic matrix composites have been made in a chemical vapor infiltration (CVI) process that takes months. The finished products of the CVI process are highly porous and cannot withstand temperatures above 3,000 F (approx.1,600 C). In contrast, the melt-infiltration-based process takes only a few days, and the composite products are more nearly fully dense and have withstood temperatures as high as 4,350 F (approx.2,400 C) in a highly oxidizing thrust chamber environment. Moreover, because the melt- infiltration-based process takes much less time, the finished products are expected to cost much less. Fabrication begins with the preparation of a carbon fiber preform that, typically, is of the size and shape of a part to be fabricated. By use of low-temperature ultraviolet-enhanced chemical vapor deposition, the carbon fibers in the preform are coated with one or more interfacial material(s), which could include oxides. The interfacial material helps to protect the fibers against chemical attack during the remainder of the fabrication process and against oxidation during subsequent use; it also enables slippage between the fibers and the matrix material, thereby helping to deflect cracks and distribute loads. Once the fibers have been coated with the interfacial material, the fiber preform is further infiltrated with a controlled amount of additional carbon, which serves as a reactant for the formation of the carbide matrix material. The next step is melt infiltration. The preform is exposed to molten zirconium, which wicks into the preform, drawn by capillary action. The molten metal fills most of the interstices of the preform and reacts with the added carbon to form the zirconium carbide matrix material. The zirconium does not react with the underlying fibers because they

  8. The effect of bromination of carbon fibers on the coefficient of thermal expansion of graphite fiber-epoxy composites

    Science.gov (United States)

    Jaworske, D. A.; Maciag, C.

    1987-01-01

    To examine the effect of bromination of carbon fibers on the coefficient of thermal expansion (CTE) of carbon fiber epoxy composites, several pristine and brominated carbon fiber-epoxy composite samples were subjected to thermomechanical analysis. The CTE's of these samples were measured in the uniaxial and transverse directions. The CTE was dominated by the fibers in the uniaxial direction, while it was dominated by the matrix in the transverse directions. Bromination had no effect on the CTE of any of the composites. In addition, the CTE of fiber tow was measured in the absence of a polymer matrix, using an extension probe. The results from this technique were inconclusive.

  9. Carbon Nanotube (CNT) and Carbon Fiber Reinforced SiC Optical Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — M Cubed has developed and patented technology to make carbon fiber reinforced SiC composites and components. In addition, the feasibility of doubling the toughness...

  10. Atomically isolated nickel species anchored on graphitized carbon for efficient hydrogen evolution electrocatalysis

    Science.gov (United States)

    Fan, Lili; Liu, Peng Fei; Yan, Xuecheng; Gu, Lin; Yang, Zhen Zhong; Yang, Hua Gui; Qiu, Shilun; Yao, Xiangdong

    2016-02-01

    Hydrogen production through electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells. Despite tremendous efforts, exploring cheap, efficient and durable electrocatalysts for hydrogen evolution still remains as a great challenge. Here we synthesize a nickel-carbon-based catalyst, from carbonization of metal-organic frameworks, to replace currently best-known platinum-based materials for electrocatalytic hydrogen evolution. This nickel-carbon-based catalyst can be activated to obtain isolated nickel atoms on the graphitic carbon support when applying electrochemical potential, exhibiting highly efficient hydrogen evolution performance with high exchange current density of 1.2 mA cm-2 and impressive durability. This work may enable new opportunities for designing and tuning properties of electrocatalysts at atomic scale for large-scale water electrolysis.

  11. Polarization insensitive all-fiber mode-lockers functioned by carbon nanotubes deposited onto tapered fibers

    Science.gov (United States)

    Song, Yong-Won; Morimune, Keiyo; Set, Sze Y.; Yamashita, Shinji

    2007-01-01

    The authors demonstrate a nonblocked all-fiber mode locker operated by the interaction of carbon nanotubes with the evanescent field of propagating light in a tapered fiber. Symmetric cross section of the device with the randomly oriented nanotubes guarantees the polarization insensitive operation of the pulse formation. In order to minimize the scattering, the carbon nanotubes are deposited within a designed area around the tapered waist. The demonstrated passively pulsed laser has the repetition rate of 7.3MHz and the pulse width of 829fs.

  12. Cellulosic carbon fibers with branching carbon nanotubes for enhanced electrochemical activities for bioprocessing applications.

    Science.gov (United States)

    Zhao, Xueyan; Lu, Xin; Tze, William Tai Yin; Kim, Jungbae; Wang, Ping

    2013-09-25

    Renewable biobased carbon fibers are promising materials for large-scale electrochemical applications including chemical processing, energy storage, and biofuel cells. Their performance is, however, often limited by low activity. Herein we report that branching carbon nanotubes can enhance the activity of carbonized cellulosic fibers, such that the oxidation potential of NAD(H) was reduced to 0.55 V from 0.9 V when applied for bioprocessing. Coordinating with enzyme catalysts, such hierarchical carbon materials effectively facilitated the biotransformation of glycerol, with the total turnover number of NAD(H) over 3500 within 5 h of reaction.

  13. Octahedral Tin Dioxide Nanocrystals Anchored on Vertically Aligned Carbon Aerogels as High Capacity Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Liu, Mingkai; Liu, Yuqing; Zhang, Yuting; Li, Yiliao; Zhang, Peng; Yan, Yan; Liu, Tianxi

    2016-01-01

    A novel binder-free graphene - carbon nanotubes - SnO2 (GCNT-SnO2) aerogel with vertically aligned pores was prepared via a simple and efficient directional freezing method. SnO2 octahedrons exposed of {221} high energy facets were uniformly distributed and tightly anchored on multidimensional graphene/carbon nanotube (GCNT) composites. Vertically aligned pores can effectively prevent the emersion of “closed” pores which cannot load the active SnO2 nanoparticles, further ensure quick immersion of electrolyte throughout the aerogel, and can largely shorten the transport distance between lithium ions and active sites of SnO2. Especially, excellent electrical conductivity of GCNT-SnO2 aerogel was achieved as a result of good interconnected networks of graphene and CNTs. Furthermore, meso- and macroporous structures with large surface area created by the vertically aligned pores can provide great benefit to the favorable transport kinetics for both lithium ion and electrons and afford sufficient space for volume expansion of SnO2. Due to the well-designed architecture of GCNT-SnO2 aerogel, a high specific capacity of 1190 mAh/g with good long-term cycling stability up to 1000 times was achieved. This work provides a promising strategy for preparing free-standing and binder-free active electrode materials with high performance for lithium ion batteries and other energy storage devices. PMID:27510357

  14. Octahedral Tin Dioxide Nanocrystals Anchored on Vertically Aligned Carbon Aerogels as High Capacity Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Liu, Mingkai; Liu, Yuqing; Zhang, Yuting; Li, Yiliao; Zhang, Peng; Yan, Yan; Liu, Tianxi

    2016-08-01

    A novel binder-free graphene - carbon nanotubes - SnO2 (GCNT-SnO2) aerogel with vertically aligned pores was prepared via a simple and efficient directional freezing method. SnO2 octahedrons exposed of {221} high energy facets were uniformly distributed and tightly anchored on multidimensional graphene/carbon nanotube (GCNT) composites. Vertically aligned pores can effectively prevent the emersion of “closed” pores which cannot load the active SnO2 nanoparticles, further ensure quick immersion of electrolyte throughout the aerogel, and can largely shorten the transport distance between lithium ions and active sites of SnO2. Especially, excellent electrical conductivity of GCNT-SnO2 aerogel was achieved as a result of good interconnected networks of graphene and CNTs. Furthermore, meso- and macroporous structures with large surface area created by the vertically aligned pores can provide great benefit to the favorable transport kinetics for both lithium ion and electrons and afford sufficient space for volume expansion of SnO2. Due to the well-designed architecture of GCNT-SnO2 aerogel, a high specific capacity of 1190 mAh/g with good long-term cycling stability up to 1000 times was achieved. This work provides a promising strategy for preparing free-standing and binder-free active electrode materials with high performance for lithium ion batteries and other energy storage devices.

  15. Composite materials formed with anchored nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  16. Fabrication of polytetrafluoroethylene/carbon fiber composites using radiation crosslinking

    Science.gov (United States)

    Oshima, Akihiro; Udagawa, Akira; Tanaka, Shigeru

    2001-07-01

    A fabrication method for fiber-reinforced plastic (FRP) composites based on carbon fibers and polytetrafluoroethylene (PTFE) which was crosslinked by electron beam (EB) irradiation under specific conditions was studied. Though the fabricated composite showed high mechanical properties compared with a ready-made PTFE composite (non-crosslinked PTFE with 5˜20 wt% filler), mechanical properties of laminated panels were a bit poor compared with those of usual FRP. It was found that the toughness of the PTFE matrix is poor in the composite. On the other hand, the one-ply sheet of carbon fibers and crosslinked PTFE composite showed good mechanical properties for sheet-shape materials. The wettability of the obtained crosslinked PTFE composite is hardly changed by crosslinking and reinforcement.

  17. Fabrication of polytetrafluoroethylene/carbon fiber composites using radiation crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Akihiro E-mail: aks@taka.jaeri.go.jp; Udagawa, Akira; Tanaka, Shigeru

    2001-07-01

    A fabrication method for fiber-reinforced plastic (FRP) composites based on carbon fibers and polytetrafluoroethylene (PTFE) which was crosslinked by electron beam (EB) irradiation under specific conditions was studied. Though the fabricated composite showed high mechanical properties compared with a ready-made PTFE composite (non-crosslinked PTFE with 5{approx}20 wt% filler), mechanical properties of laminated panels were a bit poor compared with those of usual FRP. It was found that the toughness of the PTFE matrix is poor in the composite. On the other hand, the one-ply sheet of carbon fibers and crosslinked PTFE composite showed good mechanical properties for sheet-shape materials. The wettability of the obtained crosslinked PTFE composite is hardly changed by crosslinking and reinforcement.

  18. Smart Behavior of Carbon Fiber Reinforced Cement-based Composite

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The electrical characteristics of cement-based material can be remarkably improved by the addition of short carbon fibers.Carbon fiber reinforced cement composite (CFRC) is an intrinsically smart material that can sense not only the stress andstrain, but also the temperature. In this paper, variations of electrical resistivity with external applied load, and relationof thermoelectric force and temperature were investigated. Test results indicated that the electrical signal is related to theincrease in the material volume resistivity during crack generation or propagation and the decrease in the resistivity duringcrack closure. Moreover, it was found that the fiber addition increased the linearity and reversibility of the Seebeck effect inthe cement-based materials. The change of electrical characteristics reflects large amount of information of inner damage andtemperature differential of composite, which can be used for stress-strain or thermal self-monitoring by embedding it in theconcrete structures.

  19. Aspen SUCROSE TRANSPORTER3 allocates carbon into wood fibers.

    Science.gov (United States)

    Mahboubi, Amir; Ratke, Christine; Gorzsás, András; Kumar, Manoj; Mellerowicz, Ewa J; Niittylä, Totte

    2013-12-01

    Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species, including Populus species, the majority of this carbon is derived from sucrose (Suc) transported in the phloem. The mechanism of radial Suc transport from phloem to developing wood is not well understood. We investigated the role of active Suc transport during secondary cell wall formation in hybrid aspen (Populus tremula × Populus tremuloides). We show that RNA interference-mediated reduction of PttSUT3 (for Suc/H(+) symporter) during secondary cell wall formation in developing wood caused thinner wood fiber walls accompanied by a reduction in cellulose and an increase in lignin. Suc content in the phloem and developing wood was not significantly changed. However, after (13)CO2 assimilation, the SUT3RNAi lines contained more (13)C than the wild type in the Suc-containing extract of developing wood. Hence, Suc was transported into developing wood, but the Suc-derived carbon was not efficiently incorporated to wood fiber walls. A yellow fluorescent protein:PttSUT3 fusion localized to plasma membrane, suggesting that reduced Suc import into developing wood fibers was the cause of the observed cell wall phenotype. The results show the importance of active Suc transport for wood formation in a symplasmically phloem-loading tree species and identify PttSUT3 as a principal transporter for carbon delivery into secondary cell wall-forming wood fibers.

  20. Clean Energy Manufacturing Analysis Center. 2015 Research Highlights -- Carbon Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-03-01

    CEMAC has conducted four major studies on the manufacturing of clean energy technologies. Three of these focused on the end product: solar photovoltaic modules, wind turbines, and automotive lithium-ion batteries. The fourth area focused on a key material for manufacturing clean energy technologies, carbon fiber.

  1. Seebeck effect in carbon fiber-reinforced cement

    Energy Technology Data Exchange (ETDEWEB)

    Wen, S.; Chung, D.D.L.

    1999-12-01

    The Seebeck effect in carbon fiber-reinforced cement paste was found to involve electrons from the cement matrix and holes from the biers. The two contributions were equal at the percolation threshold, with a fiber content between 0.5 and 1.0% by mass of cement. The hole contribution increased monotonically with increasing fiber content below and above the percolation threshold. The fiber addition increased the linearity and reversibility of the Seebeck effect. Silica fume and latex as admixtures had minor influence on the Seebeck effect. The Seebeck effect in concrete is of interest because it gives the concrete the ability to sense its own temperature. No attached or embedded sensor is needed since the concrete itself is the sensor. This means low cost, high durability, large sensing volume, and absence of mechanical property degradation due to embedded sensors. As the temperature affects the performance and reliability of concrete, its detection is valuable.

  2. Electromechanical behavior of carbon nanotube fibers under transverse compression

    Science.gov (United States)

    Li, Yuanyuan; Lu, Weibang; Sockalingam, Subramani; Gu, Bohong; Sun, Baozhong; Gillespie, John W.; Chou, Tsu-Wei

    2017-03-01

    Although in most cases carbon nanotube (CNT) fibers experience axial stretch or compression, they can also be subjected to transverse compression, for example, under impact loading. In this paper, the electromechanical properties of both aerogel-spun and dry-spun CNT fibers under quasi-static transverse compressive loading are investigated for the first time. Transverse compression shows a nonlinear and inelastic behavior. The compressive modulus/strength of the aerogel-spun and dry-spun CNT fibers are about 0.21 GPa/0.796 GPa and 1.73 GPa/1.036 GPa, respectively. The electrical resistance goes through three stages during transverse compressive loading/unloading: initially it decreases, then it increases during the loading, and finally it decreases upon unloading. This study extends our knowledge of the overall properties of CNT fibers, and will be helpful in promoting their engineering applications.

  3. Preliminary research on movement regularity of fine carbon fiber powder injected into intracrania of mice

    Institute of Scientific and Technical Information of China (English)

    FEI Ke-xiang; LI Guo-wei; GONG Ti; WANG Hong; PENG Xian-gao; GAO Lin; Zhang Yan-xiang; LIU Lian-tao

    2001-01-01

    @@ The carbon fiber and carbon fiber for complex materials implanted have been applied to the clinic medicine, in which they are served as the materials for repairing tissues and organs as well as the materials of artificial tissuesand organs. The carbon fiber also acts as the surrogate of extracellular matrix in the study of tissue engineering tendon,and so on.

  4. Preparation of array of long carbon nanotubes and fibers therefrom

    Science.gov (United States)

    Arendt, Paul N.; DePaula, Ramond F.; Zhu, Yuntian T.; Usov, Igor O.

    2015-11-19

    An array of carbon nanotubes is prepared by exposing a catalyst structure to a carbon nanotube precursor. Embodiment catalyst structures include one or more trenches, channels, or a combination of trenches and channels. A system for preparing the array includes a heated surface for heating the catalyst structure and a cooling portion that cools gas above the catalyst structure. The system heats the catalyst structure so that the interaction between the precursor and the catalyst structure results in the formation of an array of carbon nanotubes on the catalyst structure, and cools the gas near the catalyst structure and also cools any carbon nanotubes that form on the catalyst structure to prevent or at least minimize the formation of amorphous carbon. Arrays thus formed may be used for spinning fibers of carbon nanotubes.

  5. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

    Directory of Open Access Journals (Sweden)

    Noe T. Alvarez

    2014-11-01

    Full Text Available Carbon nanotubes (CNTs are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC, it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core.

  6. Laser Processing of Carbon Fiber Reinforced Plastics - Release of Carbon Fiber Segments During Short-pulsed Laser Processing of CFRP

    Science.gov (United States)

    Walter, Juergen; Brodesser, Alexander; Hustedt, Michael; Bluemel, Sven; Jaeschke, Peter; Kaierle, Stefan

    Cutting and ablation using short-pulsed laser radiation are promising technologies to produce or repair CFRP components with outstanding mechanical properties e.g. for automotive and aircraft industry. Using sophisticated laser processing strategies and avoiding excessive heating of the workpiece, a high processing quality can be achieved. However, the interaction of laser radiation and composite material causes a notable release of hazardous substances from the process zone, amongst others carbon fiber segments or fibrous particles. In this work, amounts and geometries of the released fiber segments are analyzed and discussed in terms of their hazardous potential. Moreover, it is investigated to what extent gaseous organic process emissions are adsorbed at the fiber segments, similar to an adsorption of volatile organic compounds at activated carbon, which is typically used as filter material.

  7. Three-dimensional helical carbon materials: Microcoiled carbon fibers, carbon nanocoils, carbon nanotubes: Synthesis, properties and applications

    Science.gov (United States)

    Xie, Jining

    Materials with a 3D-helical/spiral-structure in micron size have recently aroused a great deal of interests because of their helical morphology and unique properties. However, materials with a 3D helical structure are not commonly observed among industrially available materials. Researchers have been trying to synthesize various micro- and nano-sized 3D helical materials and are exploring the mechanisms, nature, and properties of these materials. Yet a systematic study on 3D helical carbon materials in micro- and nano-size has been missing. This research work is intended as a first step to fill this gap. Among various 3D helical materials, carbon element has stimulated great interests. Micro coiled carbon fibers, carbon nanocoils, and carbon nanotubes are major types of 3D helical carbon materials ranging from micron to nano size. Synthesis of these 3D helical carbon materials by a catalytic chemical vapor deposition method is presented in this thesis. It involves a pyrolysis of hydrocarbon gas (e.g. acetylene) over transition metals, such as Ni, Fe, and Co, at high reaction temperature (500--1000°C). Besides the conventional thermal filament chemical vapor deposition method, a novel microwave chemical vapor deposition (MWCVD) method has been developed to synthesize micro- and nano-sized 3D helical carbon materials economically. The faster heating and cooling processes associated with microwave CVD have potential for large-scale production in the near future. Compared with previously reported microwave plasma enhanced chemical vapor deposition (MWPECVD) method, this method does not require high vacuum and much higher deposition rate is another major advantage. It has been found in this work that microwave plays an important role on coil morphology formation for micro coiled carbon fibers and carbon nanocoils. The large temperature gradient around the catalytic particles could be the reason. Different reaction factors have been checked to optimize the deposition

  8. Self-Monitoring Strengthening System Based on Carbon Fiber Laminate

    Directory of Open Access Journals (Sweden)

    Rafal Krzywon

    2016-01-01

    Full Text Available Externally bonded composites reinforced with high-strength fibers are increasingly popular in construction, especially in structures’ strengthening, where the best possible mechanical properties are required. At the same time the ability to autodetect threats is one of the most desirable features of contemporary structures. The authors of the paper have developed an intelligent fabric, wherein the carbon fibers play the role of not only tensile reinforcement but also strain sensor. The idea is based on the construction of the strain gauge, where the thread of carbon fibers arranged in zig-zag pattern works as electrical conductor and is insulated by parallel thread of glass or acrylic fibers. Preliminary laboratory tests were designed to create effective measurement techniques and assess the effectiveness of the strengthening of selected building structures, as reinforced concrete and timber beams. Presented in the paper, selected results of these studies are very promising, although there were some noted problems to be considered in next steps. The main problem here is the control of the cross section of the fibers tow, affecting the total resistance of the fabric. One of the main deficiencies of the proposed solution is also sensitivity to moisture.

  9. Interfacial Microstructure and Enhanced Mechanical Properties of Carbon Fiber Composites Caused by Growing Generation 1-4 Dendritic Poly(amidoamine) on a Fiber Surface.

    Science.gov (United States)

    Gao, Bo; Zhang, Ruliang; Gao, Fucheng; He, Maoshuai; Wang, Chengguo; Liu, Lei; Zhao, Lifen; Cui, Hongzhi

    2016-08-23

    In an attempt to improve the mechanical properties of carbon fiber composites, propagation of poly(amidoamine) (PAMAM) dendrimers by in situ polymerization on a carbon fiber surface was performed. During polymerization processes, PAMAM was grafted on carbon fiber by repeated Michael addition and amidation reactions. The changes in surface microstructure and the chemical composition of carbon fibers before and after modification were investigated by atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. All the results indicated that PAMAM was successfully grown on the carbon fiber surface. Such propagation could significantly increase the surface roughness and introduce sufficient polar groups onto the carbon fiber surface, enhancing the surface wettability of carbon fiber. The fractured surface of carbon fiber-reinforced composites showed a great enhancement of interfacial adhesion. Compared with those of desized fiber composites, the interlaminar shear strength and interfacial shear strength of PAMAM/fiber-reinforced composites showed increases of 55.49 and 110.94%, respectively.

  10. THERMAL INSULATION FROM LIGNIN-DERIVED CARBON FIBERS

    Energy Technology Data Exchange (ETDEWEB)

    Albers, Tracy [GrafTech International; Chen, Chong [GrafTech International; Eberle, Cliff [ORNL; Webb, Daniel C [ORNL

    2014-01-01

    Oak Ridge National Laboratory (ORNL) and GrafTech International Holdings Inc. (GrafTech) have collaborated to develop and demonstrate the performance of high temperature thermal insulation prototypes made from lignin-based carbon fibers (LBCF). This was the first reported production of LBCF or resulting products at scale > 1 kg. The results will potentially lead to the first commercial application of LBCF. The goal of the commercial application is to replace expensive, foreign-sourced isotropic pitch carbon fibers with lower cost carbon fibers made from a domestically sourced, bio-derived (renewable) feedstock. LBCF can help resolve supply chain vulnerability and reduce the production cost for high temperature thermal insulation as well as create US jobs. The performance of the LBCF prototypes was measured and found to be comparable to that of the current commercial product. During production of the insulation prototypes, the project team demonstrated lignin compounding/pelletization, fiber production, heat treatment, and compositing at scales far surpassing those previously demonstrated in LBCF R&D or production.

  11. Multifunctional structural supercapacitor composites based on carbon aerogel modified high performance carbon fiber fabric.

    Science.gov (United States)

    Qian, Hui; Kucernak, Anthony R; Greenhalgh, Emile S; Bismarck, Alexander; Shaffer, Milo S P

    2013-07-10

    A novel multifunctional material has been designed to provide excellent mechanical properties while possessing a high electrochemical surface area suitable for electrochemical energy storage: structural carbon fiber fabrics are embedded in a continuous network of carbon aerogel (CAG) to form a coherent but porous monolith. The CAG-modification process was found to be scalable and to be compatible with a range of carbon fiber fabrics with different surface properties. The incorporation of CAG significantly increased the surface area of carbon fiber fabrics, and hence the electrochemical performance, by around 100-fold, resulting in a CAG-normalized specific electrode capacitance of around 62 F g(-1), determined by cyclic voltammetry in an aqueous electrolyte. Using an ionic liquid (IL) electrolyte, the estimated energy density increased from 0.003 to 1 Wh kg(-1), after introducing the CAG into the carbon fiber fabric. 'Proof-of-concept' multifunctional structural supercapacitor devices were fabricated using an IL-modified solid-state polymer electrolyte as a multifunctional matrix to provide both ionic transport and physical support for the primary fibers. Two CAG-impregnated carbon fabrics were sandwiched around an insulating separator to form a functioning structural electrochemical double layer capacitor composite. The CAG-modification not only improved the electrochemical surface area, but also reinforced the polymer matrix surrounding the primary fibers, leading to dramatic improvements in the matrix-dominated composite properties. Increases in in-plane shear strength and modulus, of up to 4.5-fold, were observed, demonstrating that CAG-modified structural carbon fiber fabrics have promise in both pure structural and multifunctional energy storage applications.

  12. Carbon fiber plume sampling for large scale fire tests at Dugway Proving Ground. [fiber release during aircraft fires

    Science.gov (United States)

    Chovit, A. R.; Lieberman, P.; Freeman, D. E.; Beggs, W. C.; Millavec, W. A.

    1980-01-01

    Carbon fiber sampling instruments were developed: passive collectors made of sticky bridal veil mesh, and active instruments using a light emitting diode (LED) source. These instruments measured the number or number rate of carbon fibers released from carbon/graphite composite material when the material was burned in a 10.7 m (35 ft) dia JP-4 pool fire for approximately 20 minutes. The instruments were placed in an array suspended from a 305 m by 305 m (1000 ft by 1000 ft) Jacob's Ladder net held vertically aloft by balloons and oriented crosswind approximately 140 meters downwind of the pool fire. Three tests were conducted during which released carbon fiber data were acquired. These data were reduced and analyzed to obtain the characteristics of the released fibers including their spatial and size distributions and estimates of the number and total mass of fibers released. The results of the data analyses showed that 2.5 to 3.5 x 10 to the 8th power single carbon fibers were released during the 20 minute burn of 30 to 50 kg mass of initial, unburned carbon fiber material. The mass released as single carbon fibers was estimated to be between 0.1 and 0.2% of the initial, unburned fiber mass.

  13. Characterisation of pulsed Carbon fiber illuminators for FIR instrument calibration

    CERN Document Server

    Henrot-Versillé, S; Couchot, F

    2007-01-01

    We manufactured pulsed illuminators emitting in the far infrared for the Planck-HFI bolometric instrument ground calibrations. Specific measurements have been conducted on these light sources, based on Carbon fibers, to understand and predict their properties. We present a modelisation of the temperature dependence of the thermal conductivity and the calorific capacitance of the fibers. A comparison between simulations and bolometer data is given, that shows the coherence of our model. Their small time constants, their stability and their emission spectrum pointing in the submm range make these illuminators a very usefull tool for calibrating FIR instruments.

  14. Carbon fiber/carbon nanotube reinforced hierarchical composites: Effect of CNT distribution on shearing strength

    DEFF Research Database (Denmark)

    Zhou, H. W.; Mishnaevsky, Leon; Yi, H. Y.;

    2016-01-01

    The strength and fracture behavior of carbon fiber reinforced polymer composites with carbon nanotube (CNT) secondary reinforcement are investigated experimentally and numerically. Short Beam Shearing tests have been carried out, with SEM observations of the damage evolution in the composites. 3D...... multiscale computational (FE) models of the carbon/polymer composite with varied CNT distributions have been developed and employed to study the effect of the secondary CNT reinforcement, its distribution and content on the strength and fracture behavior of the composites. It is shown that adding secondary...... CNT nanoreinforcement into the matrix and/or the sizing of carbon fiber/reinforced composites ensures strong increase of the composite strength. The effect of secondary CNTs reinforcement is strongest when some small addition of CNTs in the polymer matrix is complemented by the fiber sizing with high...

  15. Carbon monolith: preparation, characterization and application as microextraction fiber.

    Science.gov (United States)

    Shi, Zhi-Guo; Chen, Fei; Xing, Jun; Feng, Yu-Qi

    2009-07-10

    A carbon monolith was synthesized via a polymerization-carbonization method, styrene and divinylbenzene being adopted as precursors and dodecanol as a porogen during polymerization. The resultant monolith had bimodal porous substructure, narrowly distributed nano skeleton pores and uniform textural pores or throughpores. The carbon monolith was directly used as an extracting fiber, taking place of the coated silica fibers in commercially available solid-phase microextraction device, for the extraction of phenols followed by gas chromatography-mass spectrometry. Under the studied conditions, the calibration curves were linear from 0.5 to 50 ng mL(-1) for phenol, o-nitrophenol, 2,4-dichlorophenol and p-chlorophenol. The limits of detection were between 0.04 and 0.43 ng mL(-1). The recoveries of the phenols spiked in real water samples at 10 ng mL(-1) were between 85% and 98% with the relative standard deviations below 10%. Compared with the commercial coated ones (e.g. PDMS, CW/DVB and DVB/CAR/PDMS), the carbon monolith-based fiber had advantages of faster extraction equilibrium and higher extraction capacity due to the superior pore connectivity and pore openness resulting from its bimodal porous substructure.

  16. Coaxial fiber supercapacitor using all-carbon material electrodes.

    Science.gov (United States)

    Le, Viet Thong; Kim, Heetae; Ghosh, Arunabha; Kim, Jaesu; Chang, Jian; Vu, Quoc An; Pham, Duy Tho; Lee, Ju-Hyuck; Kim, Sang-Woo; Lee, Young Hee

    2013-07-23

    We report a coaxial fiber supercapacitor, which consists of carbon microfiber bundles coated with multiwalled carbon nanotubes as a core electrode and carbon nanofiber paper as an outer electrode. The ratio of electrode volumes was determined by a half-cell test of each electrode. The capacitance reached 6.3 mF cm(-1) (86.8 mF cm(-2)) at a core electrode diameter of 230 μm and the measured energy density was 0.7 μWh cm(-1) (9.8 μWh cm(-2)) at a power density of 13.7 μW cm(-1) (189.4 μW cm(-2)), which were much higher than the previous reports. The change in the cyclic voltammetry characteristics was negligible at 180° bending, with excellent cycling performance. The high capacitance, high energy density, and power density of the coaxial fiber supercapacitor are attributed to not only high effective surface area due to its coaxial structure and bundle of the core electrode, but also all-carbon materials electrodes which have high conductivity. Our coaxial fiber supercapacitor can promote the development of textile electronics in near future.

  17. Effect of carbon nanotube on physical and mechanical properties of natural fiber/glass fiber/cement composites

    Institute of Scientific and Technical Information of China (English)

    Hamed Younesi Kordkheili; Shokouh Etedali Shehni; Ghorban Niyatzade

    2015-01-01

    The objective of this investigation was to introduce a cement-based composite of higher quality. For this purpose new hybrid nanocomposite from bagasse fiber, glass fiber and multi-wall carbon nanotubes (MWCNTs) were manufactured. The physical and mechanical proper-ties of the manufactured composites were measured according to standard methods. The properties of the manufactured hybrid nanocomposites were dramatically better than traditional composites. Also all the reinforced composites with carbon nanotube, glass fiber or bagasse fiber exhibited better properties rather than neat cement. The results indicated that bagasse fiber proved suitable for substitution of glass fiber as a reinforcing agent in the cement composites. The hybrid nanocomposite containing 10%glass fiber, 10%bagasse fiber and 1.5%MWCNTs was selected as the best compound.

  18. Electrical conductivity improvement of aeronautical carbon fiber reinforced polyepoxy composites by insertion of carbon nanotubes

    OpenAIRE

    Lonjon, Antoine; Demont, Philippe; Dantras, Eric; Lacabanne, Colette

    2012-01-01

    International audience; An increase and homogenization of electrical conductivity is essential in epoxy carbon fiber laminar aeronautical composites. Dynamic conductivity measurements have shown a very poor transversal conductivity. Double wall carbon nanotubes have been introduced into the epoxy matrix to increase the electrical conductivity. The conductivity and the degree of dispersion of carbon nanotubes in epoxy matrix were evaluated. The epoxy matrix was filled with 0.4 wt.% of CNTs to ...

  19. Hybrid Carbon Fibers/Carbon Nanotubes Structures for Next Generation Polymeric Composites

    Directory of Open Access Journals (Sweden)

    M. Al-Haik

    2010-01-01

    Full Text Available Pitch-based carbon fibers are commonly used to produce polymeric carbon fiber structural composites. Several investigations have reported different methods for dispersing and subsequently aligning carbon nanotubes (CNTs as a filler to reinforce polymer matrix. The significant difficulty in dispersing CNTs suggested the controlled-growth of CNTs on surfaces where they are needed. Here we compare between two techniques for depositing the catalyst iron used toward growing CNTs on pitch-based carbon fiber surfaces. Electrochemical deposition of iron using pulse voltametry is compared to DC magnetron iron sputtering. Carbon nanostructures growth was performed using a thermal CVD system. Characterization for comparison between both techniques was compared via SEM, TEM, and Raman spectroscopy analysis. It is shown that while both techniques were successful to grow CNTs on the carbon fiber surfaces, iron sputtering technique was capable of producing more uniform distribution of iron catalyst and thus multiwall carbon nanotubes (MWCNTs compared to MWCNTs grown using the electrochemical deposition of iron.

  20. Influence of Fiber Orientation on Single-Point Cutting Fracture Behavior of Carbon-Fiber/Epoxy Prepreg Sheets

    OpenAIRE

    2015-01-01

    The purpose of this article is to investigate the influences of carbon fibers on the fracture mechanism of carbon fibers both in macroscopic view and microscopic view by using single-point flying cutting method. Cutting tools with three different materials were used in this research, namely, PCD (polycrystalline diamond) tool, CVD (chemical vapor deposition) diamond thin film coated carbide tool and uncoated carbide tool. The influence of fiber orientation on the cutting force and fracture to...

  1. Compression Molding of Chemical/Thermal Resistant Composite Materials Using Wastes of Glass Fiber Reinforced PTFE and Carbon Fiber

    OpenAIRE

    Kimura, Teruo

    2013-01-01

    This report proposed the compression molding method of chemical/thermal resistant composite materials reinforced by the carbon fiber extracted from CFRP waste and the waste of glass fiber coated by PTFE. The FEP resin was used for the matrix material. The contents of carbon fiber and FEP resin were varied in the experiments, and the machanical properties of composite materials were discussed in detail. As a result, the bending strength and modulus increased with increasing the content of carb...

  2. Carbon Fibers for Electrically Heated System

    Science.gov (United States)

    1975-05-01

    evaluated by several techniques. Samples of the yarn and fabric were enclosed in clean polyethylene bags which were subsequently heat-seaied and tumbled in...a home clothes dryer without heat. The result- of this test on PVA-sized polyacrylonitrile and rayon precursor yarn and PAN and rayon based fabrics...fabrics which were treated with PVA showed little or no accumulation of carbon/graphite dust within the sealed bag after an hour of tumbling , Fabrics

  3. Analysis of the strength and stiffness of timber beams reinforced with carbon fiber and glass fiber

    Directory of Open Access Journals (Sweden)

    Juliano Fiorelli

    2003-06-01

    Full Text Available An experimental analysis of pinewood beams (Pinus caribea var hondurensis reinforced with glass and/or carbon fibers is discussed. The theoretical model employed to calculate the beam's bending strength takes into account the timber's ultimate limit states of tensile strength and failure by compression, considering a model of fragile elastic tension and plastic elastic compression. The validity of the theoretical model is confirmed by a comparison of the theoretical and experimental results, while the efficiency of the fiber reinforcement is corroborated by the increased strength and stiffness of the reinforced timber beams.

  4. Modified carbon fibers to improve composite properties. [sizing fibers for reduced electrical conductivity and adhesion during combustion

    Science.gov (United States)

    Shepler, R. E.

    1979-01-01

    Thin coatings, 5 to 10 wt. percent, were applied to PAN-based carbon fibers. These coatings were intended to make the carbon fibers less electrically conductive or to cause fibers to stick together when a carbon fiber/epoxy composite burned. The effectiveness of the coatings in these regards was evaluated in burn tests with a test rig designed to simulate burning, impact and wind conditions which might release carbon fibers. The effect of the coatings on fiber and composite properties and handling was also investigated. Attempts at sizing carbon fibers with silicon dioxide, silicon carbide and boron nitride meet with varying degrees of success; however, none of these materials provided an electrically nonconductive coating. Coatings intended to stick carbon fibers together after a composite burned were sodium silicate, silica gel, ethyl silicate, boric acid and ammonium borate. Of these, only the sodium silicate and silica gel provided any sticking together of fibers. The amount of sticking was insufficient to achieve the desired objectives.

  5. Macroscopic Crosslinked Neat Carbon Nanotube Materials and CNT/Carbon Fiber Hybrid Composites: Supermolecular Structure and New Failure Mode Study

    Science.gov (United States)

    2015-10-01

    bubbles in carbon fiber layers were not able to be expelled, resulting in a high void content. In contrast to the CF layers, SEM examination indicated... Reinforcement on the Processing and the Mechanical Behaviour of Carbon Fiber/epoxy Composites. Carbon 2009, 47 (12), 2914–2923. (135) Kharisov, B. I...50  4.4 Permeability  Results

  6. Dry synthesis of lithium intercalated graphite powders and carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Sacci, Robert L [ORNL; Adamczyk, Leslie A [ORNL; Veith, Gabriel M [ORNL; Dudney, Nancy J [ORNL

    2014-01-01

    Herein we describe the direct synthesis of lithium intercalated graphite by heating under vacuum or ball milling under pressurized Ar(g). Both methods allow for stoichometric control of Li-C ratio in batter-grade graphites and carbon fibers prior formation of a solid electrolyte interphase. The products' surface chemistries, as probed by XPS, suggest that LiC6 are extremely reactive with trace amounts of moisture or oxygen. The open circuit potential and SEM data show that the reactivity of the lithiated battery-grade graphite and the carbon fiber can be related to the density of edge/defect sites on the surfaces. Preliminary results of spontaneous SEI formation on Li-graphite in electrolyte are also given.

