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Sample records for carbon fiber microelectrodes

  1. Glass pipette-carbon fiber microelectrodes for evoked potential recordings

    Directory of Open Access Journals (Sweden)

    Moraes M.F.D.

    1997-01-01

    Full Text Available Current methods for recording field potentials with tungsten electrodes make it virtually impossible to use the same recording electrode also as a lesioning electrode, for example for histological confirmation of the recorded site, because the lesioning procedure usually wears off the tungsten tip. Therefore, the electrode would have to be replaced after each lesioning procedure, which is a very high cost solution to the problem. We present here a low cost, easy to make, high quality glass pipette-carbon fiber microelectrode that shows resistive, signal/noise and electrochemical coupling advantages over tungsten electrodes. Also, currently used carbon fiber microelectrodes often show problems with electrical continuity, especially regarding electrochemical applications using a carbon-powder/resin mixture, with consequent low performance, besides the inconvenience of handling such a mixture. We propose here a new method for manufacturing glass pipette-carbon fiber microelectrodes with several advantages when recording intracerebral field potentials

  2. Chitosan coated carbon fiber microelectrode for selective in vivo detection of neurotransmitters in live zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Ozel, Rifat Emrah [Department of Chemistry and Biomolecular Science, 8 Clarkson Ave, Potsdam, NY 136995810 (United States); Wallace, Kenneth N. [Department of Biology, Clarkson University, Potsdam, NY 136995810 (United States); Andreescu, Silvana, E-mail: eandrees@clarkson.edu [Department of Chemistry and Biomolecular Science, 8 Clarkson Ave, Potsdam, NY 136995810 (United States)

    2011-06-10

    Graphical abstract: Chitosan coated fiber electrodes are sensitive to serotonin detection while rejecting physiological levels of ascorbic acid interferences. - Abstract: We report the development of a chitosan modified carbon fiber microelectrode for in vivo detection of serotonin. We find that chitosan has the ability to reject physiological levels of ascorbic acid interferences and facilitate selective and sensitive detection of in vivo levels of serotonin, a common catecholamine neurotransmitter. Presence of chitosan on the microelectrode surface was investigated using scanning electron microscopy (SEM) and cyclic voltammetry (CV). The electrode was characterized using differential pulse voltammetry (DPV). A detection limit of 1.6 nM serotonin with a sensitivity of 5.12 nA/{mu}M, a linear range from 2 to 100 nM and a reproducibility of 6.5% for n = 6 electrodes were obtained. Chitosan modified microelectrodes selectively measure serotonin in presence of physiological levels of ascorbic acid. In vivo measurements were performed to measure concentration of serotonin in the live embryonic zebrafish intestine. The sensor quantifies in vivo intestinal levels of serotonin while successfully rejecting ascorbic acid interferences. We demonstrate that chitosan can be used as an effective coating to reject ascorbic acid interferences at carbon fiber microelectrodes, as an alternative to Nafion, and that chitosan modified microelectrodes are reliable tools for in vivo monitoring of changes in neurotransmitter levels.

  3. Chitosan coated carbon fiber microelectrode for selective in vivo detection of neurotransmitters in live zebrafish embryos

    International Nuclear Information System (INIS)

    Graphical abstract: Chitosan coated fiber electrodes are sensitive to serotonin detection while rejecting physiological levels of ascorbic acid interferences. - Abstract: We report the development of a chitosan modified carbon fiber microelectrode for in vivo detection of serotonin. We find that chitosan has the ability to reject physiological levels of ascorbic acid interferences and facilitate selective and sensitive detection of in vivo levels of serotonin, a common catecholamine neurotransmitter. Presence of chitosan on the microelectrode surface was investigated using scanning electron microscopy (SEM) and cyclic voltammetry (CV). The electrode was characterized using differential pulse voltammetry (DPV). A detection limit of 1.6 nM serotonin with a sensitivity of 5.12 nA/μM, a linear range from 2 to 100 nM and a reproducibility of 6.5% for n = 6 electrodes were obtained. Chitosan modified microelectrodes selectively measure serotonin in presence of physiological levels of ascorbic acid. In vivo measurements were performed to measure concentration of serotonin in the live embryonic zebrafish intestine. The sensor quantifies in vivo intestinal levels of serotonin while successfully rejecting ascorbic acid interferences. We demonstrate that chitosan can be used as an effective coating to reject ascorbic acid interferences at carbon fiber microelectrodes, as an alternative to Nafion, and that chitosan modified microelectrodes are reliable tools for in vivo monitoring of changes in neurotransmitter levels.

  4. Nanostructured silver and platinum modified carbon fiber microelectrodes coated with nafion for H2O2 determination

    OpenAIRE

    Vladimir Halouzka; Petr Jakubec; Cenek Gregor; Dalibor Jancik; Gabriela Valaskova; Kyriakos Papadopoulos; Theodor Triantis; Jan Hrbac

    2010-01-01

    Carbon fiber microelectrodes equipped with nanostructured metals(platinum and silver) and covered with a Nafion layer constitutesensitive H2O2 sensors. Metallic layers on carbon fibers wereprepared by surfactant assisted electrodeposition. In the case ofsilver, the procedure leads to coating which is composed of porous,partially aggregated and crystalline deposits containing silvernanoparticles. The electrodeposition of platinum leads to carbonfiber decorated with clusters of platinum nanopar...

  5. Novel carbon-fiber microelectrode batch fabrication using a 3D-printed mold and polyimide resin.

    Science.gov (United States)

    Trikantzopoulos, Elefterios; Yang, Cheng; Ganesana, Mallikarjunarao; Wang, Ying; Venton, B Jill

    2016-09-21

    Glass insulated carbon-fiber microelectrodes (CFMEs) are standard tools for the measurement of neurotransmitters. However, electrodes are fabricated individually and the glass can shatter, limiting application in higher order mammals. Here, we developed a novel microelectrode batch fabrication method using a 3D-printed mold and polyimide resin insulating agent. The 3D-printed mold is low cost, customizable to change the electrode shape, and allows 40 electrodes to be made simultaneously. The polyimide resin is biocompatible, quick to cure, and does not adhere to the plastic mold. The electrodes were tested for the response to dopamine with fast-scan cyclic voltammetry both in vitro and in vivo and performed similarly to traditional glass-insulated electrodes, but with lower background currents. Thus, polyimide-insulated electrodes can be mass-produced using a 3D-printed mold and are an attractive alternative for making cheap, biocompatible microelectrodes. PMID:27536741

  6. Head-to-Head Comparisons of Carbon Fiber Microelectrode Coatings for Sensitive and Selective Neurotransmitter Detection by Voltammetry

    OpenAIRE

    Singh, Yogesh S.; Sawarynski, Lauren E.; Dabiri, Pasha D.; Choi, Wonwoo R.; Andrews, Anne M.

    2011-01-01

    Voltammetry is widely used to investigate neurotransmission and other biological processes but is limited by poor chemical selectivity and fouling of commonly used carbon fiber microelectrodes (CFMs). We performed direct comparisons of three key coating materials purported to impart selectivity and fouling resistance to electrodes: Nafion, base-hydrolyzed cellulose acetate (BCA), and fibronectin. We systematically evaluated the impact on a range of electrode parameters. Fouling due to exposur...

  7. Nanostructured silver and platinum modified carbon fiber microelectrodes coated with nafion for H2O2 determination

    Directory of Open Access Journals (Sweden)

    Vladimir Halouzka

    2010-12-01

    Full Text Available Carbon fiber microelectrodes equipped with nanostructured metals(platinum and silver and covered with a Nafion layer constitutesensitive H2O2 sensors. Metallic layers on carbon fibers wereprepared by surfactant assisted electrodeposition. In the case ofsilver, the procedure leads to coating which is composed of porous,partially aggregated and crystalline deposits containing silvernanoparticles. The electrodeposition of platinum leads to carbonfiber decorated with clusters of platinum nanoparticles. Aftercoating the electrodes with protective and antiinterference barriermade of Nafion, the sensing properties of the preparedmicroelectrodes towards hydrogen peroxide are investigated.

  8. Redox-filled Carbon-Fiber Microelectrodes for Single-Cell Exocytosis

    Science.gov (United States)

    Cox, Jonathan T.; Gunderson, Christopher G.; Zhang, Bo

    2014-01-01

    Carbon-fiber microelectrodes (CFEs) are the primary electroanalytical tool in single-cell exocytosis and in-vivo studies. Here we report a new study on the kinetic properties of electrolyte-filled CFEs in single-cell measurements and demonstrate that the addition of outer sphere redox species, such as Fe(CN)63− and Ru(NH3)63+, in the backfill electrolyte solution can greatly enhance the kinetic response of CFEs. We show that at 750 mV, a voltage normally applied for detection of dopamine, the presence of fast outer sphere redox species in the backfilling solution significantly enhances the kinetic response of CFEs toward fast dopamine detection at single PC12 cells. Moreover, we also demonstrate that the use of Fe(CN)63− in the backfilling solution has enabled direct measurement of dopamine at applied voltages as low as 200 mV. This kinetic enhancement is believed to be due to faster electron-transfer kinetics on the coupling pole as compared to the sluggish reduction of oxygen. We anticipate that such redox-filled CFE ultramicroelectrodes will find many useful applications in single cell exocytosis and in-vivo sensing. PMID:24833889

  9. Te/Pt nanonetwork modified carbon fiber microelectrodes for methanol oxidation

    Science.gov (United States)

    Tsai, Hsiang-Yu; Shih, Zih-Yu; Lin, Zong-Hong; Chang, Huan-Tsung

    2013-05-01

    Te/Pt nanonetwork-decorated carbon fiber microelectrodes (CFMEs) have been fabricated and employed as anodic catalysts in a direct methanol fuel cell (DMFC). Te nanowires were prepared from tellurite ions (TeO32-) through a seed-mediated growth process and were deposited onto CFMEs to form three-dimensional Te nanonetworks. The Te nanonetworks then acted as a framework and reducing agent to reduce PtCl62- ions to form Te/Pt through a galvanic replacement reaction, leading to the formation of Te/PtCFMEs. By controlling the reaction time, the amount of Pt and morphology of Te/Pt nanonetworks were controlled, leading to various degrees of electrocatalytic activity. The Te/PtCFMEs provide a high electrochemical active surface area (129.2 m2 g-1), good catalytic activity (1.2 A mg-1), high current density (20.0 mA cm-2), long durability, and tolerance toward the poisoning species for methanol oxidation in 0.5 M sulfuric acid containing 1 M methanol. We have further demonstrated an enhanced current density by separately using 3 and 5 Te/PtCFMEs. Our results show that the low-cost, stable, and effective Te/PtCFMEs have great potential in the fabrication of cost-effective fuel cells.

  10. Real-Time, Selective Detection of Copper(II) Using Ionophore-Grafted Carbon-Fiber Microelectrodes.

    Science.gov (United States)

    Yang, Yuanyuan; Ibrahim, Ahmad A; Hashemi, Parastoo; Stockdill, Jennifer L

    2016-07-19

    Rapid, selective detection of metals in complex samples remains an elusive goal that could provide critical analytical information for biological and environmental sciences and industrial waste management. Fast-scan cyclic voltammetry (FSCV) using carbon-fiber microelectrodes (CFMs) is an emerging technique for metal analysis with broad potential applicability because of its rapid response to changes in analyte concentration and minimal disturbance to the analysis medium. In this communication, we report the first effective application of covalently modified CFMs to achieve highly selective, subsecond Cu(II) measurements using FSCV. A two-part strategy is employed for maximum selectivity: Cu(II) binding is augmented by a covalently grafted ionophore, while binding of other metals is prevented by chemical blocking of nonselective surface adsorption sites. The resulting electrodes selectively detect Cu(II) in a complex medium comprising several interfering metals. Overall, this strategy represents a transformative innovation in real-time electrochemical detection of metal analytes. PMID:27079730

  11. Ferricyanide-backfilled cylindrical carbon fiber microelectrodes for in vivo analysis with high stability and low polarized potential.

    Science.gov (United States)

    Zhong, Peipei; Yu, Ping; Wang, Kai; Hao, Jie; Fei, Junjie; Mao, Lanqun

    2015-11-01

    The development of stable and reproducible methods for in vivo electrochemical monitoring of neurochemicals is of great physiological importance. In this study, we demonstrate ferricyanide-filled cylindrical carbon fiber microelectrodes (CFEs) of high stability and low polarized potential for in vivo electrochemical analysis. We first studied the voltammetric behavior of cylindrical CFEs by using a model system consisting of two separated cells each containing potassium ferricyanide (K3Fe(CN)6) or potassium ferrocyanide (K4Fe(CN)6). We observed that E1/2 values of the system were dependent on the ratio of the lengths of the cylindrical CFEs and of the concentrations of the redox species on both poles. Based on this property, we prepared the ferricyanide-backfilled cylindrical CFEs, and found that this kind of electrode exhibits a more stable current response and a lower polarized potential than the CFEs backfilled with KCl or Ru(NH3)6Cl3. Animal experiments with the ferricyanide-backfilled cylindrical CFEs demonstrate that this kind of electrode could be used for in vivo monitoring of neurochemical release with a high stability under some physiological conditions. PMID:26378690

  12. A comparison of electrochemically pre-treated and spark-platinized carbon fiber microelectrode. Measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine in human urine and plasma.

    Science.gov (United States)

    Bartosova, Z; Riman, D; Halouzka, V; Vostalova, J; Simanek, V; Hrbac, J; Jirovsky, D

    2016-09-01

    A novel method of carbon fiber microelectrode activation using spark discharge was demonstrated and compared to conventional electrochemical pretreatment by potential cycling. The spark discharge was performed at 800 V between the microelectrode connected to positive pole of the power supply and platinum counter electrode. Spark discharge led both to trimming of the fiber tip into conical shape and to the modification of carbon fiber microelectrode with platinum, as proven by scanning electron microscopy and electron dispersive X-ray spectroscopy. After the characterization of electrochemical properties using ferricyanide voltammetry, the activated electrodes were used for electrochemical analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine, an oxidative stress marker. Subnanomolar detection limits (0.55 nmol L(-1)) in high-performance liquid chromatography were achieved for spark platinized electrodes incorporated into the flow detection cell. PMID:27543016

  13. A miniature glucose/O{sub 2} biofuel cell with single-walled carbon nanotubes-modified carbon fiber microelectrodes as the substrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xianchan; Zhou, Haojie [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100080 (China); Graduate School of CAS, Beijing 100049 (China); Yu, Ping; Su, Lei; Mao, Lanqun [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing 100080 (China); Ohsaka, Takeo [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

    2008-06-15

    This study demonstrates a new kind of miniature glucose/O{sub 2} biofuel cells (BFCs) based on carbon fiber microelectrodes (CFMEs) modified with single-walled carbon nanotubes (SWNTs). SWNTs are used as a support both for stably confining the electrocatalyst (i.e., methylene green, MG) for the oxidation of NADH and the anodic biocatalyst (i.e., NAD{sup +}-dependent glucose dehydrogenase, GDH) for the oxidation of glucose and for efficiently facilitating direct electrochemistry of the cathodic biocatalyst (i.e., laccase) for the O{sub 2} reduction. The prepared micro-sized GDH-based bioanode and laccase-based biocathode exhibit good bioelectrocatalytic activity toward the oxidation of glucose and the reduction of oxygen, respectively. In 0.10 M phosphate buffer containing 10 mM NAD{sup +} and 45 mM glucose under ambient air, the power density of the assembled miniature compartment-less glucose/O{sub 2} BFC reaches 58 {mu}W cm{sup -2} at 0.40 V. The stability of the miniature glucose/O{sub 2} BFC is also evaluated. (author)

  14. Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference

    Science.gov (United States)

    Amperometric monochloramine detection using newly fabricated gold, platinum, and carbon-fiber microsensors was investigated to optimize sensor operation and eliminate oxygen interference. Gold and platinum microsensors exhibited no oxygen interference during monochloramine measu...