  7. Activation and micropore structure of carbon-fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    1997-12-01

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The main focus of recent work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites to produce controlled pore structures. Processes have been developed using activation in steam and CO{sub 2}, and a less conventional method involving oxygen chemisorption and subsequent heat treatment. Another objective has been to explore applications for the activated composites in environmental applications related to fossil energy production.

  8. The development of high precision carbon fiber composite mirror

    Science.gov (United States)

    Xu, Liang; Ding, Jiao-teng; Wang, Yong-jie; Xie, Yong-jie; Ma, Zhen; Fan, Xue-wu

    2016-10-01

    Due to low density, high stiffness, low thermal expansion coefficient, duplicate molding, etc., carbon fiber reinforced polymer (CFRP) is one of the potential materials of the optical mirror. The process developed for Φ300mm high precision CFRP mirror described in this paper. A placement tool used to improve laying accuracy up to ± 0.1°.A special reinforced cell structure designed to increase rigidity and thermal stability. Optical replication process adopted for surface modification of the carbon fiber composite mirror blank. Finally, surface accuracy RMS of Φ300mm CFRP mirror is 0.22μm, surface roughness Ra is about 2nm, and the thermal stability can achieve 13nm /°C from the test result. The research content is of some reference value in the infrared as well as visible light applications.

  9. A New Fiber Preform with Nanocarbon Binder for Manufacturing Carbon Fiber Reinforced Composite by Liquid Molding Process.

    Science.gov (United States)

    Seong, Dong Gi; Ha, Jong Rok; Lee, Jea Uk; Lee, Wonoh; Kim, Byung Sun

    2015-11-01

    Carbon fiber reinforced composite has been a good candidate of lightweight structural component in the automotive industry. As fast production speed is essential to apply the composite materials for the mass production area such as automotive components, the high speed liquid composite molding processes have been developed. Fast resin injection through the fiber preform by high pressure is required to improve the production speed, but it often results in undesirable deformations of the fiber preform which causes defectives in size and properties of the final composite products. In order to prevent the undesirable deformation and improve the stability of preform shape, polymer type binder materials are used. More stable fiber preform can be obtained by increasing the amount of binder material, but it disturbs the resin impregnation through the fiber preform. In this study, carbon nanomaterials such as graphene oxide were embedded on the surface of carbon fiber by electrophoretic deposition method in order to improve the shape stability of fiber preform and interfacial bonding between polymer and the reinforcing fiber. Effects of the modified reinforcing fiber were investigated in two respects. One is to increase the binding energy between fiber tows, and the other is to increase the interfacial bonding between polymer matrix and fiber surface. The effects were analyzed by measuring the binding force of fiber preform and interlaminar shear strength of the composite. This study also investigated the high speed liquid molding process of the composite materials composed of polymer matrix and the carbon fiber preforms embedded by carbon nanomaterials. Process parameter such as permeability of fiber preform was measured to investigate the effect of nanoscale surface modification on the macroscale processing condition for composite manufacturing.

  10. Characteristics of Nonafluorobutyl Methyl Ether (NFE) Adsorption onto Activated Carbon Fibers and Different-Size-Activated Carbon Particles.

    Science.gov (United States)

    Tanada; Kawasaki; Nakamura; Araki; Tachibana

    2000-08-15

    The characteristics of adsorption of 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (NFE), a chlorofluorocarbon (CFC) replacement, onto six different activated carbon; preparations (three activated carbon fibers and three different-sized activated carbon particles) were investigated to evaluate the interaction between activated carbon surfaces and NFE. The amount of NFE adsorbed onto the three activated carbon fibers increased with increasing specific surface area and pore volume. The amount of NFE adsorbed onto the three different-sized-activated carbon particles increased with an increase in the particle diameter of the granular activated carbon. The differential heat of the NFE adsorption onto three activated carbon fibers depended on the porosity structure of the activated carbon fibers. The adsorption rate of NFE was also investigated in order to evaluate the efficiency of NFE recovery by the activated carbon surface. The Sameshima equation was used to obtain the isotherms of NFE adsorption onto the activated carbon fibers and different-sized-activated carbon particles. The rate constant k for NFE adsorption onto activated carbon fibers was larger for increased specific surface area and pore volume. The rate of NFE adsorption on activated carbons of three different particle sizes decreased with increasing particle diameter at a low initial pressure. The adsorption isotherms of NFE for the six activated carbons conformed to the Dubinin-Radushkevich equation; the constants BE(0) (the affinity between adsorbate and adsorbent) and W(0) (the adsorption capacity) were calculated. These results indicated that the interaction between the activated carbon and NFE was larger with the smaller specific surface area of the activated carbon fibers and with the smaller particle diameter of the different-sized-activated carbon particles. The degree of packing of NFE in the pores of the activated carbon fibers was greater than that in the pores of the granular activated

  11. Fracture morphology of carbon fiber reinforced plastic composite laminates

    OpenAIRE

    Vinod Srinivasa; Vinay Shivakumar; Vinay Nayaka; Sunil Jagadeeshaiaih; Murali Seethram; Raghavendra Shenoy; Abdelhakim Nafidi

    2010-01-01

    Carbon fiber reinforced plastic (CFRP) composites have been extensively used in fabrication of primary structures for aerospace, automobile and other engineering applications. With continuous and widespread use of these composites in several advanced technology, the frequency of failures is likely to increase. Therefore, to establish the reasons for failures, the fracture modes should be understood thoroughly and unambiguously. In this paper, CFRP composite have been tested in tension, compre...

  12. Raman Spectroscopy for the Nondestructive Testing of Carbon Fiber

    OpenAIRE

    Glenn Washer; Frank Blum

    2008-01-01

    The goal of this research is to evaluate the potential of Raman spectroscopy as a method of condition assessment for carbon fiber composite materials used in high performance situations such as composite overwrapped pressure vessels (COPVs). There are currently limited nondestructive evaluation (NDE) technologies to evaluate these composite materials in situ. Variations in elastic strain in the composite material can manifest from degradation or damage, and as such could provide a tool for co...

  13. Carbon-Fiber/Epoxy Tube Lined With Aluminum Foil

    Science.gov (United States)

    Gernet, Nelson J.; Kerr, Gregory K.

    1995-01-01

    Carbon-fiber/epoxy composite tube lined with welded aluminum foil useful as part of lightweight heat pipe in which working fluid ammonia. Aluminum liner provides impermeability for vacuum seal, to contain ammonia in heat pipe, and to prevent flow of noncondensable gases into heat pipe. Similar composite-material tubes lined with foils also incorporated into radiators, single- and two-phase thermal buses, tanks for storage of cryogenic materials, and other plumbing required to be lightweight.

  14. Carbon fibers: precursor systems, processing, structure, and properties.

    Science.gov (United States)

    Frank, Erik; Steudle, Lisa M; Ingildeev, Denis; Spörl, Johanna M; Buchmeiser, Michael R

    2014-05-19

    This Review gives an overview of precursor systems, their processing, and the final precursor-dependent structure of carbon fibers (CFs) including new developments in precursor systems for low-cost CFs. The following CF precursor systems are discussed: poly(acrylonitrile)-based copolymers, pitch, cellulose, lignin, poly(ethylene), and new synthetic polymeric precursors for high-end CFs. In addition, structure-property relationships and the different models for describing both the structure and morphology of CFs will be presented.

  15. Processing of thermo-structural carbon-fiber reinforced carbon composites

    Directory of Open Access Journals (Sweden)

    Luiz Cláudio Pardini

    2009-06-01

    Full Text Available The present work describes the processes used to obtain thermostructural Carbon/Carbon composites. The processing of these materials begins with the definition of the architecture of the carbon fiber reinforcement, in the form of stacked plies or in the form of fabrics or multidirectional reinforcement. Incorporating fiber reinforcement into the carbon matrix, by filling the voids and interstices, leads to the densification of the material and a continuous increase in density. There are two principal processing routes for obtaining these materials: liquid phase processing and gas phase processing. In both cases, thermal processes lead to the formation of a carbon matrix with specific properties related to their precursor. These processes also differ in terms of yield. With liquid phase impregnation the yield is around 45 per cent, while gas phase processing yields around 15 per cent.

  16. Multiscale Hybrid Micro-Nanocomposites Based on Carbon Nanotubes and Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Fawad Inam

    2010-01-01

    Full Text Available Amino-modified double wall carbon nanotube (DWCNT-NH2/carbon fiber (CF/epoxy hybrid micro-nanocomposite laminates were prepared by a resin infusion technique. DWCNT-NH2/epoxy nanocomposites and carbon fiber/epoxy microcomposites were made for comparison. Morphological analysis of the hybrid composites was performed using field emission scanning electron microscope. A good dispersion at low loadings of carbon nanotubes (CNTs in epoxy matrix was achieved by a bath ultrasonication method. Mechanical characterization of the hybrid micro-nanocomposites manufactured by a resin infusion process included three-point bending, mode I interlaminar toughness, dynamic mechanical analysis, and drop-weight impact testing. The addition of small amounts of CNTs (0.025, 0.05, and 0.1 wt% to epoxy resins for the fabrication of multiscale carbon fiber composites resulted in a maximum enhancement in flexural modulus by 35%, a 5% improvement in flexural strength, a 6% improvement in absorbed impact energy, and 23% decrease in the mode I interlaminar toughness. Hybridization of carbon fiber-reinforced epoxy using CNTs resulted in a reduction in and dampening characteristics, presumably as a result of the presence of micron-sized agglomerates.

  17. Effect of surface modification on carbon fiber and its reinforced phenolic matrix composite

    Science.gov (United States)

    Yuan, Hua; Wang, Chengguo; Zhang, Shan; Lin, Xue

    2012-10-01

    In this work, polyacrylonitrile (PAN)-based carbon fiber were chemically modified with H2SO4, KClO3 and silane coupling agent (γ-aminopropyltriethoxysilane, APS), and carbon fiber reinforced phenolic matrix composites were prepared. The structural and surface characteristics of the carbon fiber were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman scattering (LRS) and Fourier transform infrared spectroscopy (FTIR). Single fiber mechanical properties, specific surface area, composite impact properties and interfacial shear strength (ILSS) were researched to indicate the effects of surface modification on fibers and the interaction between modified fiber surface and phenolic matrix. The results showed that carbon fiber surface modification by oxidation and APS can strengthen fiber surface chemical activity and enlarge the fiber surface area as well as its roughness. When carbon fiber (CF) is oxidized treatment, the oxygen content as well as the O/C ratio will be obviously increased. Oxygen functional groups increase with oxidation time increasing. Carbon fiber treated with APS will make Csbnd Osbnd R content increase and Osbnd Cdbnd O content decrease due to surface reaction. Proper treatment of carbon fiber with acid and silane coupling agent prove an effective way to increase the interfacial adhesion and improve the mechanical and outdoor performance of the resulting fiber/resin composites.

  18. Formation of aromatic thermoplastic and carbon-fiber prepreg by electrochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Li Hong.

    1991-01-01

    A new technique was developed and demonstrated for combining carbon fibers with aromatic thermoplastic matrices to form a high-quality towpreg. The developed technique utilizes an in-situ electrochemical process (Electrochemical polymerization - ECP) to create the entire polymer matrix surrounding the fiber array by direct polymerization of monomer. Poly-paraxylylene (PPX) and derivatives are successfully polymerized in-situ on carbon fiber surfaces through ECP. A PPX/carbon-fiber towpreg with 40 vol % of matrix is achieved in a fairly short reaction time with a high polymer-coating efficiency. Vapor deposition polymerization (VDP) was also studied. PPX and carbon-fiber towpreg were made successfully by this process. A comparison between ECP and VDP was conducted. A study on electrochemical oxidation (ECO) of carbon fibers was also performed. The ECO treatment may be suitable for carbon fibers incorporated in composites with high-temperature curing resins and thermoplastic matrices.

  19. Microstructure and properties of SiC-coated carbon fibers prepared by radio frequency magnetron sputtering

    Science.gov (United States)

    Cheng, Yong; Huang, Xiaozhong; Du, Zuojuan; Xiao, Jianrong; Zhou, Shan; Wei, Yongshan

    2016-04-01

    SiC-coated carbon fibers are prepared at room temperature with different radio-frequency magnetron sputtering powers. Results show that the coated carbon fibers have uniform, continuous, and flawless surfaces. The mean strengths of the coated carbon fibers with different sputtering powers are not influenced by other factors. Filament strength of SiC-coated carbon fibers increases by approximately 2% compared with that of uncoated carbon fibers at a sputtering power of coated fibers increase by 9.3% and 12% at sputtering powers of 250 and 300 W, respectively. However, the mean strength of the SiC-coated carbon fibers decreased by 8% at a sputtering power of 400 W.

  20. Characterization of the major reactions during conversion of lignin to carbon fiber

    Directory of Open Access Journals (Sweden)

    Hendrik Mainka

    2015-10-01

    Full Text Available Lightweight design is an essential part of the overall Volkswagen strategy for reducing the CO2 emissions. The use of carbon fiber offers an enormous lightweight potential. In comparison to steel enabling a mass reduction of up to 70% in automotive parts without a degradation of the functionalities is possible. Today, the use of carbon fiber is limited in mass series applications of the automotive industry by the cost of the conventional C-fiber precursor polyacrylonitrile (PAN. 50% of the cost of a conventional carbon fiber already belongs to the cost of the PAN precursor. Lignin as a precursor for carbon fiber production can realize enormous savings in cost. For qualifying lignin-based carbon fiber for automotive mass production a detailed characterization of this new material is necessary. Therefore, nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy are used. Using the results of these experiments, the major reactions during conversion of lignin to carbon fiber are proposed.

  1. Carbon felt and carbon fiber - A techno-economic assessment of felt electrodes for redox flow battery applications

    Science.gov (United States)

    Minke, Christine; Kunz, Ulrich; Turek, Thomas

    2017-02-01

    Carbon felt electrodes belong to the key components of redox flow batteries. The purpose of this techno-economic assessment is to uncover the production costs of PAN- and rayon-based carbon felt electrodes. Raw material costs, energy demand and the impact of processability of fiber and felt are considered. This innovative, interdisciplinary approach combines deep insights into technical, ecologic and economic aspects of carbon felt and carbon fiber production. Main results of the calculation model are mass balances, cumulative energy demands (CED) and the production costs of conventional and biogenic carbon felts supplemented by market assessments considering textile and carbon fibers.

  2. Ultrasonic Fatigue Endurance of Thin Carbon Fiber Sheets

    Science.gov (United States)

    Domínguez Almaraz, Gonzalo M.; Ruiz Vilchez, Julio A.; Dominguez, Aymeric; Meyer, Yann

    2016-04-01

    Ultrasonic fatigue tests were carried out on thin carbon fiber sheets (0.3 mm of thickness) to determine the fatigue endurance under very high-frequency loading (20 kHz). This material, called the gas diffusion layer (GDL), plays a major role in the overall performances of proton exchange membrane fuel cells (PEMFCs). The study of its physical-chemical properties is an on-going subject in the literature; nevertheless, no knowledge is available concerning the high-frequency fatigue endurance. A principal difficulty in carrying out ultrasonic fatigue tests on this material was to determine the dimensions of testing specimen to fit the resonance condition. This aspect was solved by modal numerical simulation: The testing specimen has been a combination of a low-strength steel frame (to facilitate the attachment to the ultrasonic machine and to increase the mass of the specimen), and the carbon fiber hourglass-shape profile. Under resonance condition, a stationary elastic wave is generated along the specimen that induces high stress at the neck section and high displacements at the ends. Results show that fatigue life was close to 3 × 108 cycles when the high Von Misses stress at the neck section was 170 MPa, whereas fatigue life attains the 4.5 × 109 cycles when stress decreases to 117 MPa. Crack initiation and propagation were analyzed, and conclusions were drawn concerning the fatigue endurance of these fiber carbon sheets under ultrasonic fatigue testing.

  3. Model for the Effect of Fiber Bridging on the Fracture Resistance of Reinforced-Carbon-Carbon

    Science.gov (United States)

    Chan, Kwai S.; Lee, Yi-Der; Hudak, Stephen J., Jr.

    2009-01-01

    A micromechanical methodology has been developed for analyzing fiber bridging and resistance-curve behavior in reinforced-carbon-carbon (RCC) panels with a three-dimensional (3D) composite architecture and a silicon carbide (SiC) surface coating. The methodology involves treating fiber bridging traction on the crack surfaces in terms of a weight function approach and a bridging law that relates the bridging stress to the crack opening displacement. A procedure has been developed to deduce material constants in the bridging law from the linear portion of the K-resistance curve. This report contains information on the application of procedures and outcomes.

  4. Comparison of ORNL Low Cost Carbon Fiber with Commercially Available Industrial Grade Carbon Fiber in Pultrusion Samples

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Jr, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McCay, Jeff A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Connie D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-01

    Composite Applications Group LLC in collaboration with Heil Trailer International partnered in a project to design and develop solutions for light weighting of aluminum dry bulk tank trailers. The project approach was to utilize pultruded composite sections in place of aluminum components to reduce weight thereby saving energy through more efficient transport. Low cost carbon fiber was evaluated as a potential cost saving option that could enhance weight savings at reduced cost versus current commercial material.

  5. Photoelectrochemical cell using dye sensitized zinc oxide nanowires grown on carbon fibers

    Science.gov (United States)

    Unalan, Husnu Emrah; Wei, Di; Suzuki, Kenichi; Dalal, Sharvari; Hiralal, Pritesh; Matsumoto, Hidetoshi; Imaizumi, Shinji; Minagawa, Mie; Tanioka, Akihiko; Flewitt, Andrew J.; Milne, William I.; Amaratunga, Gehan A. J.

    2008-09-01

    Zinc oxide (ZnO) nanowires (NWs) grown on carbon fibers using a vapor transport and condensation approach are used as the cathode of a photoelectrochemical cell. The carbon fibers were obtained by electrospray deposition and take the form of a flexible carbon fabric. The ZnO NW on carbon fiber anode is combined with a "black dye" photoabsorber, an electrolyte, and a platinum (Pt) counterelectrode to complete the cell. The results show that ZnO NW and carbon fibers can be used for photoinduced charge separation/charge transport and current collection, respectively, in a photoelectrochemical cell.

  6. Enhanced performance of electrospun carbon fibers modified with carbon nanotubes: promising electrodes for enzymatic biofuel cells.

    Science.gov (United States)

    Engel, A Both; Cherifi, A; Tingry, S; Cornu, D; Peigney, A; Laurent, Ch

    2013-06-21

    New nanostructured electrodes, promising for the production of clean and renewable energy in biofuel cells, were developed with success. For this purpose, carbon nanofibers were produced by the electrospinning of polyacrylonitrile solution followed by convenient thermal treatments (stabilization followed by carbonization at 1000, 1200 and 1400° C), and carbon nanotubes were adsorbed on the surfaces of the fibers by a dipping method. The morphology of the developed electrodes was characterized by several techniques (SEM, Raman spectroscopy, electrical conductivity measurement). The electrochemical properties were evaluated through cyclic voltammetry, where the influence of the carbonization temperature of the fibers and the beneficial contribution of the carbon nanotubes were observed through the reversibility and size of the redox peaks of K3Fe(CN)6 versus Ag/AgCl. Subsequently, redox enzymes were immobilized on the electrodes and the electroreduction of oxygen to water was realized as a test of their efficiency as biocathodes. Due to the fibrous and porous structure of these new electrodes, and to the fact that carbon nanotubes may have the ability to promote electron transfer reactions of redox biomolecules, the new electrodes developed were capable of producing higher current densities than an electrode composed only of electrospun carbon fibers.

  7. Process Optimization of Bismaleimide (BMI) Resin Infused Carbon Fiber Composite

    Science.gov (United States)

    Ehrlich, Joshua W.; Tate, LaNetra C.; Cox, Sarah B.; Taylor, Brian J.; Wright, M. Clara; Faughnan, Patrick D.; Batterson, Lawrence M.; Caraccio, Anne J.; Sampson, Jeffery W.

    2013-01-01

    Engineers today are presented with the opportunity to design and build the next generation of space vehicles out of the lightest, strongest, and most durable materials available. Composites offer excellent structural characteristics and outstanding reliability in many forms that will be utilized in future aerospace applications including the Commercial Crew and Cargo Program and the Orion space capsule. NASA's Composites for Exploration (CoEx) project researches the various methods of manufacturing composite materials of different fiber characteristics while using proven infusion methods of different resin compositions. Development and testing on these different material combinations will provide engineers the opportunity to produce optimal material compounds for multidisciplinary applications. Through the CoEx project, engineers pursue the opportunity to research and develop repair patch procedures for damaged spacecraft. Working in conjunction with Raptor Resins Inc., NASA engineers are utilizing high flow liquid infusion molding practices to manufacture high-temperature composite parts comprised of intermediate modulus 7 (IM7) carbon fiber material. IM7 is a continuous, high-tensile strength composite with outstanding structural qualities such as high shear strength, tensile strength and modulus as well as excellent corrosion, creep, and fatigue resistance. IM7 carbon fiber, combined with existing thermoset and thermoplastic resin systems, can provide improvements in material strength reinforcement and deformation-resistant properties for high-temperature applications. Void analysis of the different layups of the IM7 material discovered the largest total void composition within the [ +45 , 90 , 90 , -45 ] composite panel. Tensile and compressional testing proved the highest mechanical strength was found in the [0 4] layup. This paper further investigates the infusion procedure of a low-cost/high-performance BMI resin into an IM7 carbon fiber material and the

  8. Thermal conductivity, electrical conductivity and specific heat of copper-carbon fiber composite

    Science.gov (United States)

    Kuniya, Keiichi; Arakawa, Hideo; Kanai, Tsuneyuki; Chiba, Akio

    1988-01-01

    A new material of copper/carbon fiber composite is developed which retains the properties of copper, i.e., its excellent electrical and thermal conductivity, and the property of carbon, i.e., a small thermal expansion coefficient. These properties of the composite are adjustable within a certain range by changing the volume and/or the orientation of the carbon fibers. The effects of carbon fiber volume and arrangement changes on the thermal and electrical conductivity, and specific heat of the composite are studied. Results obtained are as follows: the thermal and electrical conductivity of the composite decrease as the volume of the carbon fiber increases, and were influenced by the fiber orientation. The results are predictable from a careful application of the rule of mixtures for composites. The specific heat of the composite was dependent, not on fiber orientation, but on fiber volume. In the thermal fatigue tests, no degradation in the electrical conductivity of this composite was observed.

  9. Nanocomposite fibers and film containing polyolefin and surface-modified carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Chu,Benjamin (Setauket, NY); Hsiao, Benjamin S. (Setauket, NY)

    2010-01-26

    Methods for modifying carbon nanotubes with organic compounds are disclosed. The modified carbon nanotubes have enhanced compatibility with polyolefins. Nanocomposites of the organo-modified carbon nanotubes and polyolefins can be used to produce both fibers and films having enhanced mechanical and electrical properties, especially the elongation-to-break ratio and the toughness of the fibers and/or films.

  10. Hybrid use of steel and carbon-fiber reinforced concrete for monitoring of crack behavior

    OpenAIRE

    Ding, Yining; Han, Z; Zhang, Y; Azevedo, Cecília Maria

    2012-01-01

    In order to study the damage after concrete cracking, the influence of the combined use of steel fiber and carbon fiber on the conductivity and crack resistance of concrete beam under flexural loading were investigated. Carbon fiber and steel fiber were added as diphasic conductive materials to produce the electric conductive and ductile concrete. This paper reports the experimental and analytical work associated with establishing the crack width in relation to the fractional c...

  11. Influence of Fiber Orientation on Single-Point Cutting Fracture Behavior of Carbon-Fiber/Epoxy Prepreg Sheets

    Directory of Open Access Journals (Sweden)

    Yingying Wei

    2015-10-01

    Full Text Available The purpose of this article is to investigate the influences of carbon fibers on the fracture mechanism of carbon fibers both in macroscopic view and microscopic view by using single-point flying cutting method. Cutting tools with three different materials were used in this research, namely, PCD (polycrystalline diamond tool, CVD (chemical vapor deposition diamond thin film coated carbide tool and uncoated carbide tool. The influence of fiber orientation on the cutting force and fracture topography were analyzed and conclusions were drawn that cutting forces are not affected by cutting speeds but significantly influenced by the fiber orientation. Cutting forces presented smaller values in the fiber orientation of 0/180° and 15/165° but the highest one in 30/150°. The fracture mechanism of carbon fibers was studied in different cutting conditions such as 0° orientation angle, 90° orientation angle, orientation angles along fiber direction, and orientation angles inverse to the fiber direction. In addition, a prediction model on the cutting defects of carbon fiber reinforced plastic was established based on acoustic emission (AE signals.

  12. Aligned Carbon Nanotube Reinforcement of Aerospace Carbon Fiber Composites: Substructural Strength Evaluation for Aerostructure Applications

    OpenAIRE

    Guzman de Villoria, Roberto; Ydrefors, L.; Hallander, P.; Ishiguro, Kyoko; Nordin, P.; Wardle, Brian L.

    2012-01-01

    Vertically aligned carbon nanotubes (VACNTs) are placed between all plies in an aerospace carbon fiber reinforced plastic laminate (unidirectional plies, [(0/90/±45)2]s) to reinforce the interlaminar region in the z-direction. Significant improvement in Mode I and II interlaminar toughness have been observed previously. In this work, several substructural in-plane strength tests relevant to aerostructures were undertaken: bolt/tension-bearing, open hole compression, and L-shape laminate be...

  13. Multi-scale Rule-of-Mixtures Model of Carbon Nanotube/Carbon Fiber/Epoxy Lamina

    Science.gov (United States)

    Frankland, Sarah-Jane V.; Roddick, Jaret C.; Gates, Thomas S.

    2005-01-01

    A unidirectional carbon fiber/epoxy lamina in which the carbon fibers are coated with single-walled carbon nanotubes is modeled with a multi-scale method, the atomistically informed rule-of-mixtures. This multi-scale model is designed to include the effect of the carbon nanotubes on the constitutive properties of the lamina. It included concepts from the molecular dynamics/equivalent continuum methods, micromechanics, and the strength of materials. Within the model both the nanotube volume fraction and nanotube distribution were varied. It was found that for a lamina with 60% carbon fiber volume fraction, the Young's modulus in the fiber direction varied with changes in the nanotube distribution, from 138.8 to 140 GPa with nanotube volume fractions ranging from 0.0001 to 0.0125. The presence of nanotube near the surface of the carbon fiber is therefore expected to have a small, but positive, effect on the constitutive properties of the lamina.

  14. Electromagnetic Wave Shieding Effectiveness of Carbon Fiber Sheet Coated Ferrite Film by Microwave-Hydrothermal Process

    Science.gov (United States)

    Murakami, Ri Ichi; Yamamoto, Hidetoshi; Kim, Chan Kong; Yim, Cheol Mun; Kim, Yun Hae

    The developments of electromagnetic wave shielding materials are strongly required because the malfunction of electronic equipment, mobile phone and wireless LAN avoids. In this study, it was investigated that the electromagnetic shielding effectiveness of carbon fiber sheets were enhanced by the ferrite which was coated by the microwave hydrothermal process. For coated carbon fiber sheet, the effects of ferrite and lamination of carbon fiber textile on the electromagnetic wave shielding effectiveness were discussed. In the range of frequency (100 1 GHz), the electromagnetic wave shielding effectiveness was measured by using TEM-Cell. The electromagnetic wave shielding effectiveness was greater for the coated carbon fiber sheets than for the uncoated carbon fiber sheets. When the insulation film was located between two carbon fiber sheets, the electromagnetic wave shielding effectiveness increased.

  15. ELECTRO-THERMAL EFFECTS AND DEFORMATION RESPONSE OF CARBON FIBER MAT CEMENT BEAMS

    Institute of Scientific and Technical Information of China (English)

    ZhuSirong; LiZhuoqiu; SongXianhui

    2003-01-01

    A carbon fiber mat is a sheet composed of intercrossing short carbon fibers, which has more stable and lower electrical resistivity compared with dispersed short carbon fiber mixed in cement. Thereby carbon fiber mat cement could exhibit obvious electro-thermal effect. When electrified, the temperature of composite structures made up of cement mortar and carbon fiber mat will rise rapidly. If the temperature field is not uniform, temperature difference will cause structures to deform, which can be used to adjust the deformation of structures. The temperature field and deformation response driven by the electro-thermal effects of a type of carbon fiber mat cement beams are studied. Firstly, the temperature and deformation responses are studied using theories of thermal conduction and elasticity. Secondly, experimental results are given to verify the theoretical solution. These two parts lay the foundation for temperature and deformation adjustment.

  16. Influence of thermal treatment on porosity formation on carbon fiber from textile PAN

    Directory of Open Access Journals (Sweden)

    Jossano Saldanha Marcuzzo

    2012-01-01

    Full Text Available Activated carbon fibers (ACFs are known as an excellent adsorbent material due to their particular characteristics such as their high speed adsorption rate and for being easy to handle. The ACFs are commercially manufactured from carbon fibers (CF which receive an additional activation process and can be produced from celluloses, phenolic resin, pitch and Polyacrylonitrile (PAN. In the present work, the oxidized 5.0 dtex textile PAN fiber was carbonized to CFs formation. During the carbonization process in different heating rates, the topographic features changes on fibers were monitored in order to determine the best carbonization condition for CFs production to be used as raw material for ACF. Different heating rates and maximum temperature of treatment were tested and the results indicated that it is possible to produce poorly activated carbon fiber, directly from oxidized textile PAN fiber, by one single step production process.

  17. Effects of Graphene Oxide Modified Sizing Agents on Interfacial Properties of Carbon Fibers/Epoxy Composites.

    Science.gov (United States)

    Zhang, Qingbo; Jiang, Dawei; Liu, Li; Huang, Yudong; Long, Jun; Wu, Guangshun; Wu, Zijian; Umar, Ahmad; Guo, Jiang; Zhang, Xi; Guo, Zhanhu

    2015-12-01

    A kind of graphene oxide (GO) modified sizing agent was used to improve the interfacial properties of carbon fibers/epoxy composites. The surface topography of carbon fibers was investigated by scanning electron microscopy (SEM). The surface compositions of carbon fibers were determined by X-ray photoelectron spectroscopy (XPS) and the interfacial properties of composites were studied by interlaminar shear strength (ILSS). The results show that the existence of GO increases the content of reactive functional groups on carbon fiber surface. Thus it enhances the interfacial properties of carbon fibers/epoxy composites. When GO loading in sizing agents is 1 wt%, the ILSS value of composite reaches to 96.2 MPa, which is increased by 27.2% while comparing with unsized carbon fiber composites. Furthermore, the ILSS of composites after aging is also increased significantly with GO modified sizing agents.

  18. Influence of thermal treatment on porosity formation on carbon fiber from textile PAN

    Directory of Open Access Journals (Sweden)

    Jossano Saldanha Marcuzzo

    2013-02-01

    Full Text Available Activated carbon fibers (ACFs are known as an excellent adsorbent material due to their particular characteristics such as their high speed adsorption rate and for being easy to handle. The ACFs are commercially manufactured from carbon fibers (CF which receive an additional activation process and can be produced from celluloses, phenolic resin, pitch and Polyacrylonitrile (PAN. In the present work, the oxidized 5.0 dtex textile PAN fiber was carbonized to CFs formation. During the carbonization process in different heating rates, the topographic features changes on fibers were monitored in order to determine the best carbonization condition for CFs production to be used as raw material for ACF. Different heating rates and maximum temperature of treatment were tested and the results indicated that it is possible to produce poorly activated carbon fiber, directly from oxidized textile PAN fiber, by one single step production process.

  19. Carbon Fibers from UV-Assisted Stabilization of Lignin-Based Precursors

    Directory of Open Access Journals (Sweden)

    Meng Zhang

    2015-06-01

    Full Text Available Production of high strength carbon fibers from bio-derived precursors is of topical interest. Recently, we reported on dry-spinning of a partially acetylated softwood kraft lignin to produce carbon fibers with superior properties, but the thermo-oxidative stabilization step required a long time due to a slow heating rate needed to prevent the fibers from being heated too rapidly and sticking to each other. Here we report a rapid strategy of dual UV-thermoxidative stabilization (crosslinking of dry-spun lignin fibers that significantly reduces the stabilization time. The fibers undergo reaction close to the surface such that they can be subsequently thermally stabilized at a rapid heating rate without fibers fusing together, which reduces the total stabilization time significantly from 40 to 4 h. Consequently, the glass transition temperature of UV irradiated fibers was about 15 °C higher than that of fibers without UV treatment. Stabilized fibers were successfully carbonized at 1000 °C and resulting carbon fibers displayed a tensile strength of 900 ± 100 MPa, which is amongst the highest reported for carbon fibers derived from softwood lignin-based precursors. These results establish that UV irradiation is a rapid step that can effectively shorten the total stabilization time for production of lignin-derived carbon fibers.

  20. [Raman spectra of PAN-based carbon fibers during surface treatment].

    Science.gov (United States)

    Cao, Wei-wei; Zhu, Bo; Jing, Min; Wang, Cheng-guo

    2008-12-01

    Laser Raman spectroscopy was employed to characterize the microstructure changes of PAN based carbon fibers among different surface treatments, and the characteristics of first-order Raman spectra of carbon fibers during surface treatment were investigated in the present paper. The results show that the variety of carbon fibers' phase structures can be represented by Raman spectroscopy parameters, such as the Raman frequency shifts of main D and G bands, FWHMs and additive bands' area ratios at the positions of different Raman frequency shifts. During different surface treatment, some changes in the first-order Raman spectroscopy parameters of PAN based carbon fibers were observed, the Raman frequency shifts of D and G bands moved toward higher wavenumber, and the values of R(I(D)/I(G)) also improved, which can be used to measure the graphite crystallite size of carbon fiber. It is suggested that the graphite microstructure of carbon fibers is decomposed during surface treatment, the crystallite size is reduced, and the activity of the graphite crystallite boundary is improved. Moreover, the full-widths at half maximum (FWHM) of D and G bands both decrease, which can give information on the order of graphite microstructure and the quantity of defects in carbon fibers, and the relative bands' areas of A and D" bands also decrease, which can be attributed to the structure of amorphous carbon or some kinds of organic functional groups in carbon fibers. These differences among the spectra demonstrate that the structure of amorphous carbon in carbon fibers is easier to oxidize or decompose than multilayer graphite structure, so the relative proportion of amorphous carbon decreases during surface treatment. The conclusions obtained by Raman spectra are basically in agreement with the improvement of apparent crystallization degrees of carbon fibers during surface treatment, which were calculated by X-ray diffraction method. So the variety rules of carbon fibers' phase

  1. Tailoring micro-mesoporosity in activated carbon fibers to enhance SO₂ catalytic oxidation.

    Science.gov (United States)

    Diez, Noel; Alvarez, Patricia; Granda, Marcos; Blanco, Clara; Gryglewicz, Grażyna; Wróbel-Iwaniec, Iwona; Sliwak, Agata; Machnikowski, Jacek; Menendez, Rosa

    2014-08-15

    Enhanced SO2 adsorption of activated carbon fibers is obtained by tailoring a specific micro-mesoporous structure in the fibers. This architecture is obtained via metal catalytic activation of the fibers with a novel precursor, cobalt naphthenate, which contrary to other precursors, also enhances spinnability and carbon fiber yield. In the SO2 oxidation, it is demonstrated that the combination of micropores and large mesopores is the main factor for an enhanced catalytic activity which is superior to that observed in other similar microporous activated carbon fibers. This provides an alternative way for the development of a new generation of catalytic material.

  2. Fabrication and characterization of poly(vinyl alcohol)/carbon nanotube melt-spinning composites fiber

    OpenAIRE

    Zhiqian Yang; Degen Xu; Jianzhong Liu; Jiaping Liu; Lin Li; Lihui Zhang; Jin Lv

    2015-01-01

    A composite fiber based on carbon nanotube (CNT) and poly(vinyl alcohol) (PVA) was prepared by melt-spinning. Structural features and the mechanical performances of the PVA/CNT composite fiber were investigated as a function of draw condition. Initial moduli and tensile strengths of the drawn composite fibers are much higher than those of undrawn composite fiber. It is identified from XRD and 2D XRD that the composite fiber exhibits enhanced crystallinity and orientation degree with increasin...

  3. A small-scale test for fiber release from carbon composites. [pyrolysis and impact

    Science.gov (United States)

    Gilwee, W. J., Jr.; Fish, R. H.

    1980-01-01

    A test method was developed to determine relative fiber loss from pyrolyzed composites with different resins and fiber construction. Eleven composites consisting of woven and unwoven carbon fiber reinforcement and different resins were subjected to the burn and impact test device. The composites made with undirectional tape had higher fiber loss than those with woven fabric. Also, the fiber loss was inversely proportional to the char yield of the resin.