  15. Electrochemical Performance of Ionic Liquid-Graphene Modified Carbon Fiber Microelectrode%离子液体-石墨烯修饰碳纤维微电极电化学性能研究

    Institute of Scientific and Technical Information of China (English)

    范跃娟; 沙翠翠; 唐旻奕; 冉菊; 程寒

    2015-01-01

    本实验制备了离子液体-石墨烯修饰碳纤维微电极,采用循环伏安法和差分脉冲伏安法测定多巴胺(DA)在该修饰电极上的电化学行为。实验结果显示,修饰后电极的稳定性和重现性明显增加,DA在修饰电极上的氧化过程受扩散控制。在5×10-7-1×10-4mol/L浓度范围内,DA在修饰电极上的氧化峰电流与其浓度呈现良好的线性关系。%[Abstract]In this paper, the carbon fiber microelectrode modified with ionic liquid-graphene composites was fabricated, the electrochemical behaviors of dopamine (DA) at the modified carbon fiber microelectrode were determined with cyclic voltammetry and differential pulse voltammetric method. The results showed that the modified electrode showed good stability and duplicability. The oxidation of DA on the surface of the modified carbon fiber microelectrode belongs to the diffusion controlled reaction. In the 20mmol/L Tris-HCl (pH7.4) buffer solution, for DA determination, the oxidation peak current and the concentration of DA showed good linear relationships.

  16. Pyrolytic 3D Carbon Microelectrodes for Electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Amato, Letizia;

    2016-01-01

    electrochemical activity, chemical stability, and ease in surface functionalization [1]. The most common carbon microfabrication techniques (i.e. screen printing) produce two-dimensional (2D) electrodes, which limit the detection sensitivity. Hence several 3D microfabrication techniques have been explored......This work presents the fabrication and characterization of multi-layered three-dimensional (3D) pyrolysed carbon microelectrodes for electrochemical applications. For this purpose, an optimized UV photolithography and pyrolysis process with the negative tone photoresist SU-8 has been developed....... The fabricated three electrode electrochemical cell is characterized with cyclic voltammetry (CV) using the standard potassium ferri-ferrocyanide redox probe. Carbon materials have several attractive characteristics as microelectrodes for electrochemical applications, such as wide potential window, good...

  17. Carbon Nanotube-based microelectrodes for enhanced detection of neurotransmitters

    Science.gov (United States)

    Jacobs, Christopher B.

    Fast-scan cyclic voltammetry (FSCV) is one of the common techniques used for rapid measurement of neurotransmitters in vivo. Carbon-fiber microelectrodes (CFMEs) are typically used for neurotransmitter detection because of sub-second measurement capabilities, ability to measure changes in neurotransmitter concentration during neurotransmission, and the small size electrode diameter, which limits the amount of damage caused to tissue. Cylinder CFMEs, typically 50 -- 100 microm long, are commonly used for in vivo experiments because the electrode sensitivity is directly related to the electrode surface area. However the length of the electrode can limit the spatial resolution of neurotransmitter detection, which can restrict experiments in Drosophila and other small model systems. In addition, the electrode sensitivity toward dopamine and serotonin detection drops significantly for measurements at rates faster than 10 Hz, limiting the temporal resolution of CFMEs. While the use of FSCV at carbon-fiber microelectrodes has led to substantial strides in our understanding of neurotransmission, techniques that expand the capabilities of CFMEs are crucial to fully maximize the potential uses of FSCV. This dissertation introduces new methods to integrate carbon nanotubes (CNT) into microelectrodes and discusses the electrochemical enhancements of these CNT-microelectrodes. The electrodes are specifically designed with simple fabrication procedures so that highly specialized equipment is not necessary, and they utilize commercially available materials so that the electrodes could be easily integrated into existing systems. The electrochemical properties of CNT modified CFMEs are characterized using FSCV and the effect of CNT functionalization on these properties is explored in Chapter 2. For example, CFME modification using carboxylic acid functionalized CNTs yield about a 6-fold increase in dopamine oxidation current, but modification with octadecylamine CNTs results in a

  18. Modification of Carbon Nanotube Powder Microelectrode and Nitrite Reduction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The properties of the carbon nanotube powder microelectrodes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled carbon nanotubes to be partially cut shorter, resulting in more openings as shown by TEM. Besides, the anodic pretreatment may adjust the hydrophobicity of nanotubes to match with that of Os(bpy)32+. As a result, the real surface area and the ability of adsorbing mediator Os(bpy)32+ of the nanotubes are markedly increased so as to effectively catalyze NO2- reduction in acidic solution.

  19. Effects of carbon nanotube and conducting polymer coated microelectrodes on single-unit recordings in vitro.

    Science.gov (United States)

    Charkhkar, Hamid; Knaack, Gretchen L; Mandal, Himadri S; Keefer, Edward W; Pancrazio, Joseph J

    2014-01-01

    Neuronal networks cultured on microelectrode arrays (MEAs) have been utilized as biosensors that can detect all or nothing extracellular action potentials, or spikes. Coating the microelectrodes with carbon nanotubes (CNTs), either pristine or conjugated with a conductive polymer, has been previously reported to improve extracellular recordings presumably via reduction in microelectrode impedance. The goal of this work was to examine the basis of such improvement in vitro. Every other microelectrode of in vitro MEAs was electrochemically modified with either conducting polymer, poly-3,4-ethylenedioxythiophene (PEDOT) or a blend of CNT and PEDOT. Mouse cortical tissue was dissociated and cultured on the MEAs to form functional neuronal networks. The performance of the modified and unmodified microelectrodes was evaluated by activity measures such as spike rate, spike amplitude, burst duration and burst rate. We observed that the yield, defined as percentage of microelectrodes with neuronal activity, was significantly higher by 55% for modified microelectrodes compared to the unmodified sites. However, the spike rate and burst parameters were similar for modified and unmodified microelectrodes suggesting that neuronal networks were not physiologically altered by presence of PEDOT or PEDOT-CNT. Our observations from immunocytochemistry indicated that neuronal cells were more abundant in proximity to modified microelectrodes. PMID:25569998

  20. An active, flexible carbon nanotube microelectrode array for recording electrocorticograms

    Science.gov (United States)

    Chen, Yung-Chan; Hsu, Hui-Lin; Lee, Yu-Tao; Su, Huan-Chieh; Yen, Shiang-Jie; Chen, Chang-Hsiao; Hsu, Wei-Lun; Yew, Tri-Rung; Yeh, Shih-Rung; Yao, Da-Jeng; Chang, Yen-Chung; Chen, Hsin

    2011-06-01

    A variety of microelectrode arrays (MEAs) has been developed for monitoring intra-cortical neural activity at a high spatio-temporal resolution, opening a promising future for brain research and neural prostheses. However, most MEAs are based on metal electrodes on rigid substrates, and the intra-cortical implantation normally causes neural damage and immune responses that impede long-term recordings. This communication presents a flexible, carbon-nanotube MEA (CMEA) with integrated circuitry. The flexibility allows the electrodes to fit on the irregular surface of the brain to record electrocorticograms in a less invasive way. Carbon nanotubes (CNTs) further improve both the electrode impedance and the charge-transfer capacity by more than six times. Moreover, the CNTs are grown on the polyimide substrate directly to improve the adhesion to the substrate. With the integrated recording circuitry, the flexible CMEA is proved capable of recording the neural activity of crayfish in vitro, as well as the electrocorticogram of a rat cortex in vivo, with an improved signal-to-noise ratio. Therefore, the proposed CMEA can be employed as a less-invasive, biocompatible and reliable neuro-electronic interface for long-term usage.

  1. Direct-growth carbon nanotubes on 3D structural microelectrodes for electrophysiological recording.

    Science.gov (United States)

    Pan, Alice Ian; Lin, Min-Hsuan; Chung, Hui-Wen; Chen, Hsin; Yeh, Shih-Rung; Chuang, Yung-Jen; Chang, Yen-Chung; Yew, Tri-Rung

    2016-01-01

    A novel 3D carbon nanotube (CNT) microelectrode was developed through direct growth of CNTs on a gold pin-shaped 3D microelectrode at a low temperature (400 °C) for applications in neural and cardiac recording. With an electroplated Ni catalyst layer covering the entire surface of the pin-shaped structure, CNTs were synthesized on a 3D microelectrode by catalytic thermal chemical vapor deposition (CVD). According to the analyses by electrochemical impedance spectroscopy, the impedance of 3D microelectrodes after CNT growth and UV/O3 treatment decreased from 9.3 Ω mm(-2) to 1.2 Ω mm(-2) and the capacitance increased largely from 2.2 mF cm(-2) to 73.3 mF cm(-2). The existence of UVO3-treated CNT led to a large improvement of interfacial capacitance, contributing to the decrease of impedance. The electrophysiological detection capability of this 3D CNT microelectrode was demonstrated by the distinguished P waves, QRS complex and T waves in the electrocardiogram of the zebrafish heart and the action potential recorded from individual rat hippocampal neurons. The compatibility of integration with ICs, high resolution in space, electrophysiological signals, and non-invasive long-term recording suggest that the 3D CNT microelectrode exhibits promising potential for applications in electrophysiological research and clinical trials.

  2. Novel estradiol sensors based on carbon nanotube multilayer modified gold hair microelectrodes

    Institute of Scientific and Technical Information of China (English)

    Jun Hui Xu; Cheng Guo Hu; Sheng Shui Hu

    2009-01-01

    Multi-walled carbon nanotube multilayers were modified onto a newly proposed gold hair microelectrode via a simple layer-by-layer assembling method. The resulting electrode showed a sensitive oxidation response to estradiol with detection limit as low as 1.0×10~(-8) mol/L, foreseeing a promising approach to the fabrication of high-sensitive microsensors.

  3. Investigation of parameters controlling the dielectrophoretic assembly of carbon nanotubes on microelectrodes

    DEFF Research Database (Denmark)

    Dimaki, Maria; Bøggild, Peter

    2008-01-01

    Networks of single-walled carbon nanotubes were assembled onto microelectrodes by dielectrophoresis. The dependence of the obtained networks on several assembly parameters such as bias voltage, field application time, frequency, electrode geometry and the nanotube solvent were investigated both s...

  4. Nanotube composite carbon fibers

    Science.gov (United States)

    Andrews, R.; Jacques, D.; Rao, A. M.; Rantell, T.; Derbyshire, F.; Chen, Y.; Chen, J.; Haddon, R. C.

    1999-08-01

    Single walled carbon nanotubes (SWNTs) were dispersed in isotropic petroleum pitch matrices to form nanotube composite carbon fibers with enhanced mechanical and electrical properties. We find that the tensile strength, modulus, and electrical conductivity of a pitch composite fiber with 5 wt % loading of purified SWNTs are enhanced by ˜90%, ˜150%, and 340% respectively, as compared to the corresponding values in unmodified isotropic pitch fibers. These results serve to highlight the potential that exits for developing a spectrum of material properties through the selection of the matrix, nanotube dispersion, alignment, and interfacial bonding.

  5. Modification of Carbon Nanotube Powder Microelectrode and Nitrite Reduction

    Institute of Scientific and Technical Information of China (English)

    PeiFangLIU; JunFuHU

    2002-01-01

    The properties of the carbon nanotube powder microelectroes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled carbon nanotubes to be partially cut shorter, resulting in more openings as shown by TEM. Besides, the anodic pretreatment may adjust the hydrophobicity of nanotubes to match with that of Os(bpy)32+. As a result, the real surface area and the ability of adsorbing mediator Os(bpy)32+ of the nanotubes are markedly increased so as to effectively catalyze NO2- reduction in acidic solution.

  6. PEDOT Modified Carbon Paste Microelectrodes for Scanning Electrochemical Microscopy

    OpenAIRE

    Csoka, Balazs; Mekhalif, Zineb

    2011-01-01

    Only one measuring tip was used in three different modes of operation of the Scanning Electrochemical Microscope (feed-back mode, generation-collection mode, potentiometry) to collect chemical information about copper targets. The tip was formed from 5 and 25 μm diameter conventional platinum microdisk electrode by etching a cavity, then electrochemically depositing poly(3,4-ethylenedioxythiophene) (PEDOT) layer doped with hexacyanoferrate and finally filling with modified carbon ...

  7. Boron nitride converted carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Carbon Fiber Composites

    Science.gov (United States)

    1997-01-01

    HyComp(R), Inc. development a line of high temperature carbon fiber composite products to solve wear problems in the harsh environment of steel and aluminum mills. WearComp(R), self-lubricating composite wear liners and bushings, combines carbon graphite fibers with a polyimide binder. The binder, in conjunction with the fibers, provides the slippery surface, one that demands no lubrication, yet wears at a very slow rate. WearComp(R) typically lasts six to ten times longer than aluminum bronze. Unlike bronze, WearComp polishes the same surface and imparts a self-lube film for years of service. It is designed for continuous operation at temperatures of 550 degrees Fahrenheit and can operate under high compressive loads.

  9. Purification of carbon nanotubes through an electric field near the arranged microelectrodes

    Science.gov (United States)

    Shim, Hyung Cheoul; Lee, Hyung Woo; Yeom, Sujin; Kwak, Yoon Keun; Lee, Seung S.; Kim, Soo Hyun

    2007-03-01

    In this work, we attempt to purify multi-walled carbon nanotubes (MWNTs) using electrophoresis induced by the application of an AC electric field to a set of microelectrodes in a microliquid channel. This purifying method is different from conventional methods based on chemical processes. It was observed that most of the MWNTs could pass along the microliquid channel without attaching to the electrode under specific conditions of 1 kHz, at 0.2 Vrms μm-1. On the other hand, the majority of the carbon impurities attached to the electrodes under identical conditions. Field emission scanning electron microscopy (FESEM) images and Raman spectra confirm that this condition is beneficial for removing carbon impurities. The proposed approach has potential applicability in the development of microdevices that can simultaneously perform the purification and fabrication of MWNTs.

  10. Purification of carbon nanotubes through an electric field near the arranged microelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hyung Cheoul [School of Mechanical, Aerospace and Systems Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Hyung Woo [Massachusetts Institute of Technology (MIT), Micro and Nano Systems Laboratory, 77 Massachusetts Avenue, Room 5-008, Cambridge, MA 02139 (United States); Yeom, Sujin [School of Mechanical, Aerospace and Systems Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kwak, Yoon Keun [School of Mechanical, Aerospace and Systems Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Seung S [School of Mechanical, Aerospace and Systems Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Soo Hyun [School of Mechanical, Aerospace and Systems Engineering, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2007-03-21

    In this work, we attempt to purify multi-walled carbon nanotubes (MWNTs) using electrophoresis induced by the application of an AC electric field to a set of microelectrodes in a microliquid channel. This purifying method is different from conventional methods based on chemical processes. It was observed that most of the MWNTs could pass along the microliquid channel without attaching to the electrode under specific conditions of 1 kHz, at 0.2 V{sub rms} {mu}m{sup -1}. On the other hand, the majority of the carbon impurities attached to the electrodes under identical conditions. Field emission scanning electron microscopy (FESEM) images and Raman spectra confirm that this condition is beneficial for removing carbon impurities. The proposed approach has potential applicability in the development of microdevices that can simultaneously perform the purification and fabrication of MWNTs.