  4. Hierarchical Carbon Fibers with ZnO Nanowires for Volatile Sensing in Composite Curing (Postprint)

    Science.gov (United States)

    2014-07-01

    AFRL-RX-WP-JA-2014-0171 HIERARCHICAL CARBON FIBERS WITH ZnO NANOWIRES FOR VOLATILE SENSING IN COMPOSITE CURING (POSTPRINT) Gregory...REPORT TYPE Interim 3. DATES COVERED (From – To) 16 April 2012 – 02 June 2014 4. TITLE AND SUBTITLE HIERARCHICAL CARBON FIBERS WITH ZnO NANOWIRES...needed to demonstrate the use of Zinc Oxide ( ZnO ) nanowire coated carbon fibers as a volatile sensor. ZnO nanowires are demonstrated to function as

  5. Application of carbon fibers to biomaterials: a new era of nano-level control of carbon fibers after 30-years of development.

    Science.gov (United States)

    Saito, Naoto; Aoki, Kaoru; Usui, Yuki; Shimizu, Masayuki; Hara, Kazuo; Narita, Nobuyo; Ogihara, Nobuhide; Nakamura, Koichi; Ishigaki, Norio; Kato, Hiroyuki; Haniu, Hisao; Taruta, Seiichi; Kim, Yoong Ahm; Endo, Morinobu

    2011-07-01

    Carbon fibers are state-of-the-art materials with properties that include being light weight, high strength, and chemically stable, and are applied in various fields including aeronautical science and space science. Investigation of applications of carbon fibers to biomaterials was started 30 or more years ago, and various products have been developed. Because the latest technological progress has realized nano-level control of carbon fibers, applications to biomaterials have also progressed to the age of nano-size. Carbon fibers with diameters in the nano-scale (carbon nanofibers) dramatically improve the functions of conventional biomaterials and make the development of new composite materials possible. Carbon nanofibers also open possibilities for new applications in regenerative medicine and cancer treatment. The first three-dimensional constructions with carbon nanofibers have been realized, and it has been found that the materials could be used as excellent scaffolding for bone tissue regeneration. In this critical review, we summarize the history of carbon fiber application to the biomaterials and describe future perspectives in the new age of nano-level control of carbon fibers (122 references).

  6. Strengthened PAN-based carbon fibers obtained by slow heating rate carbonization.

    Science.gov (United States)

    Kim, Min-A; Jang, Dawon; Tejima, Syogo; Cruz-Silva, Rodolfo; Joh, Han-Ik; Kim, Hwan Chul; Lee, Sungho; Endo, Morinobu

    2016-03-23

    Large efforts have been made over the last 40 years to increase the mechanical strength of polyacrylonitrile (PAN)-based carbon fibers (CFs) using a variety of chemical or physical protocols. In this paper, we report a new method to increase CFs mechanical strength using a slow heating rate during the carbonization process. This new approach increases both the carbon sp(3) bonding and the number of nitrogen atoms with quaternary bonding in the hexagonal carbon network. Theoretical calculations support a crosslinking model promoted by the interstitial carbon atoms located in the graphitic interlayer spaces. The improvement in mechanical performance by a controlled crosslinking between the carbon hexagonal layers of the PAN based CFs is a new concept that can contribute further in the tailoring of CFs performance based on the understanding of their microstructure down to the atomic scale.

  7. Anchor Modeling

    Science.gov (United States)

    Regardt, Olle; Rönnbäck, Lars; Bergholtz, Maria; Johannesson, Paul; Wohed, Petia

    Maintaining and evolving data warehouses is a complex, error prone, and time consuming activity. The main reason for this state of affairs is that the environment of a data warehouse is in constant change, while the warehouse itself needs to provide a stable and consistent interface to information spanning extended periods of time. In this paper, we propose a modeling technique for data warehousing, called anchor modeling, that offers non-destructive extensibility mechanisms, thereby enabling robust and flexible management of changes in source systems. A key benefit of anchor modeling is that changes in a data warehouse environment only require extensions, not modifications, to the data warehouse. This ensures that existing data warehouse applications will remain unaffected by the evolution of the data warehouse, i.e. existing views and functions will not have to be modified as a result of changes in the warehouse model.

  8. Laser cutting of carbon fiber reinforced thermo-plastics (CFRTP) by single-mode fiber laser irradiation

    Science.gov (United States)

    Niino, Hiroyuki; Kawaguchi, Yoshizo; Sato, Tadatake; Narazaki, Aiko; Kurosaki, Ryozo; Muramatsu, Mayu; Harada, Yoshihisa; Anzai, Kenji; Aoyama, Mitsuaki; Matsushita, Masafumi; Furukawa, Koichi; Nishino, Michiteru; Fujisaki, Akira; Miyato, Taizo; Kayahara, Takashi

    2014-03-01

    We report on the laser cutting of carbon fiber reinforced thermo-plastics (CFRTP) with a cw IR fiber laser (single-mode fiber laser, average power: 350 W). CFRTP is a high strength composite material with a lightweight, and is increasingly being used various applications. A well-defined cutting of CFRTP which were free of debris and thermal-damages around the grooves, were performed by the laser irradiation with a fast beam galvanometer scanning on a multiple-scanpass method.

  9. Fabrication of Ultrafine Carbon Fibers Possessing a Nanoporous Structure from Electrospun Polyvinyl Alcohol Fibers Containing Silica Nanoparticles

    OpenAIRE

    2014-01-01

    Ultrafine carbon fibers with a nanoporous structure were fabricated by the template method using silica nanoparticles (NPs) embedded in fibers of approximate diameter 500 nm, electrospun from an aqueous solution of polyvinyl alcohol, CoCl2, silica NPs, and N,N-dimethylformamide. Black, conductive fibers were obtained by heat treatment in air and a chemical vapor deposition reaction under methanol vapor for more than 5 h. Transmission electron microscopy (TEM) demonstrated that the fabricated ...

  10. Towards the carbon fibers in the building industry

    Directory of Open Access Journals (Sweden)

    Miravete, A.

    2001-12-01

    Full Text Available There are two mainstreams in the building industry in the area of carbon fibers: rehabilitation and use as building material. The using of carbon fiber as a building material is taking place slower than as rehab system due to the very low cost of traditional building materials, the limitations of composite structure manufacturing processes and the conservative building regulations concerning materials in all the industrialized countries. However, these three issues are being solved in a very efficient way, as we will see along the coming paragraphs of this paper. This paper is split in two parts, first the carbon fiber as a material system, its typologies, manufacturing processes and industrial presentations will be described. Second, rehab and building applications will be analyzed.

    En el área de fibra de carbono en la construcción hay actualmente dos líneas de trabajo: reparaciones e implantación en obra: La implantación en la obra civil está avanzando más despacio que la utilización en reparaciones debido al bajo coste de los materiales tradicionales, a la limitación de procesos de fabricación de estructuras de materiales compuestos y al conservadurismo de las normativas de edificación y obra civil en todos los países industrializados. Sin embargo, los tres asuntos mencionados están siendo abordados con eficiencia, como se explicará más adelante. En el presente artículo, se va a describir, el primer lugar, la fibra de carbono, sus tipos, procesos de fabricación y presentaciones industriales. En segundo lugar se tratarán las aplicaciones en la construcción, haciendo énfasis en las reparaciones y en la implantación en obra civil.

  11. RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E; Eric Skidmore, E

    2008-12-12

    The Department of Energy Savannah River Site vitrifies nuclear waste incident to defense programs through its Defense Waste Processing Facility (DWPF). The piping in the DWPF seal pot jumper configuration must withstand the stresses during an unlikely but potential deflagration event, and maintain its safety function for a 20-year service life. Carbon fiber-reinforced epoxy composites (CFR) were proposed for protection and reinforcement of piping during such an event. The proposed CFR materials have been ASME-approved (Section XI, Code Case N-589-1) for post-construction maintenance and is DOT-compliant per 49CFR 192 and 195. The proposed carbon fiber/epoxy composite reinforcement system was originally developed for pipeline rehabilitation and post-construction maintenance in petrochemical, refineries, DOT applications and other industries. The effects of ionizing radiation on polymers and organic materials have been studied for many years. The majority of available data are based on traditional exposures to gamma irradiation at high dose rates ({approx}10,000 Gy/hr) allowing high total dose within reasonable test periods and general comparison of different materials exposed at such conditions. However, studies in recent years have shown that degradation of many polymers are sensitive to dose rate, with more severe degradation often observed at similar or even lower total doses when exposed to lower dose rates. This behavior has been primarily attributed to diffusion-limited oxidation which is minimized during very high dose rate exposures. Most test standards for accelerated aging and nuclear qualification of components acknowledge these limitations. The results of testing to determine the radiation resistance and microstructural effects of gamma irradiation exposure on a bisphenol-A based epoxy matrix composite reinforced with carbon fibers are presented. This work provides a foundation for a more extensive evaluation of dose rate effects on advanced epoxy

  12. Electron microscopy investigation of interface between carbon fiber and ultra high molecular weight polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Stepashkin, A.A.; Chukov, D.I., E-mail: dil_chukov@yahoo.com; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-02-15

    Highlights: • Effect of the carbon fibers surface treatments on the adhesive interactions in UHMWPE composites was studied. • Air oxidation of carbon filler ensures most significant increase in adhesion interaction in UHMWPE based composites. • Nanosized UHMWPE fibers with 20–40 nm in diameter and with 6–10 μm in length, was observed on the surface of carbon fibers. -- Abstract: Scanning electron microscopy was used to investigate the surface of initial and modified high-strength and high-modulus carbon fibers as well as interfaces in the ultra high molecular weight polyethylene, filled with above-mentioned fibers. Effect of the fibers surface modifying method on the adhesive interactions in composites was studied. It was observed that interaction of matrix with a modified surface of fibers results in a formation of bonds with strength higher than the yield strength of the polymer. It results in a formation of long nanosized polymer wires at tensile fracture of composites.

  13. Surface Characteristics of Rare Earth Treated Carbon Fibers and Interfacial Properties of Composites

    Institute of Scientific and Technical Information of China (English)

    Xu Zhiwei; Huang Yudong; Song Yuanjun; Zhang Chunhua; Liu Li

    2007-01-01

    Effect of rare earth treatment on surface physicochemical properties of carbon fibers and interfacial properties of carbon fiber/epoxy composites was investigated, and the interfacial adhesion mechanism of treated carbon fiber/epoxy composite was analyzed. It was found that rare earth treatment led to an increase of fiber surface roughness, improvement of oxygen-containing groups, and introduction of rare earth element on the carbon fiber surface. As a result, coordination linkages between fibers and rare earth, and between rare earth and resin matrix were formed separately, thereby the interlaminar shear strength (ILSS) of composites increased, which indicated the improvement of the interfacial adhesion between fibers and matrix resin resulting from the increase of carboxyl and carbonyl.

  14. Carbon nanotube coated fiber Bragg grating for photomechanical optic modulator.

    Science.gov (United States)

    Shivananju, B N; Suri, Ashish; Asokan, Sundarrajan; Misra, Abha

    2013-09-01

    We have demonstrated novel concept of utilizing the photomechanical actuation in carbon nanotubes (CNTs) to tune and reversibly switch the Bragg wavelength. When fiber Bragg grating coated with CNTs (CNT-FBG) is exposed externally to a wide range of optical wavelengths, e.g., ultraviolet to infrared (0.2-200 μm), a strain is induced in the CNTs which alters the grating pitch and refractive index in the CNT-FBG system resulting in a shift in the Bragg wavelength. This novel approach will find applications in telecommunication, sensors and actuators, and also for real time monitoring of the photomechanical actuation in nanoscale materials.

  15. Defect depth measurement of carbon fiber reinforced polymers by thermography

    Science.gov (United States)

    Chen, Terry Y.; Chen, Jian-Lun

    2016-01-01

    Carbon fiber reinforced polymers has been widely used in all kind of the industries. However the internal defects can result in the change of material or mechanical properties, and cause safety problem. In this study, step-heating thermography is employed to measure the time series temperature distribution of composite plate. The principle of heat conduction in a flat plate with defect inside is introduced. A temperature separation criterion to determine the depth of defect inside the specimen is obtained experimentally. Applying this criterion to CFRP specimens with embedded defects, the depth of embedded defect in CFRP can be determined quite well from the time series thermograms obtained experimentally.

  16. Damage-tolerant composite materials produced by stitching carbon fibers

    Science.gov (United States)

    Dow, Marvin B.; Smith, Donald L.

    1989-01-01

    NASA-Langley has undertaken the investigation of composite damage-tolerance enhancement and fabrication economies-maximization via reinforcement-stitching, in combination with resin transfer molding. Attention is given to results obtained by an experimental evaluation of composites tailored for damage tolerance by stitching layers of dry carbon-fiber fabric with closely-spaced threads, in order to furnish through-the-thickness reinforcement. Various stitching patterns and thread materials have been evaluated, using flat-plate specimens; blade-stiffened structural elements have been fabricated and tested. The results presented indicate that stitched laminates furnish damage tolerance performance comparable to that of more expensive, toughened-matrix composites.

  17. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Cuiqin [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Julin, E-mail: julinwang@126.com [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Tao [Beijing Institute of Ancient Architecture, Beijing 100050 (China)

    2014-12-01

    Graphical abstract: - Highlights: • COOH-CNTs can react with sizing agent, and the optimum reaction ratio was 1:20. • Carbon fibers were dipped into the mixture bath of CNTs and sizing agent. • SEM results indicate that fibers surfaces were coated with CNTs and sizing agent. • ILSS was increased by 67.01% for the composites after the mixture coating process. • Single fibers tensile strength was maintained after the deposited process. - Abstract: The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer.

  18. A carbonyl iron/carbon fiber material for electromagnetic wave absorption.

    Science.gov (United States)

    Youh, Meng-Jey; Wu, Hung-Chih; Lin, Wang-Hua; Chiu, Sheng-Cheng; Huang, Chien-Fa; Yu, Hsin-Chih; Hsu, Jen-Sung; Li, Yuan-Yao

    2011-03-01

    A carbonyl iron/carbon fiber material consisting of carbon fibers grown on micrometer-sized carbonyl iron sphere, was synthesized by chemical vapor deposition using a mixture of C2H2 and H2. The hollow-core carbon fibers (outer diameter: 140 nm and inner diameter: 40 nm) were composed of well-ordered graphene layers which were almost parallel to the long axis of the fibers. A composite (2 mm thick) consisting of the carbonyl iron/carbon fibers and epoxy resin demonstrated excellent electromagnetic (EM) wave absorption. Minimum reflection losses of -36 dB (99.95% of EM wave absorption) at 7.6 GHz and -32 dB (99.92% of EM wave absorption) at 34.1 GHz were achieved. The well-dispersed and network-like carbon fibers in the resin matrix affected the dielectric loss of the EM wave while the carbonyl iron affected the magnetic loss.

  19. Hybrid carbon fiber/carbon nanotube composites for structural damping applications.

    Science.gov (United States)

    Tehrani, M; Safdari, M; Boroujeni, A Y; Razavi, Z; Case, S W; Dahmen, K; Garmestani, H; Al-Haik, M S

    2013-04-19

    Carbon nanotubes (CNTs) were grown on the surface of carbon fibers utilizing a relatively low temperature synthesis technique; graphitic structures by design (GSD). To probe the effects of the synthesis protocols on the mechanical properties, other samples with surface grown CNTs were prepared using catalytic chemical vapor deposition (CCVD). The woven graphite fabrics were thermally shielded with a thin film of SiO2 and CNTs were grown on top of this film. Raman spectroscopy and electron microscopy revealed the grown species to be multi-walled carbon nanotubes (MWCNTs). The damping performance of the hybrid CNT-carbon fiber-reinforced epoxy composite was examined using dynamic mechanical analysis (DMA). Mechanical testing confirmed that the degradations in the strength and stiffness as a result of the GSD process are far less than those encountered through using the CCVD technique and yet are negligible compared to the reference samples. The DMA results indicated that, despite the minimal degradation in the storage modulus, the loss tangent (damping) for the hybrid composites utilizing GSD-grown MWCNTs improved by 56% compared to the reference samples (based on raw carbon fibers with no surface treatment or surface grown carbon nanotubes) over the frequency range 1-60 Hz. These results indicated that the energy dissipation in the GSD-grown MWCNTs composite can be primarily attributed to the frictional sliding at the nanotube/epoxy interface and to a lesser extent to the stiff thermal shielding SiO2 film on the fiber/matrix interface.

  20. Carbon Fiber Morphology. 2. Expanded Wide-Angle X-Ray Diffraction Studies of Carbon Fibers

    Science.gov (United States)

    1991-02-01

    X- Ray Diffraction," JPS. Polym. Phys. Ed., 16, 939 (1978). 17. Rosalind E. Franklin , "The Structure of Graphitic Carbons," Acta Cryst., 4, 253 (1951...18. Rosalind E. Franklin , "The Interpretation of Diffuse X-ray Diagrams of Carbon," Acta CrL, 3, 107 (1950). 19. K. Jain and A. S. Abhiraman...been generally mentioned much earlier by Franklin [17,18]. Jain and Abhiraman [19] demonstrated that these corrections can make significant differences

  1. Bond strength of individual carbon nanotubes grown directly on carbon fibers

    Science.gov (United States)

    Kim, Kyoung Ju; Lee, Geunsung; Kim, Sung-Dae; Kim, Seong-Il; Youk, Ji Ho; Lee, Jinyong; Kim, Young-Woon; Yu, Woong-Ryeol

    2016-10-01

    The performance of carbon nanotube (CNT)-based devices strongly depends on the adhesion of CNTs to the substrate on which they were directly grown. We report on the bond strength of CNTs grown on a carbon fiber (T700SC Toray), measured via in situ pulling of individual CNTs inside a transmission electron microscope. The bond strength of an individual CNT, obtained from the measured pulling force and CNT cross-section, was very high (˜200 MPa), 8-10 times higher than that of an adhesion model assuming only van der Waals interactions (25 MPa), presumably due to carbon-carbon interactions between the CNT (its bottom atoms) and the carbon substrate.

  2. Bond strength of individual carbon nanotubes grown directly on carbon fibers.

    Science.gov (United States)

    Kim, Kyoung Ju; Lee, Geunsung; Kim, Sung-Dae; Kim, Seong-Il; Youk, Ji Ho; Lee, Jinyong; Kim, Young-Woon; Yu, Woong-Ryeol

    2016-10-07

    The performance of carbon nanotube (CNT)-based devices strongly depends on the adhesion of CNTs to the substrate on which they were directly grown. We report on the bond strength of CNTs grown on a carbon fiber (T700SC Toray), measured via in situ pulling of individual CNTs inside a transmission electron microscope. The bond strength of an individual CNT, obtained from the measured pulling force and CNT cross-section, was very high (∼200 MPa), 8-10 times higher than that of an adhesion model assuming only van der Waals interactions (25 MPa), presumably due to carbon-carbon interactions between the CNT (its bottom atoms) and the carbon substrate.

  3. Methane Decomposition into Carbon Fibers over Coprecipitated Nickel-Based Catalysts

    Institute of Scientific and Technical Information of China (English)

    Yan Ju; Fengyi Li; Renzhong Wei

    2005-01-01

    Decomposition of methane in the presence of coprecipitated nickel-based catalysts to produce carbon fibers was investigated. The reaction was studied in the temperature range of 773 K to 1073 K.At 1023 K, the catalytic activities of three catalysts kept high at the initial period and then decreased with the reaction time. The lifetimes of Ni-Cu-Al and Ni-La-Al catalysts are longer than that of Ni-Al catalyst. With three catalysts, the yield of carbon fibers was very low at 773 K. The yield of carbon fibers for Ni-La-Al catalyst was more than those for Ni-Al and Ni-Cu-Al catalysts. For Ni-La-Al catalyst, the elevation of temperature from 873 K up to 1073 K led gradually to an increase in the yield of carbon fibers.XRD studies on the Ni-La-Al catalyst indicate that La2NiO4 was formed. The formation of La2NiO4 is responsible for the increase in the catalytic lifetime and the yield of carbon fibers synthesized on Ni-La-Al at 773-1073 K. Carbon fibers synthesized on Ni-Al catalyst are thin, long carbon nanotubes. There are bamboo-shaped carbon fibers synthesized on Ni-Cu-Al catalyst. Carbon fibers synthesized on Ni-La-Al catalyst have large hollow core, thin wall and good graphitization.

  4. Processes for preparing carbon fibers using sulfur trioxide in a halogenated solvent

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Jasson T.; Barton, Bryan E.; Bernius, Mark T.; Chen, Xiaoyun; Hukkanen, Eric J.; Rhoton, Christina A.; Lysenko, Zenon

    2015-12-29

    Disclosed here are processes for preparing carbonized polymers (preferably carbon fibers), comprising sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 dissolved in a solvent to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of the solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C. Carbon fibers made according to these methods are also disclosed herein.

  5. Dosimetric characteristics of the Siemens IGRT carbon fiber tabletop.

    Science.gov (United States)

    Spezi, Emiliano; Ferri, Andrea

    2007-01-01

    In this work, the dosimetric characteristics of a new commercial carbon fiber treatment table are investigated. The photon beam attenuation properties of the Siemens image-guided radiation therapy (IGRT) tabletop were studied in detail. Two sets of dosimetric measurements were performed. In the first experiment a polystyrene slab phantom was used: the central axis attenuation and the skin-sparing detriment were investigated. In the second experiment, the off-axis treatment table transmission was investigated using a polystyrene cylindrical phantom. Measurements were taken at the isocenter for a 360 degrees rotation of the radiation beam. Our results show that the photon beam attenuation of the Siemens IGRT carbon fiber tabletop varies from a minimum of 2.1% (central axis) to a maximum of 4.6% (120 degrees and 240 degrees beam incidence). The beam entrance dose increases from 82% to 97% of the dose at the depth of maximum for a clinical 6-MV radiation field. The depth of maximum also decreases by 0.4 cm. Despite the wedge cross section of the table the beam attenuation properties of the IGRT tabletop remain constant along the longitudinal direction. American Association of Medical Dosimetrists.

  6. RC T beams strengthened to shear with carbon fiber composites

    Directory of Open Access Journals (Sweden)

    L. A. Spagnolo JR

    Full Text Available This paper presents the experimental data of the behavior of reinforced concrete beams strengthened to shear with carbon fiber composites. The tests were composed of eight T beams, b w=15 cm, h=40 cm, flange width 40 cm, flange height 8 cm, and length 300 cm, divided into two series with the same longitudinal steel reinforcement and a reference beam without strengthening in each series. The beams had two types of arrangement of internal steel stirrups. The test variables were the internal and external geometric ratio of the transverse reinforcement and the mechanical ratio of carbon fiber composites stirrups. All the beams were loaded at two points. The strengthened beams were submitted to a preloading and the strengthening was applied to the cracked beam. All the beams were designed in order to guarantee shear failure, and the ultimate load of the strengthened beams was 36% to 54% greater than the reference beams. The Cracking Sliding Model applied to the strengthened beams was evaluated and showed good agreement with the experimental results.

  7. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    Science.gov (United States)

    Sugama, Toshifumi

    1990-01-01

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed.

  8. 玻璃钢锚环承载性能的有限元分析%Finite Element Analysis of Bearing Capacity of Glass Fiber Reinforced Plastics Anchor Ring

    Institute of Scientific and Technical Information of China (English)

    刘建月; 崔小朝; 刘伟婧; 郑亚东

    2016-01-01

    通过 ABAQUS 有限元分析软件建立了连续玻璃纤维缠绕的聚酯树脂基玻璃钢锚环的有限元计算模型,对玻璃钢锚环与金属夹片、钢绞线配合使用的支护系统进行了加载分析。通过改变玻璃钢锚环的半锥角,研究了玻璃钢锚环与夹片的锥角搭配对锚具承载性能的影响。计算分析表明,在300 kN载荷作用下,计算模型中锚环纤维方向承载性能良好;轴对称面内最大主应力集中在锚环与夹片接触面附近,此处小范围基体开裂对锚环承载性能影响不大;锚环对称面内剪应力大面积超出基体强度极限,是影响锚环承载性能的主要因素。当夹片半锥角为7°时,玻璃钢锚环半锥角为6.3°~6.5°能改善锚环的应力分布状态,提高锚具的承载能力。%This paper established a finite element calculation model of continuous glass fiber winding and polyester resin GFRP anchor ring with ABAQUS,which conducted a loading analysis on the supporting system consisting of GFRP anchor ring,metal clip and steel strand.A research was made on the influence on the loading capacity of an-chor ring by changing the match of taper angles of GFRP anchor ring and clip.According to the calculation analy-sis,the anchor ring of the calculation model has a good bearing capacity in fiber direction under the load of 300 kN;in the symmetrical plane,the maximum principal stress is concentrated nearby the contact face between anchor ring and clip,and the crack of resin in small scale has small influence on the anchor ring bearing capacity;in sym-metrical plane,a large area of shearing stress of anchor ring surpassing resin ultimate stress is the main factor which can influence the loading capacity of anchor ring.When the half taper angle of clip is 7°and that of GFRP anchor ring is 6.3°~6.5°,the stress distribution and loading capacity of anchor ring can be well improved.

  9. Hybrid carbon/glass fiber composites: Micromechanical analysis of structure–damage resistance relationships

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Dai, Gaoming

    2014-01-01

    A computational study of the effect of microstructure of hybrid carbon/glass fiber composites on their strength is presented. Unit cells with hundreds of randomly located and misaligned fibers of various properties and arrangements are subject to tensile and compression loading, and the evolution...... of fiber damages is analyzed in numerical experiments. The effects of fiber clustering, matrix properties, nanoreinforcement, load sharing rules on the strength and damage resistance of composites are studied. It was observed that hybrid composites under uniform displacement loading might have lower...... strength than pure composites, while the strength of hybrid composites under inform force loading increases steadily with increasing the volume content of carbon fibers....

  10. Effects of Electrochemical Treatment on the Superficial Properties of Rayon-based Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    韩风; 黄永秋; 潘鼎

    2001-01-01

    The development of surface acidity on rayon-based carbon fibers during mild electrochemical treatment was investigated. Conductimetric titration was the primary method used to investigate the functionalities on the carbon fiber surface. The acidity on the surface of the untreated carbon fiber was very low, while for the treated fibers, the acidity increased significantly.Moreover, with the treatment extent proceeded, the acidity on the fiber surface also increased. SEM analysis shows electrochemical treatment under intense treatment degree caused considerable etch on the fiber surface.Cavities and grooves can be observed on the surface via the SEM microphotograph. While in a more mild treatment, electrochemical treatment didn't cause great etch on the surface of the fiber.

  11. STUDIES ON THE PREPARATION OF ZINC-CONTAINING ACTIVATED CARBON FIBERS AND THEIR ANTIBACTERIAL ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several kinds of activated carbon fibers, using sisal fiber as precursors, were preparedwith steam activation or with ZnCl2 activation. Zinc or its compounds were dispersed in them. Theantibacterial activities of these activated carbon fibers were determined and compared. The researchresults showed that these sisal based activated carbon fibers supporting zinc have strongerantibacterial activity against Escherichia coli and S. aureus. The antibacterial activity is related tothe precursors, the pyrolysis temperature, and the zinc content. In addition, small quantity of silversupported on zinc-containing ACFs will greatly enhance the antibacterial activity of ACFs.

  12. Ceramic silicon-boron-carbon fibers from organic silicon-boron-polymers

    Science.gov (United States)

    Riccitiello, Salvatore R. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

    1993-01-01

    Novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers are discussed. The ceramic fibers are thermally stable up to and beyond 1200 C in air. The method of preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymer of the general formula Si(R2)BR(sup 1) includes melt-spinning, crosslinking, and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200 C, from 1200 to 1300 C, and in some cases higher than 1300 C.

  13. [Modification of activated carbon fiber for electro-Fenton degradation of phenol].

    Science.gov (United States)

    Ma, Nan; Tian, Yao-Jin; Yang, Guang-Ping; Xie, Xin-Yuan

    2014-07-01

    Microwave-modified activated carbon fiber (ACF-1), nitric acid-modified activated carbon fiber (ACF-2), phosphoric acid-modified activated carbon fiber (ACF-3) and ammonia-modified activated carbon fiber (ACF-4) were successfully fabricated. The electro-Fenton catalytic activities of modified activated carbon fiber were evaluated using phenol as a model pollutant. H2O2 formation, COD removal efficiency and phenol removal efficiency were investigated compared with the unmodified activated carbon fiber (ACF-0). Results indicated that ACF-1 showed the best adsorption and electrocatalytic activity. Modification was in favor of the formation of H2O2. The performance of different systems on phenol degradation and COD removal were ACF-1 > ACF-3 > ACF-4 > ACF-2 > ACF-0 and ACF-1 > ACF-4 > ACF-3 > ACF-2 > ACF-0, respectively, which confirmed that electrocatalytic activities of modified activated carbon fiber were better than the unmodified. In addition, phenol intermediates were not the same while using different modified activated carbon fibers.

  14. 21 CFR 878.3500 - Polytetrafluoroethylene with carbon fibers composite implant material.

    Science.gov (United States)

    2010-04-01

    ... composite implant material. 878.3500 Section 878.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION... Prosthetic Devices § 878.3500 Polytetrafluoroethylene with carbon fibers composite implant material. (a) Identification. A polytetrafluoroethylene with carbon fibers composite implant material is a porous...

  15. Effect of electropolymer sizing of carbon fiber on mechanical properties of phenolic resin composites

    Institute of Scientific and Technical Information of China (English)

    LI Jin; FAN Qun; CHEN Zhen-hua; HUANG Kai-bing; CHENG Ying-liang

    2006-01-01

    Carbon fiber/phenolic resin composites were reinforced by the carbon fiber sized with the polymer films of phenol,m-phenylenediamine or acrylic acid,which was electropolymerized by cyclic voltammetry or chronopotentiometry. The contact angles of the sized carbon fibers with deionized water and diiodomethane were measured by the wicking method based on the modified Washburn equation,to show the effects of the different electropolymer film on the surface free energy of the carbon fiber after sizing by the electropolymerization. Compared with the unsized carbon fiber,which has 85.6°of contact angle of water,52.2° of contact angle of diiodomethane,and 33.1 mJ/m2 of surface free energy with 29.3 mJ/m2 of dispersive components (γL) and 3.8 mJ/m2 of polar components (γsp),respectively. It is found that the electropolymer sized carbon fiber tends to reduce the surface energy due to the decrease of dispersive γL with the increase of the polymer film on the surface of the carbon fiber that plays an important role in improving the mechanical properties of carbon/phenolic resin composites. Compared with the phenolic resin composites reinforced by the unsized carbon fiber,the impact,flexural and interlaminar shear strength of the phenolic resin composites were improved by 44 %,68% and 87% when reinforced with the carbon fiber sized by the electropolymer of m-phenylenediamine,66%,100%,and 112% by the electropolymer of phenol,and 20%,80 %,100% by the electropolymer of acrylic acid. The results indicate the skills of electropolymerization may provide a feasible method for the sizing of carbon fiber in a composite system,so as to improve the interfacial performance between the reinforce materials and the matrix and to increase the mechanical properties of the composites.

  16. Surface and sub-surface degradation of unidirectional carbon fiber reinforced epoxy composites under dry and wet reciprocating sliding

    OpenAIRE

    Dhieb, H.; Buijnsters, J.G.; Eddoumy, F.; Vázquez, Luis; Celis, J. P.

    2013-01-01

    The role of water on the sub-surface degradation of unidirectional carbon fiber reinforced epoxy composite is examined. The correlation between the debonding of carbon fibers at the fiber-epoxy interface, and the wear behavior of the carbon fiber composite are discussed based on an in-depth analysis of the worn surfaces. We demonstrate that a reciprocating sliding performed along an anti-parallel direction to the fiber orientation under dry conditions results in a large degradation by debondi...

  17. Load Transfer Analysis in Short Carbon Fibers with Radially-Aligned Carbon Nanotubes Embedded in a Polymer Matrix

    OpenAIRE

    2009-01-01

    A novel shortfiber composite in which the microscopic advanced fiber reinforcements are coated with radially aligned carbon nanotubes (CNTs) is analyzed in this study. A shear-lag model is developed to analyze the load transferred to such coated fibers from the aligned-CNT reinforced matrix in a hybrid composite application. It is found that if the carbon fibers are coated with radially aligned CNTs, then the axial load transferred to the fiber is reduced due to stiffening of the matrix by th...

  18. Interfacial enhancement of carbon fiber composites by generation 1–3 dendritic hexamethylenetetramine functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Lichun; Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Dapeng [College of Material and Chemical Engineering, Heilongjiang Institute of Technology (China); He, Jinmei; Yu, Jiali; Qi, Meiwei; Chen, Zhongwu [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-03-01

    Highlights: • A new chemical grafting method for carbon fibers was proposed. • The oxidation system adopts K{sub 2}S{sub 2}O{sub 8} and AgNO{sub 3}. • The interfacial shear strength (IFSS) of carbon fiber increased by 61%, and the interfacial adhesion increased with dendritic generation number. • The tensile strength of carbon fiber does not decrease distinctly. • The treatment conditions are mild and convenient. - Abstract: PAN-based carbon fibers (CF) were functionalized with generation (n) 1–3 dendritic hexamethylenetetramine (HMTA) (denoted as CF-G{sub n}-HMTA, n = 1, 2 and 3) in an attempt to improve the interfacial properties between carbon fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS) and single fiber tensile testing were carried out to investigate the functionalization process of carbon fibers and the interfacial properties of the composites. Experimental results showed that generation (n) 1–3 dendritic hexamethylenetetramine was grafted uniformly on the fiber surface through the chemical reaction, and then it increased significantly the fiber surface polarity and roughness. The surface energy and IFSS of carbon fibers increased obviously after the graft CF-G{sub 3}-HMTA, by 147.6% and 81%, respectively. Generation (n) 1–3 dendritic hexamethylenetetramine enhanced effectively the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking, and the interfacial adhesion increased with dendritic generation number. Moreover, the grafting of generation (n) 1–3 dendritic hexamethylenetetramine on the carbon fiber surface improved the fiber tensile strength, which is beneficial to the in-plane properties of the resulting composites.

  19. Treatment of Lignin Precursors to Improve their Suitability for Carbon Fibers: A Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Ryan [GrafTech International Holdings Inc.; Naskar, Amit [Oak Ridge National Laboratory; Gallego, Nidia [Oak Ridge National Laboratory; Dai, Xuliang [GrafTech International Holdings Inc.; Hausner, Andrew [GrafTech International Holdings Inc.

    2015-04-17

    Lignin has been investigated as a carbon fiber precursor since the 1960s. Although there have been a number of reports of successful lignin-based carbon fiber production at the lab scale, lignin-based carbon fibers are not currently commercially available. This review will highlight some of the known challenges, and also the reported methods for purifying and modifying lignin to improve it as a precursor. Lignin can come from different sources (e.g. hardwood, softwood, grasses) and extraction methods (e.g. organosolv, kraft), meaning that lignin can be found with a diversity of purity and structure. The implication of these conditions on lignin as carbon fiber precursor is not comprehensively known, especially as the lignin landscape is evolving. The work presented in this review will help guide the direction of a project between GrafTech and ORNL to develop lignin carbon fiber technology, as part of a cooperative agreement with the DOE Advanced Manufacturing Office.

  20. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    OpenAIRE

    2015-01-01

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT se...

  1. Hybrid Carbon Fibers/Carbon Nanotubes Structures for Next Generation Polymeric Composites

    Science.gov (United States)

    2010-01-01

    carbon fiber surfaces. Electrochemical deposition of iron using pulse voltametry is compared to DC magnetron iron sputtering. Carbon nanostructures...04 5E − 04 6E − 04 Figure 2: Cyclic Voltammogramm 0f 0.05 M FeCl3. 6H2O/KOH (pH = 3), with scan rate 50 mV/s. 0 100 200 300 400 500 600 Time (s) C u...deposition the electrolyte-electrode interface was studies to set suitable parameters for the deposition experiment. Cyclic voltammetry was utilized to set

  2. Nanoporous structured submicrometer carbon fibers prepared via solution electrospinning of polymer blends.

    Science.gov (United States)

    Peng, Mao; Li, Dasong; Shen, Lie; Chen, Ying; Zheng, Qiang; Wang, Huijun

    2006-10-24

    A facile means for obtaining submicrometer carbon fibers with a nanoporous structure is presented. A mixture of polyacrylonitrile (PAN) and a copolymer of acrylonitrile and methyl methacrylate (poly(AN-co-MMA)) in dimethylformamide was electrospun into submicrometer fibers with a microphase-separated structure. During the followed oxidation process, the copolymer domains were pyrolyzed, resulting in a nanoporous structure that was preserved after carbonization. The microphase-separated structure of the PAN/poly(AN-co-MMA) electrospun fibers, the morphology, and porous structure of both the oxidized and the carbonized fibers were observed with scanning electron microscopy and transmission electron microscopy. The carbon fibers have diameters ranging from several hundred nanometers to about 1 microm. The nanopores or nanoslits throughout the fiber surface and interior with diameters of several tens of nanometers are interconnected and oriented along the longitudinal axis of the fibers. This unique nanoporous morphology similar to the microphase-separated structure in the PAN/poly(AN-co-MMA) fibers is attributed to the rapid phase separation, solidification, as well as the stretching of the fibers during electrospinning. The pore volume and pore size distribution of the carbonized fibers were investigated by nitrogen adsorption and desorption.

  3. One pot synthesis of highly luminescent polyethylene glycol anchored carbon dots functionalized with a nuclear localization signal peptide for cell nucleus imaging.

    Science.gov (United States)

    Yang, Lei; Jiang, Weihua; Qiu, Lipeng; Jiang, Xuewei; Zuo, Daiying; Wang, Dongkai; Yang, Li

    2015-04-14

    Strong blue fluorescent polyethylene glycol (PEG) anchored carbon nitride dots (CDs@PEG) with a high quantum yield (QY) of 75.8% have been synthesized by a one step hydrothermal treatment. CDs with a diameter of ca. 6 nm are well dispersed in water and present a graphite-like structure. Photoluminescence (PL) studies reveal that CDs display excitation-dependent behavior and are stable under various test conditions. Based on the as-prepared CDs, we designed novel cell nucleus targeting imaging carbon dots functionalized with a nuclear localization signal (NLS) peptide. The favourable biocompatibilities of CDs and NLS modified CDs (NLS-CDs) are confirmed by in vitro cytotoxicity assays. Importantly, intracellular localization experiments in MCF7 and A549 cells demonstrate that NLS-CDs could be internalized in the nucleus and show blue light, which indicates that CDs may serve as cell nucleus imaging probes.

  4. RADAR ABSORPTION PROPERTY AND MECHANISM OF CARBON FIBER AND CARBON FIBER COMPOSITES%炭纤维及其复合材料的吸波性能和吸波机理

    Institute of Scientific and Technical Information of China (English)

    赵东林; 沈曾民; 迟伟东

    2001-01-01

    炭纤维和炭纤维复合材料在隐身技术中已经得到了广泛应用。通过分析连续炭纤维、短切炭纤维、螺旋形炭纤维、异形截面炭纤维、掺杂改性炭纤维及其复合材料的微波电磁特性和吸波性能,探讨了以上几种炭纤维的吸波机理,其中螺旋形炭纤维和异形截面炭纤维是最有发展前景的两种吸波炭纤维。%Carbon fiber and carbon fiber composites are widely used in stealth technology. Microwave permittivities and permeabilities and radar absorption properties of continuous carbon fiber, shot carbon fibers, coiled carbon fibers, non-circular carbon fibers, modified carbon fibers and carbon fiber composites were discussed. The radar absorption mechanisms of these carbon fibers and carbon fiber composites were analyzed. The coiled carbon fibers and non-circular carbon fibers are two kinds of the most promising candidates for radar absorbing material.

  5. Carbon Nanotube Chopped Fiber for Enhanced Properties in Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Menchhofer, Paul A [ORNL; Lindahl, John M [ORNL; JohnsonPhD, DR Joseph E. [Nanocomp Technologies, Inc.

    2016-06-06

    Nanocomp Technologies, Inc. is working with Oak Ridge National Laboratory to develop carbon nanotube (CNT) composite materials and evaluate their use in additive manufacturing (3D printing). The first phase demonstrated feasibility and improvements for carbon nanotube (CNT)- acrylonitrile butadiene styrene (ABS) composite filaments use in additive manufacturing, with potential future work centering on further improvements. By focusing the initial phase on standard processing methods (developed mainly for the incorporation of carbon fibers in ABS) and characterization techniques, a basis of knowledge for the incorporation of CNTs in ABS was learned. The ability to understand the various processing variables is critical to the successful development of these composites. From the degradation effects on ABS (caused by excessive temperatures), to the length of time the ABS is in the melt state, to the order of addition of constituents, and also to the many possible mixing approaches, a workable flow sequence that addresses each processing step is critical to the final material properties. Although this initial phase could not deal with each of these variables in-depth, a future study is recommended that will build on the lessons learned for this effort.

  6. Plasma characterization on carbon fiber cathode by spectroscopic diagnostics

    Institute of Scientific and Technical Information of China (English)

    Liu Lie; Li Li-Min; Xu Qi-Fu; Chang Lei; Wen Jian-Chun

    2009-01-01

    This paper mainly investigates plasma characterization on carbon fiber cathodes with and without cesium iodide (CsI) coating powered by a~300 ns,~200 kV accelerating pulse. It was found that the CsI layers can not only improve the diode voltage,but also maintain a stable perveance.This indicates a slowly changed diode gap or a low cathode plasma expansion velocity.By spectroscopic diagnostics,in the vicinity of the cathode surface the average plasma density and temperature were found to be~3×1014 cm-3 and~5 eV,respectively,for an electron current density of~40 A/cm2.Furthermore,there exists a multicomponent plasma expansion toward the anode.The plasma expansion velocity,corresponding to the carbon and hydrogen ions,is estimated to be~1.5 cm/μs.Most notably,Cs spectroscopic line was obtained only at the distance ≤0.5 mm from the cathode surface.Carbon and hydrogen ions are obtained up to the distance of 2.5 mm from the cathode surface.Cs ions almost remain at the vicinity of the cathode surface.These results show that the addition of Cal enables a slow cathode plasma expansion toward the anode,providing a positive prospect for developing long-pulse electron beam sources.

  7. Synergetic Effects of Mechanical Properties on Graphene Nanoplatelet and Multiwalled Carbon Nanotube Hybrids Reinforced Epoxy/Carbon Fiber Composites

    OpenAIRE

    Pin-Ning Wang; Tsung-Han Hsieh; Chin-Lung Chiang; Ming-Yuan Shen

    2015-01-01

    Graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) are novel nanofillers possessing attractive characteristics, including robust compatibility with most polymers, high absolute strength, and cost effectiveness. In this study, an outstanding synergetic effect on the grapheme nanoplatelets (GNPs) and multiwalled carbon nanotubes (CNTs) hybrids were used to reinforce epoxy composite and epoxy/carbon fiber composite laminates to enhance their mechanical properties. The mechanical propertie...

  8. Applications research in ultrasonic testing of carbon fiber composite based on an optical fiber F-p sensor

    Science.gov (United States)

    Shan, Ning

    2016-10-01

    Carbon fiber composite is widely applied to the field of aerospace engineering because of its excellent performance. But it will be able to form more defects in the process of manufacturing inevitably on account of unique manufacturing process. Meanwhile it has sophisticated structure and services in the bad environment long time. The existence of defects will be able to cause the sharp decline in component's performance when the defect accumulates to a certain degree. So the reliability and safety test demand of carbon fiber composite is higher and higher. Ultrasonic testing technology is the important means used for characteristics of component inspection of composite materials. Ultrasonic information detection uses acoustic transducer generally. It need coupling agent and is higher demand for the surface of sample. It has narrow frequency band and low test precision. The extrinsic type optical fiber F-P interference cavity structure is designed to this problem. Its optical interference model is studied. The initial length of F-P cavity is designed. The realtime online detection system of carbon fiber composite is established based on optical fiber F-P Ultrasound sensing technology. Finally, the testing experiment study is conducted. The results show that the system can realize real-time online detection of carbon fiber composite's defect effectively. It operates simply and realizes easily. It has low cost and is easy to practical engineering.

  9. Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

    Science.gov (United States)

    Kumamoto, Soichiro; Okubo, Kazuya; Fujii, Toru

    2016-01-01

    The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP). To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF) test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages) in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

  10. Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

    Directory of Open Access Journals (Sweden)

    Kumamoto Soichiro

    2016-01-01

    Full Text Available The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP. To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

  11. Isothermal and hygrothermal agings of hybrid glass fiber/carbon fiber composite

    Science.gov (United States)

    Barjasteh, Ehsan

    New applications of fiber-reinforced polymer composites (FRPCs) are arising in non-traditional sectors of industry, such as civil infrastructure, automotive, and power distribution. For example, composites are being used in place of steel to support high-voltage overhead conductors. In this application, conductive strands of aluminum are wrapped around a solid composite rod comprised of unidirectional carbon and glass fibers in an epoxy matrix, which is commercially called ACCC conductor. Composite-core conductors such as these are expected to eventually replace conventional steel-reinforced conductors because of the reduced sag at high temperatures, lower weight, higher ampacity, and reduced line losses. Despite the considerable advantages in mechanical performance, long-term durability of composite conductors is a major concern, as overhead conductors are expected to retain properties (with minimal maintenance) over a service life that spans multiple decades. These concerns stem from the uncertain effects of long-term environmental exposure, which includes temperature, moisture, radiation, and aggressive chemicals, all of which can be exacerbated by cyclic loads. In general, the mechanical and physical properties of polymer composites are adversely affected by such environmental factors. Consequently, the ability to forecast changes in material properties as a function of environmental exposure, particularly bulk mechanical properties, which are affected by the integrity of fiber-matrix interfaces, is required to design for extended service lives. Polymer composites are susceptible to oxidative degradation at high temperatures approaching but not quite reaching the glass transition temperature ( Tg). Although the fibers are stable at such temperatures, the matrix and especially the fiber-matrix interface can undergo degradation that affects the physical and mechanical properties of the structure over time. Therefore, as a first step, the thermal aging of an

  12. Orientation of Carbon Fibers in Copper matrix Produced by Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Irfan Shirazi M.

    2014-07-01

    Full Text Available Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection molding (PIM process has some intrinsic fiber alignment associated with it. During PIM process fibers in skin region of moldings are aligned as these regions experience higher shear flow caused by the mold walls. Fibers in the core region remain randomly aligned as these regions are far from mold walls and experience lesser shear flow. In this study short carbon fiber (CF reinforced copper matrix composite was developed by PIM process. Two copper composite feedstock formulations were prepared having 5 vol% and 10 vol% CFs and a wax based binder system. Fiber orientation was controlled during injection molding by using a modified mold that has a diverging sprue. The sprue creates converging flow when feedstock enters into the mold cavity. Fiber orientation was analysed after molding using FESEM. The orientation of fibers can be controlled by controlling flow of feedstock into the mold.

  13. Development and characterization of carbon-bonded carbon fiber insulation for radioisotope space power systems

    Energy Technology Data Exchange (ETDEWEB)

    Wei, G.C.; Robbins, J.M.

    1985-06-01

    The General-Purpose Heat Source (GPHS), an improved radioisotope heat source, employs a unique thermal insulation material, carbon-bonded carbon fiber (CBCF), to protect the fuel capsule and to help achieve the highest possible specific power. The CBCF insulation is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF shapes, both tubes and plates, are formed in a multiple molding facility by vacuum molding a water slurry of the carbonized chopped-rayon fiber (54 wt %) and phenolic resin (46 wt %). The molded shapes are subsequently dried and cured. Final carbonization of the resin is at 1600/sup 0/C. Machining to close tolerances (+-0.08 mm) is accomplished by conventional tooling and fixturing. The resulting material is an excellent lightweight insulation with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W(m.K) in vacuum at 2000/sup 0/C. Several attributes that make CBCF superior to other known high-temperature insulation materials for the GPHS application have been identified. It has the excellent attributes of light weight, low thermal conductivity, chemical compatibility, and high-temperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the GPHS application; it has passed vibration tests simulating launch conditions. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to incease the fabrication rate by a factor of 10. The specific properties of the CBCF were tailored by adjusting material and processing variables to obtain the desired results. We report here how work on CBCF characterization and development conducted at ORNL from 1978 through 1980 has contributed to the GPHS program to meet the requirements of both the Galileo and Ulysees Missions.

  14. Very-high-strength (60-GPa) carbon nanotube fiber design based on molecular dynamics simulations

    Science.gov (United States)

    Cornwell, Charles F.; Welch, Charles R.

    2011-05-01

    The mechanical properties of carbon nanotubes such as low density, high stiffness, and exceptional strength make them ideal candidates for reinforcement material in a wide range of high-performance composites. Molecular dynamics simulations are used to predict the tensile response of fibers composed of aligned carbon nanotubes with intermolecular bonds of interstitial carbon atoms. The effects of bond density and carbon nanotube length distribution on fiber strength and stiffness are investigated. The interstitial carbon bonds significantly increase load transfer between the carbon nanotubes over that obtained with van der Waals forces. The simulation results indicate that fibers with tensile strengths to 60 GPa could be produced by employing interstitial cross-link atoms. The elastic modulus of the fibers is also increased by the bonds.

  15. Fracture morphology of carbon fiber reinforced plastic composite laminates

    Directory of Open Access Journals (Sweden)

    Vinod Srinivasa

    2010-09-01

    Full Text Available Carbon fiber reinforced plastic (CFRP composites have been extensively used in fabrication of primary structures for aerospace, automobile and other engineering applications. With continuous and widespread use of these composites in several advanced technology, the frequency of failures is likely to increase. Therefore, to establish the reasons for failures, the fracture modes should be understood thoroughly and unambiguously. In this paper, CFRP composite have been tested in tension, compression and flexural loadings; and microscopic study with the aid of Scanning Electron Microscope (SEM has been performed on failed (fractured composite surfaces to identify the principle features of failure. Efforts have been made in correlating the fracture surface characteristics to the failure mode. The micro-mechanics analysis of failure serves as a useful guide in selecting constituent materials and designing composites from the failure behavior point of view. Also, the local failure initiation results obtained here has been reliably extended to global failure prediction.

  16. Adsorption Models and Structural Characterization for Activated Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    CHEN Chuan-juan; WANG Ru-zhu; OLIVEIRA R.G.; HU Jin-qiang

    2009-01-01

    The nitrogen adsorption isotherms at 77.69 K were measured for two samples of activated carbon fibers and their microstructures were investigated. Among established isotherm equations, the Dubinin-Radushkevich equation showed the best agreement with the experimental data, while the Langmuir equation showed a large deviation when employed at low relative pressures. The MP method, t-method and αs-method were used to analyze the pore size distribution. The calculated average pore widths and BET (Brunauer-Emmett-Teller) surface areas for the sample A-13 were 0.86 nm and 1 286.60 m2/g, while for the sample A-16, they were 0.82 nm and 1 490.64 m2/g. The sample with larger pore width was more suitable to be used as additive in chemical heat pumps, while the other one could be used as adsorbent in adsorption refrigeration systems.

  17. Preparation and Properties of Carbon Fiber Chiral Materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping; HUANG Zhixin; WANG Guoqing

    2008-01-01

    The chiral materials were prepared by using the carbon fiber helices as chiral inclusions,and the composite of Fe3O4 and polyaniline as matrix.The electromagnetic properties,including the rotation angles,the axial ratios and the complex chirality parameters,were measured by using a circular waveguide method in the 8.5-11.0 GHz frequency range.The dependence of these electromagnetic properties on the frequency and the concentration of the Fe3O4 in the composite matrix were analyzed.The results show that an appropriate concentration of Fe3O4 in the matrix is useful in improving the electromagnetic properties of the chiral material.

  18. Standard Test Method for Thermal Oxidative Resistance of Carbon Fibers

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1982-01-01

    1.1 This test method covers the apparatus and procedure for the determination of the weight loss of carbon fibers, exposed to ambient hot air, as a means of characterizing their oxidative resistance. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units which are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard information, see Section 8.

  19. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane

    Directory of Open Access Journals (Sweden)

    A. G. Gaikwad

    2012-06-01

    Full Text Available Transport of carbonate ions was explored through fiber supported solid membrane. A novel fiber supported solid membrane was prepared by chemical modification of cellulose fiber with citric acid, 2′2-bipyridine and magnesium carbonate. The factors affecting the permeability of carbonate ions such as immobilization of citric acid-magnesium metal ion -2′2-bipyridine complex (0 to 2.5 mmol/g range over cellulose fiber, carbon-ate ion concentration in source phase and NaOH concentration in receiving phase were investigated. Ki-netic of carbonate, sulfate, and nitrate ions was investigated through fiber supported solid membrane. Transport of carbonate ions with/without bubbling of CO2 (0 to 10 ml/min in source phase was explored from source to receiving phase. The novel idea is to explore the adsorptive transport of CO2 from source to receiving phase through cellulose fiber containing magnesium metal ion organic framework. Copyright © 2012 BCREC UNDIP. All rights reserved.Received: 25th November 2011; Revised: 17th December 2011; Accepted: 19th December 2011[How to Cite: A.G. Gaikwad. (2012. Transport of Carbonate Ions by Novel Cellulose Fiber Supported Solid Membrane. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 49– 57.  doi:10.9767/bcrec.7.1.1225.49-57][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1225.49-57 ] | View in 

  20. Optimization of interfacial properties of carbon fiber/epoxy composites via a modified polyacrylate emulsion sizing

    Science.gov (United States)

    Yuan, Xiaomin; Zhu, Bo; Cai, Xun; Liu, Jianjun; Qiao, Kun; Yu, Junwei

    2017-04-01

    The adhesion behavior of epoxy resin to carbon fibers has always been a challenge, on account of the inertness of carbon fibers and the lack of reactive functional groups. In this work, a modified polyacrylate sizing agent was prepared to modify the interface between the carbon fiber and the epoxy matrix. The surface characteristics of carbon fibers were investigated to determine chemical composition, morphology, wettability, interfacial phase analysis and interfacial adhesion. Sized carbon fibers featured improved wettability and a slightly decreased surface roughness due to the coverage of a smooth sizing layer, compared with the unsized ones. Moreover, the content of surface activated carbon atoms increased from 12.65% to 24.70% and the interlaminar shear strength (ILSS) of carbon fiber/epoxy composites raised by 14.2%, indicating a significant improvement of chemical activity and mechanical property. SEM images of the fractured surface of composites further proved that a gradient interfacial structure with increased thicknesses was formed due to the transition role of the sizing. Based on these results, a sizing mechanism consisting of chemical interaction bonding and physical force absorption was proposed, which provides an efficient and feasible method to solve the poor adhesion between carbon fiber and epoxy matrix.

  1. Effect of Fiber Length on Carbon Nanotube-Induced Fibrogenesis

    Directory of Open Access Journals (Sweden)

    Amruta Manke

    2014-04-01

    Full Text Available Given their extremely small size and light weight, carbon nanotubes (CNTs can be readily inhaled by human lungs resulting in increased rates of pulmonary disorders, particularly fibrosis. Although the fibrogenic potential of CNTs is well established, there is a lack of consensus regarding the contribution of physicochemical attributes of CNTs on the underlying fibrotic outcome. We designed an experimentally validated in vitro fibroblast culture model aimed at investigating the effect of fiber length on single-walled CNT (SWCNT-induced pulmonary fibrosis. The fibrogenic response to short and long SWCNTs was assessed via oxidative stress generation, collagen expression and transforming growth factor-beta (TGF-β production as potential fibrosis biomarkers. Long SWCNTs were significantly more potent than short SWCNTs in terms of reactive oxygen species (ROS response, collagen production and TGF-β release. Furthermore, our finding on the length-dependent in vitro fibrogenic response was validated by the in vivo lung fibrosis outcome, thus supporting the predictive value of the in vitro model. Our results also demonstrated the key role of ROS in SWCNT-induced collagen expression and TGF-β activation, indicating the potential mechanisms of length-dependent SWCNT-induced fibrosis. Together, our study provides new evidence for the role of fiber length in SWCNT-induced lung fibrosis and offers a rapid cell-based assay for fibrogenicity testing of nanomaterials with the ability to predict pulmonary fibrogenic response in vivo.

  2. Effect of fiber length on carbon nanotube-induced fibrogenesis.

    Science.gov (United States)

    Manke, Amruta; Luanpitpong, Sudjit; Dong, Chenbo; Wang, Liying; He, Xiaoqing; Battelli, Lori; Derk, Raymond; Stueckle, Todd A; Porter, Dale W; Sager, Tina; Gou, Honglei; Dinu, Cerasela Zoica; Wu, Nianqiang; Mercer, Robert R; Rojanasakul, Yon

    2014-04-29

    Given their extremely small size and light weight, carbon nanotubes (CNTs) can be readily inhaled by human lungs resulting in increased rates of pulmonary disorders, particularly fibrosis. Although the fibrogenic potential of CNTs is well established, there is a lack of consensus regarding the contribution of physicochemical attributes of CNTs on the underlying fibrotic outcome. We designed an experimentally validated in vitro fibroblast culture model aimed at investigating the effect of fiber length on single-walled CNT (SWCNT)-induced pulmonary fibrosis. The fibrogenic response to short and long SWCNTs was assessed via oxidative stress generation, collagen expression and transforming growth factor-beta (TGF-β) production as potential fibrosis biomarkers. Long SWCNTs were significantly more potent than short SWCNTs in terms of reactive oxygen species (ROS) response, collagen production and TGF-β release. Furthermore, our finding on the length-dependent in vitro fibrogenic response was validated by the in vivo lung fibrosis outcome, thus supporting the predictive value of the in vitro model. Our results also demonstrated the key role of ROS in SWCNT-induced collagen expression and TGF-β activation, indicating the potential mechanisms of length-dependent SWCNT-induced fibrosis. Together, our study provides new evidence for the role of fiber length in SWCNT-induced lung fibrosis and offers a rapid cell-based assay for fibrogenicity testing of nanomaterials with the ability to predict pulmonary fibrogenic response in vivo.

  3. ORGANIC CHELATING REAGENT ON REDOX ADSORPTION OF ACTIVATED CARBON FIBER TOWARDS Au3+

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Organic chelating reagent influences upon the redox adsorption of activated carbon fibertowards Au3- were systematically investigated. The experimental results indicated that the presenceof organic chelating reagent on activated carbon fiber strongly affects adsorption capacity ofactivated carbon fiber towards Au3+. The reduction-adsorption amount of Au3+ increased three timesby the presence of 8-quinolinol. Furthermore, The reduction-adsorption amount of Au3+ depended onthe pH value of adsorption and temperature.

  4. Ply Orientation of Carbon Fiber Reinforced Aircraft Wing - A Parametric Study

    Directory of Open Access Journals (Sweden)

    Dr. Alice Mathai

    2014-05-01

    Full Text Available In the present day scenario, use of carbon fiber composites has been extended to a large number of aircraft components which includes structural and non-structural components. Carbon fiber reinforced polymer (CFRP is a composite material which consists of laminates having reinforcing fibers (carbon of significant strength embedded in a matrix material. Each lamina can have distinct fiber orientations which may vary from the adjoining lamina. The present study focuses on the effect of the ply orientation on the strength of the panels. The wing of a subsonic aircraft was modeled in the ANSYS software. The performance of wing under the application of loads was studied by varying the orientation of fiber layers. From the study, it was observed that the variation in stress occurs with variation in orientation of fiber layers of CFRP composites.

  5. Edge Delamination and Residual Properties of Drilled Carbon Fiber Composites with and without Short-Aramid-Fiber Interleaf

    Science.gov (United States)

    Sun, Zhi; Hu, Xiaozhi; Shi, Shanshan; Guo, Xu; Zhang, Yupeng; Chen, Haoran

    2016-10-01

    Edge delamination is frequently observed in carbon fiber reinforced plastic (CFRP) laminates after machining, due to the low fracture toughness of the resin interfaces between carbon fiber plies. In this study, the effects of incorporating tough aramid fibers into the brittle CFRP system are quantified by measuring the residual properties of bolted CFRP. By adding short-aramid-fiber interleaves in CFRP laminates, the residual tensile strength have been substantially increased by 14 % for twill-weave laminates and 45 % for unidirectional laminates respectively. Moreover, tensile failure was observed as the major mode of toughened laminates, in contrast to shear failure of plain laminates. The qualitative FEM results agreed well with the experimental results that edge delamination would cause relatively higher shear stress and therefore alter the failure mode from tensile failure to shear failure.

  6. Chemical vapor deposition fabrication and characterization of silica-coated carbon fiber ultramicroelectrodes.

    Science.gov (United States)

    Zhao, G; Giolando, D M; Kirchhoff, J R

    1995-08-01

    Carbon fiber disk ultramicroelectrodes (UMEs) with well-defined geometries were prepared by chemical vapor deposition techniques. Transparent silica films with thicknesses from 1 to 600 microns were deposited on the cylindrical length of 5 and 10 microns carbon fibers from a SiCl4, H2, and O2 ternary precursor system at 850-1150 degrees C or sequential deposition from Si(OEt)4 as a single source precursor at 700 degrees C followed by the SiCl4, H2, and O2 precursor system. Film thickness, film adhesion to the fiber substrate, and the overall dimensions of the silica-coated carbon fiber were studied and found to be a function of the precursor system, precursor concentrations, fiber diameter, deposition time, and fiber temperature. The silica films were found to be free of microcracks and characterized by a quality seal between the carbon fiber and the coating. As a result, the silica-coated disk UME exhibits an excellent electrochemical response without the need to use an epoxy sealant at the electrode tip. Furthermore, the deposition of hard and inert ceramic materials imparts durability to fragile carbon fibers and facilitates the handling of UMEs in microenvironments. Finally, the advantage of concentric deposition about the fibers to produce a disk UME in the center of an insulating plane was used to examine the effect of the thickness of the insulating coating on the limiting current response.

  7. Interfacial enhancement of carbon fiber composites by generation 1-3 dendritic hexamethylenetetramine functionalization

    Science.gov (United States)

    Ma, Lichun; Meng, Linghui; Fan, Dapeng; He, Jinmei; Yu, Jiali; Qi, Meiwei; Chen, Zhongwu; Huang, Yudong

    2014-03-01

    PAN-based carbon fibers (CF) were functionalized with generation (n) 1-3 dendritic hexamethylenetetramine (HMTA) (denoted as CF-Gn-HMTA, n = 1, 2 and 3) in an attempt to improve the interfacial properties between carbon fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS) and single fiber tensile testing were carried out to investigate the functionalization process of carbon fibers and the interfacial properties of the composites. Experimental results showed that generation (n) 1-3 dendritic hexamethylenetetramine was grafted uniformly on the fiber surface through the chemical reaction, and then it increased significantly the fiber surface polarity and roughness. The surface energy and IFSS of carbon fibers increased obviously after the graft CF-G3-HMTA, by 147.6% and 81%, respectively. Generation (n) 1-3 dendritic hexamethylenetetramine enhanced effectively the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking, and the interfacial adhesion increased with dendritic generation number. Moreover, the grafting of generation (n) 1-3 dendritic hexamethylenetetramine on the carbon fiber surface improved the fiber tensile strength, which is beneficial to the in-plane properties of the resulting composites.

  8. Interfacial behavior between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride).

    Science.gov (United States)

    Ho, Kingsley K C; Lamoriniere, Steven; Kalinka, Gerhard; Schulz, Eckhard; Bismarck, Alexander

    2007-09-15

    Atmospheric-plasma fluorination was used to introduce fluorine functionalities onto the surface of carbon fibers without affecting their bulk properties. The interfacial adhesion between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride) (PVDF) was studied by means of direct wetting measurements and single fiber pullout tests. Measured contact angles of PVDF melt droplets on modified carbon fibers show that short exposure times of carbon fibers to atmospheric-plasma fluorination (corresponding to a degree of surface fluorination of F/C = 0.01 (1.1%)) leads to improved wettability of the fibers by PVDF melts. The apparent interfacial shear strength as a measure of practical adhesion, determined by the single-fiber pullout test, increases by 65% under optimal treatment conditions. The improved practical adhesion is not due to the formation of transcrystalline regions around the fibers or a change of the bulk matrix crystallinity or to an increased surface roughness; it seems to be due to the compatibilization of the interface caused of the atmospheric-plasma fluorination of the carbon fibers.

  9. Modification of the Interfacial Interaction between Carbon Fiber and Epoxy with Carbon Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Kejing Yu

    2016-05-01

    Full Text Available The mechanical properties of the hybrid materials and epoxy and carbon fiber (CF composites were improved significantly as compared to the CF composites made from unmodified epoxy. The reasons could be attributed to the strong interfacial interaction between the CF and the epoxy composites for the existence of carbon nanomaterials. The microstructure and dispersion of carbon nanomaterials were characterized by transmission electron microscopy (TEM and optical microscopy (OM. The results showed that the dispersion of the hybrid materials in the polymer was superior to other carbon nanomaterials. The high viscosity and shear stress characterized by a rheometer and the high interfacial friction and damping behavior characterized by dynamic mechanical analysis (DMA indicated that the strong interfacial interaction was greatly improved between fibers and epoxy composites. Remarkably, the tensile tests presented that the CF composites with hybrid materials and epoxy composites have a better reinforcing and toughening effect on CF, which further verified the strong interfacial interaction between epoxy and CF for special structural hybrid materials.

  10. Carbon fiber CVD coating by carbon nanostructured for space materials protection against atomic oxygen

    Science.gov (United States)

    Pastore, Roberto; Bueno Morles, Ramon; Micheli, Davide

    2016-07-01

    adhesion and durability in the environment. Though these coatings are efficient in protecting polymer composites, their application imposes severe constraints. Their thermal expansion coefficients may differ markedly from those of polymer composite substrates: as a result, cracks develop in the coatings on thermal cycling and AO can penetrate through them to the substrate. In addition to the technicalities of forming an effective barrier, such factors as cost, convenience of application and ease of repair are important considerations in the selection of a coating for a particular application. The latter issues drive the aerospace research toward the development of novel light composite materials, like the so called polymer nanocomposites, which are materials with a polymer matrix and a filler with at least one dimension less than 100 nanometers. Current interest in nanocomposites has been generated and maintained because nanoparticle-filled polymers exhibit unique combinations of properties not achievable with traditional composites. These combinations of properties can be achieved because of the small size of the fillers, the large surface area the fillers provide, and in many cases the unique properties of the fillers themselves. In particular, the carbon fiber-based polymeric composite materials are the basic point of interest: the aim of the present study is to find new solution to produce carbon fiber-based composites with even more upgraded performances. One intriguing strategy to tackle such an issue has been picked out in the coupling between the carbon fibers and the carbon nanostructures. That for two main reasons: first, carbon nanostructures have shown fancy potentialities for any kind of technological applications since their discovery, second, the chemical affinity between fiber and nanostructure (made of the same element) should be a likely route to approach the typical problems due to thermo-mechanical compatibility. This work is joined in such framework

  11. Porous core-shell carbon fibers derived from lignin and cellulose nanofibrils

    KAUST Repository

    Xu, Xuezhu

    2013-10-01

    This letter reports a method to produce lignin and cellulose nanofibrils (CNFs) based porous core-shell carbon fibers via co-electrospinning followed by controlled carbonization. Lignin formed the shell of the fiber while CNF network formed the porous core. Polyacrylonitrile (PAN) was added to the lignin solution to increase its electrospinability. CNFs were surface acetylated and dispersed in silicon oil to obtain a homogenous dispersion for electrospinning the porous core. Hollow lignin fibers were also electrospun using glycerin as the core material. FT-IR measurements confirmed the CNF acetylation. SEM micrographs showed the core-shell and hollow fiber nanostructures before and after carbonization. The novel carbon fibers synthesized in this study exhibited increased surface area and porosity that are promising for many advanced applications. © 2013 Elsevier B.V.

  12. UV-cured adhesives for carbon fiber composite applications

    Science.gov (United States)

    Lu, Hsiao-Chun

    Carbon fiber composite materials are increasingly used in automobile, marine, and aerospace industries due to their unique properties, including high strength, high stiffness and low weight. However, due to their brittle characteristic, these structures are prone to physical damage, such as a bird strike or impact damage. Once the structure is damaged, it is important to have fast and reliable temporary repair until the permanent repair or replacement can take place. In this dissertation, UV-based adhesives were used to provide a bonding strength for temporary repair. Adhesively bonded patch repair is an efficient and effective method for temporary repair. In this study, precured patches (hard patches) and dry fabric patches with laminating resins (soft patches) were performed. UV-based epoxy adhesives were applied to both patch repair systems. For precured patch repair, the bonding strengths were investigated under different surface treatments for bonding area and different adhesives thicknesses. The shear stresses of different UV exposure times and curing times were tested. Besides, the large patch repair was investigated as well. For soft patch repair, the hand wet lay-up was applied due to high viscosity of UV resins. A modified single lap shear testing (ASTM D5868) was applied to determine the shear stress. The large patches used fiber glass instead of carbon fiber to prove the possibility of repair with UV epoxy resin by hand wet lay-up process. The hand lay-up procedure was applied and assisted by vacuum pressure to eliminate the air bubbles and consolidate the patches. To enhance the bonding strength and effective soft patch repair, vacuum assisted resin transferring molding (VaRTM) is the better option. However, only low viscosity resins can be operated by VaRTM. Hence, new UV-based adhesives were formulated. The new UV-based adhesives included photoinitiator (PI), epoxy and different solvents. Solvents were used to compound the photoinitiator into epoxy

  13. Characterization and Effects of Fiber Pull-Outs in Hole Quality of Carbon Fiber Reinforced Plastics Composite

    Directory of Open Access Journals (Sweden)

    Sina Alizadeh Ashrafi

    2016-10-01

    Full Text Available Hole quality plays a crucial role in the production of close-tolerance holes utilized in aircraft assembly. Through drilling experiments of carbon fiber-reinforced plastic composites (CFRP, this study investigates the impact of varying drilling feed and speed conditions on fiber pull-out geometries and resulting hole quality parameters. For this study, hole quality parameters include hole size variance, hole roundness, and surface roughness. Fiber pull-out geometries are quantified by using scanning electron microscope (SEM images of the mechanically-sectioned CFRP-machined holes, to measure pull-out length and depth. Fiber pull-out geometries and the hole quality parameter results are dependent on the drilling feed and spindle speed condition, which determines the forces and undeformed chip thickness during the process. Fiber pull-out geometries influence surface roughness parameters from a surface profilometer, while their effect on other hole quality parameters obtained from a coordinate measuring machine is minimal.

  14. Catalytic graphitization of polyacrylonitrile-based carbon fibers coated with Prussian blue

    Institute of Scientific and Technical Information of China (English)

    PENG Qi-ling; ZHOU Hai-hui; HUANG Zhen-hua; CHEN Jin-hua; KUANG Ya-fei

    2010-01-01

    Prussian blue(PB)was used as catalyst to improve the extent of graphitization of polyacrylonitrile(PAN)-based carbon fibers.PB was deposited on carbon fibers by anodic electrodeposition and the thickness of PB coating(PB content)was controlled by adjusting the electrodeposition time.PAN-based carbon fibers with PB coating were heat-treated and the extent of graphitization was measured by X-ray diffractometry and Raman spectroscopy.The results indicate that the extent of graphitization of PAN-based carbon fibers is enhanced in the presence of the coating.When the PB-coated carbon fibers were heat-treated at 1 900 ℃,interlayer spacing(d002)and crystallite size(Lc)reach 0.336 8 and 21.2 nm respectively.Contrarily,the values of d002 and Lc are 0.341 4 and7.4 nm respectively when the bare carbon fibers were heat-treated at 2 800℃.Compared with the bare carbon fibers,PB can make the heat treatment temperature(HTT)drop more than 500 ℃ in order to reach the same extent of graphitization.Furthermore,the research results show that PB content also has a certain influence on the extent of graphitization at the same HTT.

  15. Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical performance used as anodes of structural lithium-ion batteries

    Science.gov (United States)

    Feng, Mengjie; Wang, Shubin; Yu, Yalin; Feng, Qihang; Yang, Jiping; Zhang, Boming

    2017-01-01

    Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical properties were acquired through a simple chemical oxidation method, and the proposed underlying mechanism was verified. The surface of carboxyl functionalizing carbon fibers is necessary in acquiring functional groups on the surface of carbon fibers to further improve the thermal, electrical or mechanical properties of the fibers. Functionalization should preserve the tensile strength and electrochemical properties of carbon fibers, because the anodes of structural batteries need to have high strength and electrochemical properties. Functionalized with mixed H2SO4/HNO3 considerably reduced the tensile strength of carbon fibers. By contrast, the appearance of H3PO4 preserved the tensile strength of functionalized carbon fibers, reduced the dispersion level of tensile strength values, and effectively increased the concentration of functional acid groups on the surface of carbon fibers. The presence of phosphoric acid hindered the over-oxidation of turbostratic carbon, and consequently preserved the tensile strength of carbon fibers. The increased proportion of turbostratic carbon on the surface of carbon fibers concurrently enhanced the electrochemical properties of carbon fibers.

  16. Mechanical properties of carbon fiber composites for applications in space

    Science.gov (United States)

    Hana, P.; Inneman, A.; Daniel, V.; Sieger, L.; Petru, M.

    2015-01-01

    This article describes method of measurement mechanical properties of carbon fiber composites in space. New material structures are specifically designed for use on space satellites. Composite structures will be exposed to cosmic radiation in Earth orbit on board of a '2U CubeSat' satellite. Piezoelectric ceramic sensors are used for detection mechanical vibrations of composite test strip. A great deal of attention is paid to signal processing using 8-bit microcontroler. Fast Fourier Transformation is used. Fundamental harmonic frequencies and damping from on-board measurements will serve as the input data for terrestrial data processing. The other step of elaboration data is creation of the physical model for evaluating mechanical properties of Carbon composite - Piezoelectric ceramic system. Evaluation of anisotropic mechanical properties of piezoelectric ceramics is an interesting secondary outcome of the investigation. Extreme changes in temperature and the effect of cosmic rays will affect the mechanical properties and durability of the material used for the external construction of satellites. Comparative terrestrial measurements will be performed.