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

    Science.gov (United States)

    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. Voltammetric studies on the electrochemical determination of methylmercury in chloride medium at carbon microelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, F. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal); Neto, M.M.M. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal) and Departamento de Quimica Agricola e Ambiental, Instituto Superior de Agronomia, Tapada da Ajuda, 1349-017 Lisbon (Portugal)]. E-mail: mm.neto@netcabo.pt; Rocha, M.M. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal); Fonseca, I.T.E. [Centro de Electroquimica e Cinetica da Universidade de Lisboa, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisbon (Portugal)

    2006-10-10

    Electroanalytical techniques have been used to determine methylmercury at low levels in environmental matrices. The electrochemical behaviour of methylmercury at carbon microelectrodes in a hydrochloric acid medium using cyclic, square wave and fast-scan linear-sweep voltammetric techniques has been investigated. The analytical utility of the methylmercury reoxidation peak has been explored, but the recorded peak currents were found to be poorly reproducible. This is ascribed to two factors: the adsorption of insoluble chloromercury compounds on the electrode surface, which appears to be an important contribution to hinder the voltammetric signal of methylmercury; and the competition between the reoxidation of the methylmercury radical and its dimerization reaction, which limits the reproducibility of the methylmercury peak. These problems were successfully overcome by adopting the appropriate experimental conditions. Fast-scan rates were employed and an efficient electrochemical regeneration procedure of the electrode surface was achieved, under potentiostatic conditions in a mercury-free solution containing potassium thiocyanate-a strong complexing agent. The influence of chloride ion concentration was analysed. Interference by metals, such as lead and cadmium, was considered. Calibration plots were obtained in the micromolar and submicromolar concentration ranges, allowing the electrochemical determination of methylmercury in trace amounts. An estuarine water sample was analysed using the new method with a glassy carbon microelectrode.

  13. 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.

  14. Hydrophilic modification of neural microelectrode arrays based on multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chang-Hsiao; Chuang, Shih-Chang; Lee, Yu-Tao; Chang, Yen-Chung; Yao, Da-Jeng [Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Su, Huan-Chieh; Yen, Shiang-Jie; Yew, Tri-Rung [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Yung-Chan; Chen, Hsin [Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Yeh, Shih-Rung, E-mail: djyao@mx.nthu.edu.tw [Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2010-12-03

    To decrease the impedance of microelectrode arrays, for neuroscience applications we have fabricated and tested MEA based on multi-walled carbon nanotubes. With decreasing physical size of a microelectrode, its impedance increases and charge-transfer capability decreases. To decrease the impedance, the effective surface area of the electrode must generally be increased. We explored the effect of plasma treatment on the surface wettability of MWCNT. With a steam-plasma treatment the surface of MWCNT becomes converted from superhydrophobic to superhydrophilic; this hydrophilic property is attributed to -OH bonding on the surface of MWCNT. We reported the synthesis at 400 deg. C of MWCNT on nickel-titanium multilayered metal catalysts by thermal chemical vapor deposition. Applying plasma with a power less than 25 W for 10 s improved the electrochemical and biological properties, and circumvented the limitation of the surface reverting to a hydrophobic condition; a hydrophilic state is maintained for at least one month. The MEA was used to record neural signals of a lateral giant cell from an American crayfish. The response amplitude of the action potential was about 275 {mu}V with 1 ms period; the recorded data had a ratio of signal to noise up to 40.12 dB. The improved performance of the electrode makes feasible the separation of neural signals and the recognition of their distinct shapes. With further development the rapid treatment will be useful for long-term recording applications.

  15. Glass pipette-carbon fiber microelectrodes for evoked potential recordings

    OpenAIRE

    Moraes M.F.D.; Garcia-Cairasco N.

    1997-01-01

    Current methods for recording field potentials with tungsten electrodes make it virtually impossible to use the same recording electrode also as a lesioning electrode, for example for histological confirmation of the recorded site, because the lesioning procedure usually wears off the tungsten tip. Therefore, the electrode would have to be replaced after each lesioning procedure, which is a very high cost solution to the problem. We present here a low cost, easy to make, high quality glass pi...

  16. Impedimetric microbial biosensor based on single wall carbon nanotube modified microelectrodes for trichloroethylene detection

    International Nuclear Information System (INIS)

    Highlights: ► We propose an impedimetric microbial biosensor for trichloroethylene detection. ► A new transducer modified with carbon nanotubes and Pseudomonas putida is evaluated. ► Functionalization steps are controlled by impedance spectroscopy and AFM. ► The biosensor offers good sensitivity, selectivity, linear range and stability. ► The biosensor is successfully applied to spiked natural water samples. - Abstract: Contamination of soils and groundwaters with persistent organic pollutants is a matter of increasing concern. The most common organic pollutants are chlorinated hydrocarbons such as perchloroethylene and trichloroethylene (TCE). In this study, we developed a bacterial impedimetric biosensor for TCE detection, based on the immobilization of Pseudomonas putida F1 strain on gold microelectrodes functionalized with single wall carbon nanotubes covalently linked to anti-Pseudomonas antibodies. The different steps of microelectrodes functionalization were characterized by electrochemical impedance and atomic force spectroscopies, and analytical performances of the developed microbial biosensor were determined. The impedimetric biosensor response was linear with TCE concentration up to 150 μg L−1 and a low limit of detection (20 μg L−1) was achieved. No significant loss of signal was observed after 4 weeks of storage at 4 °C in phosphate buffer saline pH 7 (three to four measurements a week). After 5 weeks, 90% of the initial value still remained. cis-1,2-Dichloroethylene and vinylchloride, the main TCE degradation products, did not significantly interfere with TCE. The microbial sensor was finally applied to the determination of TCE in natural water samples spiked at the 30, 50 and 75 μg L−1 levels. Recoveries were very good, ranging from 100 to 103%.

  17. Purification of Carbon Nanotubes through an Electric Field near a Microelectrode

    Energy Technology Data Exchange (ETDEWEB)

    Shim, H C [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Lee, H W [Massachusetts Institute of Technology(MIT), Micro and Nano Systems Laboratory, 77 Massachusetts Ave. Room 5-008, Cambridge, MA 02139 (United States); Yeom, S J [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Kwak, Y K [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Lee, S S [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Kim, S H [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology(KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

    2007-04-15

    In this work, we attempt to purify multi-walled carbon nanotubes (MWNTs) using electrophoresis induced by application of an ac electric field to a set of microelectrodes in a microliquid channel. This purifying method is different from conventional methods based on chemical processes. We observed that the most of the MWNTs could pass along the microliquid channel without attaching to the electrode under specific conditions of 1 kHz, 0.2 V{sub rms}/{mu}m. On the other hand, the majority of the carbon impurities attached to the electrodes under same condition. Field emission scanning electron microscopy (FESEM) images confirm that this condition is beneficial for removing the carbon impurities. We aligned and attached this purified MWNTs and raw materials to extra electrodes with 5 MHz, 0.8 V{sub rms}/{mu}m. This experimental FESEM images show a clear difference between before and after purification. The proposed approach has potential applicability to the development of microdevices that can simultaneously perform purification and fabrication of MWNTs.

  18. Purification of Carbon Nanotubes through an Electric Field near a Microelectrode

    Science.gov (United States)

    Shim, H. C.; Lee, H. W.; Yeom, S. J.; Kwak, Y. K.; Lee, S. S.; Kim, S. H.

    2007-04-01

    In this work, we attempt to purify multi-walled carbon nanotubes (MWNTs) using electrophoresis induced by application of an ac electric field to a set of microelectrodes in a microliquid channel. This purifying method is different from conventional methods based on chemical processes. We observed that the most of the MWNTs could pass along the microliquid channel without attaching to the electrode under specific conditions of 1 kHz, 0.2 Vrms/μm. On the other hand, the majority of the carbon impurities attached to the electrodes under same condition. Field emission scanning electron microscopy (FESEM) images confirm that this condition is beneficial for removing the carbon impurities. We aligned and attached this purified MWNTs and raw materials to extra electrodes with 5 MHz, 0.8 Vrms/μm. This experimental FESEM images show a clear difference between before and after purification. The proposed approach has potential applicability to the development of microdevices that can simultaneously perform purification and fabrication of MWNTs.

  19. Carbon nanotube core graphitic shell hybrid fibers.

    Science.gov (United States)

    Hahm, Myung Gwan; Lee, Jae-Hwang; Hart, Amelia H C; Song, Sung Moo; Nam, Jaewook; Jung, Hyun Young; Hashim, Daniel Paul; Li, Bo; Narayanan, Tharangattu N; Park, Chi-Dong; Zhao, Yao; Vajtai, Robert; Kim, Yoong Ahm; Hayashi, Takuya; Ku, Bon-Cheol; Endo, Morinobu; Barrera, Enrique; Jung, Yung Joon; Thomas, Edwin L; Ajayan, Pulickel M

    2013-12-23

    A carbon nanotube yarn core graphitic shell hybrid fiber was fabricated via facile heat treatment of epoxy-based negative photoresist (SU-8) on carbon nanotube yarn. The effective encapsulation of carbon nanotube yarn in carbon fiber and a glassy carbon outer shell determines their physical properties. The higher electrical conductivity (than carbon fiber) of the carbon nanotube yarn overcomes the drawbacks of carbon fiber/glassy carbon, and the better properties (than carbon nanotubes) of the carbon fiber/glassy carbon make up for the lower thermal and mechanical properties of the carbon nanotube yarn via synergistic hybridization without any chemical doping and additional processes. PMID:24224730

  20. 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.

  1. 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.

  2. 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...

  3. 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,

  4. 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.

  5. Thermoplastic coating of carbon fibers

    Science.gov (United States)

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

    1989-01-01

    A continuous powder coating system was developed for coating carbon fiber with LaRC-TPI (Langley Research Center-Thermoplastic Polyimide), a high-temperature thermoplastic polymide invented by NASA-Langley. The coating line developed used a pneumatic fiber spreader to separate the individual fibers. The polymer was applied within a recirculating powder coating chamber then melted using a combination of direct electrical resistance and convective heating to make it adhere to the fiber tow. The tension and speed of the line were controlled with a dancer arm and an electrically driven fiber wind-up and wind-off. The effects of heating during the coating process on the flexibility of the prepreg produced were investigated. The uniformity with which the fiber tow could be coated with polymer also was examined. Composite specimens were fabricated from the prepreg and tested to determine optimum process conditions. The study showed that a very uniform and flexible prepeg with up to 50 percent by volume polymer could be produced with this powder coating system. The coating line minimized powder loss and produced prepeg in lengths of up to 300 m. The fiber spreading was found to have a major effect on the coating uniformity and flexibility. Though test results showed low composite tensile strengths, analysis of fracture surfaces under scanning electron microscope indicated that fiber/matrix adhesion was adequate.

  6. 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.

  7. 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.

  8. Fiber Length and Orientation in Long Carbon Fiber Thermoplastic Composites

    OpenAIRE

    Hanhan, Imad; Sullivan, Connor; Sharma, Bhisham; Sangid, Michael

    2014-01-01

    Carbon fiber composites have become popular in aerospace applications because of their lightweight yet strong material properties. The injection molding process can be used to produce discontinuous fiber composites using less time and resources than traditional methods, thereby broadening carbon fiber composites’ applications in different industries. Utilization of longer fibers offers more load carrying capability and superior strength properties for injected molded composites. Since the fib...

  9. 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.

  10. 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).

  11. A flexible and implantable microelectrode arrays using high-temperature grown vertical carbon nanotubes and a biocompatible polymer substrate

    International Nuclear Information System (INIS)

    This paper presents a novel microelectrode arrays using high-temperature grown vertically aligned carbon nanotubes (CNTs) integrated on a flexible and biocompatible parylene substrate. A simple microfabrication process is proposed to unite the high quality vertical CNTs grown at high temperature with the heat sensitive parylene substrate in a highly controllable manner. Briefly, the CNTs electrode is encapsulated by two layers of parylene and the device is released using xenon difluoride (XeF2). The process is compatible with wafer-scale post complementary metal oxide semiconductor integration. Lower impedance and larger interfacial capacitance have been demonstrated using CNTs compared to a Pt electrode. The flexible CNT electrodes have been utilized for extracellular neuronal recording and stimulation in rats. The signal-to-noise ratio of the device is about 12.5. The threshold voltage for initiating action potential is about 0.5 V. (paper)

  12. Fabrication and Properties of Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Xiaosong Huang

    2009-12-01

    Full Text Available This paper reviews the research and development activities conducted over the past few decades on carbon fibers. The two most important precursors in the carbon fiber industry are polyacrylonitrile (PAN and mesophase pitch (MP. The structure and composition of the precursor affect the properties of the resultant carbon fibers significantly. Although the essential processes for carbon fiber production are similar, different precursors require different processing conditions in order to achieve improved performance. The research efforts on process optimization are discussed in this review. The review also attempts to cover the research on other precursor materials developed mainly for the purpose of cost reduction.

  13. 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...

  14. Fabrication of Carbon Film-Based Flexible Neural Microelectrode Array%基于碳膜的柔性神经微电极阵列加工

    Institute of Scientific and Technical Information of China (English)

    朱壮晖; 周亮; 张华; 李刚; 金庆辉; 赵建龙

    2012-01-01

    To achieve long-term safe and effective stimulation and to avoid erosion of electrodes, a novel flexible retinal stimulation microelectrode array was developed using pyrolyzed photoresist carbon film as a conducting material in this paper. Firstly, the patterned photoresists were pyrolyzed to produce conduc-ting carbon films at high temperature. Then, a photosensitive polyimide (Durimide 7510) was used as the substrate material. By patterning with photolithography techniques, sequentially transferring the car-bon film, bonding two insulting layers and etching the sacrifice layer, the flexible carbon film microelec-trode arrays were successfully fabricated. Experimental results show that the charge storage capacity of the carbon film microelectrodes is 6. 625 mC/cm2, which is about 12.4 times greater than that of the gold microelectrodes, indicating that the carbon film microelectrodes have a good electrochemical stability and a large charge injection capability, which is beneficial to their long-term implantation and safe work. This flexible carbon film microelectrode array can be a promising candidate for retinal prosthesis.%为了实现长期安全有效的神经电刺激,避免电极腐蚀情况,提出了一种基于热解光刻胶形成碳膜作为导电材料的柔性视网膜神经微电极阵列.首先,通过高温热解图形化的光刻胶形成导电碳膜,然后利用光敏性聚酰亚胺( Durimide 7510)作为基底材料,通过光刻结合转膜、键合和牺牲层腐蚀技术,实现了具有柔性特征的碳膜神经微电极阵列.实验结果显示这种碳膜电极的电荷存储能力达到6.625 mC/cm2,是金电极的12.4倍,显示了良好的电化学稳定性和电荷注入能力,有利于其长期植入和安全有效地工作,可应用于新一代人工视网膜系统的构建.

  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. Development and Characterization of Carbon-Fiber Microbiosensors for Fast-Scan Cyclic Voltammetry

    Science.gov (United States)

    Lugo-Morales, Leyda Zoraida

    Electrochemistry has been shown to be a robust tool in neuroscience. The use of carbon-fiber microelectrodes coupled with background-subtracted fast-scan cyclic voltammetry (FSCV) offers high sensitivity, selectivity, as well as the spatial and temporal resolution necessary for monitoring rapid fluctuations of electroactive molecules in live brain tissue. Dopamine (DA) is a neurotransmitter playing a key role in the regulation of reward and motivated behavior. FSCV has been used to understand DA dynamics and how these underlie discrete aspects of brain function. The methodological aspects of real-time DA detection at carbon-fiber microelectrodes using FSCV in anesthetized and awake animals are presented. Furthermore, the combination of FSCV with other neuroanalytical techniques is also explained. The advantages of FSCV and carbon-fiber microelectrodes can be expanded to the detection of non-electroactive analytes. This broadens the scope of FSCV such that it can be used to investigate how changes in non-electroactive chemicals underlie disease, cognition, and behavior. Carbon-fiber microelectrodes can be modified with an enzyme to monitor non-electroactive molecules, generating an electroactive product (usually hydrogen peroxide, H2O2). The first voltammetric detection of H2O 2 at bare carbon-fiber microelectrodes using FSCV has recently been reported. Thus, an avenue exists to utilize FSCV at enzyme-modified microelectrodes to voltammetrically identify and quantify non-electroactive analytes in real-time. Such an approach will overcome many limitations associated with the traditional amperometric detection scheme, which lacks electrochemical selectivity. Electrodeposition of the biopolymer chitosan with glucose oxidase (GOx) at the carbon surface yields a stable, sensitive, and selective glucose microbiosensor that has been utilized to detect glucose fluctuations in vivo with unprecedented speed. This new method has revealed the first rapid glucose fluctuations in

  17. Surface analysis of plasma grafted carbon fiber

    International Nuclear Information System (INIS)

    The surface characteristics of carbon fibers were studied by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and wetting measurements. The surface of carbon fiber was modified by means of plasma graft silsesquioxane. The oxygen/carbon and silicon/carbon ratio increased rapidly after treatments. Fitting the C 1s, O 1s, and Si 2p spectra demonstrated that new photopeaks were emerged, which were indicated C-Si, Si-O groups, respectively. The degree of surface roughness and the wettability of carbon fiber surface were both increased by plasma graft silsesquioxane. The results may shed some light on the design of the appropriate surface structure, which could react with resin, and the manufacture of the carbon fiber reinforced composites

  18. 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.

  19. 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.

  20. 聚亚甲蓝修饰碳纤维微电极同时测定多巴胺和抗坏血酸%Simultaneously Determining of Dopamine and Ascorbic Acid at Poly(Methylene blue) Coated Carbon Fiber Microelectrodes

    Institute of Scientific and Technical Information of China (English)

    刘灵芳; 曲松; 夏萍; 冶保献

    2002-01-01

    研究了聚亚甲蓝修饰碳纤维微电极同时测定多巴胺和抗坏血酸的分析方法,在该修饰电极上,多巴胺和抗坏血酸均具有高的灵敏度,并且在电极反应过程中不沾污电极,重现性好,测定过程无需除氧,这对于生物活体在线检测是一个非常重要的条件.%The utilization of poly(Methylene blue) coated carbonfiber microelectrodes for simultaneously determining of dopamine andascorbic acid was proposed in this paper. This approach offered several advantages such as simultaneous determination of dopamine andascorbic acid with high sensitivity and the detected species didn'tsully (adsorb) electrodes. More importantly, this analytical processcan be performed without deaeration, which was an important condition for in vivo studies.

  1. Growth of carbon nanotubes on carbon fibers without strength degradation

    Energy Technology Data Exchange (ETDEWEB)

    De Greef, Niels [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Magrez, Arnaud; Forro, Laszlo [Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Couteau, Edina; Locquet, Jean-Pierre [Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Seo, Jin Won [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2012-12-15

    Carbon nanotubes (CNTs) are grown on PAN-based carbon fibers by means of catalytic chemical vapor deposition technique. By using catalytic thermal decomposition of hydrocarbon, CNTs can be grown in the temperature range of 650-750 C. However, carbon fibers suffer significant damages resulting in decrease of initial tensile strength. By applying the oxidative dehydrogenation reaction of C{sub 2}H{sub 2} with CO{sub 2}, we found an alternative way to grow CNTs on carbon fibers at low temperatures, such as 500 C. Scanning electron microscope results combined with single fiber tests indicate that this low temperature growth enables homogeneous grafting of CNTs onto carbon fibers without degradation of tensile strength. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. 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

  3. 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.

  4. 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).

  5. Characterization of electrospun lignin based carbon fibers

    International Nuclear Information System (INIS)

    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

  6. 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.

  7. A novel pattern transfer technique for mounting glassy carbon microelectrodes on polymeric flexible substrates

    International Nuclear Information System (INIS)

    We present a novel technology for transferring glassy carbon microstructures, originally fabricated on a silicon wafer through a high-temperature process, to a polymeric flexible substrate such as polyimide. This new transfer technique addresses a major barrier in Carbon-MEMS technology whose widespread use so has been hampered by the high-temperature pyrolysis process (⩾900 °C), which limits selection of substrates. In the new approach presented, patterning and pyrolysis of polymer precursor on silicon substrate is carried out first, followed by coating with a polymer layer that forms a hydrogen bond with glassy carbon and then releasing the ensuing glassy carbon structure; hence, transferring it to a flexible substrate. This enables the fabrication of a unique set of glassy carbon microstructures critical in applications that demand substrates that conform to the shape of the stimulated/actuated or sensed surface. Our findings based on Fourier transform infared spectroscopy on the complete electrode set demonstrate—for the first time—that carbonyl groups on polyimide substrate form a strong hydrogen bond with hydroxyl groups on glassy carbon resulting in carboxylic acid dimers (peaks at 2660 and 2585 cm−1). This strong bond is further confirmed by a tensile test that demonstrated an almost perfect bond between these materials that behave as an ideal composite material. Further, mechanical characterization shows that ultimate strain for such a structure is as high as 15% with yield stress of ∼20 MPa. We propose that this novel technology not only offers a compelling case for the widespread use of carbon-MEMS, but also helps move the field in new and exciting directions. (paper)

  8. Fabrication of a 3D micro/nano dual-scale carbon array and its demonstration as the microelectrodes for supercapacitors

    International Nuclear Information System (INIS)

    An easily accessible method is proposed for the fabrication of a 3D micro/nano dual-scale carbon array with a large surface area. The process mainly consists of three critical steps. Firstly, a hemispherical photoresist micro-array was obtained by the cost-effective nanoimprint lithography process. Then the micro-array was transformed into hierarchical structures with longitudinal nanowires on the microstructure surface by oxygen plasma etching. Finally, the micro/nano dual-scale carbon array was fabricated by carbonizing these hierarchical photoresist structures. It has also been demonstrated that the micro/nano dual-scale carbon array can be used as the microelectrodes for supercapacitors by the electrodeposition of a manganese dioxide (MnO2) film onto the hierarchical carbon structures with greatly enhanced electrochemical performance. The specific gravimetric capacitance of the deposited micro/nano dual-scale microelectrodes is estimated to be 337 F g−1 at the scan rate of 5 mV s−1. This proposed approach of fabricating a micro/nano dual-scale carbon array provides a facile way in large-scale microstructures’ manufacturing for a wide variety of applications, including sensors and on-chip energy storage devices. (paper)

  9. Dense high-aspect ratio 3D carbon pillars on interdigitated microelectrode arrays

    DEFF Research Database (Denmark)

    Amato, Letizia; Heiskanen, Arto; Hansen, Rasmus;

    2015-01-01

    In this work we present high-aspect ratio carbon pillars (1.4 μm in diameter and ∼11 μm in height) on top of interdigitated electrode arrays to be used for electrochemical applications. For this purpose, different types of 2D and 3D pyrolysed carbon structures were fabricated and characterised...... including surface- and microstructure, electrical and electrochemical properties. A pre-treatment of oxidised Si wafers is introduced to eliminate electrode delamination and ensure structure stability in water during long time-experiments. Additionally, a heat treatment method is reported for regeneration...

  10. 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.

  11. 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.

  12. Microelectrode characterization of coral daytime interior pH and carbonate chemistry

    Science.gov (United States)

    Cai, Wei-Jun; Ma, Yuening; Hopkinson, Brian M.; Grottoli, Andréa G.; Warner, Mark E.; Ding, Qian; Hu, Xinping; Yuan, Xiangchen; Schoepf, Verena; Xu, Hui; Han, Chenhua; Melman, Todd F.; Hoadley, Kenneth D.; Pettay, D. Tye; Matsui, Yohei; Baumann, Justin H.; Levas, Stephen; Ying, Ye; Wang, Yongchen

    2016-01-01

    Reliably predicting how coral calcification may respond to ocean acidification and warming depends on our understanding of coral calcification mechanisms. However, the concentration and speciation of dissolved inorganic carbon (DIC) inside corals remain unclear, as only pH has been measured while a necessary second parameter to constrain carbonate chemistry has been missing. Here we report the first carbonate ion concentration ([CO32−]) measurements together with pH inside corals during the light period. We observe sharp increases in [CO32−] and pH from the gastric cavity to the calcifying fluid, confirming the existence of a proton (H+) pumping mechanism. We also show that corals can achieve a high aragonite saturation state (Ωarag) in the calcifying fluid by elevating pH while at the same time keeping [DIC] low. Such a mechanism may require less H+-pumping and energy for upregulating pH compared with the high [DIC] scenario and thus may allow corals to be more resistant to climate change related stressors. PMID:27041668

  13. Microelectrode characterization of coral daytime interior pH and carbonate chemistry

    Science.gov (United States)

    Cai, Wei-Jun; Ma, Yuening; Hopkinson, Brian M.; Grottoli, Andréa G.; Warner, Mark E.; Ding, Qian; Hu, Xinping; Yuan, Xiangchen; Schoepf, Verena; Xu, Hui; Han, Chenhua; Melman, Todd F.; Hoadley, Kenneth D.; Pettay, D. Tye; Matsui, Yohei; Baumann, Justin H.; Levas, Stephen; Ying, Ye; Wang, Yongchen

    2016-04-01

    Reliably predicting how coral calcification may respond to ocean acidification and warming depends on our understanding of coral calcification mechanisms. However, the concentration and speciation of dissolved inorganic carbon (DIC) inside corals remain unclear, as only pH has been measured while a necessary second parameter to constrain carbonate chemistry has been missing. Here we report the first carbonate ion concentration ([CO32-]) measurements together with pH inside corals during the light period. We observe sharp increases in [CO32-] and pH from the gastric cavity to the calcifying fluid, confirming the existence of a proton (H+) pumping mechanism. We also show that corals can achieve a high aragonite saturation state (Ωarag) in the calcifying fluid by elevating pH while at the same time keeping [DIC] low. Such a mechanism may require less H+-pumping and energy for upregulating pH compared with the high [DIC] scenario and thus may allow corals to be more resistant to climate change related stressors.

  14. Carbon storage potential in natural fiber composites

    International Nuclear Information System (INIS)

    The environmental performance of hemp based natural fiber mat thermoplastic (NMT) has been evaluated in this study by quantifying carbon storage potential and CO2 emissions and comparing the results with commercially available glass fiber composites. Non-woven mats of hemp fiber and polypropylene matrix were used to make NMT samples by film-stacking method without using any binder aid. The results showed that hemp based NMT have compatible or even better strength properties as compared to conventional flax based thermoplastics. A value of 63 MPa for flexural strength is achieved at 64% fiber content by weight. Similarly, impact energy values (84-154 J/m) are also promising. The carbon sequestration and storage by hemp crop through photosynthesis is estimated by quantifying dry biomass of fibers based on one metric ton of NMT. A value of 325 kg carbon per metric ton of hemp based composite is estimated which can be stored by the product during its useful life. An extra 22% carbon storage can be achieved by increasing the compression ratio by 13% while maintaining same flexural strength. Further, net carbon sequestration by industrial hemp crop is estimated as 0.67 ton/h/year, which is compatible to all USA urban trees and very close to naturally, regenerated forests. A comparative life cycle analysis focused on non-renewable energy consumption of natural and glass fiber composites shows that a net saving of 50 000 MJ (3 ton CO2 emissions) per ton of thermoplastic can be achieved by replacing 30% glass fiber reinforcement with 65% hemp fiber. It is further estimated that 3.07 million ton CO2 emissions (4.3% of total USA industrial emissions) and 1.19 million m3 crude oil (1.0% of total Canadian oil consumption) can be saved by substituting 50% fiber glass plastics with natural fiber composites in North American auto applications. However, to compete with glass fiber effectively, further research is needed to improve natural fiber processing, interfacial bonding and

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

    2016-12-01

    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. PMID:27216603

  2. 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

  3. Carbon-Fiber Brush Heat Exchangers

    Science.gov (United States)

    Knowles, Timothy R.

    2004-01-01

    Velvetlike and brushlike pads of carbon fibers have been proposed for use as mechanically compliant, highly thermally conductive interfaces for transferring heat. A pad of this type would be formed by attaching short carbon fibers to either or both of two objects that one desires to place in thermal contact with each other. The purpose of using a thermal-contact pad of this or any other type is to reduce the thermal resistance of an interface between a heat source and a heat sink.

  4. Carbon Fiber Reinforced Carbon Composite Valve for an Internal Combustion Engine

    Science.gov (United States)

    Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor)

    1999-01-01

    A carbon fiber reinforced carbon composite valve for internal combustion engines and the like formed of continuous carbon fibers throughout the valve's stem and head is disclosed. The valve includes braided carbon fiber material over axially aligned unidirectional carbon fibers forming a valve stem; the braided and unidirectional carbon fibers being broomed out at one end of the valve stem forming the shape of the valve head; the valve-shaped structure being densified and rigidized with a matrix of carbon containing discontinuous carbon fibers: and the finished valve being treated to resist oxidation. Also disclosed is a carbon matrix plug containing continuous and discontinuous carbon fibers and forming a net-shape valve head acting as a mandrel over which the unidirectional and braided carbon fibers are formed according to textile processes. Also disclosed are various preform valves and processes for making finished and preform carbon fiber reinforced carbon composite valves.

  5. 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.

  6. Carbon fiber masculinity: Disability and surfaces of homosociality

    OpenAIRE

    Hickey-Moody, Anna Catherine

    2015-01-01

    In this paper I am concerned with instances in which carbon fiber extends performances of masculinity that are attached to particular kinds of hegemonic male bodies. In examining carbon fiber as a prosthetic form of masculinity, I advance three main arguments. Firstly, carbon fiber can be a site of the supersession of disability that is affected through masculinized technology. Disability can be ‘overcome’ through carbon fiber. Disability is often culturally coded as feminine (Pedersen, 2001;...

  7. Studies on copper coating on carbon fibers

    Institute of Scientific and Technical Information of China (English)

    CAO; Zhuo-kun; LIU; Yi-han; YAO; Guang-chun

    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.

  8. Microwave axial dielectric properties of carbon fiber

    Science.gov (United States)

    Hong, Wen; Xiao, Peng; Luo, Heng; Li, Zhuan

    2015-10-01

    Randomly distributed carbon fibers (CFs) reinforced epoxy resin composites are prepared by the pouring method, the dielectric properties of CF composites with different fiber content and length have been performed in the frequency range from 8.2 to 12.4 GHz. The complex permittivity of the composite increases with the fiber length, which is attributed to the decrease of depolarization field, and increases with the volume fraction, which is attributed to the increase of polarization. A formula, based on the theory of Reynolds-Hugh, is proposed to calculate the effective permittivity of CF composites, and validated by the experiments. The proposed formula is further applied to derive the axial permittivity of CF and analyze the effect of fiber length on the axial permittivity.

  9. Superconductive niobium films coating carbon nanotube fibers

    Science.gov (United States)

    Salvato, M.; Lucci, M.; Ottaviani, I.; Cirillo, M.; Behabtu, N.; Young, C. C.; Pasquali, M.; Vecchione, A.; Fittipaldi, R.; Corato, V.

    2014-11-01

    Superconducting niobium (Nb) has been successfully obtained by sputter deposition on carbon nanotube fibers. The transport properties of the niobium coating the fibers are compared to those of niobium thin films deposited on oxidized Si substrates during the same deposition run. For niobium films with thicknesses above 300 nm, the niobium coating the fibers and the thin films show similar normal state and superconducting properties with critical current density, measured at T = 4.2 K, of the order of 105 A cm-2. Thinner niobium layers coating the fibers also show the onset of the superconducting transition in the resistivity versus temperature dependence, but zero resistance is not observed down to T = 1 K. We evidence by scanning electron microscopy (SEM) and current-voltage measurements that the granular structure of the samples is the main reason for the lack of true global superconductivity for thicknesses below 300 nm.

  10. Superconductive niobium films coating carbon nanotube fibers

    International Nuclear Information System (INIS)

    Superconducting niobium (Nb) has been successfully obtained by sputter deposition on carbon nanotube fibers. The transport properties of the niobium coating the fibers are compared to those of niobium thin films deposited on oxidized Si substrates during the same deposition run. For niobium films with thicknesses above 300 nm, the niobium coating the fibers and the thin films show similar normal state and superconducting properties with critical current density, measured at T = 4.2 K, of the order of 105 A cm−2. Thinner niobium layers coating the fibers also show the onset of the superconducting transition in the resistivity versus temperature dependence, but zero resistance is not observed down to T = 1 K. We evidence by scanning electron microscopy (SEM) and current-voltage measurements that the granular structure of the samples is the main reason for the lack of true global superconductivity for thicknesses below 300 nm. (paper)

  11. 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.