  17. New generation fiber reinforced polymer composites incorporating carbon nanotubes

    Science.gov (United States)

    Soliman, Eslam

    The last five decades observed an increasing use of fiber reinforced polymer (FRP) composites as alternative construction materials for aerospace and infrastructure. The high specific strength of FRP attracted its use as non-corrosive reinforcement. However, FRP materials were characterized with a relatively low ductility and low shear strength compared with steel reinforcement. On the other hand, carbon nanotubes (CNTs) have been introduced in the last decade as a material with minimal defect that is capable of increasing the mechanical properties of polymer matrices. This dissertation reports experimental investigations on the use of multi-walled carbon nanotubes (MWCNTs) to produce a new generation of FRP composites. The experiments showed significant improvements in the flexure properties of the nanocomposite when functionalized MWCNTs were used. In addition, MWCNTs were used to produce FRP composites in order to examine static, dynamic, and creep behavior. The MWCNTs improved the off-axis tension, off-axis flexure, FRP lap shear joint responses. In addition, they reduced the creep of FRP-concrete interface, enhanced the fracture toughness, and altered the impact resistance significantly. In general, the MWCNTs are found to affect the behaviour of the FRP composites when matrix failure dominates the behaviour. The improvement in the mechanical response with the addition of low contents of MWCNTs would benefit many industrial and military applications such as strengthening structures using FRP composites, composite pipelines, aircrafts, and armoured vehicles.

  18. Shockwave response of two carbon fiber-polymer composites to 50 GPa

    Science.gov (United States)

    Dattelbaum, Dana M.; Coe, Joshua D.; Rigg, Paulo A.; Scharff, R. Jason; Gammel, J. Tinka

    2014-11-01

    Shock compression of two molded, carbon fiber-filled polymer composites was performed in gas gun-driven plate impact experiments at impact velocities up to ≈5 km/s. Hugoniot states for both composites were obtained from chopped carbon fibers, bound by either phenolic or cyanate ester polymeric resins. Their dynamic responses were similar, although the 10 wt. % difference of carbon fill produced measureable divergence in shock compressibility. The chopped carbon fibers in the polymer matrix led to moderately anisotropic shocks, particularly when compared with the more commonly encountered filament-wound carbon fiber-epoxy composites. A discontinuity, or cusp, was observed in the principal Hugoniot of both materials near 25 GPa. We attribute the accompanying volume collapse to shock-driven chemical decomposition above this condition. Inert and reacted products equations of state were used to capture the response of the two materials below and above the cusp.

  19. Method of fabrication of anchored nanostructure materials

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-11-26

    Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

  20. Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

    2016-01-01

    The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography, and ......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

  1. As assessment of power system vulnerability to release of carbon fibers during commercial aviation accidents

    Science.gov (United States)

    Larocque, G. R.

    1980-01-01

    The vulnerability of a power distribution system in Bedford and Lexington, Massachusetts to power outages as a result of exposure to carbon fibers released in a commercial aviation accident in 1993 was examined. Possible crash scenarios at Logan Airport based on current operational data and estimated carbon fiber usage levels were used to predict exposure levels and occurrence probabilities. The analysis predicts a mean time between carbon fiber induced power outages of 2300 years with an expected annual consequence of 0.7 persons losing power. In comparison to historical outage data for the system, this represents a 0.007% increase in outage rate and 0.07% increase in consequence.

  2. PREPARATION OF ACTIVATED CARBON FIBER AND THEIR XENON ADSORPTION PROPERTIES (Ⅱ)-XENON ADSORPTION PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The adsorption of xenon from air has an interest in the monitoring of nuclear explosion oraccident, or in the treatment of nuclear waste gas. In this paper, the pore structure of several series ofactivated carbon fibers has been characterized. The adsorption properties of xenon on theseactivated carbon fibers under different temperatures have been studied in details. The results showthat the xenon adsorption amount on activated carbon fibers do not increase with specific surfacearea of adsorbents, but are closely related to their pore size distribution. Pores whose radius equal toor narrow than 0.4nm would be more advantageous to the adsorption of xenon.

  3. The effect of rapid thermal annealing on characteristics of carbon coatings on optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jen-Feng; Chen, Tsuen-Sung; Lin, Hung-Chien; Shiue, Sham-Tsong [Department of Materials Science and Engineering, National Chung Hsing University, Taichung (China)

    2010-02-15

    Carbon films are deposited on silica glass fibers by radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD), and the properties of these optical fibers are improved by rapid thermal annealing. The annealing temperatures are set to 100, 200, 300, 400, 500, 550, 600, and 700 C. Experimental results show that the thickness and surface roughness of carbon films decrease with increasing annealing temperature, ranging from as-deposited to 500 C, while the sp{sup 2} carbon bonding, sp{sup 3} CH{sub 3} bonding, optical bandgap, and water contact angle (CA) of carbon films increase. As the annealing temperature increases from 550 to 700 C, parts of the carbon films are delaminated. The sp{sup 3} CH{sub 3} bonding in carbon films is shifted to the sp{sup 3} CH{sub 2} bonding, and the sp{sup 3} CH{sub 2} bonding is subsequently transferred to the sp{sup 2} CH bonding. Meanwhile, the amount of the sp{sup 2} carbon bonding in carbon films increases, while the optical bandgap decreases. Based on the evaluation of water repellency and low-temperature morphology of carbon films, the carbon film annealed at a temperature of 500 C is the best for production of carbon-coated optical fibers. As compared to conventional thermal annealing (CTA), rapid thermal annealing (RTA) is more effective to improve the properties of carbon-coated optical fibers. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. Preparation and characterization of porous carbon material-coated solid-phase microextraction metal fibers.

    Science.gov (United States)

    Zhu, Fang; Guo, Jiaming; Zeng, Feng; Fu, Ruowen; Wu, Dingcai; Luan, Tiangang; Tong, Yexiang; Lu, Tongbu; Ouyang, Gangfeng

    2010-12-10

    Two kinds of porous carbon materials, including carbon aerogels (CAs), wormhole-like mesoporous carbons (WMCs), were synthesized and used as the coatings of solid-phase microextraction (SPME) fibers. By using stainless steel wire as the supporting core, six types of fibers were prepared with sol-gel method, direct coating method and direct coating plus sol-gel method. Headspace SPME experiments indicated that the extraction efficiencies of the CA fibers are better than those of the WMC fibers, although the surface area of WMCs is much higher than that of CAs. The sol-gel-CA fiber (CA-A) exhibited excellent extraction properties for non-polar compounds (BTEX, benzene, toluene, ethylbenzene, o-xylene), while direct-coated CA fiber (CA-B) presented the best performance in extracting polar compounds (phenols). The two CA fibers showed wide linear ranges, low detection limits (0.008-0.047μgL(-1) for BTEX, 0.15-5.7μgL(-1) for phenols) and good repeatabilities (RSDs less than 4.6% for BTEX, and less than 9.5% for phenols) and satisfying reproducibilities between fibers (RSDs less than 5.2% for BTEX, and less than 9.9% for phenols). These fibers were successfully used for the analysis of water samples from the Pearl River, which demonstrated the applicability of the home-made CA fibers.

  5. Properties of Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Matrix Composites

    Science.gov (United States)

    Cano, Roberto J.; Kang, Jin Ho; Grimsley, Brian W.; Ratcliffe, James G.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strength- and stiffness-to-weight ratios, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Carbon nanotubes (CNT) offer the potential to enhance the multi-functionality of composites with improved thermal and electrical conductivity. In this study, hybrid CNT/carbon fiber (CF) polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing. Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated.

  6. Lignin-based carbon fibers: Carbon nanotube decoration and superior thermal stability

    KAUST Repository

    Xu, Xuezhu

    2014-08-23

    Lignin-based carbon fibers (CFs) decorated with carbon nanotubes (CNTs) were synthesized and their structure, thermal stability and wettability were systematically studied. The carbon fiber precursors were produced by electrospinning lignin/polyacrylonitrile solutions. CFs were obtained by pyrolyzing the precursors and CNTs were subsequently grown on the CFs to eventually achieve a CF–CNT hybrid structure. The processes of pyrolysis and CNT growth were conducted in a tube furnace using different conditions and the properties of the resultant products were studied and compared. The CF–CNT hybrid structure produced at 850 °C using a palladium catalyst showed the highest thermal stability, i.e., 98.3% residual weight at 950 °C. A mechanism for such superior thermal stability was postulated based on the results from X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and electron energy loss spectroscopy analyses. The dense CNT decoration was found to increase the hydrophobicity of the CFs.

  7. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    Science.gov (United States)

    Fang, Cuiqin; Wang, Julin; Zhang, Tao

    2014-12-01

    The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer.

  8. Preparation and mechanism of calcium phosphate coatings on chemical modified carbon fibers by biomineralization

    Institute of Scientific and Technical Information of China (English)

    HUANG Su-ping; ZHOU Ke-chao; LI Zhi-you

    2008-01-01

    In order to prepare HA coatings on the carbon fibers, chemical modification and biomineralization processes were applied. The phase components, morphologies, and possible growth mechanism of calcium phosphate were studied by infrared spectroscopy(IR), X-ray diffractometry(XRD) and scanning electron microscopy(SEM). The results show that calcium phosphate coating on carbon fibers can be obtained by biomineralization. But the phase components and morphologies of calcium phosphate coatings are different due to different modification methods. Plate-like CaHPO4-2H2O (DCPD) crystals grow from one site of the active centre by HNO3 treatment. While on the para-aminobenzoic acid treated fibers, the coating is composed of nano-structural HA crystal homogeneously. This is because the -COOH functional groups of para-aminobenzoic acid graft on fibers, with negative charge and arranged structure, accelerating the HA crystal nucleation and crystallization on the carbon fibers.

  9. Tensile strength and its scatter of unidirectional carbon fiber reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, H.; Oya, N.; Yamashita, K.; Maekawa, Z.I. [Kyoto Inst. of Technology (Japan)

    1995-12-31

    0 (along the fiber direction) and 90 degree (transverse to the fiber direction) tension tests of Carbon Fiber Reinforced Plastics (CFRP) using a great number of specimens were conducted. Tensile properties and their scatter were evaluated by means of the data base. Materials used in this study were seven kinds of carbon fibers and three kinds of epoxy resins. Reinforcing fiber and matrix resin properties strongly affected on 0 and 90 degree properties of CFRP respectively. In 0 degree tension tests, fracture mode of specimen vaned in each material, and a relationship between the scatter of strength and the fracture mode existed. From the results of 9 degree tension tests, some differences of interfacial properties between each laminate were` also detected. According to some considerations on fracture mechanism in 0 degree tension test, it was deduced that the fracture mode depended on the balance of fiber, matrix and interface properties.

  10. Rate dependent response and failure of a ductile epoxy and carbon fiber reinforced epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Rae, Philip J [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Stahl, David B [Los Alamos National Laboratory

    2010-01-01

    An extensive characterization suite has been performed on the response and failure of a ductile epoxy 55A and uniaxial carbon fiber reinforced epoxy composite of IM7 fibers in 55A resin from the quasistatic to shock regime. The quasistatic and intermediate strain rate response, including elastic modulus, yield and failure have are characterized by quasistatic, SHPB, and DMA measurements as a function of fiber orientation and temperature. The high strain rate shock effect of fiber orientation in the composite and response of the pure resin are presented for plate impact experiments. It has previously been shown that at lower impact velocities the shock velocity is strongly dependent on fiber orientation but at higher impact velocity the in-plane and through thickness Hugoniots converge. The current results are compared with previous studies of the shock response of carbon fiber composites with more conventional brittle epoxy matrices. The spall response of the composite is measured and compared with quasistatic fracture toughness measurements.

  11. Structure and Properties of poly (para phynelyne benzobisoxazole) (PBO) /single wall carbon nano tube composite fibers

    Science.gov (United States)

    Kumar, Satish; Zhang, Xiefei; Bhattacharyya, Arup R.; Min, Byung G.; Dang, T. D.; Arnold, F. E.; Vaia, Richard A.; Ramesh, S.; Willis, P. A.; Hauge, R. H.; Smalley, R. E.

    2002-03-01

    The liquid crystalline compositions are prepared by the in-situ polycondensation of diamines and diacid monomers in the presence of single wall carbon nano tubes (SWNT). Processing of the new compositions into fibers provide hybrid materials with improved mechanical properties. The in-situ polymerizations were carried out in polyphosphoric acid (PPA). Carbon nano tubes as high as 10 wt.polymer weight have been utilized. Fiber spinning has been carried out using dry jet wet spinning using a piston driven spinning system and the fiber coagulated in water and subsequently vacuum dried and heat treated in nitrogen at 400oC. Structure and properties of these fibers have been studied. Tensile strength of the composite fibers increased by about 50morphology of these fibers have been studied using X- ray diffraction and scanning electron microscopy.

  12. Determination of pressure drop across activated carbon fiber respirator cartridges.

    Science.gov (United States)

    Balanay, Jo Anne G; Lungu, Claudiu T

    2016-01-01

    Activated carbon fiber (ACF) is considered as an alternative adsorbent to granular activated carbon (GAC) for the development of thinner, lighter, and efficient respirators because of their larger surface area and adsorption capacities, thinner critical bed depth, lighter weight, and fabric form. This study aims to measure the pressure drop across different types of commercially available ACFs in respirator cartridges to determine the ACF composition and density that will result in acceptably breathable respirators. Seven ACF types in cloth (ACFC) and felt (ACFF) forms were tested. ACFs in cartridges were challenged with pre-conditioned constant air flow (43 LPM, 23°C, 50% RH) at different compositions (single- or combination-ACF type) in a test chamber. Pressure drop across ACF cartridges were obtained using a micromanometer, and compared among different cartridge configurations, to those of the GAC cartridge, and to the NIOSH breathing resistance requirements for respirator cartridges. Single-ACF type cartridges filled with any ACFF had pressure drop measurements (23.71-39.93 mmH2O) within the NIOSH inhalation resistance requirement of 40 mmH2O, while those of the ACFC cartridges (85.47±3.67 mmH2O) exceeded twice the limit due possibly to the denser weaving of ACFC fibers. All single ACFF-type cartridges had higher pressure drop compared to the GAC cartridge (23.13±1.14 mmH2O). Certain ACF combinations (2 ACFF or ACFC/ACFF types) resulted to pressure drop (26.39-32.81 mmH2O) below the NIOSH limit. All single-ACFF type and all combination-ACF type cartridges with acceptable pressure drop had much lower adsorbent weights than GAC (≤15.2% of GAC weight), showing potential for light-weight respirator cartridges. 100% ACFC in cartridges may result to respirators with high breathing resistance and, thus, is not recommended. The more dense ACFF and ACFC types may still be possibly used in respirators by combining them with less dense ACFF materials and/or by

  13. [Study on the skin-core evolvement of carbon fibers as a function of heat treatment temperature by Raman spectroscopy].

    Science.gov (United States)

    Liu, Fu-jie; Fan, Li-dong; Wang, Hao-jing; Zhu, Zhen-ping

    2008-08-01

    The skin-core evolvement of the carbon fibers was studied as a function of heat-treatment temperature though the analysis of Raman spectroscopy of the carbon fibers surface and core. It was found that the change of the Raman spectra of the carbon fibers core was similar to that on the surface with the increase in heat-treatment temperature. At 1600 degrees C, the Rs and Rc values were almost equal, indicating that the degrees of the graphitization of the carbon fibers surface and core were almost uniform. The Rs and Rc values decreased dramatically with the increase in heat-treatment temperature, and Rs decreased more. At 2800 degrees C, the Rs value came to 0.429, lowered 77.2%, while the Rc value then came to 1.101, lowered 38.7% only. It implied that the graphitization degree of the carbon fibers was enhanced with increasing the heat treatment temperature, and that of carbon fibers surface was enhanced more. The graphite characters of the carbon of the carbon fibers surface were different from that of the carbon fibers core. The former is close to soft carbon, which is easy to graphitize, while the latter is close to hard carbon, which is difficult to graphitize, and it may be resin carbon Skin-core structure gene Rsc (= Rs/Rc) which denoted the skin-core degree of the carbon fibers was first brought forward and adopted. The Rsc value is between 0 and 1. When the Rsc value is equal to 1, the carbon fibers are homogenous. When the Rsc value is close to zero, there are serious skin-core structures in the carbon fibers. The Rsc value reduced linearly with the increase in heat-treatment temperature, indicating that the homogeneous degrees of the carbon fibers decreased and the skin-core degrees of the carbon fibers increased. The crystallite size of the carbon fibers surface and core increased gradually with the increase in heat-treatment temperature, but the surface's increased more quickly, indicating that the carbon of the carbon fibers surface was easier to

  14. Influence of chemical agents on the surface area and porosity of active carbon hollow fibers

    Directory of Open Access Journals (Sweden)

    LJILJANA M. KLJAJEVIĆ

    2011-09-01

    Full Text Available Active carbon hollow fibers were prepared from regenerated polysulfone hollow fibers by chemical activation using: disodium hydrogen phosphate 2-hydrate, disodium tetraborate 10-hydrate, hydrogen peroxide, and diammonium hydrogen phosphate. After chemical activation fibers were carbonized in an inert atmosphere. The specific surface area and porosity of obtained carbons were studied by nitrogen adsorption–desorption isotherms at 77 K, while the structures were examined with scanning electron microscopy and X-ray diffraction. The activation process increases these adsorption properties of fibers being more pronounced for active carbon fibers obtained with disodium tetraborate 10-hydrate and hydrogen peroxide as activator. The obtained active hollow carbons are microporous with different pore size distribution. Chemical activation with phosphates produces active carbon material with small surface area but with both mesopores and micropores. X-ray diffraction shows that besides turbostratic structure typical for carbon materials, there are some peaks which indicate some intermediate reaction products when sodium salts were used as activating agent. Based on data from the electrochemical measurements the activity and porosity of the active fibers depend strongly on the oxidizing agent applied.

  15. Conductivity and Ambient Stability of Halogen-Doped Carbon Nanotube Fibers

    Science.gov (United States)

    Gaier, J. R.; Chirino, C. M.; Chen, M.; Waters, D. L.; Tran, Mai Kim; Headrick, R.; Young, C. C.; Tsentalovich, D.; Whiting, B.; Pasquali, M.; Waarbeek, Ron ter; Otto, Marcin J.

    2014-01-01

    Carbon nanotube fibers were fabricated using a variety of spinning conditions and post-spinning processing with the goal of creating a high-conductivity yet environmentally stable fiber. These fiber variants were then doped with bromine, iodine, iodine chloride, or iodine bromide and their electrical and microstructural properties were characterized. Environmentally stable compounds were synthesized with electrical conductivity greater than 50,000 Scm.

  16. Activation and Micropore Structure Determination of Activated Carbon-Fiber Composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.

    1999-04-23

    Previous work focused on the production of carbon fiber composites and subsequently activating them to induce adsorbent properties. One problem related to this approach is the difficulty of uniformly activating large composites. In order to overcome this problem, composites have been made from pre-activated fibers. The loss of surface area upon forming the composites after activation of the fibers was investigated. The electrical resistivity and strength of these composites were compared to those made by activation after forming. It was found that the surface area is reduced by about 35% by forming the composite from pre-activated fibers. However, the properties of the activated sample are very uniform: the variation in surface area is less than {+-}0.5%. So, although the surface area is somewhat reduced, it is believed that making composites from pre-activated fibers could be useful in applications where the BET surface area is not required to be very high. The strength of the composites produced from pre-activated fibers is lower than for composites activated after forming when the carbon burnoff is below 45%. For higher burnoffs, the strength of composites made with pre-activated fibers is as good or better. In both cases, there is a dramatic decrease in strength when the fiber:binder ratio is reduced below 4:1. The electrical resistivity is slightly higher for composites made from pre-activated fibers than for composites that are activated after forming, other parameters being constant (P-200 fibers, similar carbon burnoffs). For both types of composite the resistivity was also found to increase with carbon burnoff. This is attributed to breakage of the fiber causing shorter conductive paths. The electrical resistivity also increases when the binder content is lowered, which suggests that there are fewer solid contact points between the fibers.

  17. Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol

    Institute of Scientific and Technical Information of China (English)

    WU Kezhong; MENG Xu; WANG Xindong; LI Jingling

    2005-01-01

    Platinum was electrodeposited onto a polyaniline-modified carbon fiber electrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in the level of platinum u tilization currently achieved in electrocatalyric systems. This electrode preparation consists of a two-step procedure: first electropolymerization of aniline onto carbon fiber and then electrodeposition of platinum. The catalytic activity of the platinum-polyaniline-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a bare carbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current of methanol on Pt/PAni/C is 50.7 mA.cm-2, which is 6.7 times higher than 7.6 mA.cm-2 on the Pt/C.Scanning electron microscopy was used to investigate the dispersion of the platinum particles of about 0.4 μm.

  18. Catalytic graphitization of Mo-B-doped polyacrylonitrile(PAN)-based carbon fibers

    Institute of Scientific and Technical Information of China (English)

    XU Shi-hai; ZHANG Feng-ying; LIU Shao-huan; HE Dong-mei; CAI Qing-yun

    2010-01-01

    A novel carbon fiber pretreatment was proposed.Polyacrylonitrile(PAN)-based carbon fibers were first anodized in H3PO4electrolyte to achieve an active surface,and then coated with Mo-B catalysts by immersed the carbon fibers in a uniformly dispersed Mo-B sol.The as-treated carbon fibers were then graphitized at 2 400 ℃ for 2 h.The structural changes were characterized by X-ray diffractometry(XRD),Raman spectroscopy,scanning electron microscopy(SEM)and high-resolution transmission electronic microscopy(HRTEM).The results show that much better graphitization can be achieved in the presence of Mo-B,with an interlayer spacing(d002)of 0.335 8 nm and a crystalline size(Lc)of 28 nm.

  19. Nanoscale characterization of carbazole-indole copolymers modified carbon fiber surfaces.

    Science.gov (United States)

    Sarac, A Sezai; Serantoni, Marina; Tofail, Syed A M; Cunnane, Vincent J

    2005-10-01

    Polycarbazole, carbazole and indole containing copolymers were electrochemically coated onto carbon fiber. The resulting polymers and copolymers were characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Characterization of the thin polymer films were performed on the polymer-coated surface of the carbon fiber. Therefore, the results obtained could elucidate the relationship between the initial feed monomer ratio, the resulting polymer/copolymer film morphology and the surface structure formed. The thickness increase (in diameter) was 0.3 and 0.9 microm, for two different composition of carbazole/indole on the carbon fiber. The carbon fibers coated with copolymer thin films were from 6.5 to 8.2 microm in diameter (from AFM measurement).

  20. Circuit models for Salisbury screens made from unidirectional carbon fiber composite sandwich structures

    Science.gov (United States)

    Riley, Elliot J.; Lenzing, Erik H.; Narayanan, Ram M.

    2016-05-01

    Carbon fiber composite materials have many useful structural material properties. The electromagnetic perfor- mance of these materials is of great interest for future applications. The work presented in this paper deals with the construction of Salisbury screen microwave absorbers made from unidirectional carbon fiber composite sand- wich structures. Specifically, absorbers centered at 7.25 GHz and 12.56 GHz are investigated. Circuit models are created to match the measured performance of the carbon fiber Salisbury screens using a genetic algorithm to extract lumped element circuit values. The screens presented in this paper utilize unidirectional carbon fiber sheets in place of the resistive sheet utilized in the classic Salisbury screen. The theory, models, prototypes, and measurements of these absorbers are discussed.

  1. Advanced in situ multi-scale characterization of hardness of carbon-fiber-reinforced plastic

    Science.gov (United States)

    Wang, Hongxin; Masuda, Hideki; Kitazawa, Hideaki; Onishi, Keiko; Kawai, Masamichi; Fujita, Daisuke

    2016-10-01

    In situ multi-scale characterization of hardness of carbon-fiber-reinforced plastic (CFRP) is demonstrated by a traditional hardness tester, instrumented indentation tester and atomic-force-microscope (AFM)-based nanoindentation. In particular, due to the large residual indentation and nonuniform distribution of the microscale carbon fibers, the Vickers hardness could not be calculated by the traditional hardness tester. In addition, the clear residual microindentation could not be formed on the CFRP by instrumented indentation tester because of the large tip half angle of the Berkovich indenter. Therefore, an efficient technique for characterizing the true nanoscale hardness of CFRP was proposed and evaluated. The local hardness of the carbon fibers or plastic matrix on the nanoscale did not vary with nanoindentation location. The Vickers hardnesses of the carbon fiber and plastic matrix determined by AFM-based nanoindentation were 340 ± 30 and 40 ± 2 kgf/mm2, respectively.

  2. NASA Invention of the year Award - 2004. The revolutionary unique braided carbon-fiber thermal barr

    Science.gov (United States)

    2005-01-01

    NASA Invention of the year Award - 2004. The revolutionary unique braided carbon-fiber thermal barrier is designed to with stand the extreme temperature environments in current and future solid rocket motors with application to industrial equipment

  3. Experimental determinations of the eigenmodes for composite bars made with carbon and Kevlar-carbon fibers

    Science.gov (United States)

    Miriţoiu, C. M.; Stănescu, M. M.; Burada, C. O.; Bolcu, D.; Roşca, V.

    2015-11-01

    For modal identification, the single-point excitation method has been widely used in modal tests and it consists in applying a force in a given point and recording the vibratory structure response in all interest points, including the excitation point. There will be presented the experimental recordings for the studied bars (with Kevlar-carbon or carbon fibers), the frequency response function in Cartesian and polar coordinates. By using the frequency response functions we determine the eigenparameters for each bar. We present the final panel of the eigenmodes (with the damping factors, eigenfrequencies and critical damping) for each considered bar. Using the eigenfrequency of the first determined eigenmode, the bars stiffness has been determined. The presented bars can be used in practical engineering for: car or bus body parts, planes body parts, bullet-proof vests, reinforcements for sandwich beams, and so on.

  4. Microwave absorption properties of helical carbon nanofibers-coated carbon fibers

    Directory of Open Access Journals (Sweden)

    Lei Liu

    2013-08-01

    Full Text Available Helical carbon nanofibers (HCNFs coated-carbon fibers (CFs were fabricated by catalytic chemical vapor deposition method. TEM and Raman spectroscopy characterizations indicate that the graphitic layers of the HCNFs changed from disorder to order after high temperature annealing. The electromagnetic parameters and microwave absorption properties were measured at 2–18 GHz. The maximum reflection loss is 32 dB at 9 GHz and the widest bandwidth under −10 dB is 9.8 GHz from 8.2 to 18 GHz for the unannealed HCNFs coated-CFs composite with 2.5 mm in thickness, suggesting that HCNFs coated-CFs should have potential applications in high performance microwave absorption materials.

  5. Novel catalytic applications of carbon nanofibers on sintered metal fibers filters as structured supports

    OpenAIRE

    2009-01-01

    Supported metal catalysts are important from both an industrial and a scientific point of view. They are used, amongst others, in large-scale processes such as catalytic reforming, hydrotreating, polymerization reactions and hydrogenations. Often, these catalysts consist of nanosized metal particles deposited on a suitable support, which acts as an anchor for the active phase and, in several cases, contributes to improve the overall catalyst performances. The growth of carbon nanofibers on si...

  6. Novel catalytic applications of carbon nanofibers on sintered metal fibers filters as structured supports

    OpenAIRE

    2008-01-01

    Supported metal catalysts are important from both an industrial and a scientific point of view. They are used, amongst others, in large-scale processes such as catalytic reforming, hydrotreating, polymerization reactions and hydrogenations. Often, these catalysts consist of nanosized metal particles deposited on a suitable support, which acts as an anchor for the active phase and, in several cases, contributes to improve the overall catalyst performances. The growth of carbon nanofibers on si...

  7. Study on the Mechanical Properties of Carbon Nanotube/Polyacrylonitrile Composite Fibers

    Institute of Scientific and Technical Information of China (English)

    李建梅; 王彪; 张玉梅; 王华平; 杨崇倡

    2003-01-01

    The method of preparing the multi-walled carbon nanotubes(MWNTs)-polyacrylonitrile (PAN) composite fibers is described and the effects of draw ratio on the mechanical properties of CNT/PAN fibers have also been discussed.The results show that the degrees of MWNTs dispersion in the polymer matrix have much effect on the mechanical properties.

  8. Adsorption of SO2 onto oxidized and heat-treated activated carbon fibers (ACFs)

    Science.gov (United States)

    Daley, M.A.; Mangun, C.L.; DeBarr, J.A.; Riha, S.; Lizzio, A.A.; Donnals, G.L.; Economy, J.

    1997-01-01

    A series of activated carbon fibers (ACFs) and heat-treated oxidized ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore surface chemistry and pore volume for the adsorption of SO2 and its catalytic conversion to H2SO4.

  9. Evaluation of the flexural strength of carbon, quartz, and glass fiber-based posts

    Directory of Open Access Journals (Sweden)

    Sita Rama Raju

    2014-01-01

    Full Text Available Objectives: This study was done to evaluate the flexural strength of carbon, quartz, and glass fiber posts by means of three-point bending test. Materials and Methods: Thirty pre-fabricated fiber posts were used and divided into three groups. Group I carbon fiber posts (C-Post, group II quartz fiber post (Aestheti Plus, group III glass fiber post (Para Post White Ten posts (N = 10 were used for each experimental group and were measured with digital caliper before test accomplishment. The fracture load of post specimens was measured, and flexural strength was obtained by the formula using S = 8FL/pd 3 . The values in Kgf/mm 2 were obtained and calculated to Mpa and submitted to ANOVA (a = 0.01 and to the Tukey′s test. Results: The mean values of flexural strength show that group II quartz fiber posts (666 MPa are significantly higher than group I carbon fiber (614 MPa and group III glass fiber (575 MPa. C onclusion: Hence, this study concluded that quartz fiber post showed significantly higher flexural strength values. Further scope of this study lies in the evaluation and evolution of a restorative materials used for post and core preparation, which have modulus of elasticity in harmony with that of dentin and near-natural esthetic appearance.

  10. Environmental effects on the hybrid glass fiber/carbon fiber composites

    Science.gov (United States)

    Tsai, Yun-I.

    2009-12-01

    Fiber reinforced polymer composites (FRPCs) have been widely used to replace conventional metals due to the high specific strength, fatigue resistance, and light weight. In the power distribution industry, an advanced composites rod has been developed to replace conventional steel cable as the load-bearing core of overhead conductors. Such conductors, called aluminum conductor composite core (ACCC) significantly increases the transmitting efficiency of existing power grid system without extensive rebuilding expenses, while meeting future demand for electricity. In general, the service life of such overhead conductors is required to be at least 30 years. Therefore, the long-term endurance of the composite core in various environments must be well-understood. Accelerated aging by hygrothermal exposure was conducted to determine the effect of moisture on the glass fiber (GF)/carbon fiber (CF) hybrid composites. The influence of water immersion and humid air exposure on mechanical properties is investigated. Results indicated that immersion in water is the most severe environment for such hybrid GF/CF composites, and results in greater saturation and degradation of properties. When immersed directly in water, the hybrid GF/CF composites exhibit a moisture uptake behavior that is more complex than composite materials reinforced with only one type of fiber. The unusual diffusion behavior is attributed to a higher packing density of fibers at the annular GF/CF interface, which acts as a temporary moisture barrier. Moisture uptake leads to the mechanical and thermal degradation of such hybrid GF/CF composites. Findings presented here indicate that the degradation is a function of exposure temperature, time, and moisture uptake level. Results also indicate that such hybrid GF/CF composites recover short beam shear (SBS) strength and glass transition temperature (Tg) values comparable to pre-aged samples after removal of the absorbed moisture. In the hygrothermal environment

  11. Electrical Resistance Behavior of Vinylester Composites Filled with Glass-carbon Hybrid Fibers

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; ZHANG Lianmeng; XU Renxin; DUAN Huajun; YANG Xiaoli; WANG Xiang

    2009-01-01

    Vinylester (bismethacryloxy derivative of a bisphenol-A type EP resin, VE) composites with glass-carbon hybrid fibers (CF-GF) weight fraction of 50%, were prepared by the compress molding method. The distribution of carbon fiber in the hybrids was observed by stereomicroscope. The electrical resistance behavior of the composites filled with different carbon fiber (CF) weight contents (0.5% to 20%) was studied. The experimental results show that the electrical resistance behaviors of CF-GF/VE composites are different with those of CF/VE composites because carbon fibers' conducting networks are broken by the glass fibers in the CF-GF/VE composites. The carbon fibers distribute uniformly in the networks of glass fibers (GF) like single silk and form the semi-continuous conducting networks. Composite filled with GF-CF hybrid has a higher percolation threshold than that filled with pure CF. At that time, the resistivity of CF-GF/VE composites varies little with the temperature increasing. The temperature coefficient of resistivity in GF-CF/VE composite is less than 317 ppm and the variation of the resistivity after ten thermal cycles from 20 ℃to 240 ℃ is less than 1.96%.

  12. Numerical and Experimental Investigations on Deep Drawing of G1151 Carbon Fiber Woven Composites

    Science.gov (United States)

    Gherissi, A.; Abbassi, F.; Ammar, A.; Zghal, A.

    2016-06-01

    This study proposes to simulate the deep drawing on carbon woven composites in order to reduce the manufacturing cost and waste of composite material during the stamping process, The multi-scale anisotropic approach of woven composite was used to develop a finite element model for simulating the orientation of fibers accurately and predicting the deformation of composite during mechanical tests and forming process. The proposed experimental investigation for bias test and hemispherical deep drawing process is investigated in the G1151 Interlock. The mechanical properties of carbon fiber have great influence on the deformation of carbon fiber composites. In this study, shear angle-displacement curves and shear load-shear angle curves were obtained from a bias extension test. Deep drawing experiments and simulation were conducted, and the shear load-displacement curves under different forming depths and shear angle-displacement curves were obtained. The results showed that the compression and shear between fibers bundles were the main deformation mechanism of carbon fiber woven composite, as well as the maximum shear angle for the composites with G1151 woven fiber was 58°. In addition, during the drawing process, it has been found that the forming depth has a significant influence on the drawing force. It increases rapidly with the increasing of forming depth. In this approach the suitable forming depth deep drawing of the sheet carbon fiber woven composite was approximately 45 mm.

  13. Surface Properties of PAN-based Carbon Fibers Modified by Electrochemical Oxidization in Organic Electrolyte Systems

    Directory of Open Access Journals (Sweden)

    WU Bo

    2016-09-01

    Full Text Available PAN-based carbon fibers were modified by electrochemical oxidization using fatty alcohol polyoxyethylene ether phosphate (O3P, triethanolamine (TEOA and fatty alcohol polyoxyethylene ether ammonium phosphate (O3PNH4 as organic electrolyte respectively. Titration analysis, single fiber fracture strength measurement and field emission scanning electron microscopy (FE-SEM were used to evaluate the content of acidic functional group on the surface, mechanical properties and surface morphology of carbon fiber. The optimum process of electrochemical treatment obtained is at 50℃ for 2min and O3PNH4 (5%, mass fraction as the electrolyte with current density of 2A/g. In addition, the surface properties of modified carbon fibers were characterized by X-ray photoelectron spectroscopy (XPS and single fiber contact angle test. The results show that the hydrophilic acidic functional groups on the surface of carbon fiber which can enhance the surface energy are increased by the electrochemical oxidation using O3PNH4 as electrolyte, almost without any weakening to the mechanical properties of carbon fiber.

  14. 2D Space-Confined Synthesis of Few-Layer MoS2 Anchored on Carbon Nanosheet for Lithium-Ion Battery Anode.

    Science.gov (United States)

    Zhou, Jingwen; Qin, Jian; Zhang, Xiang; Shi, Chunsheng; Liu, Enzuo; Li, Jiajun; Zhao, Naiqin; He, Chunnian

    2015-04-28

    A facile and scalable 2D spatial confinement strategy is developed for in situ synthesizing highly crystalline MoS2 nanosheets with few layers (≤5 layers) anchored on 3D porous carbon nanosheet networks (3D FL-MoS2@PCNNs) as lithium-ion battery anode. During the synthesis, 3D self-assembly of cubic NaCl particles is adopted to not only serve as a template to direct the growth of 3D porous carbon nanosheet networks, but also create a 2D-confined space to achieve the construction of few-layer MoS2 nanosheets robustly lain on the surface of carbon nanosheet walls. In the resulting 3D architecture, the intimate contact between the surfaces of MoS2 and carbon nanosheets can effectively avoid the aggregation and restacking of MoS2 as well as remarkably enhance the structural integrity of the electrode, while the conductive matrix of 3D porous carbon nanosheet networks can ensure fast transport of both electrons and ions in the whole electrode. As a result, this unique 3D architecture manifests an outstanding long-life cycling capability at high rates, namely, a specific capacity as large as 709 mAh g(-1) is delivered at 2 A g(-1) and maintains ∼95.2% even after 520 deep charge/discharge cycles. Apart from promising lithium-ion battery anode, this 3D FL-MoS2@PCNN composite also has immense potential for applications in other areas such as supercapacitor, catalysis, and sensors.