  12. Batch fabrication of nanotubes suspended between microelectrodes

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Stöckli, T.; Knapp, H. F.;

    2007-01-01

    We report a fabrication method, which uses standard UV-lithography to pattern the catalyst for the chemical vapour deposition(CVD) of suspended double clamped single walled carbon nanotubes. By using an aqueous solution of Fe(NO3)3 the patterning of the catalyst material onto microelectrodes can...... be done with a simple lift-off process with standard photolithographic resist. An applied electric field is sustained between the microelectrodes during CVD to guide the nanotube growth. Comparison with simulations shows that the location and the orientation of the grown carbon nanotubes (CNT) correspond...... to the regions of maximum electric field, enabling accurate positioning of a nanotube by controlling the shape of the microelectrodes. The CNT bridges are deflected tens of nm when a DC voltage is applied between the nanotube and a gate microelectrode indicating that the clamping through the catalyst particles...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. CARBONIZED STARCH MICROCELLULAR FOAM-CELLULOSE FIBER COMPOSITE STRUCTURES

    OpenAIRE

    Andrew R. Rutledge; Richard A. Venditti; Joel J. Pawlak; Sameer Patel; Janderson L. Cibils

    2008-01-01

    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. ...

  1. 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.

  2. Soldering of Nanotubes onto Microelectrodes

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina;

    2003-01-01

    Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing solder...... bonds were formed at the intersection of the nanotube and the electrodes. Current-voltage curves indicated metallic conduction of the nanotubes, with resistances in the range of 9-29 kOmega. Bridges made entirely of the soldering material exhibited resistances on the order of 100 Omega, and the solder...... bonds were consistently found to be mechanically stronger than the carbon nanotubes....

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    as a model for unsized carbon fiber has been demonstrated as appropriate for the study of interactions between the materials in composite carbon fiber-epoxy systems. The HSP of glassy carbon are similar to those of carbon fibers and epoxy matrix. (C) 2007 Elsevier Ltd. All rights reserved.......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...

  4. Preparation and characterization of carbon nanotube-hybridized carbon fiber to reinforce epoxy composite

    International Nuclear Information System (INIS)

    Highlights: → CNTs were uniformly grown onto the carbon fibers. → No obvious mechanical properties of carbon fiber were observed after CNT growth. → The IFSS of multiscale epoxy composite was measured by single fiber pull-out tests. → Observing fractography of composite, the fracture modes of CNTs were discussed. -- Abstract: The multiscale carbon nanotube-hybridized carbon fiber was prepared by a newly developed aerosol-assisted chemical vapour deposition. Scanning electron microscopy and transmission electron microscope were carried out to characterize this multiscale material. Compared with the original carbon fibers, the fabrication of this hybrid fiber resulted in an almost threefold increase of BET surface area to reach 2.22 m2/g. Meanwhile, there was a slight degradation of fiber tensile strength within 10%, while the fiber modulus was not significantly affected. The interfacial shearing strength of a carbon fiber-reinforced polymer composite with carbon nanotube-hybridized carbon fiber and an epoxy matrix was determined from the single fiber pull-out tests of microdroplet composite. Due to an efficient increase of load transfer at the fiber/matrix interfaces, the interracial shear strength of composite reinforced by carbon nanotube-hybridized carbon fiber is almost 94% higher than that of one reinforced by the original carbon fiber. Based on the fractured morphologies of the composites, the interfacial reinforcing mechanisms were discussed through proposing different types of carbon nanotube fracture modes along with fiber pulling out from epoxy composites.

  5. Activated carbon fibers and engineered forms from renewable resources

    Science.gov (United States)

    Baker, Frederick S

    2013-02-19

    A method of producing activated carbon fibers (ACFs) includes the steps of providing a natural carbonaceous precursor fiber material, blending the carbonaceous precursor material with a chemical activation agent to form chemical agent-impregnated precursor fibers, spinning the chemical agent-impregnated precursor material into fibers, and thermally treating the chemical agent-impregnated precursor fibers. The carbonaceous precursor material is both carbonized and activated to form ACFs in a single step. The method produces ACFs exclusive of a step to isolate an intermediate carbon fiber.

  6. 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.

  7. 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.

  8. Plasma electrolytic polishing of metalized carbon fibers

    OpenAIRE

    Falko Böttger-Hiller; Klaus Nestler; Henning Zeidler; Gunther Glowa; Thomas Lampke

    2016-01-01

    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 e...

  9. 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. PMID:27227575

  10. 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.

  11. Polyacrylonitrile/carbon nanotube composite fibers: Reinforcement efficiency and carbonization studies

    Science.gov (United States)

    Chae, Han Gi

    Polyacrylonitrile (PAN)/carbon nanotube (CNT) composite fibers were made using various processing methods such as conventional solution spinning, gel spinning, and bi-component gel spinning. The detailed characterization exhibited that the smaller and longer CNT will reinforce polymer matrix mostly in tensile strength and modulus, respectively. Gel spinning combined with CNT also showed the promising potential of PAN/CNT composite fiber as precursor fiber of the next generation carbon fiber. High resolution transmission electron microscopy showed the highly ordered PAN crystal layer on the CNT, which attributed to the enhanced physical properties. The subsequent carbonization study revealed that carbonized PAN/CNT fibers have at least 50% higher tensile strength and modulus as compared to those of carbonized PAN fibers. Electrical conductivity of CNT containing carbon fiber was also 50% higher than that of carbonized PAN fiber. In order to have carbon fiber with high tensile strength, the smaller diameter precursor fiber is preferable. Bi-component gel spinning produced 1-2 mum precursor fiber, resulting in ˜1 mum carbon fiber. The tensile strength of the carbonized bi-component fiber (islands fibers) is as high as 6 GPa with tensile modulus of ˜500 GPa. Further processing optimization may lead to the next generation carbon fiber.

  12. Determination of carbon fiber adhesion to thermoplastic polymers using the single fiber/matrix tensile test

    Science.gov (United States)

    Bascom, W. D.; Cordner, L. W.; Hinkley, J. L.; Johnston, N. J.

    1986-01-01

    The single fiber adhesion shear test has been adapted to testing the adhesion between carbon fiber and thermoplastic polymers. Tests of three thermoplastics, polycarbonate, polyphenylene oxide and polyetherimide indicate the shear adhesion strength is significantly less than of an epoxy polymer to the same carbon fiber.

  13. Carbon and glass hierarchical fibers: Influence of carbon nanotubes on tensile, flexural and impact properties of short fiber reinforced composites

    International Nuclear Information System (INIS)

    Highlights: ► Dense CNT were grown on carbon fiber and glass fiber by use of floating catalyst CVD method. ► CNT showed different growing mechanism on carbon and glass fiber. ► Short fiber-CNT-composites showed enhanced mechanical properties. ► CNT coating enhanced fiber–matrix interaction and acted as additional reinforcement. -- Abstract: Dense carbon nanotubes (CNTs) were grown uniformly on the surface of carbon fibers and glass fibers to create hierarchical fibers by use of floating catalyst chemical vapor deposition. Morphologies of the CNTs were investigated using scanning electronic microscope (SEM) and transmission electron microscope (TEM). Larger diameter dimension and distinct growing mechanism of nanotubes on glass fiber were revealed. Short carbon and glass fiber reinforced polypropylene composites were fabricated using the hierarchical fibers and compared with composites made using neat fibers. Tensile, flexural and impact properties of the composites were measured, which showed evident enhancement in all mechanical properties compared to neat short fiber composites. SEM micrographs of composite fracture surface demonstrated improved adhesion between CNT-coated fiber and the matrix. The enhanced mechanical properties of short fiber composites was attributed to the synergistic effects of CNTs in improving fiber–matrix interfacial properties as well as the CNTs acting as supplemental reinforcement in short fiber-composites.

  14. Carbon molecular sieves for air separation from Nomex aramid fibers.

    Science.gov (United States)

    Villar-Rodil, Silvia; Martínez-Alonso, Amelia; Tascón, Juan M D

    2002-10-15

    Activated carbon fibers prepared from aramid fibers have proved to possess outstanding homogeneity in pore size, most of all when Nomex aramid fiber is used as precursor. Taking advantage of this feature, microporous carbon molecular sieves for air separation have been prepared through carbon vapor deposition of benzene on Nomex-derived carbon fibers activated to two different burnoff degrees. Carbon molecular sieves with good selectivity for this separation and showing acceptable adsorption capacities were obtained from ACFs activated to the two burnoff degrees chosen. PMID:12702417

  15. 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

  16. In-Vivo Characterization of Glassy Carbon Micro-Electrode Arrays for Neural Applications and Histological Analysis of the Brain Tissue

    Science.gov (United States)

    Vomero, Maria

    The aim of this work is to fabricate and characterize glassy carbon Microelectrode Arrays (MEAs) for sensing and stimulating neural activity, and conduct histological analysis of the brain tissue after the implant to determine long-term performance. Neural applications often require robust electrical and electrochemical response over a long period of time, and for those applications we propose to replace the commonly used noble metals like platinum, gold and iridium with glassy carbon. We submit that such material has the potential to improve the performances of traditional neural prostheses, thanks to better charge transfer capabilities and higher electrochemical stability. Great interest and attention is given in this work, in particular, to the investigation of tissue response after several weeks of implants in rodents' brain motor cortex and the associated materials degradation. As part of this work, a new set of devices for Electrocorticography (ECoG) has been designed and fabricated to improve durability and quality of the previous generation of devices, designed and manufactured by the same research group in 2014. In-vivo long-term impedance measurements and brain activity recordings were performed to test the functionality of the neural devices. In-vitro electrical characterization of the carbon electrodes, as well as the study of the adhesion mechanisms between glassy carbon and different substrates is also part of the research described in this book.

  17. Vibration damping with active carbon fiber structures

    Science.gov (United States)

    Neugebauer, Reimund; Kunze, Holger; Riedel, Mathias; Roscher, Hans-Jürgen

    2007-04-01

    This paper presents a mechatronic strategy for active reduction of vibrations on machine tool struts or car shafts. The active structure is built from a carbon fiber composite with embedded piezofiber actuators that are composed of piezopatches based on the Macro Fiber Composite (MFC) technology, licensed by NASA and produced by Smart Material GmbH in Dresden, Germany. The structure of these actuators allows separate or selectively combined bending and torsion, meaning that both bending and torsion vibrations can be actively absorbed. Initial simulation work was done with a finite element model (ANSYS). This paper describes how state space models are generated out of a structure based on the finite element model and how controller codes are integrated into finite element models for transient analysis and the model-based control design. Finally, it showcases initial experimental findings and provides an outlook for damping multi-mode resonances with a parallel combination of resonant controllers.

  18. 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...

  19. 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...

  20. Electrochemical sensor for nitric oxide using layered films composed of a polycationic dendrimer and nickel(II) phthalocyaninetetrasulfonate deposited on a carbon fiber electrode

    International Nuclear Information System (INIS)

    We have developed an electrochemical sensor for nitric oxide that is based on multi-layers of nickel(II) phthalocyaninetetrasulfonate and a polyamidoamine dendrimer assembled on the surface of a carbon-fiber microelectrode. This sensor responds to nitric oxide at a working potential of 800 mV with a sensitivity of 5.54 pA∙μM-1 which, however, depends on the dendrimer layer position deposited on the microelectrode. The limit of detection is as low as 5.5 μM at a signal-to-noise ratio of 3. The electrode exhibits good selectivity for nitric oxide over common interferents including dopamine, nitrite, hydrogen peroxide, norepinephrine, epinephrine and ascorbic acid. (author)

  1. 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

    2014-01-01

    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.

  2. 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.

  3. 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,...

  4. 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. PMID:20953048

  5. Laser Cutting of Carbon Fiber Fabrics

    Science.gov (United States)

    Fuchs, A. N.; Schoeberl, M.; Tremmer, J.; Zaeh, M. F.

    Due to their high weight-specific mechanical stiffness and strength, parts made from carbon fiber reinforced polymers (CFRP) are increasingly used as structural components in the aircraft and automotive industry. However, the cutting of preforms, as with most automated manufacturing processes for CFRP components, has not yet been fully optimized. This paper discusses laser cutting, an alternative method to the mechanical cutting of preforms. Experiments with remote laser cutting and gas assisted laser cutting were carried out in order to identify achievable machining speeds. The advantages of the two different processes as well as their fitness for use in mass production are discussed.

  6. 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.

  7. 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.

  8. Carbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers

    Energy Technology Data Exchange (ETDEWEB)

    Li Jiangling; Su Shi; Kundrat, Vojtech; Abbot, Andrew M.; Ye, Haitao [School of Engineering and Applied Science, Aston University, Birmingham B4 7ET (United Kingdom); Zhou Lei [Department of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); Mushtaq, Fajer [Department of Mechanical Engineering, ETH Zurich, Zurich 8092 (Switzerland); Ouyang Defang [School of Life and Health Science, Aston University, Birmingham B4 7ET (United Kingdom); James, David; Roberts, Darren [Thermo Fisher Scientific, Stafford House, Hemel Hempstead HP2 7GE (United Kingdom)

    2013-01-14

    We used microwave plasma enhanced chemical vapor deposition (MPECVD) to carbonize an electrospun polyacrylonitrile (PAN) precursor to form carbon fibers. Scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the fibers at different evolution stages. It was found that MPECVD-carbonized PAN fibers do not exhibit any significant change in the fiber diameter, whilst conventionally carbonized PAN fibers show a 33% reduction in the fiber diameter. An additional coating of carbon nanowalls (CNWs) was formed on the surface of the carbonized PAN fibers during the MPECVD process without the assistance of any metallic catalysts. The result presented here may have a potential to develop a novel, economical, and straightforward approach towards the mass production of carbon fibrous materials containing CNWs.

  9. Carbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers

    Science.gov (United States)

    Li, Jiangling; Su, Shi; Zhou, Lei; Kundrát, Vojtěch; Abbot, Andrew M.; Mushtaq, Fajer; Ouyang, Defang; James, David; Roberts, Darren; Ye, Haitao

    2013-01-01

    We used microwave plasma enhanced chemical vapor deposition (MPECVD) to carbonize an electrospun polyacrylonitrile (PAN) precursor to form carbon fibers. Scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the fibers at different evolution stages. It was found that MPECVD-carbonized PAN fibers do not exhibit any significant change in the fiber diameter, whilst conventionally carbonized PAN fibers show a 33% reduction in the fiber diameter. An additional coating of carbon nanowalls (CNWs) was formed on the surface of the carbonized PAN fibers during the MPECVD process without the assistance of any metallic catalysts. The result presented here may have a potential to develop a novel, economical, and straightforward approach towards the mass production of carbon fibrous materials containing CNWs.

  10. Improvement of cement concrete strength properties by carbon fiber additives

    Science.gov (United States)

    Nevsky, Andrey; Kudyakov, Konstantin; Danke, Ilia; Kudyakov, Aleksandr; Kudyakov, Vitaly

    2016-01-01

    The paper presents the results of studies of fiber-reinforced concrete with carbon fibers. The effectiveness of carbon fibers uniform distribution in the concrete was obtained as a result of its preliminary mechanical mixing in water solution with chemical additives. Additives are to be used in the concrete technology as modifiers at initial stage of concrete mix preparing. The technology of preparing of fiber-reinforced concrete mix with carbon fibers is developed. The superplasticizer is based on ether carboxylates as a separator for carbon fibers. The technology allows increasing of concrete compressive strength up to 43.4% and tensile strength up to 17.5% as well as improving stability of mechanical properties.

  11. 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.

  12. 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%.

  13. 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.