  15. Linear and nonlinear optical properties of carbon nanotube-coated single-mode optical fiber gratings.

    Science.gov (United States)

    Villanueva, Guillermo E; Jakubinek, Michael B; Simard, Benoit; Oton, Claudio J; Matres, Joaquín; Shao, Li-Yang; Pérez-Millán, Pere; Albert, Jacques

    2011-06-01

    Single-wall carbon nanotube deposition on the cladding of optical fibers has been carried out to fabricate an all-fiber nonlinear device. Two different nanotube deposition techniques were studied. The first consisted of repeatedly immersing the optical fiber into a nanotube supension, increasing the thickness of the coating in each step. The second deposition involved wrapping a thin film of nanotubes around the optical fiber. For both cases, interaction of transmitted light through the fiber core with the external coating was assisted by the cladding mode resonances of a tilted fiber Bragg grating. Ultrafast nonlinear effects of the nanotube-coated fiber were measured by means of a pump-probe pulses experiment.

  16. Residual stresses in boron/tungsten and boron/carbon fibers

    Science.gov (United States)

    Behrendt, D. R.

    1977-01-01

    Longitudinal residual stress distribution is determined for 102-micron diam B/W and B/C fibers. The 102-micron diam B/W fibers are deposited on a 12.7-micron diam tungsten wire resistively heated in a BCl3-H2 reactor. The 102-micron diam B/C fibers are made by deposition of boron on a pyrolytic graphite-coated carbon fiber. The longitudinal residual stress distribution is calculated from measurements of the change in length of the fiber produced by removal of the surface through electropolishing. It is found that for both types of fibers, the residual stress vary from a compressive stress at the surface to a tensile stress in the boron near the core. Closer to the core and in the core, significant differences in the residual stresses are observed for the B/W and B/C fibers.

  17. Electrochemical Dopamine Detection: Comparing Gold and Carbon Fiber Microelectrodes using Background Subtracted Fast Scan Cyclic Voltammetry

    OpenAIRE

    Zachek, Matthew K.; Hermans, Andre; Wightman, R. Mark; McCarty, Gregory S.

    2008-01-01

    Electrochemical detection is becoming increasingly important for the detection of biological species. Most current biological research with electrochemical detection is done with carbon fiber electrodes due to their many beneficial properties. The ability to build electrochemical sensor from noble metals instead of carbon fibers may be beneficial in developing inexpensive multiplexed electrochemical detection schemes. To advance understanding and to test the feasibility of using noble metal e...

  18. Repairable Woven Carbon Fiber Composites with Full Recyclability Enabled by Malleable Polyimine Networks.

    Science.gov (United States)

    Taynton, Philip; Ni, Huagang; Zhu, Chengpu; Yu, Kai; Loob, Samuel; Jin, Yinghua; Qi, H Jerry; Zhang, Wei

    2016-04-20

    Carbon-fiber reinforced composites are prepared using catalyst-free malleable polyimine networks as binders. An energy neutral closed-loop recycling process has been developed, enabling recovery of 100% of the imine components and carbon fibers in their original form. Polyimine films made using >21% recycled content exhibit no loss of mechanical performance, therefore indicating all of the thermoset composite material can be recycled and reused for the same purpose.

  19. Rheological behavior of composites based on carbon fibers recycled from aircraft waste

    OpenAIRE

    Marcaníková, Lucie; Hausnerová, Berenika; KITANO, Takeshi

    2009-01-01

    Rheological investigation of composite materials prepared from the recycled aircraft waste materials based on thermoset (epoxy/resin) matrix and long carbon fibers (CF) is presented with the aim of their utilization in consumer industry applications. The carbon fibers recovered via thermal process of pyrolysis were cut into about 150 pm length and melt mixed with thermoplastic matrices based on polypropylene (PP) and polyamide 6 (PA) and various modifiers - ethylene-ethyl acrylate-maleic anhy...

  20. Mechanical and Electrical Characterization of Novel Carbon Nano Fiber Ultralow Density Foam

    Science.gov (United States)

    2013-12-01

    instances of such composites are: A study that implanted carbon black, graphite powder and carbon fibers into an insulating polymer matrix and then...determined the effects of applying tensile and compressive stresses found that the resistance changed when stretching the polymer by 40 percent or...sizing. The term sizing refers to an organic mixture that commonly covers the surface of commercial fibers prepared by extrusion or injection

  1. Thermal diffusivity measurements on porous carbon fiber reinforced polymer tubes

    Science.gov (United States)

    Gruber, Jürgen; Gresslehner, Karl Heinz; Mayr, Günther; Hendorfer, Günther

    2017-02-01

    This work presents the application of methods for the determination of the thermal diffusivity well suited for flat bodies adapted to cylindrical bodies. Green's functions were used to get the temperature time history for small and large times, for the approach of intersecting these two straight lines. To verify the theoretical considerations noise free data are generated by finite element simulations. Furthermore effects of inhomogeneous excitation and the anisotropic heat conduction of carbon fiber reinforced polymers were taken into account in these numerical simulations. It could be shown that the intersection of the two straight lines is suitable for the determination of the thermal diffusivity, although the results have to be corrected depending on the ratio of the cylinders inner and outer radii. Inhomogeneous excitation affects the results of this approach as it lead to multidimensional heat flux. However, based on the numerical simulations a range of the azimuthal angle exists, where the thermal diffusivity is nearly independent of the angle. The method to determine the thermal diffusivity for curved geometries by the well suited Thermographic Signal Reconstruction method and taking into account deviations from the slab by a single correction factor has great advantages from an industrial point of view, just like an easy implementation into evaluation software and the Thermographic Signal Reconstruction methods rather short processing time.

  2. [Design and study of carbon fiber tracheal prosthesis].

    Science.gov (United States)

    Qi, L; Liu, D; Han, Z; Wang, F

    1998-12-01

    32 healty adult dogs were selected for this experiment. 10 of them were subjected to the tracheal biomechanics test using indices including the relation between stretcher ratio (lambda) and stress (T), the squeeze stress (delta jy) of medical silk thread on trachea, the side stress (Ts) inducing the tracheal collapse, the functional maximum angle (psi max) of tracheal, and the sever area torsion angle (theta max) of tracheal functional maximum curved. According to the indices measured, two types of tracheal prosthesis were designed, and were made of carbon fiber and silicon. They were the straight tube type tracheal prosthesis and the bifurcate type tracheal prosthesis. The straight tube type tracheal prosthesis was studied with a design of two groups comprising a total of 11 dogs. In the experiment group (n = 6), the outer surface of the tube was not coated with silicon, the average survival period was 379.8 days. In the control group (n = 5), the outer surface of the tube was coated with silicon, the average survival period was 90.4 days. The bifurcate type tracheal prosthesis was studied in 11 dogs, the average survival period was 4.32 days. The main causes of death in the experiment were infection and anastomotic dehiscent.

  3. Quasi-Static Indentation Analysis of Carbon-Fiber Laminates.

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Timothy [Sandia National Lab. (SNL-CA), Livermore, CA (United States); English, Shawn Allen [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nelson, Stacy Michelle [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-12-01

    A series of quasi - static indentation experiments are conducted on carbon fiber reinforced polymer laminates with a systematic variation of thicknesses and fixture boundary conditions. Different deformation mechanisms and their resulting damage mechanisms are activated b y changing the thickn ess and boundary conditions. The quasi - static indentation experiments have been shown to achieve damage mechanisms similar to impact and penetration, however without strain rate effects. The low rate allows for the detailed analysis on the load response. Moreover, interrupted tests allow for the incremental analysis of various damage mechanisms and pr ogressions. The experimentally tested specimens are non - destructively evaluated (NDE) with optical imaging, ultrasonics and computed tomography. The load displacement responses and the NDE are then utilized in numerical simulations for the purpose of model validation and vetting. The accompanying numerical simulation work serves two purposes. First, the results further reveal the time sequence of events and the meaning behind load dro ps not clear from NDE . Second, the simulations demonstrate insufficiencies in the code and can then direct future efforts for development.

  4. Piezoresistivity in Carbon Fiber Reinforced Cement Based Composites

    Institute of Scientific and Technical Information of China (English)

    Bing CHEN; Keru WU; Wu YAO

    2004-01-01

    The resu lts of some i nteresti ng investigation on the piezoresistivity of ca rbon fi ber reinforced cement based com posites (CFRC) are presented with the prospect of developing a new nondestructive testing method to assess the integrity of the composite. The addition of short carbon fibers to cement-based mortar or concrete improves the structural performance and at the same time significantly decreases the bulk electrical resistivity. This makes CFRC responsive to the smart behavior by measuring the resistance change with uniaxial pressure. The piezoresistivity of CFRC under different stress was studied, at the same time the damage occurring inner specimens was detected by acoustic emission as well. Test results show that there exists a marking pressure dependence of the conductivity in CFRC, in which the so-called negative pressure coefficient of resistive (NPCR) and positive pressure coefficient of resistive (PPCR) are observed under low and high pressure. Under constant pressures, time-dependent resistivity is an outstanding characteristic for the composites, which is defined as resistance creep. The breakdown and rebuild-up process of conductive network under pressure may be responsible for the pressure dependence of resistivity.

  5. Guided wave propagation in porous unidirectional carbon fiber reinforced plastic

    Science.gov (United States)

    Dobmann, Nicolas; Bach, Martin

    2017-02-01

    Networks of piezoelectric transducers mounted on aircraft structures for Acousto Ultrasonics (AU) purposes are designed to be applied during the service life of the aircraft. The approach to integrate these sensor networks already during the manufacture of carbon fiber reinforced plastic (CFRP) host structures prompts ideas to achieve an additional benefit by their application for cure monitoring, thus extending their use to the manufacturing chain. This benefit could be extended even further if guided waves generated by AU sensor networks could be used for porosity testing extensively applied for CFRP aircraft structures. In light of this, an experimental study was conducted to investigate effects of porosity on the propagation of guided waves in a basic configuration of unidirectional CFRP. Several samples were manufactured at different porosity levels by variation of the processing pressure. Wave fields were acquired using an ultrasonic scanning device. In the present work, phase velocities are chosen as best measurable and quantifiable propagation feature and the approach for the analysis of phase velocities in porosity samples is outlined. First results are presented and discussed regarding the influence of porosity on guided wave phase velocity and basic applicability for porosity testing of aircraft structures.

  6. Circumventing the mechanochemical origins of strength loss in the synthesis of hierarchical carbon fibers.

    Science.gov (United States)

    Steiner, Stephen A; Li, Richard; Wardle, Brian L

    2013-06-12

    Hierarchical carbon fibers (CFs) sheathed with radial arrays of carbon nanotubes (CNTs) are promising candidates for improving the intra- and interlaminar properties of advanced fiber-reinforced composites (e.g., graphite/epoxy) and for high-surface-area electrodes for battery and supercapacitor architectures. While CVD growth of CNTs on CFs has been previously shown to improve the apparent shear strength between fibers and polymer matrices (up to 60%), this has to date been achieved only at the expense of significant reductions in tensile strength (~30-50%) and stiffness (~10-20%) of the underlying fiber. Here we demonstrate two approaches for growing aligned and unaligned CNTs on CFs that enable preservation of fiber strength and stiffness. We observe that CVD-induced reduction of fiber strength and stiffness is primarily attributable to mechanochemical reorganization of the underlying fiber when heated untensioned above ~550 °C in both hydrocarbon-containing and inert atmospheres. We show that tensioning fibers to ≥12% of tensile strength during CVD enables aligned CNT growth while simultaneously preserving fiber strength and stiffness even at growth temperatures >700 °C. We also show that CNT growth employing CO2/acetylene at 480 °C without tensioning-below the identified critical strength-loss temperature-preserves fiber strength. These results highlight previously unidentified mechanisms underlying synthesis of hierarchical CFs and demonstrate scalable, facile methods for doing so.

  7. High Per formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

    Science.gov (United States)

    Zequine, Camila; Ranaweera, C. K.; Wang, Z.; Singh, Sweta; Tripathi, Prashant; Srivastava, O. N.; Gupta, Bipin Kumar; Ramasamy, K.; Kahol, P. K.; Dvornic, P. R.; Gupta, Ram K.

    2016-08-01

    High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of ~1.55 F/cm2 at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited ~65% improvement at 70 °C compare to that at 10 °C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices.

  8. Effect of Hybrid Surface Modifications on Tensile Properties of Polyacrylonitrile- and Pitch-Based Carbon Fibers

    Science.gov (United States)

    Naito, Kimiyoshi

    2016-05-01

    Recent interest has emerged in techniques that modify the surfaces of carbon fibers, such as carbon nanotube (CNT) grafting or polymer coating. Hybridization of these surface modifications has the potential to generate highly tunable, high-performance materials. In this study, the mechanical properties of surface-modified polyacrylonitrile (PAN)-based and pitch-based carbon fibers were investigated. Single-filament tensile tests were performed for fibers modified by CNT grafting, dipped polyimide coating, high-temperature vapor deposition polymerized polyimide coating, grafting-dipping hybridization, and grafting-vapor deposition hybridization. The Weibull statistical distributions of the tensile strengths of the surface-modified PAN- and pitch-based carbon fibers were examined. All surface modifications, especially hybrid modifications, improved the tensile strengths and Weibull moduli of the carbon fibers. The results exhibited a linear relationship between the Weibull modulus and average tensile strength on a log-log scale for all surface-modified PAN- and pitch-based carbon fibers.

  9. Three-Phase Carbon Fiber Amine Functionalized Carbon Nanotubes Epoxy Composite: Processing, Characterisation, and Multiscale Modeling

    Directory of Open Access Journals (Sweden)

    Kamal Sharma

    2014-01-01

    Full Text Available The present paper discusses the key issues of carbon nanotube (CNT dispersion and effect of functionalisation on the mechanical properties of multiscale carbon epoxy composites. In this study, CNTs were added in epoxy matrix and further reinforced with carbon fibres. Predetermined amounts of optimally amine functionalised CNTs were dispersed in epoxy matrix, and unidirectional carbon fiber laminates were produced. The effect of the presence of CNTs (1.0 wt% in the resin was reflected by pronounced increase in Young’s modulus, inter-laminar shear strength, and flexural modulus by 51.46%, 39.62%, and 38.04%, respectively. However, 1.5 wt% CNT loading in epoxy resin decreased the overall properties of the three-phase composites. A combination of Halpin-Tsai equations and micromechanics modeling approach was also used to evaluate the mechanical properties of multiscale composites and the differences between the predicted and experimental values are reported. These multiscale composites are likely to be used for potential missile and aerospace structural applications.

  10. Experimental lumbar spine fusion with novel tantalum-coated carbon fiber implant

    DEFF Research Database (Denmark)

    Li, Haisheng; Zou, Xuenong; Woo, Charlotte

    2007-01-01

    Implants of carbon fiber composite have been widely used in orthopedic and spinal surgeries. However, studies using carbon fiber-reinforced cages demonstrate frequent appearance of fibrous layer interposed between the implant and the surrounding bone. The aim of the present study was to test...... the possibility of coating a biocompatible metal layer on top of the carbon fiber material, to improve its biological performance. Tantalum was chosen because of its bone compatibility, based on our previous studies. A novel spinal fusion cage was fabricated by applying a thin tantalum coating on the surface...... of carbon-carbon composite material through chemical vapor deposition. Mechanical and biological performance was tested in vitro and in vivo. Compress strength was found to be 4.9 kN (SD, 0.2). Fatigue test with 500,000 cycles was passed. In vitro radiological evaluation demonstrated good compatibility...

  11. Adsorption characteristics of acetone, chloroform and acetonitrile on sludge-derived adsorbent, commercial granular activated carbon and activated carbon fibers.

    Science.gov (United States)

    Tsai, Jiun-Horng; Chiang, Hsiu-Mei; Huang, Guan-Yinag; Chiang, Hung-Lung

    2008-06-15

    The adsorption characteristics of chloroform, acetone, and acetonitrile on commercial activated carbon (C1), two types of activated carbon fibers (F1 and F2), and sludge adsorbent (S1) was investigated. The chloroform influent concentration ranged from 90 to 7800 ppm and the acetone concentration from 80 to 6900 ppm; the sequence of the adsorption capacity of chloroform and acetone on adsorbents was F2>F1 approximately C1 approximately S1. The adsorption capacity of acetonitrile ranged from 4 to 100 mg/g, corresponding to the influent range from 43 to 2700 ppm for C1, S1, and F1. The acetonitrile adsorption capacity of F2 was approximately 20% higher than that of the other adsorbents at temperaturescarbon fibers is higher than that of the other adsorbents due to their smaller fiber diameter and higher surface area. The micropore diffusion coefficient of VOC on activated carbon and sludge adsorbent was approximately 10(-4) cm2 s(-1). The diffusion coefficient of VOC on carbon fibers ranged from 10(-8) to 10(-7) cm2 s(-1). The small carbon fiber pore size corresponds to a smaller diffusion coefficient.

  12. Research on the melt impregnation of continuous carbon fiber reinforced nylon 66 composites

    Science.gov (United States)

    Jia, M. Y.; Li, C. X.; Xue, P.; Chen, K.; Chen, T. H.

    2016-07-01

    Impregnation mold of continuous carbon fiber reinforced thermoplastic composites was designed and built in the article. Based on the theory of fluid mechanics and Darcy's law, a model of the melt impregnation was also established. The influences of fiber bundle width and impregnation pins’ diameter on the impregnation degree were studied by numerical simulation. Continuous carbon fiber reinforced nylon 66 composites were prepared. The effects of coated angle and impregnation mold temperature on the mechanical properties of the composites were also described.The agreement between the experimental data and prediction by the model was found to be satisfactory.

  13. Thermophysical ESEM and TEM Characterization of Carbon Fibers CTE, Spectroscopy and Roughness Studies at High Temperatures

    Science.gov (United States)

    Ochoa, Ozden O.

    2004-01-01

    Accurate determination of the transverse properties of carbon fibers is important for assessment and prediction of local material as well as global structural response of composite components. However the measurements are extremely difficult due to the very small diameters of the fibers (few microns only) and must be conducted within a microscope. In this work, environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM) are used to determine the transverse coefficient of thermal expansion of different carbon fibers as a function of temperature.

  14. Development of Carbon Fiber Reinforced Stellite Alloy Based Composites for Tribocorrosion Applications

    Science.gov (United States)

    Khoddamzadeh, Alireza

    This thesis reports the design and development of two classes of new composite materials, which are low-carbon Stellite alloy matrices, reinforced with either chopped plain carbon fiber or chopped nickel-coated carbon fiber. The focus of this research is on obviating the problems related to the presence of carbides in Stellite alloys by substituting carbides as the main strengthening agent in Stellite alloys with the aforementioned carbon fibers. Stellite 25 was selected as the matrix because of its very low carbon content (0.1 wt%) and thereby relatively carbide free microstructure. The nickel coating was intended to eliminate any chance of carbide formation due to the possible reaction between carbon fibers and the matrix alloying additions. The composite specimens were fabricated using the designed hot isostatic pressing and sintering cycles. The fabricated specimens were microstructurally analyzed in order to identify the main phases present in the specimens and also to determine the possible carbide formation from the carbon fibers. The material characterization of the specimens was achieved through density, hardness, microhardness, corrosion, wear, friction, and thermal conductivity tests. These novel materials exhibit superior properties compared to existing Stellite alloys and are expected to spawn a new generation of materials used for high temperature, severe corrosion, and wear resistant applications in various industries.

  15. Conversion of lignin precursors to carbon fibers with nanoscale graphitic domains

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sabornie [ORNL; Jones, Eric B [ORNL; Clingenpeel, Amy [National High Magnetic Field Laboratory (Magnet Lab), Florida; McKenna, Amy [National High Magnetic Field Laboratory (Magnet Lab), Florida; Rios, Orlando [ORNL; McNutt, Nicholas W [ORNL; Keffer, David J. [University of Tennessee, Knoxville (UTK); Johs, Alexander [ORNL

    2014-08-04

    Lignin is one of the most abundant and inexpensive natural biopolymers. It can be efficiently converted to low cost carbon fiber, monolithic structures or powders that could be used directly in the production of anodes for lithium-ion batteries. In this work, we report processing parameters relevant for the conversion of lignin precursors into electrochemically active carbon fibers, the impact of lignin precursor modification on melt processing and the microstructure of the final carbon material. The conversion process encompasses melt spinning of the lignin precursor, oxidative stabilization and a low temperature carbonization step in a nitrogen/hydrogen atmosphere. To assess electrochemical performance, we determined resistivities of individual carbon fiber samples and characterized the microstructure by scanning electron microscopy and neutron diffraction. The chemical modification and subsequent thermomechanical processing methods reported here are effective for conversion into carbon fibers while preserving the macromolecular backbone structure of lignin. Modification of softwood lignin produced functionalities and rheological properties that more closely resemble hardwood lignin thereby enabling the melt processing of softwood lignin in oxidative atmospheres (air). Structural characterization of the carbonized fibers reveals nanoscale graphitic domains that are linked to enhanced electrochemical performance.

  16. Mixed polyvalent-monovalent metal coating for carbon-graphite fibers

    Science.gov (United States)

    Harper-Tervet, J.; Tervet, F. W.; Humphrey, M. F. (Inventor)

    1982-01-01

    An improved coating of gasification catalyst for carbon-graphite fibers is provided comprising a mixture of a polyvalent metal such as calcium and a monovalent metal such as lithium. The addition of lithium provides a lighter coating and a more flexible coating when applied to a coating of a carboxyl containing resin such as polyacrylic acid since it reduces the crosslink density. Furthermore, the presence of lithium provides a glass-like substance during combustion which holds the fiber together resulting in slow, even combustion with much reduced evolution of conductive fragments. The coated fibers are utilized as fiber reinforcement for composites.

  17. Improved thermoplastic composite by alignment of vapor-grown carbon fiber

    Science.gov (United States)

    Kuriger, Rex Jerrald

    2000-10-01

    Vapor grown carbon fiber (VGCF) is a new and inexpensive carbon fiber produced by vapor deposition of hydrocarbons on metal catalysts. Unlike continuous conventional PAN or pitch-derived carbon fibers, VGCF is discontinuous with diameters of about 200 nanometers and lengths ranging from 10 to 200 micrometers. The microscopic size and random entanglement of the fibers create several problems when processing VGCF composites. It is particularly difficult to disperse the entangled fibers in the matrix and orient them along a preferred axis to provide directional reinforcement. This work introduces a technique to produce an improved polymeric composite by alignment of vapor grown carbon nano-fibers in a polypropylene matrix. A twin-screw extruder was used to shear mix and disperse the fibers in the polymer matrix. The composite mixtures were extruded through a converging-annular die that generates flow-induced fiber alignment along the extrusion direction. The effect that the various extrusion conditions have on the bulk properties of the extrudate was investigated. It was found that the extrusion process is strongly dependent on the fiber content of the composite. The extrusion pressure increased and the flow rate decreased with fiber volume fraction. The tensile strength and modulus for the composite samples varied with extrusion temperature and screw speed, and the void content increased with fiber volume fraction. It was shown that fiber alignment could be improved by increasing the residence time in the die channel and was verified using x-ray diffraction. The mechanical properties of the aligned samples increased with fiber content. Also, the tensile strength improved with greater fiber orientation; however, more fiber alignment had little affect on the modulus. To better predict the strength of these partially aligned fiber composites, an experimental and theoretical approach was introduced. The experimental data correspond reasonably well when compared with the

  18. Fracture Toughness of Carbon Fiber Composites Containing Various Fiber Sizings and a Puncture Self-Healing Thermoplastic Matrix

    Science.gov (United States)

    Cano, Roberto J.; Grimsley, Brian W.; Ratcliffe, James G.; Gordon, Keith L.; Smith, Joseph G.; Siochi, Emilie J.

    2015-01-01

    Ongoing efforts at NASA Langley Research Center (LaRC) have resulted in the identification of several commercially available thermoplastic resin systems which self-heal after ballistic impact and through penetration. One of these resins, polybutylene graft copolymer (PBg), was selected as a matrix for processing with unsized carbon fibers to fabricate reinforced composites for further evaluation. During process development, data from thermo-physical analyses was utilized to determine a processing cycle to fabricate laminate panels, which were analyzed by photo microscopy and acid digestion. The process cycle was further optimized based on these results to fabricate panels for mechanical property characterization. The results of the processing development effort of this composite material, as well as the results of the mechanical property characterization, indicated that bonding between the fiber and PBg was not adequate. Therefore, three sizings were investigated in this work to assess their potential to improve fiber/matrix bonding compared to previously tested unsized IM7 fiber. Unidirectional prepreg was made at NASA LaRC from three sized carbon fibers and utilized to fabricate test coupons that were tested in double cantilever beam configurations to determine GIc fracture toughness.

  19. A novel surface modification of carbon fiber for high-performance thermoplastic polyurethane composites

    Science.gov (United States)

    Zhang, Yuanyuan; Zhang, Yizhen; Liu, Yuan; Wang, Xinling; Yang, Bin

    2016-09-01

    Properties of carbon fiber (CF) reinforced composites depend largely on the interfacial bonding strength between fiber and the matrix. In the present work, CF was grafted by 4,4‧-diphenylmethane diisocyanate (MDI) molecules after electrochemical oxidation treatment. The existence of functional groups introduced to the fiber surface and the changes of surface roughness were confirmed by FTIR, AFM, XPS, SEM and Raman spectroscopy. To evaluate the possible applications of this surface modification of carbon fiber, we examined the mechanical properties as well as the friction and wear performance of pristine CF and MDI-CF reinforced thermoplastic polyurethane (TPU) composites with 5-30 wt.% fiber contents, and found that the mechanical properties of TPU composites were all significantly improved. It is remarkable that when fiber content was 30 wt.%, the tensile strength of TPU/MDI-CF was increased by 99.3%, which was greater than TPU/CF (53.2%), and the friction loss of TPU/MDI-CF was decreased by 49.09%. The results of DMA and SEM analysis indicated the positive effects of MDI modification on the interfacial bonding between fibers and matrix. We believed that this simple and effective method could be used to the development of surface modified carbon fiber for high-performance TPU.

  20. Microstructure/Property Relationships for Carbon Fiber Reinforced Aluminum Alloys.

    Science.gov (United States)

    1985-07-25

    hypodermic syringe and blunted needle . After mounting the fiber, the card containing the fiber is inserted into the test fixture (figure 2). The edges... theory suggesting that this may not necessarily be the case [211. They showed that a weak interface may, 14 in fact, lead to improved composite properties...agree, at least in principle , with Ochai and Murakami’s theory and composites produced from Cornie’s fibers proved to be quite strong longitudinally

  1. [Preparation of carbon fiber reinforced fluid type resin denture (author's transl)].

    Science.gov (United States)

    Kasuga, H; Sato, H; Nakabayashi, N

    1980-01-01

    Transverse strength of cured fluid resins is weaker than that of the heat cured. We have studied to improve the mechanical strength of self-cured acrylic resin by application of carbon fibers as reinforcement and simple methods which must be acceptable for technicians are proposed. A cloth type carbon fiber was the best reinforcement among studied carbon fibers such as chopped or mat. The chopped fibers were difficult to mix homogeneously with fluid resins and effectiveness of the reinforcement was low. Breaking often occurred at the interface between the reinforcement and resin in the cases of mat which gave defects to the test specimens. To prepare reinforced denture, the cloth was trimmed on the master cast after removal of wax and the prepreg was formed with the alginate impression on the cast by Palapress and the cloth. Other steps were same as the usual fluid resin.

  2. Electromagnetic Interference Shielding Properties of Electroless Nickel-coated Carbon Fiber Paper Reinforced Epoxy Composites

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; WANG Jun; WANG Tao; WANG Junpeng; XU Renxin; YANG Xiaoli

    2014-01-01

    Carbon fibers (CFs) were coated with a nickel-phosphorus (Ni-P) film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. Wet paper-making method was used to prepare nickle coated carbon fiber paper (NCFP). Vacuum assisted infusion molding process (VAIMP) was employed to manufacture the NCFP reinforced epoxy composites, and carbon fiber paper (CFP) reinforced epoxy composites were also produced as a comparison. Electromagnetic interference (EMI) shielding properties of the composites were measured in the 3.22-4.9 GHz frequency range using waveguide method. Both NCFP and CFP reinforced epoxy composites of 0.5 mm thickness exhibited high EMI shielding effectiveness (SE) at 8wt%fiber content, 35 dB and 30 dB, respectively, and reflection was the dominant shielding mechanism.

  3. 2D SAXS/WAXD ANALYSIS OF PAN CARBON FIBER MICROSTRUCTURE IN ORGANIC/INORGANIC TRANSFORMATION

    Institute of Scientific and Technical Information of China (English)

    Cai-zhen Zhu; Xiao-lan Yu; Xiao-fang Liu; Yun-zen Mao; Rui-gang Liu; Ning Zhao; Xiao-li Zhang

    2013-01-01

    Structure of PAN fibers during pre-oxidation and carbonization was studied using two dimensional small angle X-ray scattering/wide angle X-ray diffraction (2D SAXS/WAXD).The SAXS results show that during pre-oxidation between 180 ℃ and 275 ℃,the volume content of microvoids increases with the temperature increasing,which may be one of reasons for the decrease of tensile strength of pre-oxidized fibers.253 ℃ was the critical transition temperature,the length,diameter,aspect ratio and orientation distribution of microvoids increased with temperature before this temperature and decreased after this temperature.After the high temperature carbonization,lots of spindly microvoids formed.WAXD patterns demonstrate that the crystallite size of PAN fibers first increased before 230 ℃ and then decreased with the increase of temperature during the pre-oxidation.The diffraction peak of PAN fibers at 2θ ≈ 17 almost disappeared at the end of preoxidation while the diffraction peak of aromatic structure at 2θ ≈ 25 appeared at 253 ℃.During carbonization,the peak intensity at 2θ ≈ 25 increased apparently due to the formation of graphite structure.The results obtained give a deep understanding of the microstructure development in the PAN fibers during pre-oxidation and carbonization,which is important for the preparation of high performance carbon fibers.

  4. Electromagnetism and Absorptivity of the Modified Micro-coiled Chiral Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    Zheng Tianliang; Wang Yuehong; Zheng Kuangyu; Li Qian; Tao Ye

    2007-01-01

    Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to compare the composition and morphology of the unmodified and the modified fibers. The results show that electromagnetism parameters of the modified are different from those of the unmodified. After modification by nano-Ni, the micro-coiled chiral carbon fibers have decreased permittivity and electrical loss. The permeability and magnetic loss of the modified carbon fibers become larger than those of the unmodified ones. Moreover, the modification of unmodified chiral carbon fibers into the modified is much like changing hollow electric windings into those with magnetic cores inside. The modifier intensifies the cross polarization of the chiral carbon fibers and makes the permittivity and the permeability get closer to each other which improves the matching performance and enhances absorbability of coatings. In the range of 6-18 GHz, the reflectivity of the coating is 6-8dB and the bandwidth is 12 GHz. The area density of the coating is below 3 kg/m2.

  5. Study on fine carbon fiber powder injected into cranium of rabbits

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: To study dynamically the effect on the rabbits after fine carbon fiber powder was transplanted into their cranium. METHODS: After fine carbon fiber powder was injected into subdural cavity of rabbits, examination of histopathology and EEG were carried out. RESULTS: General observation: 1-104 weeks after injecting, no neuropathological changes concerning with the injecting of the carbon fiber powder were found in the rabbits of experimental group; Under optical microscopes: 1-2 weeks after injecting, slight inflammatory reaction in meninx was found and disappeared generally 4 weeks after injecting, no obvious fiber membrane was found around the carbon fiber, no significant differences were showed between the experimental group (EG) and the control group (CG); Examination of EEG: 1-2 weeks after injecting, slight abnormal changes of EEG in both two groups were showed, but no significant differences was found between them. 4 weeks after injecting, the EEG of the two groups was restored to their normal state before injecting. 1-8 weeks after injecting, no obvious epilepsy waves were showed. CONCLUSION: The fine carbon fiber powder showed excellent histocompatibility after injected into the subdural cavity of rabbits.

  6. Optimization of interfacial microstructure and mechanical properties of carbon fiber/epoxy composites via carbon nanotube sizing

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Hongwei; Sui, Xianhang; Zhao, Zhongbo; Xu, Zhiwei; Chen, Lei, E-mail: chenlei@tjpu.edu.cn; Deng, Hui; Liu, Ya; Qian, Xiaoming, E-mail: qianxiaoming@tjpu.edu.cn

    2015-08-30

    Highlights: • Multiple sizing treatments were used to modify the surface of carbon fiber with carbon nanotubes. • The distribution state of carbon nanotubes in interface had a great effect on the performance of carbon fiber composites. • Interfacial microstructure changes brought by sizing treatment were detected by energy dispersive X-ray spectroscopy and atomic force microscope. • Gradient interphase composed of carbon nanotubes and epoxy was favorable to improve the mechanical properties of carbon composites. - Abstract: Repetitious sizing treatment was used to modify the carbon fiber (CF) surface with carbon nanotubes (CNTs) for improving interfacial properties of CF/epoxy composites. Interlaminar shear and flexural results showed that mechanical properties of composites were significantly depended on the dispersion state and contents of CNTs in interfacial regions. Increases of 13.45% in interlaminar shear strength and 20.31% in flexural strength were achieved in quintuple sized-CF/epoxy composites, whereas excessive CNTs led to decrease of interfacial performance due to defects induced by agglomerated CNTs. Energy dispersive X-ray spectroscopy and force modulation atomic force microscope were used to detect the structure of interfacial phase and results indicated that gradient interfacial structure with various thicknesses was formed due to CNT incorporation. This means that such a simple and efficient method to improve interfacial performance of composites via regulating the fiber–matrix interphase structure was developed and showed great commercial application potential.

  7. Carbon fiber intramedullary nails reduce artifact in postoperative advanced imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zimel, Melissa N. [Memorial Sloan Kettering Cancer Center, Orthopaedic Surgery Service, Department of Surgery, New York, NY (United States); Hwang, Sinchun [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Riedel, Elyn R. [Memorial Sloan Kettering Cancer Center, Department of Epidemiology and Biostatistics, New York, NY (United States); Healey, John H. [Memorial Sloan Kettering Cancer Center, Orthopaedic Surgery Service, Department of Surgery, New York, NY (United States); Weill Medical College of Cornell University, Department of Orthopaedic Surgery, New York, NY (United States)

    2015-09-15

    This study assessed whether radiolucent carbon fiber reinforced-polyetheretherketone (CFR-PEEK) intramedullary nails decreased hardware artifact on magnetic resonance imaging (MRI) and computed tomography (CT) in vitro and in an oncologic patient population. In vitro and clinical evaluations were done. A qualitative assessment of metal artifact was performed using CFR-PEEK and titanium nail MRI phantoms. Eight patients with a femoral or tibial prophylactic CFR-PEEK nail were retrospectively identified. All patients had postoperative surveillance imaging by MRI, CT, and were followed for a median 20 months (range, 12-28 months). CFR-PEEK images were compared to images from a comparative group of patients with titanium femoral intramedullary nails who had a postoperative MRI or CT. A musculoskeletal-trained radiologist graded visualization of the cortex, corticomedullary junction, and bone-muscle interface, on T1-weighted (T1W), STIR, and contrast-enhanced T1-weighted fat-saturated (T1W FS) sequences of both groups with a five-point scale, performing independent reviews 4 months apart. Statistical analysis used the Wilcoxon rank-sum test and a weighted kappa. Substantially less MRI signal loss occurred in the CFR-PEEK phantom than in the titanium phantom simulation, particularly as the angle increased with respect to direction of the static magnetic field. CFR-PEEK nails had less MRI artifact than titanium nails on scored T1W, STIR, and contrast-enhanced T1W FS MRI sequences (p ≤ 0.03). The mean weighted kappa was 0.64, showing excellent intraobserver reliability between readings. CFR-PEEK intramedullary nail fixation is a superior alternative to minimize implant artifact on MRI or CT imaging for patients requiring long bone fixation. (orig.)

  8. Process Optimization of Bismaleimide (BMI) Resin Infused Carbon Fiber Composite

    Science.gov (United States)

    Ehrlich, Joshua W.; Tate, LaNetra C.; Cox, Sarah B.; Taylor, Brian J.; Wright, M. Clara; Caraccio, Anne J.; Sampson, Jeffery W.