  14. 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%.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. Preparation of anti-oxidative carbon fiber at high temperature

    Science.gov (United States)

    Kim, Bo-Hye; Kim, Su Yeun; Kim, Chang Hyo; Yang, Kap Seung; Lee, Young-Jun

    2010-11-01

    In this paper, carbon fibers with improved thermal stability and oxidation resistive properties were prepared and evaluated their physical performances under oxidation condition. Carbon fibers were coated with SiC particles dispersed in a polyacrylonitrile solution and then followed by pyrolyzed at 1400 °C to obtain the SiC nanoparticle deposition on the surface of the carbon fiber. The SiC coated carbon fiber showed extended oxidation resistive property as remaining 80-88% of the original weight even at high temperature 1000 °C under air, as compared with the control of zero weight at 600 °C. The effects of the coating conditions on the oxidation resistive properties of the coated fibers were studied in detail.

  2. Properties of Retinal Precursor Cells Grown on Vertically Aligned Multiwalled Carbon Nanotubes Generated for the Modification of Retinal Implant-Embedded Microelectrode Arrays.

    Science.gov (United States)

    Johnen, Sandra; Meißner, Frank; Krug, Mario; Baltz, Thomas; Endler, Ingolf; Mokwa, Wilfried; Walter, Peter

    2016-01-01

    Background. To analyze the biocompatibility of vertically aligned multiwalled carbon nanotubes (MWCNT), used as nanomodification to optimize the properties of prostheses-embedded microelectrodes that induce electrical stimulation of surviving retinal cells. Methods. MWCNT were synthesized on silicon wafers. Their growth was achieved by iron particles (Fe) or mixtures of iron-platinum (Fe-Pt) and iron-titanium (Fe-Ti) acting as catalysts. Viability, growth, adhesion, and gene expression of L-929 and retinal precursor (R28) cells were analyzed after nondirect and direct contact. Results. Nondirect contact had almost no influence on cell growth, as measured in comparison to reference materials with defined levels of cytotoxicity. Both cell types exhibited good proliferation properties on each MWCNT-coated wafer. Viability ranged from 95.9 to 99.8%, in which better survival was observed for nonfunctionalized MWCNT generated with the Fe-Pt and Fe-Ti catalyst mixtures. R28 cells grown on the MWCNT-coated wafers showed a decreased gene expression associated with neural and glial properties. Expression of the cell cycle-related genes CCNC, MYC, and TP53 was slightly downregulated. Cultivation on plasma-treated MWCNT did not lead to additional changes. Conclusions. All tested MWCNT-covered slices showed good biocompatibility profiles, confirming that this nanotechnology is a promising tool to improve prostheses bearing electrodes which connect with retinal tissue. PMID:27200182

  3. Properties of Retinal Precursor Cells Grown on Vertically Aligned Multiwalled Carbon Nanotubes Generated for the Modification of Retinal Implant-Embedded Microelectrode Arrays

    Directory of Open Access Journals (Sweden)

    Sandra Johnen

    2016-01-01

    Full Text Available Background. To analyze the biocompatibility of vertically aligned multiwalled carbon nanotubes (MWCNT, used as nanomodification to optimize the properties of prostheses-embedded microelectrodes that induce electrical stimulation of surviving retinal cells. Methods. MWCNT were synthesized on silicon wafers. Their growth was achieved by iron particles (Fe or mixtures of iron-platinum (Fe-Pt and iron-titanium (Fe-Ti acting as catalysts. Viability, growth, adhesion, and gene expression of L-929 and retinal precursor (R28 cells were analyzed after nondirect and direct contact. Results. Nondirect contact had almost no influence on cell growth, as measured in comparison to reference materials with defined levels of cytotoxicity. Both cell types exhibited good proliferation properties on each MWCNT-coated wafer. Viability ranged from 95.9 to 99.8%, in which better survival was observed for nonfunctionalized MWCNT generated with the Fe-Pt and Fe-Ti catalyst mixtures. R28 cells grown on the MWCNT-coated wafers showed a decreased gene expression associated with neural and glial properties. Expression of the cell cycle-related genes CCNC, MYC, and TP53 was slightly downregulated. Cultivation on plasma-treated MWCNT did not lead to additional changes. Conclusions. All tested MWCNT-covered slices showed good biocompatibility profiles, confirming that this nanotechnology is a promising tool to improve prostheses bearing electrodes which connect with retinal tissue.

  4. 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.

  5. Microscopic measurement of pH with iridium oxide microelectrodes

    Science.gov (United States)

    Wipf; Ge; Spaine; Baur

    2000-10-15

    Microscopic pH electrodes were produced by deposition of hydrous iridium oxide onto carbon fiber microelectrodes. The electrodes exhibit two linear regions of potentiometric response between pH 2-6 and pH 6-12. The electrodes respond to pH changes within 50 ms, and an equilibrium value is reached within 30 s. By using these electrodes as probes in the scanning electrochemical microscope, dynamic pH changes occurring at or near a surface can be measured and pH maps of the surface can be generated. Vertical pH profiles and images of pH were obtained at substrates where electrochemical (oxidation and reduction of H2O2, hydrogen evolution) or enzymatic (glucose oxidase) reactions involving proton transfers occur. PMID:11055710

  6. [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.

  7. 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.

  8. 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.

  9. 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. PMID:27278219

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. Evaluation of carbon fiber composites modified by in situ incorporation of carbon nanofibers

    Directory of Open Access Journals (Sweden)

    André Navarro de Miranda

    2011-12-01

    Full Text Available Nano-carbon materials, such as carbon nanotubes and carbon nanofibers, are being thought to be used as multifunctional reinforcement in composites. The growing of carbon nanofiber at the carbon fiber/epoxy interface results in composites having better electrical properties than conventional carbon fiber/epoxy composites. In this work, carbon nanofibers were grown in situ over the surface of a carbon fiber fabric by chemical vapor deposition. Specimens of carbon fiber/nanofiber/epoxy (CF/CNF/epoxy composites were molded and electrical conductivity was measured. Also, the CF/CNF/epoxy composites were tested under flexure and interlaminar shear. The results showed an overall reduction in mechanical properties as a function of added nanofiber, although electrical conductivity increased up to 74% with the addition of nanofibers. Thus CF/CNF/epoxy composites can be used as electrical dissipation discharge materials.

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

    OpenAIRE

    Yongfeng Luo; Xi Li; Jianxiong Zhang; Chunrong Liao; Xianjun Li

    2014-01-01

    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 lo...

  18. 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.

  19. 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.

  20. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-11

    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.

  1. 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.

  2. 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.

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

    OpenAIRE

    Marioli-Riga Z.; Bartholome C.; Alexopoulos N.; Poulin P.

    2010-01-01

    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 sens...

  4. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    OpenAIRE

    Zhu, Z.; Song, W.; Burugapalli, K; Moussy, F; Li, Y-L; Zhong, X-H

    2010-01-01

    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 IOP Publishing Ltd. A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon...

  5. 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.

  6. 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.

  7. 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.

  8. 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. PMID:27162144

  9. 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.

  10. Carbon Fiber Reinforced Carbon Composites Rotary Valves for Internal Combustion Engines

    Science.gov (United States)

    Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

    1999-01-01

    Carbon fiber reinforced carbon composite rotary, sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or warp-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties, do not present the sealing and lubrication problems that have prevented rotary, sleeve, and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

  11. Carbon Fiber Reinforced Carbon Composite Rotary Valve for an Internal Combustion Engine

    Science.gov (United States)

    Northam, G.Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

    2000-01-01

    Carbon fiber reinforced carbon composite rotary sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or wrap-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties do not present the sealing and lubrication problems that have prevented rotary sleeve and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

  12. A Label-Free Microelectrode Array Based on One-Step Synthesis of Chitosan–Multi-Walled Carbon Nanotube–Thionine for Ultrasensitive Detection of Carcinoembryonic Antigen

    Directory of Open Access Journals (Sweden)

    Huiren Xu

    2016-07-01

    Full Text Available Carcinoembryonic antigen (CEA has been an extensively used tumor marker responsible for clinical early diagnosis of cervical carcinomas, and pancreatic, colorectal, gastric and lung cancer. Combined with micro-electro mechanical system (MEMS technology, it is important to develop a novel immune microelectrode array (MEA not only for rapid analysis of serum samples, but also for cell detection in vitro and in vivo. In this work, we depict a simple approach to modify chitosan–multi-walled carbon nanotubes–thionine (CS–MWCNTs–THI hybrid film through one-step electrochemical deposition and the CS-MWCNTs-THI hybrid films are successfully employed to immobilize anti-CEA for fabricating simple, label-free, and highly sensitive electro-chemical immune MEAs. The detection principle of immune MEA was based on the fact that the increasing formation of the antigen-antibody immunocomplex resulted in the decreased response currents and the relationship between the current reductions with the corresponding CEA concentrations was directly proportional. Experimental results indicated that the label-free MEA had good selectivity and the limit of detection for CEA is 0.5 pg/mL signal to noise ratio (SNR = 3. A linear calibration plot for the detection of CEA was obtained in a wide concentration range from 1 pg/mL to 100 ng/mL (r = 0.996. This novel MEA has potential applications for detecting CEA for the research on cancer cells and cancer tissue slices as well as for effective early diagnosis.

  13. Molecularly imprinted polymer solid-phase extraction coupled to square wave voltammetry at carbon fibre microelectrodes for the determination of fenbendazole in beef liver.

    Science.gov (United States)

    Guzmán-Vázquez de Prada, A; Loaiza, Oscar A; Serra, B; Morales, D; Martínez-Ruiz, P; Reviejo, A J; Pingarrón, J M

    2007-05-01

    A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium for electrochemical detection of fenbendazole. The limit of detection was 1.9x10(-7) mol L-1 (57 microg L-1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission (500 microg kg-1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed. The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton-Robinson Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate of 2.0 mL min-1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 microg kg-1. Results obtained for ten different liver samples yielded mean recoveries of (95+/-12)% and (96+/-11)% for the upper and lower concentration level, respectively.

  14. Porous texture evolution in Nomex-derived activated carbon fibers.

    Science.gov (United States)

    Villar-Rodil, S; Denoyel, R; Rouquerol, J; Martínez-Alonso, A; Tascón, J M D

    2002-08-01

    In the present work, the textural evolution of a series of activated carbon fibers with increasing burn-off degree, prepared by the pyrolysis and steam activation of Nomex aramid fibers, is followed by measurements of physical adsorption of N(2) (77 K) and CO(2) (273 K) and immersion calorimetry into different liquids (dichloromethane, benzene, cyclohexane). The immersion calorimetry results are discussed in depth, paying special attention to the choice of the reference material. The activated carbon fibers studied possess an essentially homogeneous microporous texture, which suggests that these materials may be applied in gas separation, either directly or with additional CVD treatment. PMID:16290775

  15. 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.

  16. 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.

  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. 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.

  19. Cohesive zone model of carbon nanotube-coated carbon fiber/polyester composites

    International Nuclear Information System (INIS)

    It has been previously reported that the average properties of carbon nanotube-coated carbon fiber/polyester multiscale composites critically depend on the length and density of nanotubes on the fiber surface. In this paper the effect of nanotube length and density on the interfacial properties of the carbon nanotube-coated carbon fiber–polymer interface has been studied using shear lag and a cohesive zone model. The latter model incorporates frictional sliding after complete debonding between the fiber and matrix and has been developed to quantify the effect of nanotube coating on various interfacial characterizing parameters. Our numerical results indicate that fibers with an optimal coverage and length of nanotubes significantly increase the interfacial strength and friction between the fiber and polymer. However, they also embrittle the interface compared with bare fibers. (paper)

  20. 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.

  1. 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.

  2. 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.

  3. Fabrication of highly conductive carbon nanotube fibers for electrical application

    Science.gov (United States)

    Guo, Fengmei; Li, Can; Wei, Jinquan; Xu, Ruiqiao; Zhang, Zelin; Cui, Xian; Wang, Kunlin; Wu, Dehai

    2015-09-01

    Carbon nanotubes (CNTs) have great potential for use as electrical wires because of their outstanding electrical and mechanical properties. Here, we fabricate lightweight CNT fibers with electrical conductivity as high as that of stainless steel from macroscopic CNT films by drawing them through diamond wire-drawing dies. The entangled CNT bundles are straightened by suffering tension, which improves the alignment of the fibers. The loose fibers are squeezed by the diamond wire-drawing dies, which reduces the intertube space and contact resistance. The CNT fibers prepared by drawing have an electrical conductivity as high as 1.6 × 106 s m-1. The fibers are very stable when kept in the air and under cyclic tensile test. A prototype of CNT motor is demonstrated by replacing the copper wires with the CNT fibers.

  4. Carbon nanofiber electrode array for electrochemical detection of dopamine using fast scan cyclic voltammetry

    OpenAIRE

    Koehne, Jessica E.; Marsh, Michael; Boakye, Adwoa; Douglas, Brandon; Kim, In Yong; Chang, Su-Youne; Jang, Dong-Pyo; Bennet, Kevin E.; Kimble, Christopher; Andrews, Russell; Meyyappan, M.; Lee, Kendall H.

    2011-01-01

    A carbon nanofiber (CNF) electrode array was integrated with the Wireless Instantaneous Neurotransmitter Sensor System (WINCS) for detection of dopamine using fast scan cyclic voltammetry (FSCV). Dopamine detection performance by CNF arrays was comparable to that of traditional carbon fiber microelectrodes (CFMs), demonstrating that CNF arrays can be utilized as an alternative carbon electrodes for neurochemical monitoring.

  5. An intravenous implantable glucose/dioxygen biofuel cell with modified flexible carbon fiber electrodes.

    Science.gov (United States)

    Sales, Fernanda C P F; Iost, Rodrigo M; Martins, Marccus V A; Almeida, Maria C; Crespilho, Frank N

    2013-02-01

    An intravenous implantable glucose/dioxygen hybrid enzyme-Pt micro-biofuel cell (BFC) was investigated. In this miniaturized BFC, a flexible carbon fiber (FCF) microelectrode modified with neutral red redox mediator and glucose oxidase was used as the bioanode, and an FCF modified with platinum nanoparticles stabilized on PAMAM-G4 dendrimer was used as the cathode. In vitro experiments conducted using the BFC in a phosphate buffer solution (50 mmol L(-1), pH = 7.2) and glucose (47 mmol L(-1)) showed high electrocatalytic performance with an open circuit voltage (OCV) of 400 mV, a maximum current density of 2700 μA cm(-2) at 0.0 V and a maximum output power of 200 μW cm(-2) at 250 mV. Under physiological conditions, glucose from rat blood is used as a fuel in anodic reactions and dissolved molecular oxygen is used as the oxidizing agent on the cathode. For in vivo experiments, the BFC was inserted into the jugular vein of a living rat (Rattus novergicus) using a catheter (internal diameter 0.5 mm). The power density of the implantable BFC was evaluated over a period of 24 h, and an OCV of 125 mV with a maximum power density of 95 μW cm(-2) was obtained at 80 mV.

  6. 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. PMID:17326671

  7. Electrochemical Behavior of Mitoxantrone and Its Determination at a Pt/C Implanted Modified Microelectrode

    Institute of Scientific and Technical Information of China (English)

    QIAN Yong-gui; SUN Zi-jie; HU Jing-bo; LU Yi-qiang; LI Qi-long

    2004-01-01

    In a 0.02 mol/L Na2HPO4-KH2PO4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microelectrode. A sensitive reduction peak was observed. The peak potential was -0.72 V(vs.SCE), the peak current was proportional to the concentration of mitoxantrone within the ranges of 7.0×10-8-9.0×10-7 mol/L and 1.0×10-6-2.4×10-5 mol/L, with a detection limit of 4.0×10-8 mol/L. The linear correlation coefficients were 0.9994 and 0.9992, respectively. This method has been applied to the direct determination of mitoxantrone in simulated urine. The recoveries were in the range from 96.2% to 105.9%. The reduction process was a quasi-reversible one with adsorptive characteristics at the Pt/C microelectrode. The electrode reaction rate constant ks and the electron transfer coefficient α of the system were determined to be 4.5 and 0.65 s-1, respectively. The experiments showed that Pt element had surely been implanted into the surface of the carbon fiber, and the atomic Pt improved the electrocatalytic activity. The Pt/C microelectrode had a good stability and reproducibility.

  8. Tensile Modulus Measurements of Carbon Nanotube Incorporated Electrospun Polymer Fibers

    Science.gov (United States)

    Ozturk, Yavuz; Kim, Jaemin; Shin, Kwanwoo

    2006-03-01

    Electrospinning has become a popular method for producing continuous polymer fibers with diameters in sub-micron scale. By this technique uniaxially aligned fibers can also be obtained, by using two separate parallel strips as conductive collectors. Uniaxial alignment of polymer fibers gives us the chance to well-characterize their structural properties via tensile modulus measurements. Here we report a simple and new technique for tensile testing of polymer fibers which employs a computerized spring-balance/step-motor setup. The key point in our technique is the production of fibers directly on the tensile tester by using two vertical strips as collectors. By this way, even fibers of very brittle nature can be tested without handling them. Calculation of total cross-sectional areas - which is crucial for determining stress values - was done by using scanning electron and optical microscope images for each sample. In this study we have investigated mechanical properties of Polystyrene (PS), Polymethylmethacrylate (PMMA) and PS/PMMA blend fibers; as well as Carbon Nanotube (CNT) incorporated PS, PMMA and PS/PMMA blend fibers. It is expected that the extraordinary mechanical properties of CNTs can be transferred into polymer matrix, by their incorporation into confined space within electrospun fibers. Here we analyzed the influence of CNT on polymer fibers as function of CNT amounts.

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

    International Nuclear Information System (INIS)

    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

  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. 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

  12. 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.

  13. Mechanical characterization of epoxy composite with multiscale reinforcements: Carbon nanotubes and short carbon fibers

    International Nuclear Information System (INIS)

    Highlights: • Multiscale composite was prepared by incorporation of carbon nanotubes and fibers. • Carbon nanotubes were also grown on short carbon fibers to enhance stress transfer. • Significant improvements were achieved in mechanical properties of composites. • Synergic effect of carbon nanotubes and fibers was demonstrated. - Abstract: Carbon nanotubes (CNT) and short carbon fibers were incorporated into an epoxy matrix to fabricate a high performance multiscale composite. To improve the stress transfer between epoxy and carbon fibers, CNT were also grown on fibers through chemical vapor deposition (CVD) method to produce CNT grown short carbon fibers (CSCF). Mechanical characterization of composites was performed to investigate the synergy effects of CNT and CSCF in the epoxy matrix. The multiscale composites revealed significant improvement in elastic and storage modulus, strength as well as impact resistance in comparison to CNT–epoxy or CSCF–epoxy composites. An optimum content of CNT was found which provided the maximum stiffness and strength. The synergic reinforcing effects of combined fillers were analyzed on the fracture surface of composites through optical and scanning electron microscopy (SEM)

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

    OpenAIRE

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

    2013-01-01

    New and improved materials capable of binding carbon dioxide are essential to addressing the global threat of accelerating climate change. The presently used industrial methods for carbon dioxide capture have severe drawbacks, including toxicity and energy inefficiency. Newer porous materials are so far less effective in water, invariably a component of combustion gases. Here, we present a material for carbon dioxide capture. This material, amyloid fibers in powdered form, selectively capture...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Fiber optic ultrasound transducers with carbon/PDMS composite coatings

    Science.gov (United States)

    Mosse, Charles A.; Colchester, Richard J.; Bhachu, Davinder S.; Zhang, Edward Z.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2014-03-01

    Novel ultrasound transducers were created with a composite of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS) that was dip coated onto the end faces of optical fibers. The CNTs were functionalized with oleylamine to allow for their dissolution in xylene, a solvent of PDMS. Ultrasound pulses were generated by illuminating the composite coating with pulsed laser light. At distances of 2 to 16 mm from the end faces, ultrasound pressures ranged from 0.81 to 0.07 MPa and from 0.27 to 0.03 MPa with 105 and 200 μm core fibers, respectively. Using an optical fiber hydrophone positioned adjacent to the coated 200 µm core optical fiber, ultrasound reflectance measurements were obtained from the outer surface of a sheep heart ventricle. The results of this study suggest that ultrasound transducers that comprise optical fibers with CNT-PDMS composite coatings may be suitable for miniature medical imaging probes.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhigang; Burugapalli, Krishna; Moussy, Francis [Brunel Institute for Bioengineering, Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom); Song, Wenhui [Wolfson Centre for Materials Processing, Mechanical Engineering, School of Engineering and Design, Brunel University, Uxbridge, Middlesex UB8 3PH (United Kingdom); Li Yali; Zhong Xiaohua, E-mail: wenhui.song@brunel.ac.uk [School of Materials Science and Engineering, Tianjin University, Weijin Road 92, Nankai District, Tianjin 300073 (China)

    2010-04-23

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 {mu}m in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 deg. C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 {mu}M. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

  5. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor.

    Science.gov (United States)

    Zhu, Zhigang; Song, Wenhui; Burugapalli, Krishna; Moussy, Francis; Li, Ya-Li; Zhong, Xiao-Hua

    2010-04-23

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 microm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 degrees C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 microM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor. PMID:20348597

  6. 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.

  7. 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.

  8. 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.

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

    International Nuclear Information System (INIS)

    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 × 108 and 2.8 × 106 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

  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. Process for preparing tapes from thermoplastic polymers and carbon fibers

    Science.gov (United States)

    Chung, Tai-Shung (Inventor); Furst, Howard (Inventor); Gurion, Zev (Inventor); McMahon, Paul E. (Inventor); Orwoll, Richard D. (Inventor); Palangio, Daniel (Inventor)

    1986-01-01

    The instant invention involves a process for use in preparing tapes or rovings, which are formed from a thermoplastic material used to impregnate longitudinally extended bundles of carbon fibers. The process involves the steps of (a) gas spreading a tow of carbon fibers; (b) feeding the spread tow into a crosshead die; (c) impregnating the tow in the die with a thermoplastic polymer; (d) withdrawing the impregnated tow from the die; and (e) gas cooling the impregnated tow with a jet of air. The crosshead die useful in the instant invention includes a horizontally extended, carbon fiber bundle inlet channel, means for providing melted polymer under pressure to the die, means for dividing the polymeric material flowing into the die into an upper flow channel and a lower flow channel disposed above and below the moving carbon fiber bundle, means for applying the thermoplastic material from both the upper and lower channels to the fiber bundle, and means for withdrawing the resulting tape from the die.

  12. Chemical Characterization of Stabilized and Carbonized Polyacrylonitrile (PAN Fibers Treated with Oleic Acid.

    Directory of Open Access Journals (Sweden)

    Salleh Shahrul Nizam Md

    2014-07-01

    Full Text Available Polyacrylonitrile (PAN fiber is the best precursor for carbon fibers due to high carbon content after heat treatment. After the polymer was spun into fibers, the fibers will undergo pretreatment process with chemical solution known as post spinning treatment. Post spinning will directly affect conversion of PAN fiber to carbon fiber. Oleic acid was used as post spinning treatment chemical solution to PAN fibers. The pretreated PAN fiber will be heated at 250°C and 800°C. The fibers were studied using Fourier Transform Infra-Red (FTIR, X-ray Photoelectron Spectroscopy (XPS and DSC to study the chemical change during heat treatment. PAN fibers treated with oleic acid have reduced the cyclization energy and increase oxygen and carbon content leading to high performance carbon fibers.

  13. Review and developments of dissemination models for airborne carbon fibers

    Science.gov (United States)

    Elber, W.

    1980-01-01

    Dissemination prediction models were reviewed to determine their applicability to a risk assessment for airborne carbon fibers. The review showed that the Gaussian prediction models using partial reflection at the ground agreed very closely with a more elaborate diffusion analysis developed for the study. For distances beyond 10,000 m the Gaussian models predicted a slower fall-off in exposure levels than the diffusion models. This resulting level of conservatism was preferred for the carbon fiber risk assessment. The results also showed that the perfect vertical-mixing models developed herein agreed very closely with the diffusion analysis for all except the most stable atmospheric conditions.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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...

  2. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    OpenAIRE

    Marc in het Panhuis; Holly Warren; Higgins, Thomas M.

    2011-01-01

    The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs) and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that ...

  3. Synthesis and characterization of carbon fibers obtained through plasma techniques

    International Nuclear Information System (INIS)

    The study of carbon, particularly the nano technology is a recent field, the one which has important implications in the science of new materials. It investigation is of great interest for industries producers of ceramic, metallurgy, electronic, energy storage, biomedicine, among others. The diverse application fields are a reason at national as international level, so that many works are focused in the production of nano fibers of carbon. The Thermal plasma applications laboratory (LAPT) of the National Institute of Nuclear Research (ININ), it is carrying out works about carbon nano technology. The present work has as purpose to carry out the synthesis and characterization of the carbon nano fibers which are obtained by electric arch of alternating current (CA) to high frequencies and by a plasma gun of non transferred arch, where are used hydrocarbons like benzene, methane, acetylene like carbon source and ferrocene, nickel, yttrium and cerium oxide like catalysts. For both techniques its were thought about a relationship among hydrocarbon-catalyst that it favored to the nano fibers production. The obtained product of each experiment outlined it was analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD), analysis with those were obtained pictures and diffraction graphs, which were observed to arrive to one conclusion on the operation conditions, same analysis with those were characterized the tests carried out according to the nano structures formation of carbon. (Author)

  4. 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.

  5. 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.

  6. Amperometric Carbon Fiber Nitrite Microsensor for In Situ Biofilm Monitoring

    Science.gov (United States)

    A highly selective needle type solid state amperometric nitrite microsensor based on direct nitrite oxidation on carbon fiber was developed using a simplified fabrication method. The microsensor’s tip diameter was approximately 7 µm, providing a high spatial resolution of at lea...

  7. 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.

  8. Vibration monitoring of carbon fiber composites by multiple fiber optic sensors

    Science.gov (United States)

    Olivero, Massimo; Perrone, Guido; Vallan, Alberto; Chen, Wei; Tosi, Daniele

    2014-05-01

    This work presents the comparison between the fiber Bragg grating technology and a vibration-measurement technique based on the detection of polarization rotation (polarimetric sensor) in a standard optical fiber, applied to the dynamic structural monitoring of carbon reinforced composites for the automotive industry. A carbon reinforced composite test plate in a 4-layer configuration was equipped with fiber Bragg gratings and polarimetric fiber sensors, then it was mechanically stressed by static and dynamic loads while monitoring the sensors response. The fiber Bragg grating setup exhibited 1.15+/-0.0016 pm/kg static load response and reproduced dynamic excitation with 0.1% frequency uncertainty, while the polarimetric sensing system exhibited a sensitivity of 1.74+/-0.001 mV/kg and reproduced the dynamic excitation with 0.5% frequency uncertainty. It is shown that the polarimetric sensor technology represents a cheap yet efficient alternative to the fiber Bragg grating sensors in the case of vibration-monitoring of small structures at high frequency.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  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...

  15. 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.

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

    OpenAIRE

    Kimura, Teruo||木村, 照夫||キムラ, テルオ

    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...

  17. 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.

  18. 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.

  19. 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. PMID:26726642

  20. 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.

  1. 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.

  2. Electrical transport in carbon nanotube coatings of silica fibers

    Energy Technology Data Exchange (ETDEWEB)

    Ksenevich, Vitaly [Department of Physics, Belarus State University, Nezalezhnastsi ave. 4, 220030 Minsk (Belarus); Dauzhenka, Taras [Department of Physics, Belarus State University, Nezalezhnastsi ave. 4, 220030 Minsk (Belarus); CNRS; LNCMI, 143 Avenue de Rangueil, 31400 Toulouse (France); Universite de Toulouse, UPS, INSA; LNCMI; 31077 Toulouse (France); Seliuta, Dalius; Kasalynas, Irmantas; Kivaras, Tomas; Valusis, Gintaras [Semiconductor Physics Institute, A. Gostauto 11, 01108 Vilnius (Lithuania); Galibert, Jean [CNRS; LNCMI, 143 Avenue de Rangueil, 31400 Toulouse (France); Universite de Toulouse, UPS, INSA; LNCMI; 31077 Toulouse (France); Helburn, Robin [Department of Chemistry, Pace University, New York, NY 10038 (United States); Lu, Qi [Department of Physics, St. John' s University, Queens, NY 11439 (United States); Samuilov, Vladimir [Department of Physics, Belarus State University, Nezalezhnastsi ave. 4, 220030 Minsk (Belarus); Department of Physics, St. John' s University, Queens, NY 11439 (United States); Universite de Toulouse, UPS, INSA, LNCMP, 31077 Toulouse (France)

    2009-12-15

    Electrical properties and magnetoresistance (MR) of single-wall carbon nanotubes coatings of silica fibers were investigated in temperature range 1.8-300 K and magnetic fields up to 8 T. The dependence of resistance vs temperature, R (T), and MR within the range of 2{proportional_to}8 K can be explained by a 3D variable range hopping transport. In the temperature range of 8-300 K, R (T) dependencies can be interpreted by fluctuation-induced tunnelling model. The determined carrier transport features were supported by additional measurements of change in conductivity in strong 10 GHz microwave fields and measurements of THz radiation induced photocurrent at various lattice temperatures. The features of carrier transport in SWCNTs-SiO{sub 2} coatings are compared with those in free-standing single walled carbon nanotube fibers. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. 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.

  4. 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.

  5. Mechanical testing of unidirectional carbon fiber reinforced plastics

    OpenAIRE

    Näreikkö, Aleksi

    2015-01-01

    The area of composites testing has been a major topic of research since the early adoption of composites in the aerospace industry, nearly 50 years ago. Today, the mechanical characterization of different material systems is of even greater importance, since most modelling software require material data to produce accurate results. This thesis studied a component consisting of 4 pultruded carbon fiber reinforced epoxy elements coated with a thermoplastic polyurethane coating. The obje...

  6. Production of graphene oxide from pitch-based carbon fiber

    OpenAIRE

    Miyeon Lee; Jihoon Lee; Sung Young Park; Byunggak Min; Bongsoo Kim; Insik In

    2015-01-01

    Pitch-based graphene oxide (p-GO) whose compositional/structural features are comparable to those of graphene oxide (GO) was firstly produced by chemical exfoliation of pitch-based carbon fiber rather than natural graphite. Incorporation of p-GO as nanofillers into poly(methyl methacrylate) (PMMA) as a matrix polymer resulted in excellent mechanical reinforcement. p-GO/PMMA nanocomposite (1 wt.-% p-GO) demonstrated 800% higher modulus of toughness of neat PMMA.

  7. 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.

  8. 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...

  9. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Marc in het Panhuis

    2011-04-01

    Full Text Available The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases.

  10. 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.

  11. 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.

  12. The effect of gamma ray irradiation on PAN-based intermediate modulus carbon fibers

    International Nuclear Information System (INIS)

    Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were conducted on PAN-based intermediate modulus carbon fibers to investigate the structure and surface hydrophilicity of the carbon fibers before and after gamma irradiation. Two methods were used to determine Young’s modulus of the carbon fibers. The results show that gamma ray irradiation improved the degree of graphitization and introduced compressive stress into carbon fiber surface. Gamma ray also improved the carbon fiber surface hydrophilicity through increasing the value of O/C and enhancing the quantity of oxygen functional groups on carbon fibers. No distinct morphology change was observed after gamma ray irradiation. The Young’s modulus of the fibers increased with increasing irradiation dose

  13. The effect of gamma ray irradiation on PAN-based intermediate modulus carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Feng, Yi, E-mail: fyhfut@163.com [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Qian, Gang; Zhang, Jingcheng [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zhuang, Zhong; Wang, Xianping [Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2013-11-15

    Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were conducted on PAN-based intermediate modulus carbon fibers to investigate the structure and surface hydrophilicity of the carbon fibers before and after gamma irradiation. Two methods were used to determine Young’s modulus of the carbon fibers. The results show that gamma ray irradiation improved the degree of graphitization and introduced compressive stress into carbon fiber surface. Gamma ray also improved the carbon fiber surface hydrophilicity through increasing the value of O/C and enhancing the quantity of oxygen functional groups on carbon fibers. No distinct morphology change was observed after gamma ray irradiation. The Young’s modulus of the fibers increased with increasing irradiation dose.