    2013-01-01

    Bismaleimide (BMI) resins are an attractive new addition to world-wide composite applications. This type of thermosetting polyimide provides several unique characteristics such as excellent physical property retention at elevated temperatures and in wet environments, constant electrical properties over a vast array of temperature settings, and nonflammability properties as well. This makes BMI a popular choice in advance composites and electronics applications [I]. Bismaleimide-2 (BMI-2) resin was used to infuse intermediate modulus 7 (IM7) based carbon fiber. Two panel configurations consisting of 4 plies with [+45deg, 90deg]2 and [0deg]4 orientations were fabricated. For tensile testing, a [90deg]4 configuration was tested by rotating the [0deg]4 configirration to lie orthogonal with the load direction of the test fixture. Curing of the BMI-2/IM7 system utilized an optimal infusion process which focused on the integration of the manufacturer-recommended ramp rates,. hold times, and cure temperatures. Completion of the cure cycle for the BMI-2/IM7 composite yielded a product with multiple surface voids determined through visual and metallographic observation. Although the curing cycle was the same for the three panellayups, the surface voids that remained within the material post-cure were different in abundance, shape, and size. For tensile testing, the [0deg]4 layup had a 19.9% and 21.7% greater average tensile strain performance compared to the [90deg]4 and [+45deg, 90deg, 90deg,-45degg] layups, respectively, at failure. For tensile stress performance, the [0deg]4 layup had a 5.8% and 34.0% greater average performance% than the [90deg]4 and [+45deg, 90deg, 90deg,-45deg] layups.

  9. Synthesis of porous carbon fibers with strong anion exchange functional groups.

    Science.gov (United States)

    Zheng, Weihua; Hu, Jingtian; Han, Zheshen; Wang, Zixing; Zheng, Zhen; Langer, James; Economy, James

    2015-06-18

    Hybrid porous carbon fibers with strong anion-exchangeable functional groups (HACAX) were synthesized by alkylation of pyrolyzed polyacrylonitrile. HACAX exhibits generic stable positively charged functional groups. This expands the applications of porous carbon media for interacting with anions without adjusting pH, such as Cr(vi) adsorption at natural pH.

  10. Reuse performance of granular-activated carbon and activated carbon fiber in catalyzed peroxymonosulfate oxidation.

    Science.gov (United States)

    Yang, Shiying; Li, Lei; Xiao, Tuo; Zhang, Jun; Shao, Xueting

    2017-03-01

    Recently, activated carbon was investigated as an efficient heterogeneous metal-free catalyst to directly activate peroxymonosulfate (PMS) for degradation of organic compounds. In this paper, the reuse performance and the possible deactivation reasons of granular-activated carbon (GAC) and activated carbon fiber (ACF) in PMS activation were investigated. As results indicated, the reusability of GAC, especially in the presence of high PMS dosage, was relatively superior to ACF in catalyzed PMS oxidation of Acid Orange 7 (AO7), which is much more easily adsorbed by ACF than by GAC. Pre-oxidation experiments were studied and it was demonstrated that PMS oxidation on ACF would retard ACF's deactivation to a big extent. After pre-adsorption with AO7, the catalytic ability of both GAC and ACF evidently diminished. However, when methanol was employed to extract the AO7-spent ACF, the catalytic ability could recover quite a bit. GAC and ACF could also effectively catalyze PMS to degrade Reactive Black 5 (RB5), which is very difficult to be adsorbed even by ACF, but both GAC and ACF have poor reuse performance for RB5 degradation. The original organic compounds or intermediate products adsorbed by GAC or ACF would be possibly responsible for the deactivation.

  11. Effects of carbon fiber surface characteristics on interfacial bonding of epoxy resin composite subjected to hygrothermal treatments

    Science.gov (United States)

    Li, Min; Liu, Hongxin; Gu, Yizhuo; Li, Yanxia; Zhang, Zuoguang

    2014-01-01

    The changes of interfacial bonding of three types of carbon fibers/epoxy resin composite as well as their corresponding desized carbon fiber composites subjecting to hygrothermal conditions were investigated by means of single fiber fragmentation test. The interfacial fracture energy was obtained to evaluate the interfacial bonding before and after boiling water aging. The surface characteristics of the studied carbon fiber were characterized using X-ray photoelectron spectroscopy. The effects of activated carbon atoms and silicon element at carbon fiber surface on the interfacial hygrothermal resistance were further discussed. The results show that the three carbon fiber composites with the same resin matrix possess different hygrothermal resistances of interface and the interfacial fracture energy after water aging can not recovery to the level of raw dry sample (irreversible changes) for the carbon fiber composites containing silicon. Furthermore, the activated carbon atoms have little impact on the interfacial hygrothermal resistance. The irreversible variations of interfacial bonding and the differences among different carbon fiber composites are attributed to the silicon element on the carbon fiber bodies, which might result in hydrolyzation in boiling water treatment and degrade interfacial hygrothermal resistance.

  12. Preparation and characterization of aligned carbon nanotubes/polylactic acid composite fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kong Yuxia; Yuan Jie [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Qiu Jun, E-mail: qiujun@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Key Laboratory of Advanced Civil Engineering Materials of Education of Ministry, Shanghai 201804 (China)

    2012-07-01

    Aligned functionalized multiwalled carbon nanotubes/polylactic acid (MWNTs-PCL/PLA) composite fibers were successfully prepared by electrospinning processing. The MWNTs bonded with the polycaprolactone chains exhibited excellent uniform dispersion in PLA solution by comparing with the acid-functionalized MWNTs and amino-functionalized MWNTs. Optical microscopy was used to study the aligned degree of the fibers and to investigate the influences of the electrodes distance on the alignment and structure of the fibers, and results showed that the best quality of aligned fibers with dense structure and high aligned degree were obtained at an electrodes distance of 3 cm. Moreover, the MWNTs embedded inside the MWNTs-PCL/PLA fibers displayed well orientation along the axes of the fibers, which was demonstrated by field emission scanning electron microscopy, transmission electron microscopy and Raman spectroscopy.

  13. Surface modification of carbon fibers and its effect on the fiber–matrix interaction of UHMWPE based composites

    Energy Technology Data Exchange (ETDEWEB)

    Chukov, D.I., E-mail: dil_chukov@yahoo.com; Stepashkin, A.A.; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-02-15

    Highlights: • Both chemical and thermal treatments of UKN 5000 carbon fibers allow one to obtain well-developed surface. • The changes of structure and properties of VMN-4 fibers after both thermal and chemical oxidation are insignificant due to more perfect initial structure of these fibers. • The oxidative treatment of carbon fibers allows one to improve the interfacial interaction in the UHMWPE-based composites. • The oxidative treatment of the fibers allows one to a triple increase of Young’s modulus of the modified fibers reinforced UHMWPE composites. -- Abstract: The PAN-based carbon fibers (CF) were subjected to thermal and chemical oxidation under various conditions. The variation in the surface morphology of carbon fibers after surface treatment was analyzed by scanning electron microscopy (SEM). It was found that the tensile strength of carbon fibers changed after surface modification. The interaction between the fibers and the matrix OF ultra-high molecular weight polyethylene (UHMWPE) was characterized by the Young modulus of produced composites. It was shown that the Young modulus of composites reinforced with modified carbon fibers was significantly higher than that of composites reinforced with non-modified fibers.

  14. MECHANICAL AND THERMO–MECHANICAL PROPERTIES OF BI-DIRECTIONAL AND SHORT CARBON FIBER REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    G. AGARWAL

    2014-10-01

    Full Text Available This paper based on bidirectional and short carbon fiber reinforced epoxy composites reports the effect of fiber loading on physical, mechanical and thermo-mechanical properties respectively. The five different fiber loading, i.e., 10wt. %, 20wt. %, 30wt. %, 40wt. % and 50wt. % were taken for evaluating the above said properties. The physical and mechanical properties, i.e., hardness, tensile strength, flexural strength, inter-laminar shear strength and impact strength are determined to represent the behaviour of composite structures with that of fiber loading. Thermo-mechanical properties of the material are measured with the help of Dynamic Mechanical Analyser to measure the damping capacity of the material that is used to reduce the vibrations. The effect of storage modulus, loss modulus and tan delta with temperature are determined. Finally, Cole–Cole analysis is performed on both bidirectional and short carbon fiber reinforced epoxy composites to distinguish the material properties of either homogeneous or heterogeneous materials. The results show that with the increase in fiber loading the mechanical properties of bidirectional carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, as far as Loss modulus, storage modulus is concerned bidirectional carbon fiber shows better damping behaviour than short carbon fiber reinforced composites.

  15. Continuous Carbon Nanotube-Based Fibers and Films for Applications Requiring Enhanced Heat Dissipation.

    Science.gov (United States)

    Liu, Peng; Fan, Zeng; Mikhalchan, Anastasiia; Tran, Thang Q; Jewell, Daniel; Duong, Hai M; Marconnet, Amy M

    2016-07-13

    The production of continuous carbon nanotube (CNT) fibers and films has paved the way to leverage the superior properties of individual carbon nanotubes for novel macroscale applications such as electronic cables and multifunctional composites. In this manuscript, we synthesize fibers and films from CNT aerogels that are continuously grown by floating catalyst chemical vapor deposition (FCCVD) and measure thermal conductivity and natural convective heat transfer coefficient from the fiber and film. To probe the mechanisms of heat transfer, we develop a new, robust, steady-state thermal characterization technique that enables measurement of the intrinsic fiber thermal conductivity and the convective heat transfer coefficient from the fiber to the surrounding air. The thermal conductivity of the as-prepared fiber ranges from 4.7 ± 0.3 to 28.0 ± 2.4 W m(-1) K(-1) and depends on fiber volume fraction and diameter. A simple nitric acid treatment increases the thermal conductivity by as much as a factor of ∼3 for the fibers and ∼6.7 for the thin films. These acid-treated CNT materials demonstrate specific thermal conductivities significantly higher than common metals with the same absolute thermal conductivity, which means they are comparatively lightweight, thermally conductive fibers and films. Beyond thermal conductivity, the acid treatment enhances electrical conductivity by a factor of ∼2.3. Further, the measured convective heat transfer coefficients range from 25 to 200 W m(-2) K(-1) for all fibers, which is higher than expected for macroscale materials and demonstrates the impact of the nanoscale CNT features on convective heat losses from the fibers. The measured thermal and electrical performance demonstrates the promise for using these fibers and films in macroscale applications requiring effective heat dissipation.

  16. Fabrication of graphene coated carbon fiber microelectrode for highly sensitive detection application.

    Science.gov (United States)

    Bai, Jie; Wang, Xiaojuan; Meng, Yuning; Zhang, Hui-Min; Qu, Liangti

    2014-01-01

    Graphene, as a novel carbon nanomaterial, exhibits superior performance in electrochemical sensors. Here, graphene was applied to the microelectrode system by a simple method. A novel graphene coating carbon fiber microelectrode (G-CFM) was fabricated by electrodepositing graphene on the surface of carbon fiber. The fabrication method is fast and simple. Scanning electron microscopy and Raman spectroscopy demonstrated that carbon fiber was successfully modified by graphene. The electrochemical behavior of G-CFM was characterized by potassium ferricyanide and dopamine (DA). The electrode exhibited much larger current response and less overpotential response, compared to CFM. The microsensor for DA showed good sensitivity and selectivity, and the electrode had good stability. It is believable that the unique characteristic of graphene holds promise for the advanced microelectrode system for highly sensitive detection of various targets.

  17. Characterization of the chemical architecture of carbon-fiber microelectrodes. 1. Carboxylates.

    Science.gov (United States)

    Pantano, P; Kuhr, W G

    1991-07-15

    A new method to characterize the chemical architecture of a carbon-fiber microelectrode surface is described. Derivatization of carboxyl groups on the carbon surface with a poly(oxyalkalene)diamine (Jeffamine ED-600), followed by biotinylation of the free amine, allowed the attachment of a fluorescein isothiocyanate (FITC) conjugate of ExtrAvidin. The fluorescence observed after excitation at 488 nm was imaged with a fluorescence microscope equipped with a CCD camera, yielding a spatial map of the distribution of modified carboxyl groups on the surface of the carbon fiber with 0.5-micron resolution. Colloidal gold particles (15 nm diameter) coated with ExtrAvidin were used in place of the FITC-ExtrAvidin, and the carbon-fiber surface was imaged with scanning electron microscopy on a submicron scale. This selective information regarding surface-bound functional groups (i.e. carboxylates) has proven invaluable toward the rational design of novel sensors based on surface-modified ultramicroelectrodes.

  18. Oxidation Kinetics and Strength Degradation of Carbon Fibers in a Cracked Ceramic Matrix Composite

    Science.gov (United States)

    Halbig, Michael C.

    2003-01-01

    Experimental results and oxidation modeling will be presented to discuss carbon fiber susceptibility to oxidation, the oxidation kinetics regimes and composite strength degradation and failure due to oxidation. Thermogravimetric Analysis (TGA) was used to study the oxidation rates of carbon fiber and of a pyro-carbon interphase. The analysis was used to separately obtain activation energies for the carbon constituents within a C/SiC composite. TGA was also conducted on C/SiC composite material to study carbon oxidation and crack closure as a function of temperature. In order to more closely match applications conditions C/SiC tensile coupons were also tested under stressed oxidation conditions. The stressed oxidation tests show that C/SiC is much more susceptible to oxidation when the material is under an applied load where the cracks are open and allow for oxygen ingress. The results help correlate carbon oxidation with composite strength reduction and failure.

  19. SiCO-doped carbon fibers with unique dual superhydrophilicity/superoleophilicity and ductile and capacitance properties.

    Science.gov (United States)

    Lu, Ping; Huang, Qing; Mukherjee, Amiya; Hsieh, You-Lo

    2010-12-01

    Silicon oxycarbide (SiCO) glass-doped carbon fibers with an average diameter of 163 nm were successfully synthesized by electrospinning polymer mixtures of preceramic precursor polyureasilazane (PUS) and carbon precursor polyacrylonitrile (PAN) into fibers then converting to ceramic/carbon hybrid via cross-linking, stabilization, and pyrolysis at temperatures up to 1000 °C. The transformation of PUS/PAN polymer precursors to SiCO/carbon structures was confirmed by EDS and FTIR. Both carbon and SiCO/carbon fibers were amorphous and slightly oxidized. Doping with SiCO enhanced the thermal stability of carbon fibers and acquired new ductile behavior in the SiCO/carbon fibers with significantly improved flexibility and breaking elongation. Furthermore, the SiCO/carbon fibers exhibited dual superhydrophilicity and superoleophilicity with water and decane absorbing capacities of 873 and 608%, respectively. The cyclic voltammetry also showed that SiCO/carbon composite fibers possess better capacitor properties than carbon fibers.

  20. Carbon nanotube-coated solid-phase microextraction metal fiber based on sol-gel technique.

    Science.gov (United States)

    Jiang, Ruifen; Zhu, Fang; Luan, Tiangang; Tong, Yexiang; Liu, Hong; Ouyang, Gangfeng; Pawliszyn, Janusz

    2009-05-29

    A novel carbon nanotube (CNT)-coated solid-phase microextraction fiber was prepared based on sol-gel technique. Commonly used fragile fused silica fiber was replaced with stainless steel wire, which made the fiber unbreakable. An approach was also proposed for batch producing, and good reproducibilities for fiber to fiber and between fibers were achieved. Experiments showed that the sol-gel-CNT fiber exhibited high thermal stability to resist 350 degrees C and excellent solvent durability in methanol and acetonitrile. Compared to commercial polydimethylsiloxane (PDMS) fiber, the sol-gel-CNT fiber represented significantly improved extraction efficiencies for both polar (phenols) and non-polar (benzene, toluene, ethylbenzene, and o-xylene) compounds. Meanwhile, no replacement effect, low carry-over and wide linear range demonstrated that the newly prepared sol-gel-CNT coating has liquid properties, which allow a relatively easy quantification procedure. Moreover, the characterization of the sol-gel-CNT coating was also evaluated with McReynold probe solutes. The results showed that the coating has better affinity for all the five types of solutes compared to commercial 7microm PDMS fiber, which suggested that the coating has the potential to be developed as GC stationary phase.

  1. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    Science.gov (United States)

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  2. Properties of M40J Carbon/PMR-II-50 Composites Fabricated with Desized and Surface Treated Fibers. Characterization of M40J Desized and Finished Fibers

    Science.gov (United States)

    Allred, Ronald E.; Gosau, Jan M.; Shin, E. Eugene; McCorkle, Linda S.; Sutter, James K.; OMalley, Michelle; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    To increase performance and durability of high temperature composites for potential rocket engine components, it is necessary to optimize wetting and interfacial bonding between high modulus carbon fibers and high temperature polyimide resins. It has been previously demonstrated that the electro-oxidative shear treatments used by fiber manufacturers are not effective on higher modulus fibers that have fewer edge and defect sites in the surface crystallites. In addition, sizings commercially supplied on most carbon fibers are not compatible with polyimides. This study was an extension of prior work characterizing the surface chemistry and energy of high modulus carbon fibers (M40J and M60J, Torray) with typical fluorinated polyimide resins, such as PMR-II-50. A continuous desizing system which utilizes environmentally friendly chemical- mechanical processes was developed for tow level fiber and the processes were optimized based on weight loss behavior, surface elemental composition (XPS) and morphology (FE-SEM) analyses, and residual tow strength of the fiber, and the similar approaches have been applied on carbon fabrics. Both desized and further treated with a reactive finish were investigated for the composite reinforcement. The effects of desizing and/or subsequent surface retreatment on carbon fiber on composite properties and performance including fiber-matrix interfacial mechanical properties, thermal properties and blistering onset behavior will be discussed in this presentation.

  3. Polylactate-coated carbon fiber in extra-articular reconstruction of the unstable knee.

    Science.gov (United States)

    King, J B; Bulstrode, C

    1985-06-01

    Fascia lata and carbon fiber were used in identical operations for the correction of a clearly defined knee instability in cases with a follow-up period of about one year. The early results suggest an improvement of the results in the carbon group, but free carbon has been found within the joint despite careful extra-articular implantation. The long-term consequences of this await evaluation.

  4. Surface Characterization of Carbon Fiber Polymer Composites and Aluminum Alloys After Laser Interference Structuring

    Science.gov (United States)

    Sabau, Adrian S.; Greer, Clayton M.; Chen, Jian; Warren, Charles D.; Daniel, Claus

    2016-07-01

    The increasing use of carbon fiber-reinforced polymer matrix composites (CFPC) and aluminum alloys as lightweight materials in the automotive and aerospace industries demands enhanced surface preparation and control of surface morphology prior to joining. In this study, surfaces of both composite and aluminum were prepared for joining using an Nd:YAG laser in a two-beam interference setup, enabling the (1) structuring of the AL 5182 surface, (2) removal of the resin layer on top of carbon fibers, and (3) structuring of the carbon fibers. CFPC specimens of T700S carbon fiber, Prepreg—T83 epoxy, 5 ply thick, 0°/90° plaques were used. The effects of laser fluence, scanning speed, and number of shots-per-spot were investigated on the removal rate of the resin without an excessive damage of the fibers. Optical micrographs, 3D imaging, and scanning electron microscope imaging were used to study the effect of the laser processing on the surface morphology. It was found that an effective resin ablation and a low density of broken fibers for CFPC specimens was attained using laser fluences of 1-2 J/cm2 and number of 2-4 pulses per spot. A relatively large area of periodic line structures due to energy interference were formed on the aluminum surface at laser fluences of 12 J/cm2 and number of 4-6 pulses per spot.

  5. Anodization of carbon fibers on interfacial mechanical properties of epoxy matrix composites.

    Science.gov (United States)

    Park, Soo-Jin; Chang, Yong-Hwan; Kim, Yeong-Cheol; Rhee, Kyong-Yop

    2010-01-01

    The influence of anodic oxidation on the mechanical interfacial properties of carbon-fiber-reinforced epoxy resin composites was investigated. The surface properties of the anodized carbon fibers were studied through the measurement of contact angles and through SEM, XPS, and FT-IR analyses. The mechanical interfacial properties of the composites were studied through measurements of interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and critical strain energy release rate (G(IC)). It was shown that the surface functional groups containing oxygen on the anodized carbon fibers exert great effects on the surface energetics of fibers and the mechanical interfacial properties, e.g., ILSS, of the resulting composites. Contact angle measurements based on the wicking rate of a test liquid showed that anodic oxidation lead to an increase in the surface free energy of the carbon fibers, mainly in its specific (or polar) component. In terms of surface energetics, it was found that wetting played an important role in increasing the degree of adhesion at interfaces between the fibers and the resin matrices of the composites.

  6. 炭纤维上浆剂的研究进展%Research progress on carbon fiber sizing agent

    Institute of Scientific and Technical Information of China (English)

    王学兰; 曾黎明

    2011-01-01

    The research progress on carbon fiber sizing agent used in carbon fiber composite materials was reviewed, mainly including the effects and the classification of carbon fiber sizing agent and the research situation. The carbon fiber emulsion sizing agent was discussed in the last.%论述了炭纤维复合材料中的炭纤维上浆剂.先介绍了上浆剂的作用和分类,然后重点综述了炭纤维上浆剂国内外研究现状,最后就乳液型炭纤维上浆剂做了介绍.

  7. Alignment of Carbon Nanotubes in Carbon Nanotube Fibers Through Nanoparticles: A Route for Controlling Mechanical and Electrical Properties.

    Science.gov (United States)

    Hossain, Muhammad Mohsin; Islam, Md Akherul; Shima, Hossain; Hasan, Mudassir; Lee, Moonyong

    2017-02-15

    This is the first study that describes how semiconducting ZnO can act as an alignment agent in carbon nanotubes (CNTs) fibers. Because of the alignment of CNTs through the ZnO nanoparticles linking groups, the CNTs inside the fibers were equally distributed by the attraction of bonding forces into sheetlike bunches, such that any applied mechanical breaking load was equally distributed to each CNT inside the fiber, making them mechanically robust against breaking loads. Although semiconductive ZnO nanoparticles were used here, the electrical conductivity of the aligned CNT fiber was comparable to bare CNT fibers, suggesting that the total electron movement through the CNTs inside the aligned CNT fiber is not disrupted by the insulating behavior of ZnO nanoparticles. A high degree of control over the electrical conductivity was also demonstrated by the ZnO nanoparticles, working as electron movement bridges between CNTs in the longitudinal and crosswise directions. Well-organized surface interface chemistry was also observed, which supports the notion of CNT alignment inside the fibers. This research represents a new area of surface interface chemistry for interfacially linked CNTs and ZnO nanomaterials with improved mechanical properties and electrical conductivity within aligned CNT fibers.

  8. Effect of Post-spinning Modification on the PAN Precursors and Resulting Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wangxi; LIU Jie

    2006-01-01

    The impregnation of a special grade PAN precursor fibers was carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical structure and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers were characterized by the combination use of densities, wide-angle X-ray diffraction (WAXD), X-ray photoelectron spectroscopy (XPS), elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM), etc. KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor fiber,and transform C(=)N groups to C=N ones, meanwhile, it can decrease the crystal size increase the orientation index and the crystallinity index, furthermore it can increase the densities of modified PAN precursors and resulting thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 31.25 % and an improvement in elongation of 77.78 %, but a decrease of 16.52 % in Young's modulus.

  9. Adsorption of SO2 on bituminous coal char and activated carbon fiber prepared from phenol formaldehyde

    Science.gov (United States)

    DeBarr, Joseph A.; Lizzio, Anthony A.; Daley, Michael A.

    1996-01-01

    Carbon-based materials are used commercially to remove SO2 from coal combustion flue gases. Historically, these materials have consisted of granular activated carbons prepared from lignite or bituminous coal. Recent studies have reported that activated carbon fibers (ACFs) may have potential in this application due to their relatively high SO2 adsorption capacity. In this paper, a comparison of SO2 adsorption for both coal-based carbons and ACFs is presented, as well as ideas on carbon properties that may influence SO2 adsorption

  10. Bootstrap Method for Detecting Damage in Carbon Fiber Reinforced Plastic Using a Macro Fiber Composite Sensor

    OpenAIRE

    DJANSENA, Alradix; 田中, 宏明; 工藤, 亮

    2015-01-01

    CFRP has been used in aircraft structures for decades. Although CFRP is light, its laminationis its main weakness. We have developed a new method to increase the probability of detectingdelamination in carbon fiber reinforced plastic (CFRP) by narrowing the confidence interval ofthe changes in natural frequency. The changes in the natural frequency in delaminated CFRPare tiny compared with measurement errors. We use the bootstrap method, a statisticaltechnique that increases the estimation ac...

  11. Identification of Damage Types in Carbon Fiber Reinforced Plastic Laminates by a Novel Optical Fiber Acoustic Emission Sensor

    OpenAIRE

    Yu, Fengming; Wu, Qi; Okabe, Yoji; Kobayashi, Satoshi; Saito, Kazuya

    2014-01-01

    International audience; In this research, phase-shifted FBG (PS-FBG) sensor was employed to practical AE detection for carbon fiber reinforced plastic (CFRP) composite laminate. Firstly, we evaluated the characteristics of AE signals detected by this kind of sensor. Secondly, through the experiment and simulation concerning AE source orientation, quantitative information about the standard for discriminating the AE signals due to transverse cracks and delaminations was obtained. Finally, acco...

  12. The carbon fiber development for uranium centrifuges: a Brazilian cooperative research

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Paulo Cesar Beltrao de, E-mail: p.queiroz@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil); Zouain, Desiree Moraes, E-mail: dmzouain@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    This paper analyzes both the carbon fiber-based development for uranium centrifuges and the research project that supports its development effort over time. The carbon fiber-based engineering properties make it a valuable supply for high technologic products. Nevertheless, its fabrication occurs only in few developed countries and there is no production in Brazil. In addition, the carbon fiber-based products have dual applications: they can be used by the civilian and military industry. Therefore, there are international restrictions related to its use and applications that justify the internal development. Moreover, the Brazilian Navy centrifuges for uranium enrichment were developed using carbon-fiber which contains polyacrylonitrile (PAN) as an imported raw material. The PAN properties of low weight, high tensile strength increase the isotopic separation efficiency. The Brazilian financial scenario surrounded by the international uncertain economy shows that combined creative project solutions are more effective. Therefore, the Navy's Technological Center in Sao Paulo (CTMSP), the University of Campinas (UNICAMP), the University of Sao Paulo (USP), the RADICIFIBRAS Company, and the Brazilian FINEP agency, which is responsible for the project financial support, established a partnership aiming the development of a domestic PAN-based carbon fiber industry. The innovative project solutions adopted and the results of this partnership are presented here. (author)

  13. RTA-treated carbon fiber/copper core/shell hybrid for thermally conductive composites.

    Science.gov (United States)

    Yu, Seunggun; Park, Bo-In; Park, Cheolmin; Hong, Soon Man; Han, Tae Hee; Koo, Chong Min

    2014-05-28

    In this paper, we demonstrate a facile route to produce epoxy/carbon fiber composites providing continuous heat conduction pathway of Cu with a high degree of crystal perfection via electroplating, followed by rapid thermal annealing (RTA) treatment and compression molding. Copper shells on carbon fibers were coated through electroplating method and post-treated via RTA technique to reduce the degree of imperfection in the Cu crystal. The epoxy/Cu-plated carbon fiber composites with Cu shell of 12.0 vol % prepared via simple compression molding, revealed 18 times larger thermal conductivity (47.2 W m(-1) K(-1)) in parallel direction and 6 times larger thermal conductivity (3.9 W m(-1) K(-1)) in perpendicular direction than epoxy/carbon fiber composite. Our novel composites with RTA-treated carbon fiber/Cu core/shell hybrid showed heat conduction behavior of an excellent polymeric composite thermal conductor with continuous heat conduction pathway, comparable to theoretical values obtained from Hatta and Taya model.

  14. Friction Behaviour of Polymeric Composite Materials Mixed with Carbon Fibers Having Different Orientations Layout

    Science.gov (United States)

    Caliman, R.

    2016-06-01

    This paper presents a study of the friction properties of polymeric composite materials reinforced with unidirectional carbon fibers having different stratified structure. So, the composites are complex and versatile materials but their behaviour in practice is not fully studied. For instance, these polymeric composite materials mixed with carbon fibers after being investigated in terms of wear, did not elucidate the effect of fiber orientation on wear properties. Is therefore necessary to investigate the effect of carbon fibers orientation on the friction-wear properties of the reinforced composite materials tested to abrasive and adhesive friction. Research work has been done with unidirectional composite materials having overlap 18 successive layers made from a polymeric resine and 60% of carbon fibers. The stratified structure was obtained by compressing multiple pre-impregnated strips, positioned manually. During this experimental work, three types of test samples were investigated: parallel, normal and anti-parallel, taking in consideration the carbon fibre orientation with respect to the sliding direction. The friction coefficient is computed function to the friction load and loading value. Also, the specific wear rate was calculated according to: the mass loss, density, the normal contact surface, the sliding distance and load rating.

  15. Determination of Water Diffusion Coefficients and Dynamics in Adhesive/ Carbon Fiber Reinforced Epoxy Resin Composite Joints

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; WANG Zhi; WANG Jing; SU Tao

    2007-01-01

    To determinate the water diffusion coefficients and dynamics in adhesive/carbon fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis(EDX) is used to establish the content change of oxygen in the adhesive in adhesive/carbon fiber reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carbon fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analysis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of both energy dispersive X-ray spectroscopy and elemental analysis. The determined results with EDX analysis are almost the same as those determined with elemental analysis and the results also show that the durability of the adhesive/carbon fiber reinforced epoxy resin composite joints subjected to silane coupling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treatment.

  16. Electrospun carbon nanofibers for improved electrical conductivity of fiber reinforced composites

    Science.gov (United States)

    Alarifi, Ibrahim M.; Alharbi, Abdulaziz; Khan, Waseem S.; Asmatulu, Ramazan

    2015-04-01

    Polyacrylonitrile (PAN) was dissolved in dimethylformamide (DMF), and then electrospun to generate nanofibers using various electrospinning conditions, such as pump speeds, DC voltages and tip-to-collector distances. The produced nanofibers were oxidized at 270 °C for 1 hr, and then carbonized at 850 °C in an argon gas for additional 1 hr. The resultant carbonized PAN nanofibers were placed on top of the pre-preg carbon fiber composites as top layers prior to the vacuum oven curing following the pre-preg composite curing procedures. The major purpose of this study is to determine if the carbonized nanofibers on the fiber reinforced composites can detect the structural defects on the composite, which may be useful for the structural health monitoring (SHM) of the composites. Scanning electron microscopy images showed that the electrospun PAN fibers were well integrated on the pre-preg composites. Electrical conductivity studies under various tensile loads revealed that nanoscale carbon fibers on the fiber reinforced composites detected small changes of loads by changing the resistance values. Electrically conductive composite manufacturing can have huge benefits over the conventional composites primarily used for the military and civilian aircraft and wind turbine blades.

  17. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Sayed Habib, E-mail: habibkazemi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Maghami, Mostafa Ghaem [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kiani, Mohammad Ali [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of)

    2014-12-15

    Highlights: • We report a facile method for fabrication of MnO{sub 2} nanostructures on electro-etched carbon fiber. • MnO{sub 2}-ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO{sub 2}-ECF electrode. • The coulombic efficiency of MnO{sub 2}-ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO{sub 2} on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO{sub 2} electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g{sup −1} was achieved at a scan rate of 5 mV s{sup −1} for MnO{sub 2} electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes.

  18. Recent Progress in Producing Lignin-Based Carbon Fibers for Functional Applications

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Ryan [GrafTech International Holdings Inc.; Burwell, Deanna [GrafTech International Holdings Inc.; Dai, Xuliang [GrafTech International Holdings Inc.; Naskar, Amit [Oak Ridge National Laboratory; Gallego, Nidia [Oak Ridge National Laboratory; Akato, Kokouvi [Oak Ridge National Laboratory

    2015-10-29

    Lignin, a biopolymer, has been investigated as a renewable and low-cost carbon fiber precursor since the 1960s. Although successful lab-scale production of lignin-based carbon fibers has been reported, there are currently not any commercial producers. This paper will highlight some of the known challenges with converting lignin-based precursors into carbon fiber, and the reported methods for purifying and modifying lignin to improve it as a precursor. Several of the challenges with lignin are related to its diversity in chemical structure and purity, depending on its biomass source (e.g. hardwood, softwood, grasses) and extraction method (e.g. organosolv, kraft). In order to make progress in this field, GrafTech and Oak Ridge National Laboratory are collaborating to develop lignin-based carbon fiber technology and to demonstrate it in functional applications, as part of a cooperative agreement with the DOE Advanced Manufacturing Office. The progress made to date with producing lignin-based carbon fiber for functional applications, as well as developing and qualifying a supply chain and value proposition, are also highlighted.

  19. Interposition fixing structure of TiO2 film deposited on activated carbon fibers

    Institute of Scientific and Technical Information of China (English)

    FU Ping-feng; LUAN Yong; DAI Xue-gang

    2006-01-01

    The immobilized photocatalyst, TiO2 film supported on activated carbon fibers (TiO2/ACFs) prepared with molecular adsorption-deposition (MAD), exhibits high stability in cyclic photodegradation runs. The interposition fixing structure between TiO2 film and carbon fiber was investigated by means of SEM-EDX, XRD, XPS and FTIR, and a model was proposed to explain this structure. With SEM examination of carbon fiber surface after removing the deposited TiO2 film, a residual TiO2 super-thin film was found to exist still. By determining surface groups on ACFs, titanium sulfate (Ti2(SO4)3) in burnt remainders of the TiO2/ACFs was thought to be formed with an interfacial reaction between TiO2 film and carbon fibers. These provide some evidence of firm attachment of TiO2 film to carbon fiber surface. In the consideration of characteristics of the MAD, the deposition mechanism of TiO2 film on ACFs was proposed, and the interposition fixing structure was inferred to intercrossedly form between TiO2 film and ACFs' surface. This structure leaded to firm attachment and high stability of the TiO2 film.

  20. Wet spinning of PVA composite fibers with a large fraction of multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Dengpan Lai

    2015-10-01

    Full Text Available PVA composites fibers with a large fraction of multi-walled carbon nanotubes modified by both covalent and non-covalent functionalization were produced by a wet-spinning process. Model XQ-1 tensile tester, thermogravimetric analysis, scanning electron microscopy, differential scanning calorimetry, and wide-angle X-ray diffraction were used to characterize the properties of PVA/MWNT composite fibers. The TGA results suggested that MWNTs content in composite fibers were ranged from 5.3 wt% to 27.6 wt%. The mechanical properties of PVA/MWNT composite fibers were obviously superior to pure PVA fiber. The Young׳s modulus of composite fibers enhanced with increasing the content of MWNTs, and it rised gradually from 6.7 GPa for the pure PVA fiber to 12.8 GPa for the composite fibers with 27.6 wt% MWNTs. Meanwhile, the tensile strength increased gradually from 0.39 GPa for the pure PVA fiber to 0.74 GPa for the composite fibers with 14.4 wt% MWNTs. Nevertheless, the tensile strength of the composite fibers decreased as the MWNTs content up to 27.6 wt%. SEM results indicated that the MWNTs homogeneously dispersed in the composite fibers, however some agglomerates also existed when the content of MWNTs reached 27.6 wt%. DSC results proved strong interfacial interaction between MWNTs and PVA chain, which benefited composite fibers in the efficient stress-transfer. WXAD characterization showed that the orientation of PVA molecules declined from 94.1% to 90.9% with the increasing of MWNTs content. The good dispersibility of MWNTs throughout PVA matrix and efficient stress-transfer between MWNTs and PVA matrix may contributed to significant enhancement in the mechanical properties.

  1. Intercalation of Carbon Nanotube Fibers to Improve their Conductivity Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed research will explore how NASA intercalation technology can be used to lower the resistivity of the new Rice-Teijin fiber make them viable for NASA...

  2. Electroadsorption Desalination with Carbon Nanotube/PAN-Based Carbon Fiber Felt Composites as Electrodes

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2014-01-01

    Full Text Available The chemical vapor deposition method is used to prepare CNT (carbon nanotube/PCF (PAN-based carbon fiber felt composite electrodes in this paper, with the surface morphology of CNT/PCF composites and electroadsorption desalination performance being studied. Results show such electrode materials with three-dimensional network nanostructures having a larger specific surface area and narrower micropore distribution, with a huge number of reactive groups covering the surface. Compared with PCF electrodes, CNT/PCF can allow for a higher adsorption and desorption rate but lower energy consumption; meanwhile, under the condition of the same voltage change, the CNT/PCF electrodes are provided with a better desalination effect. The study also found that the higher the original concentration of the solution, the greater the adsorption capacity and the lower the adsorption rate. At the same time, the higher the solution’s pH, the better the desalting; the smaller the ions’ radius, the greater the amount of adsorption.

  3. Improvement of the electrical conductivity of carbon fibers through the growth of carbon nanofibers.

    Science.gov (United States)

    Moon, Cheol-Whan; Meng, Long-Yue; Im, Seung-Soon; Rhee, Kyong-Yop; Park, Soo-Jin

    2011-07-01

    In this work, carbon nanofibers (CNFs) were synthesized on carbon fiber (CF) surfaces precoated with metal-doped mesoporous silica films. Fe, Ni, and Co were doped in the mesoporous silica films and played the role of catalysts for the decomposition of acetylene to grow CNFs on the CF surfaces. The chemical composition and surface structure of CFs before and after the growth of the CNFs were investigated by EDX, N2 full isotherms, and SEM. The electrical property of the CFs was investigated using a four-probe volume resistivity tester. The SEM results indicated that the CNFs with diameters of 20-100 nm grew uniformly and densely on the CF surfaces. The diameter and length distributions of the CNFs were found to be dependent on the metal that was doped in the mesoporous silica films. The electrical properties of the CFs were enhanced after the CNFs' growth on the CF surfaces, and the CNFs grown over the Ni catalyst with the narrowest diameter distribution gave the lowest volume resistivity to the CFs.

  4. Effect of Sizing on the Interfacial Shear Strength of Carbon Fiber/Epoxy Resin Monofilament Composite

    Institute of Scientific and Technical Information of China (English)

    YANG Yusong; ZHAO Yan; LI Ye; DONG Qi; CHEN Da

    2014-01-01

    The single fiber fragmentation test (SFFT) was used to measure the interfacial shear strength (IFSS) of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.

  5. Influence of surface treatment of carbon fibers on electrochemical crystallization of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    TAO Ke; HUANG Su-ping; ZHOU Ke-chao

    2005-01-01

    Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.

  6. Basic failure mechanisms in advanced composites. [composed of epoxy resins reinforced with carbon fibers

    Science.gov (United States)

    Mazzio, V. F.; Mehan, R. L.; Mullin, J. V.

    1973-01-01

    The fundamental failure mechanisms which result from the interaction of thermal cycling and mechanical loading of carbon-epoxy composites were studied. This work was confined to epoxy resin uniderictionally reinforced with HTS carbon fibers, and consists of first identifying local fiber, matrix and interface failure mechanisms using the model composite specimen containing a small number of fibers so that optical techniques can be used for characterization. After the local fracture process has been established for both mechanical loading and thermal cycling, engineering composite properties and gross fracture modes are then examined to determine how the local events contribute to real composite performance. Flexural strength in high fiber content specimens shows an increase in strength with increased thermal cycling. Similar behavior is noted for 25 v/o material up to 200 cycles; however, there is a drastic reduction after 200 cycles indicating a major loss of integrity probably through the accumulation of local cleavage cracks in the tensile region.

  7. Three-dimensional nanotubes composed of carbon-anchored ultrathin MoS2 nanosheets with enhanced lithium storage.

    Science.gov (United States)

    Yi, Fenglian; Niu, Yubin; Liu, Sangui; Hou, Junke; Bao, Shujuan; Xu, Maowen

    2016-07-20

    MoS2 nanotubes (denoted as MoS2 NTs) assembled from well-aligned amorphous carbon-modified ultrathin MoS2 nanosheets (denoted as MoS2 NT@C) were successfully fabricated via a facile solvothermal method combined with subsequent annealing treatment. With the assistance of octylamine as a solvent and carbon source, interconnected MoS2 nanosheets (denoted as MoS2 NSs) can assemble into hierarchical MoS2 NTs. Such a hybrid nanostructure can effectively facilitate charge transport and accommodate volume variation upon prolonged charge/discharge cycling for reversible lithium storage. As a result, the MoS2 NT@C composite manifests a very stable high reversible capacity of around 1351 mA h g(-1) at a current density of 100 mA g(-1); even after 150 cycles, the electrode reaches a capacity of 1106 mA h g(-1) and it retains a reversible capacity of 650 mA h g(-1) after the 10th cycle at a current density of 3 A g(-1), all of which indicate that the MoS2 NT@C nanocomposite is a promising negative electrode material for high-energy lithium ion batteries.

  8. Effects of laminin-coated carbon nanotube/chitosan fibers on guided neurite growth.

    Science.gov (United States)

    Huang, Yi-Cheng; Hsu, Sung-Hao; Kuo, Wen-Chun; Chang-Chien, Cheng-Lun; Cheng, Henrich; Huang, Yi-You

    2011-10-01

    This study assesses the ability and potential of carbon nanotube (CNT)/chitosan to guide axon re-growth after nerve injuries. The CNT/chitosan fibers were produced via the coagulation and hydrodynamic focusing method. Fiber width and morphology were adjusted using such parameters as syringe pumping rate and the coagulant used. The CNT/chitosan fiber diameters were 50-300 μm for syringe pumping rates of 6-48 mL/h. Polyethylene glycol/NaOH (25%, w/w) solution was a suitable coagulant for forming fibers with small diameters. Physical property tests demonstrate that the CNT/chitosan composites had superior tensile strength and electrical conductivity compared with those of chitosan alone. The MTT and LDH tests reveal that CNT/chitosan composites were not cytotoxic. To improve the neural cell affinity of CNT/chitosan fibers, laminin was incorporated onto fiber surfaces via the oxygen plasma technique; cell adhesion ratio increased significantly from 3.5% to 72.2% with this surface modification. Immunofluorescence staining and SEM imaging indicate that PC12 cells adhered successfully and grew on the laminin (LN)-coated CNT/chitosan films and fibers. Experimental results show that PC12 grown on LN-coated CNT/chitosan fibers in vitro extend longitudinally oriented neurites in a manner similar to that of native peripheral nerves. With the inherent electrical properties of CNTs, oriented CNT/chitosan fibers have a potential for use as nerve conduits in nerve tissue engineering.

  9. SiC fibers with controllable thickness of carbon layer prepared directly by preceramic polymer pyrolysis routes

    Energy Technology Data Exchange (ETDEWEB)

    Hu Tianjiao, E-mail: tjhu617@gmail.com [College of Science, National University of Defense Technology, Changsha 410073 (China); Li Xiaodong; Li Gongyi [College of Science, National University of Defense Technology, Changsha 410073 (China); Wang Yingde; Wang Jun [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha 410073 (China)

    2011-05-25

    Continuous SiC fibers with different thickness of carbon layer were prepared through three preceramic polymer pyrolysis routes. To make the carbon layer thickness controllable, a simple improvement by using a ceramic bushing was adopted to retard the deposition of the pyrolytic carbons. Auger electron spectroscopy (AES) analysis reveals that the carbon layer thickness varies from less than 5 nm to 40 nm. The specific resistivity of the fibers increases by 5 orders of magnitude as the carbon layer thickness decreases. All of the fibers exhibit a tensile strength of around 1.8 GPa which is independent of the carbon layer thickness. The formation process of the carbon layer is discussed in three steps: the decomposition, the carbonization and the deposition. The as-received fibers have a potential application as the reinforcement of functional materials.

  10. Brazilian natural fiber (jute as raw material for activated carbon production

    Directory of Open Access Journals (Sweden)

    CARLA F.S. ROMBALDO

    2014-12-01

    Full Text Available Jute fiber is the second most common natural cellulose fiber worldwide, especially in recent years, due to its excellent physical, chemical and structural properties. The objective of this paper was to investigate: the thermal degradation of in natura jute fiber, and the production and characterization of the generated activated carbon. The production consisted of carbonization of the jute fiber and activation with steam. During the activation step the amorphous carbon produced in the initial carbonization step reacted with oxidizing gas, forming new pores and opening closed pores, which enhanced the adsorptive capacity of the activated carbon. N2 gas adsorption at 77K was used in order to evaluate the effect of the carbonization and activation steps. The results of the adsorption indicate the possibility of producing a porous material with a combination of microporous and mesoporous structure, depending on the parameters used in the processes, with resulting specific surface area around 470 m2.g–1. The thermal analysis indicates that above 600°C there is no significant mass loss.

  11. Alignment of Multi-walled Carbon Nanotubes in Polyacrylonitrile Fibers by Mechanical Drawing

    Institute of Scientific and Technical Information of China (English)

    WANG Biao; WEN Zhi-wei; PENG Kun; WANG Hua-ping

    2010-01-01

    Polyacrylonitrile(PAN)/multi-waUed carbon nanotubes(MWNTs)narmcomposites were prepared by an in-situ polymerization method and the fibers from these composites were obtained by a wet-spinning process.The orientation behavior of MWNTs in the PAN fibers was investigated by X-ray diffraction and sound velocity methods.The dispersion and the alignment of the nanotubes were also studied by scanning electron microscopy.

  12. Preparation of aqueous dispersion of thermoplastic sizing agent for carbon fiber by emulsion/solvent evaporation

    OpenAIRE

    Giraud, Isabelle; Franceschi-Messant, Sophie; Perez, Emile; Lacabanne, Colette; Dantras, Eric

    2013-01-01

    International audience; In this work, different sizing agent aqueous dispersions based on polyetherimide (PEI) were elaborated in order to improve the interface between carbon fibers and a thermoplastic matrix (PEEK). The dispersions were obtained by the emulsion/solvent evaporation technique. To optimize the stability and the film formation on the fibers, two surfactants were tested at different concentrations, with different concentrations of PEI. The dispersions obtained were characterized...

  13. Carbon nanotube/polymer composite coated tapered fiber for four wave mixing based wavelength conversion.

    Science.gov (United States)

    Xu, Bo; Omura, Mika; Takiguchi, Masato; Martinez, Amos; Ishigure, Takaaki; Yamashita, Shinji; Kuga, Takahiro

    2013-02-11

    In this paper, we demonstrate a nonlinear optical device based on a fiber taper coated with a carbon nanotube (CNT)/polymer composite. Using this device, four wave mixing (FWM) based wavelength conversion of 10 Gb/s Non-return-to-zero signal is achieved. In addition, we investigate wavelength tuning, two photon absorption and estimate the effective nonlinear coefficient of the CNTs embedded in the tapered fiber to be 1816.8 W(-1)km(-1).

  14. Mechanical properties of short carbon/glass fiber reinforced high mechanical performance epoxy resins

    Institute of Scientific and Technical Information of China (English)

    张竞; 黄培

    2009-01-01

    To research the relationship between epoxy and fiber inherent property and mechanical properties of composite,we prepared a series of composites using three kinds of high mechanical performance epoxy resins as matrices and reinforced by the same volume fraction(5%)of short carbon and glass fiber.Their mechanical properties were investigated from the perspective of chemical structure and volume shrinkage ratio of epoxy.We analyzed their tensile strength and modulus based on the mixing rule and Halpin-Tsai eq...

  15. Recycling of carbon fiber. identification of bases for a synergy between recyclers and designers.

    OpenAIRE

    Pompidou, Stéphane; PRINCAUD, Marion; Perry, Nicolas; Leray, Dimitri

    2012-01-01

    In order to decrease both energy consumption and CO 2 emissions, the automotive, aeronautics and aerospace industries aim at making lighter vehicles. To achieve this, composite materials provide good opportunities, ensuring high material properties and free definition of geometry. As an example, for cold applications, the use of carbon fiber/thermoset composites is ever increasing, in spite of a high fiber price. But in a global and eco-friendly approach, the major ...

  16. Theoretical Estimation of Thermal Effects in Drilling of Woven Carbon Fiber Composite

    OpenAIRE

    José Díaz-Álvarez; Alvaro Olmedo; Carlos Santiuste; María Henar Miguélez

    2014-01-01

    Carbon Fiber Reinforced Polymer (CFRPs) composites are extensively used in structural applications due to their attractive properties. Although the components are usually made near net shape, machining processes are needed to achieve dimensional tolerance and assembly requirements. Drilling is a common operation required for further mechanical joining of the components. CFRPs are vulnerable to processing induced damage; mainly delamination, fiber pull-out, and thermal degradation, drilling in...

  17. NDT and SHM of Carbon Fiber Composites using Linear Drive MWM-Arrays

    Science.gov (United States)

    Washabaugh, Andrew; Martin, Christopher; Lyons, Robert; Grundy, David; Goldfine, Neil; Russell, Richard; Wincheski, Russell

    2012-01-01

    Carbon fiber composites are used in a wide range of structural applications due to their excellent specific strength and stiffness. However, the anisotropic mechanical and electrical properties associated with the fibers within each composite layer present challenges, and opportunities, for Nondestructive Testing (NDT) methods used to characterize and assess the structure condition. This includes composite condition after manufacture (such as fiber orientation and density, porosity, delamination, and bond strength) and during usage (such as damage from impact, fiber breakage, thermal exposure or applied stress). Ultrasonic and thermographic methods can address some of these challenges, but eddy current methods provide an alternative method for composite structures that contain a conducting material, such as carbon fibers or a metallic liner. This presentation reviews recent advances in the development of eddy current sensors and arrays for carbon fiber composite NDT and Structural Health Monitoring (SHM) applications. The focus is on eddy current sensor constructs with linear drive windings, such as MWM -Arrays, that induce currents primarily within the linear fibers of the composite. By combining this type of sensor construct with micromechanical models that relate composite constituent properties to measurable sensor responses, insight is obtained into the volumetric distribution of electrical properties within the composite and the associated manufacturing, damage, or strain conditions. With knowledge of the fiber layup, this MWM-Array technology is able to detect damage and strain/stress as a function of depth and fiber orientation. This work has been funded by NASA, NA V AIR and the Army for applications ranging from composite overwrapped pressure vessels (COPVs) to aircraft structures and rotorcraft blades. This presentation will specifically present background on the MWM-Array technology, results from the micromechanical modeling effort, and results from

  18. Anchored nanostructure materials and method of fabrication

    Science.gov (United States)

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2012-11-27

    Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

  19. Comparison of Structure and Properties among Various PAN Fibers for Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    Dongxin HE; Chengguo WANG; Yujun BAI; Bo ZHU

    2005-01-01

    To find out the high-quality polyacrylonitrile (PAN) fibers, some differences are sought by comparing domestic PAN fibers with the foreign ones. X-ray diffractometer (XRD), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectrometer, elemental analyzer, tensile-testing machine and high-temperature differential scanning calorimeter (DSC) are used to characterize the individual microstructure, chemical structure, elemental content,mechanical properties and thermal properties. It is found that high-quality PAN fibers have high density, lower titre,higher or adequate tensile strength, and they also have better conglomeration structure, smaller crystal dimension with dispersive distribution, less microvoids and flaws.

  20. Mechanism of Functional Responses to Loading of Carbon Fiber Reinforced Cement-based Composites

    Institute of Scientific and Technical Information of China (English)

    JIANG Cuixiang; LI Zhuoqiu; SONG Xianhui; LU Yong

    2008-01-01

    Single fiber pull-out testing was conducted to study the origin of the functional responses to loading of carbon fiber reinforced cement-based composites.The variation of electrical resistance with the bonding force on the fiber-matrix interface was measured.Single fiber electromechanical testing was also conducted by measuring the electrical resistance under static tension.Comparison of the results shows that the resistance increasing during single fiber pull-out is mainly due to the changes at the interface.The conduction mechanism of the composite can be explained by the tunneling model.The interfacial stress causes the deformation of interfacial structure and the interfacial debonding.which have influences on the tunneling effect and result in the change of resistance.

  1. Transverse Coefficient of Thermal Expansion Measurements of Carbon Fibers Using ESEM at High Temperatures

    Science.gov (United States)

    Ochoa, O.; Jiang, J.; Putnam, D.; Lo, Z.; Ellis, A.; Effinger, Michael

    2003-01-01

    The transverse coefficient of thermal expansion (CTE) of single IM7, T1000, and P55 carbon fibers are measured at elevated temperatures. The specimens are prepared by press-fitting fiber tows into 0.7mm-diameter cavity in a graphite disk of 5mm in diameter and 3mm high. The specimens are placed on a crucible in an ESEM, and images of the fiber cross section are taken as the fibers are heated up to 800 C. Holding time, heating and cool down cycles are also introduced. The geometrical changes are measured using a graphics tablet. The change in area/perimeter is calculated to determine the strain and transverse CTE for each fiber. In a complimentary computational effort, displacements and stresses are calculated with finite element models.

  2. Finite Element Analysis of Fire Truck Chassis for Steel and Carbon Fiber Materials

    Directory of Open Access Journals (Sweden)

    Salvi Gauri Sanjay

    2014-07-01

    Full Text Available Chassis is the foremost component of an automobile that acts as the frame to support the vehicle body. Hence the frame ought to be very rigid and robust enough to resist shocks vibrations and stresses acting on a moving vehicle. Steel in its numerous forms is commonly used material for producing chassis and overtime alumimium has acquired its use. However, in this study traditional materials are replaced with ultra light weight carbon fiber materials. High strength and low weight of carbon fibers makes it ideal for manufacturing automotive chassis. This paper depicts the modal and static structural analysis of TATA 407 fire truck chassis frame for steel as well as carbon fibers. From the analyzed results, stress, strain and total deformation values were compared for both the materials. Since it is easy to analyze structural systems by finite element method, the chassis is modified using PRO-E and the Finite Element Analysis is performed on ANSYS workbench.

  3. CVD Synthesis of Hierarchical 3D MWCNT/Carbon-Fiber Nanostructures

    Directory of Open Access Journals (Sweden)

    Toma Susi

    2008-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs were synthesized by CVD on industrially manufactured highly crystalline vapor-grown carbon fibers (VGCFs. Two catalyst metals (Ni and Fe and carbon precursor gases (C2H2 and CO were studied. The catalysts were deposited on the fibers by sputtering and experiments carried out in two different reactors. Samples were characterized by electron microscopy (SEM and TEM. Iron was completely inactive as catalyst with both C2H2 and CO for reasons discussed in the paper. The combination of Ni and C2H2 was very active for secondary CNT synthesis, without any pretreatment of the fibers. The optimal temperature for CNT synthesis was 750∘C, with total gas flow of 650 cm3min⁡−1 of C2H2, H2, and Ar in 1.0:6.7:30 ratio.

  4. Preparation and characterization of boron nitride/carbon fiber composite with high specific surface area

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yan; Fan, Mingwen [Wuhan Univ. (China). Key Laboratory for Oral Biomedical Engineering; Yuan, Songdong; Xiong, Kun; Hu, Kunpeng; Luo, Yi [Hubei Univ. of Technology, Wuhan (China). School of Chemistry and Chemical Engineering; Li, Dong [Hubei Univ. of Technology, Wuhan (China). School of Chemistry and Chemical Engineering; Oxford Univ. (United Kingdom). Chemistry Research Lab.

    2014-06-15

    Boron nitride can be used as a good catalyst carrier because of its high thermal conductivity and chemical stability. However, a high specific surface area of boron nitride is still desirable. In this work, a carbon fiber composite coated with boron nitride villous nano-film was prepared, and was also characterized by means of scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The results indicated that the carbon fibers were covered by uniform villous boron nitride films whose thickness was about 150 - 200 nm. The specific surface area of the boron nitride/carbon fiber composite material was 96 m{sup 2} g{sup -1}, which was markedly improved compared with conventional boron nitride materials. (orig.)

  5. Facile and efficient route to polyimide-TiO2 nanocomposite coating onto carbon fiber.

    Science.gov (United States)

    He, Shuqing; Lu, Chunxiang; Zhang, Shouchun

    2011-12-01

    Polyamic acid-TiO(2) hybrid colloid emulsion with an average particle size of 200 nm was formed by dispersing nano-TiO(2) into polyamic acid colloidal emulsion. The polyimide-TiO(2) nanocomposite was coated onto carbon fiber by electrophoretic deposition. The primary properties of polyamic acid-TiO(2) hybrid colloid emulsion and polyimide-TiO(2) nanocomposite coating onto carbon fiber were characterized using laser scattering, ZetaPlus particle sizing, transmission electron microscopy, field-emission scanning electron microscope, Fourier transforms infrared spectroscopy, and X-ray Diffraction analysis. The results indicated that the small amount of nano-TiO(2) would be effectively dispersed in polyamic acid colloidal particles. The polyimide-TiO(2) hybrid nanocomposite coating carbon fiber sheet displayed an excellent photodegradation performance of methyl orange, which could be degraded more than 70 wt % after 10 cycles.

  6. Relation between the charge efficiency of activated carbon fiber and its desalination performance.

    Science.gov (United States)

    Huang, Zheng-Hong; Wang, Ming; Wang, Lei; Kang, Feiyu

    2012-03-20

    Four types of activated carbon fibers (ACFs) with different specific surface areas (SSA) were used as electrode materials for water desalination using capacitive deionization (CDI). The carbon fibers were characterized by scanning electron microscopy and N(2) adsorption at 77 K, and the CDI process was investigated by studying the salt adsorption, charge transfer, and also the charge efficiency of the electric double layers that are formed within the micropores inside the carbon electrodes. It is found that the physical adsorption capacity of NaCl by the ACFs increases with increasing Brunauer-Emmett-Teller (BET) surface area of the fibers. However, the two ACF materials with the highest BET surface area have the lowest electrosorptive capability. Experiments indicate that the charge efficiency of the double layers is a key property of the ACF-based electrodes because the ACF material which has the maximum charge efficiency also shows the highest salt adsorption capacity for CDI.

  7. Matrimid® derived carbon molecular sieve hollow fiber membranes for ethylene/ethane separation

    KAUST Repository

    Xu, Liren

    2011-09-01

    Carbon molecular sieve (CMS) membranes have shown promising separation performance compared to conventional polymeric membranes. Translating the very attractive separation properties from dense films to hollow fibers is important for applying CMS materials in realistic gas separations. The very challenging ethylene/ethane separation is the primary target of this work. Matrimid® derived CMS hollow fiber membranes have been investigated in this work. Resultant CMS fiber showed interesting separation performance for several gas pairs, especially high selectivity for C2H4/C2H6. Our comparative study between dense film and hollow fiber revealed very similar selectivity for both configurations; however, a significant difference exists in the effective separation layer thickness between precursor fibers and their resultant CMS fibers. SEM results showed that the deviation was essentially due to the collapse of the porous substructure of the precursor fiber. Polymer chain flexibility (relatively low glass transition temperature (Tg) for Matrimid® relative to actual CMS formation) appears to be the fundamental cause of substructure collapse. This collapse phenomenon must be addressed in all cases involving intense heat-treatment near or above Tg. We also found that the defect-free property of the precursor fiber was not a simple predictor of CMS fiber performance. Even some precursor fibers with Knudsen diffusion selectivity could be transformed into highly selective CMS fibers for the Matrimid® precursor. To overcome the permeance loss problem caused by substructure collapse, several engineering approaches were considered. Mixed gas permeation results under realistic conditions demonstrate the excellent performance of CMS hollow fiber membrane for the challenging ethylene/ethane separation. © 2011 Elsevier B.V.

  8. Apparatus and process for the surface treatment of carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, Felix Leonard; Ozcan, Soydan; Naskar, Amit K.

    2016-05-17

    A method for surface treating a carbon-containing material in which carbon-containing material is reacted with decomposing ozone in a reactor (e.g., a hollow tube reactor), wherein a concentration of ozone is maintained throughout the reactor by appropriate selection of at least processing temperature, gas stream flow rate, reactor dimensions, ozone concentration entering the reactor, and position of one or more ozone inlets (ports) in the reactor, wherein the method produces a surface-oxidized carbon or carbon-containing material, preferably having a surface atomic oxygen content of at least 15%. The resulting surface-oxidized carbon material and solid composites made therefrom are also described.

  9. Polymer-derived ceramic composite fibers with aligned pristine multiwalled carbon nanotubes.

    Science.gov (United States)

    Sarkar, Sourangsu; Zou, Jianhua; Liu, Jianhua; Xu, Chengying; An, Linan; Zhai, Lei

    2010-04-01

    Polymer-derived ceramic fibers with aligned multiwalled carbon nanotubes (MWCNTs) are fabricated through the electrospinning of polyaluminasilazane solutions with well-dispersed MWCNTs followed by pyrolysis. Poly(3-hexylthiophene)-b-poly (poly (ethylene glycol) methyl ether acrylate) (P3HT-b-PPEGA), a conjugated block copolymer compatible with polyaluminasilazane, is used to functionalize MWCNT surfaces with PPEGA, providing a noninvasive approach to disperse carbon nanotubes in polyaluminasilazane chloroform solutions. The electrospinning of the MWCNT/polyaluminasilazane solutions generates polymer fibers with aligned MWCNTs where MWCNTs are oriented along the electrospun jet by a sink flow. The subsequent pyrolysis of the obtained composite fibers produces ceramic fibers with aligned MWCNTs. The study of the effect of polymer and CNT concentration on the fiber structures shows that the fiber size increases with the increment of polymer concentration, whereas higher CNT content in the polymer solutions leads to thinner fibers attributable to the increased conductivity. Both the SEM and TEM characterization of the polymer and ceramic fibers demonstrates the uniform orientation of CNTs along the fibers, suggesting excellent dispersion of CNTs and efficient CNT alignment via the electrospinning. The electrical conductivity of a ceramic fibers with 1.2% aligned MWCNTs is measured to be 1.58 x 10(-6) S/cm, which is more than 500 times higher than that of bulk ceramic (3.43 x 10(-9) S/cm). Such an approach provides a versatile method to disperse CNTs in preceramic polymer solutions and offers a new approach to integrate aligned CNTs in ceramics.

  10. Chemical thermostabilization for the preparation of carbon fibers from softwood lignin

    Directory of Open Access Journals (Sweden)

    Jian Lin

    2012-11-01

    Full Text Available A thermally fusible softwood lignin was directly isolated by a solvolysis of cedar wood chips with a mixture of polyethylene glycol 400 (PEG 400 and sulfuric acid. Its fusibility was found to be due to a PEG moiety introduced into the lignin by the solvolysis. The lignin was easily formed into fibers by melt-spinning at temperatures ranging from 145 to 172 oC without any modification. The lignin fibers could be converted into infusible fibers as a precursor for carbon fibers (CFs by conventional oxidative thermal stabilization processing in air or a stream of oxygen for 2 days. We found that the infusible fibers resulted from the partial cleavage of the PEG moiety from the lignin fibers after treatment with 6 M hydrochloric acid at 100 oC for 2 h. The infusible fibers were converted into CFs with a tensile strength of 450 MPa by carbonization at 1000 oC under a N2 stream.

  11. Studies of world carbon fiber industry from a perspective of patent analysis

    Institute of Scientific and Technical Information of China (English)

    郑佳

    2016-01-01

    Patents are the manifestation of the industry R&D endeavor;therefore, World carbon fiber in-dustry from the perspective of patent analysis is studied .Findings from the analysis show a continual increase of carbon fibers patents since 1969 , and the growth rate began even faster after the year of 2005.Five countries (Japan, China, US, Germany and Korea) took dominant positions in global carbon fibers R&D , and the sum of patents applied in these five countries accounted for 80%of the total patents in the world .Corporations do play an active role in global carbon fibers R&D , and over 60%of patents were applied by corporations .Among them , the top 3 corporations were all from Ja-pan, which had much more patents than the other patent assignees .Furthermore, most corporations were not active in cooperation with others , except Toyota Motor Corp .Global carbon fibers R&D fo-cused on sheet manufacture cloth , core wire layer , heat connect provide and filter activated draw . And there is big difference between Japan and China in the R&D focus .China ’ s corporations have exhibited rapid growth in the number of patent applications in recent years , but there is still a large gap between China and foreign countries in view of global patent layout and influence .By providing the insight into the evolution of global carbon fibers industrial and technological development through the perspective of patent analysis , this study hopes to provide an objective statistic reference for fu-ture policy directions and academic researches .

  12. Commercialization of New Carbon Fiber Materials Based on Sustainable Resources for Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, Cliff [ORNL; Webb, Daniel C [ORNL; Albers, Tracy [GrafTech International; Chen, Chong [GrafTech International

    2013-03-01

    Oak Ridge National Laboratory (ORNL) and GrafTech International have collaborated to develop and demonstrate the performance of high temperature thermal insulation prototypes made from lignin-based carbon fibers. This project will potentially lead to the first commercial application of lignin-based carbon fibers (LBCF). The goal of the commercial application is to replace expensive, Chinese-sourced isotropic pitch carbon fibers with lower cost carbon fibers made from a domestically sourced, bio-derived (renewable) feedstock. LBCF can help recapture jobs that were previously exported to China while resolving a supply chain vulnerability and reducing the production cost for GrafTech s high temperature thermal insulation. The performance of the LBCF prototypes was measured and found to be comparable to that of the current commercial product. During production of the insulation prototypes, ORNL and GrafTech demonstrated lignin compounding/pelletization, fiber production, heat treatment, and compositing at scales far surpassing those previously demonstrated in LBCF R&D or production. A plan was developed for the commercialization of LBCF thermal insulation, with key milestones including qualification of multiple scalable lignin sources in 2013, tons-scale production and field testing by customers in 2014, and product launch as soon thereafter as production capabilities can be constructed and commissioned.

  13. Histopathological study on fine carbon fiber powder injected into the subdural space of mice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM and METHODS: After the fine carbon fiber powder was injected into the right subdural space of the mice, dynamic observation was carried out on their movement and histopathological changes. RESULTS: 1-52 weeks after the injecting, no neurological changes concerning with the implanting of the carbon fiber powder were found in the experimental mice. The fine carbon fiber extensively located on the inter surface of the dura mater membrane of the right temporalis and the out surface of pie mater. Only slight inflammatory cells reaction was found under optical microscopes. The degree of inflammation reaction are Grade Ⅱ 1 week after injection and was Grade Ⅰ 2 weeks after injection, inflammation was disappeared 4 weeks after injection. No obvious fiber membrane was found around the implanted materials. No significant differences were found between the experimental and the control group.CONCLUSION: It was showed that the carbon fiber shares excellent histocompatibility after injected into the subdural space and subarechnoid cavity of the right temple of mice.

  14. Reinforced concrete T-beams externally prestressed with unbonded carbon fiber-reinforced polymer tendons

    DEFF Research Database (Denmark)

    Bennitz, Anders; Nilimaa, Jonny; Ravn, Dorthe Lund

    2012-01-01

    This study describes a series of experiments examining the behavior of seven beams prestressed with unbonded external carbon fiberreinforced polymer (CFRP) tendons anchored using a newly developed anchorage and post-tensioning system. The effects of varying the initial tendon depth, prestressing...... force, and the presence of a deviator were investigated. The results were compared to those observed with analogous beams prestressed with steel tendons, common beam theory, and predictions made using an analytical model adapted from the literature. It was found that steel and CFRP tendons had very...

  15. Surface modification of carbon fibers by a polyether sulfone emulsion sizing for increased interfacial adhesion with polyether sulfone

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Haojie [National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Shouchun, E-mail: zschun@sxicc.ac.cn [National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Lu, Chunxiang [National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

    2014-10-30

    Highlights: • A polyether sulfone emulsion (PES) sizing was prepared for the first time. • The sizing enhanced the surface activity and wettability of carbon fibers. • Compared to the original sizing, the PES emulsion sizing resulted in an 18.4% increase in the interlaminar shear strength of carbon fiber/PES composites. • Important influences of emulsifier on the fiber surface and composite interface were demonstrated. • The reinforcing mechanisms are the improved fiber surface wettability and interfacial compatibility in composites. - Abstract: Interests on carbon fiber-reinforced thermoplastic composites are growing rapidly, but the challenges with poor interfacial adhesion have slowed their adoption. In this work, a polyether sulfone (PES) emulsion sizing was prepared successfully for increased interfacial adhesion of carbon fiber/PES composites. To obtain a high-quality PES emulsion sizing, the key factor, emulsifier concentration, was studied by dynamic light scattering technique. The results demonstrated that the suitable weight ratio of PES to emulsifier was 8:3, and the resulting PES emulsion sizing had an average particle diameter of 117 nm and Zeta potential of −52.6 mV. After sizing, the surface oxygen-containing functional groups, free energy and wettability of carbon fibers increased significantly, which were advantageous to promote molecular-level contact between carbon fiber and PES. Finally, short beam shear tests were performed to evaluate the interfacial adhesion of carbon fiber/PES composites. The results indicated that PES emulsion sizing played a critical role for the enhanced interfacial adhesion in carbon fiber/PES composites, and a 26% increase of interlaminar shear strength was achieved, because of the improved fiber surface wettability and interfacial compatibility between carbon fiber and PES.

  16. 3D-Printing of Meso-structurally Ordered Carbon Fiber/Polymer Composites with Unprecedented Orthotropic Physical Properties

    Science.gov (United States)

    Lewicki, James P.; Rodriguez, Jennifer N.; Zhu, Cheng; Worsley, Marcus A.; Wu, Amanda S.; Kanarska, Yuliya; Horn, John D.; Duoss, Eric B.; Ortega, Jason M.; Elmer, William; Hensleigh, Ryan; Fellini, Ryan A.; King, Michael J.

    2017-01-01

    Here we report the first example of a class of additively manufactured carbon fiber reinforced composite (AMCFRC) materials which have been achieved through the use of a latent thermal cured aromatic thermoset resin system, through an adaptation of direct ink writing (DIW) 3D-printing technology. We have developed a means of printing high performance thermoset carbon fiber composites, which allow the fiber component of a resin and carbon fiber fluid to be aligned in three dimensions via controlled micro-extrusion and subsequently cured into complex geometries. Characterization of our composite systems clearly show that we achieved a high order of fiber alignment within the composite microstructure, which in turn allows these materials to outperform equivalently filled randomly oriented carbon fiber and polymer composites. Furthermore, our AM carbon fiber composite systems exhibit highly orthotropic mechanical and electrical responses as a direct result of the alignment of carbon fiber bundles in the microscale which we predict will ultimately lead to the design of truly tailorable carbon fiber/polymer hybrid materials having locally programmable complex electrical, thermal and mechanical response. PMID:28262669

  17. 3D-Printing of Meso-structurally Ordered Carbon Fiber/Polymer Composites with Unprecedented Orthotropic Physical Properties

    Science.gov (United States)

    Lewicki, James P.; Rodriguez, Jennifer N.; Zhu, Cheng; Worsley, Marcus A.; Wu, Amanda S.; Kanarska, Yuliya; Horn, John D.; Duoss, Eric B.; Ortega, Jason M.; Elmer, William; Hensleigh, Ryan; Fellini, Ryan A.; King, Michael J.

    2017-03-01

    Here we report the first example of a class of additively manufactured carbon fiber reinforced composite (AMCFRC) materials which have been achieved through the use of a latent thermal cured aromatic thermoset resin system, through an adaptation of direct ink writing (DIW) 3D-printing technology. We have developed a means of printing high performance thermoset carbon fiber composites, which allow the fiber component of a resin and carbon fiber fluid to be aligned in three dimensions via controlled micro-extrusion and subsequently cured into complex geometries. Characterization of our composite systems clearly show that we achieved a high order of fiber alignment within the composite microstructure, which in turn allows these materials to outperform equivalently filled randomly oriented carbon fiber and polymer composites. Furthermore, our AM carbon fiber composite systems exhibit highly orthotropic mechanical and electrical responses as a direct result of the alignment of carbon fiber bundles in the microscale which we predict will ultimately lead to the design of truly tailorable carbon fiber/polymer hybrid materials having locally programmable complex electrical, thermal and mechanical response.

  18. Studies on non-oxide coating on carbon fibers using plasma enhanced chemical vapor deposition technique

    Science.gov (United States)

    Patel, R. H.; Sharma, S.; Prajapati, K. K.; Vyas, M. M.; Batra, N. M.

    2016-05-01

    A new way of improving the oxidative behavior of carbon fibers coated with SiC through Plasma Enhanced Chemical Vapor Deposition technique. The complete study includes coating of SiC on glass slab and Stainless steel specimen as a starting test subjects but the major focus was to increase the oxidation temperature of carbon fibers by PECVD technique. This method uses relatively lower substrate temperature and guarantees better stoichiometry than other coating methods and hence the substrate shows higher resistance towards mechanical and thermal stresses along with increase in oxidation temperature.

  19. Fabrication and Testing of Carbon Fiber Reinforced Truss Core Sandwich Panels

    Institute of Scientific and Technical Information of China (English)

    Bing Wang; Linzhi Wu; Li Ma; Qiang Wang; Shanyi Du

    2009-01-01

    Truss core sandwich panels reinforced by carbon fibers were assembled with bonded laminate facesheets and carbon fiber reinforced truss cores. The top and bottom facesheets were interconnected with truss cores. Both ends of the truss cores were embedded into four layers of top and bottom facesheets. The mechanical properties of truss core sandwich panels were then investigated under out-of-plane and in-plane compression loadings to reveal the failure mechanisms of sandwich panels. Experimental results indicated that the mechanical behavior of sandwich structure under in-plane loading is dominated by the buckling and debonding of facesheets.

  20. EXPERIMENTAL STUDY ON PEK-C MODIFIED EPOXIES AND THE CARBON FIBER COMPOSITES FOR AEROSPACE APPLICATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The morphological structure of various epoxies toughened with a special amorphous thermoplastic PEK-C and their carbon fiber composites were studied by using SEM. For both cases, phase separation and inversion took place to form fine epoxy-rich globules dispersing in the PEK-C matrix, in which the epoxy-rich phase had the absolutely higher volume fraction. The phase structure and the interfacial properties were also studied by means of FTIR, DSC, and DMTA as well. An accompanying mechanical determination revealed that an improved toughness was achieved both in the blend casts and in the carbon fiber composites. A composite structural model was hence suggested.