  14. The characterization of carbon nanotube infused glass fibers by single filament fragmentation test methods

    Science.gov (United States)

    Roach, Andrew Michael

    Single filament fragmentation tests were completed for individual glass fibers with varying surface treatments and carbon nanostructure infusions. Fiber fragmentation was analyzed by embedding a single filament into a standard tensile interface, which provided shear stress transfer between a conventional epoxy resin system and the constituent filament. Established single filament fragmentation techniques were used to characterize fiber and interface properties. A novel method of comparing fibers is introduced by correlating bundle tow test results to fiber fragmentation critical length data to qualitatively relate fiber performance. Photoelastic birefringent stress fringes were processed at select fiber fragmentation locations to further characterize the fiber-resin, or fiber-carbon nanostructure-resin, interface. Overall, the performance matrix qualitative comparison method, coupled with stress fringe analysis, proved to be an effective means of qualitatively evaluating fiber and processing parameters, and efficiently identifies the most fruitful path forward for optimized fiber development.

  15. 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.

  16. MNASA as a Test for Carbon Fiber Thermal Barrier Development

    Science.gov (United States)

    Bauer, Paul; McCool, Alex (Technical Monitor)

    2001-01-01

    A carbon fiber rope thermal barrier is being evaluated as a replacement for the conventional room temperature vulcanizing (RTV) thermal barrier that is currently used to protect o-rings in Reusable Solid Rocket Motor (RSRM) nozzle joints. Performance requirements include its ability to cool any incoming, hot propellant gases that fill and pressurize the nozzle joints, filter slag and particulates, and to perform adequately in various joint assembly conditions as well as dynamic flight motion. Modified National Aeronautics and Space Administration (MNASA) motors, with their inherent and unique ability to replicate select RSRM internal environment features, were an integral step in the development path leading to full scale RSRM static test demonstration of the carbon fiber rope (CFR) joint concept. These 1/4 scale RSRM motors serve to bridge the gap between the other classes of subscale test motors (extremely small and moderate duration, or small scale and short duration) and the critical asset RSRM static test motors. A series of MNASA tests have been used to demonstrate carbon fiber rope performance and have provided rationale for implementation into a full-scale static motor and flight qualification.

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

    International Nuclear Information System (INIS)

    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. (paper)

  18. 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.

  19. 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.

  20. Studies of the Surface Treatment and Sizing of Carbon Fiber Surfaces on the Mechanical Properties of Composites Containing Carbon Fibers

    Science.gov (United States)

    Sherwood, Peter M. A.; Lease, Kevin B.; Locke, James E.; Tomblin, John S.; Wang, Youqi

    1996-01-01

    Carbon fiber reinforced composites are materials where carbon fibers are used to reinforce a matrix to produce a light and strong material with important applications in the aerospace industry. There are many aspects of the preparation of these materials that would benefit from a study which combines the research of groups involved in the production, testing and analysis of these materials, and studies of the basic surface chemistry involved. This final reports presents the results of a project that has developed a collaboration between groups in all three of the major research universities in the State of Kansas, and promises to lead to a collaborative program that covers the major aspects of composite development and application. Sherwood has provided initial fiber surface treatment and sizing together with fiber and composite surface analysis; Lease, Tomblin and Wang have worked together toward the goal of preparing pre-preg and fabrication of laminated panels; Locke has developed computational models to evaluate the effect of surface treatment (and chemistry) on mechanical properties; Lease, Tomblin and Wang have worked together to perform all necessary mechanical testing. The research has been focused on materials that would benefit the High Speed Civil Transport (HSCT) program. The group has visited Dr. Howard Maars and his colleagues at NASA Langley, and has focused their studies on the NASA requirements discussed in this meeting. An important development, requested by NASA scientists, has been the acquisition and study of K3B as a matrix material for the composites. The project has led to the successful acquisition and surface analysis of K3B, together with the successful deposition of this material onto surface oxidized carbon fibers. Mechanical testing, modelling and the construction of composite preparation equipment has been achieved during the grant period.

  1. Evaluating the mechanical properties of E-Glass fiber/carbon fiber reinforced interpenetrating polymer networks

    Directory of Open Access Journals (Sweden)

    G. Suresh

    2015-02-01

    Full Text Available A series of vinyl ester and polyurethane interpenetrating polymer networks were prepared by changing the component ratios of VER (Vinyl ester and PU (Polyurethane and the polymerization process was confirmed with Fourier Transform infrared spectroscopy. IPN (Inter Penetrating Polymer Network - VER/PU reinforced Glass and carbon fiber composite laminates were made using the Hand lay up technique. The Mechanical properties of the E-glass and carbon fiber specimens were compared from tests including Tensile, Compressive, Flexural, ILSS (Inter Laminar Shear Strength, Impact & Head Deflection Test (HDT. The IPN Reinforced Carbon fiber specimen showed better results in all the tests than E-Glass fibre reinforced IPN laminate with same thickness of the specimen, according to ASTM standards. It was found that the combination of 60%VER and 40%PU IPN exhibits better impact strength and maximum elongation at break, but at the slight expense of mechanical properties such as tensile, compressive, flexural, ILSS properties. The morphology of the unreinforced and reinforced composites was analyzed with help of scanning electron microscopy.

  2. 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.

  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. Preliminary studies of epoxidized palm oil as sizing chemical for carbon fibers

    International Nuclear Information System (INIS)

    Epoxidized palm oil is derived from palm oil through chemical reaction with peracetic acid. Preliminary studies to coat carbon fibers have shown promising result towards applying natural product in carbon fibre composites. Mechanical studies of sized carbon fibers with epoxidized palm oil showed significant increase in tensile and interfacial shear strength. Surface morphology of sized or coated carbon fibers with epoxidized palm oil reveals clear increase in root means square-roughness (RMS). This indicates the change of the surface topography due to sized or coated carbon fibers with epoxidized palm oil. (author)

  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. 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.

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

    Directory of Open Access Journals (Sweden)

    Koichi Sawada

    2014-01-01

    Full Text Available 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 fibers after silica removal had a porous structure originating from 15 nm diameter silica NPs. Energy dispersive X-ray analysis combined with TEM confirmed the removal of silica from the fibers by NaOH treatment at 80°C. Total surface area and total pore volume of the fibers after silica removal, determined by nitrogen adsorption measurement, were 318 m2/g and 1.67 cm3/g, respectively. The sheet resistivities of the fabricated fibers were 35.1–477 Ω/□, which were relatively high, compared with that reported for polyacrylonitrile-based fibers carbonized at 800°C. D and G bands detected in the Raman spectrum of the NaOH-treated fibers showed that the prepared carbon fibers were more crystalline than natural carbonaceous materials.

  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. 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...

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

    Science.gov (United States)

    Chu,Benjamin; Hsiao, Benjamin S.

    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.

  11. 21 CFR 878.3500 - Polytetrafluoroethylene with carbon fibers composite implant material.

    Science.gov (United States)

    2010-04-01

    ... Prosthetic Devices § 878.3500 Polytetrafluoroethylene with carbon fibers composite implant material. (a) Identification. A polytetrafluoroethylene with carbon fibers composite implant material is a porous device... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polytetrafluoroethylene with carbon...

  12. 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.

  13. 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.

  14. 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.

  15. A series of tufted carbon fiber cathodes designed for different high power microwave sources

    Science.gov (United States)

    Liu, Lie; Li, Limin; Zhang, Jun; Zhang, Xiaoping; Wen, Jianchun; Liu, Yonggui

    2008-06-01

    We report the fabrication technique of tufted carbon fiber cathodes for different microwave sources. Three carbon fiber cathodes were constructed, including a planar cathode, an annular cathode, and a cylindrical cathode for radial emission. Experimental investigations on these cathodes were performed in a reflex triode virtual cathode oscillator (vircator), a backward wave oscillator (BWO), and a magnetically insulated transmission line oscillator (MILO), respectively. The pulse duration of microwave emission from the reflex triode vircator was lengthened by using the planar carbon fiber cathode. In the BWO with the annular carbon fiber cathode, the uniform electron beam with a kA /cm2 current density was observed. In addition, carbon fiber has great promise as field emitter for MILOs. These results show that the carbon fiber cathodes can be utilized for electron emission in high power diodes with different structures.

  16. Effect of electron beam irradiation on the properties of carbon fiber

    International Nuclear Information System (INIS)

    Carbon fibers are used as a reinforcement material in an epoxy matrix in advanced composites due to their high mechanical strength, rigidity and low specific density. An important aspect of the mechanical properties of composites is associated to the adhesion between the surface of the carbon fiber and the epoxy matrix. This paper aimed to evaluate the effects of electron beam irradiation on the physicochemical properties of carbon fibers to obtain better adhesion properties in resultant composite. Chemical structure and surface of carbon fiber were determined by FT-IR, elemental analysis and X-ray photoelectron spectroscopy, which indicated that the oxygen content increased significantly with increasing the radiation dose. Thermal stability of the carbon fibers was studied via the thermal gravimetric analysis. Surface morphology of carbon fiber was analyzed by scanning electron microscope. It was found that the degree of surface roughness was increased by electron beam irradiation

  17. Enabling long term monitoring of dopamine using dimensionally stable ultrananocrystalline diamond microelectrodes

    Science.gov (United States)

    Dutta, Gaurab; Tan, Chao; Siddiqui, Shabnam; Arumugam, Prabhu U.

    2016-09-01

    Chronic dopamine (DA) monitoring is a critical enabling technology to identify the neural basis of human behavior. Carbon fiber microelectrodes (CFM), the current gold standard electrode for in vivo fast scan cyclic voltammetry (FSCV), rapidly loses sensitivity due to surface fouling during chronic neural testing. Periodic voltage excursions at elevated anodic potentials regenerate fouled CFM surfaces but they also chemically degrade the CFM surfaces. Here, we compare the dimensional stability of 150 μm boron-doped ultrananocrystalline diamond (BDUNCD) microelectrodes in 1X PBS during ‘electrochemical cleaning’ with a similar-sized CFM. Scanning electron microscopy and Raman spectroscopy confirm the exceptional dimensional stability of BDUNCD after 40 h of FSCV cycling (∼8 million cycles). The fitting of electrochemical impedance spectroscopy data to an appropriate circuit model shows a 2x increase in charge transfer resistance and an additional RC element, which suggests oxidation of BDUNCD electrode surface. This could have likely increased the DA oxidation potential by ∼34% to +308 mV. A 2x increase in BDUNCD grain capacitance and a negligible change in grain boundary impedance suggests regeneration of grains and the exposure of new grain boundaries, respectively. Overall, DA voltammogram signals were reduced by only ∼20%. In contrast, the CFM is completely etched with a ∼90% reduction in the DA signal using the same cleaning conditions. Thus, BDUNCD provides a robust electrode surface that is amenable to repeated and aggressive cleaning which could be used for chronic DA sensing.

  18. Literature Review of the Application of Conductive Carbon Fiber-graphite Concrete in floor heating

    Directory of Open Access Journals (Sweden)

    Xie xin

    2015-07-01

    Full Text Available The technical features of conductive carbon fiber-graphite concrete are reviewed in this paper, and its generation, development and the current technology condition are also introduced. According to the researches of conductive carbon fiber-graphite concrete material in recent years, the paper presents its application in all kinds of aspects especially floor heating engineering in which its advantages can be fully used. Finally, the paper summarized the developing trend of carbon fiber-graphite conductive concrete.

  19. Activated carbon fibers prepared from quinoline and isoquinoline pitches

    Energy Technology Data Exchange (ETDEWEB)

    Mochida, I.; An, K.; Korai, Y. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Kojima, T.; Komatsu, M. [Mitsubishi Gas Chemical Co. Inc., Tokyo (Japan); Yoshikawa, M. [Osaka Gas Co. Ltd., Osaka (Japan)

    1998-11-01

    Nitrogen enriched activated carbon fibers (ACFs) were prepared from isotropic quinoline and isoquinoline pitches produced by the catalytic action of HF/BF3 through spinning, stabilization, carbonization, and oxidative activation. The pitches exhibited excellent spinnability, and the resultant fibers had mechanical properties comparable to those of commercial fibers. The surface areas and nitrogen contents of the ACFs, obtained hereby were 740-860 m{sup 2}/g and 4-5.6%, respectively, at around 50 wt% of burn-off. FT-IR and XPS analyses identified the surface oxygen and nitrogen functional groups on the stabilized and activated fibers. The ACFs from isoquinoline pitch (IQP-ACF) exhibited higher basicity (l.3 meq/g) than commercial ACFs of similar surface areas (0.68 and 0.25 meq/g for PAN (FE-300) and coal tar pitch (OG-8A) based ACFs, respectively) due to a higher basic nitrogen content on the surface. The activation appears to expose basic nitrogen atoms, which were located under the surface. The basicity of ACF from quinoline pitch (QP-ACF) was much lower than that of IQP-ACF, however, QP-ACF adsorbed 74 mg/g of SO2, which was 1.4 and 2.3 times higher than that over FE-300 and OG-8A. In contrast, IQP-ACFs showed less adsorption of SO2 than that of QP-ACF and FE-300, but more than that of OG-8A. Oxidation activity of ACF surface may participate in the adsorption of SO2 in the form of SO3 or H2SO4. The oxygen functional groups under the influence of neighboring nitrogen atoms may be the active sites for the oxidative adsorption. 15 refs., 8 figs., 4 tabs.

  20. Prospects in using carbon-carbon composite materials based on viscose carbon fibers for the space technology needs

    International Nuclear Information System (INIS)

    Due to the unique combination of low density, high mechanical strength under elevated temperatures, high resistance to thermal shock loads and ablation resistance, carbon-carbon composite materials (CCCM) are widely used for manufacturing of highly thermally loaded structural components. The important scientific and technical difficulty is to increase and stabilize CCCM properties, reduce cost and leads to searching for new raw materials and engineering solutions. The article describes the prospects of replacing carbon fiber fills based on PAN-precursors which are traditionally used for producing CCCM by carbon fillers on the basis of viscose raw material; shows the advantages of using viscose-based carbon fibers when forming products of complex shape as well as the possibility of obtaining products with high functional characteristics. The creation of CCCM of layered reinforcement structure, in which carbon fabric layers interleave with layers of discontinuous carbon fibers, enabled to increase the overall density of carbon composites, to ensure sufficiently high level of mechanical characteristics and resistance to ablation

  1. 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.

  2. 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.

  3. Effect of gamma-ray radiation on the polyacrylonitrile based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhiwei, E-mail: xuzhiwei@tjpu.edu.c [Key Laboratory of Advanced Braided Composites, Ministry of Education, Composite Research Institute, Chenglin Road, Tianjin Polytechnic University, Tianjin 300160 (China); Huang Yudong [School of Chemical Engineering and Technology, Harbin Institute of Technology, P.O. Box 410, Harbin 150001 (China); Min Chunying [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Chen Lei; Chen Li [Key Laboratory of Advanced Braided Composites, Ministry of Education, Composite Research Institute, Chenglin Road, Tianjin Polytechnic University, Tianjin 300160 (China)

    2010-08-15

    To investigate the effect of gamma-ray radiation on the microstructural and mechanical properties of carbon fibers, carbon fibers were irradiated by {sup 60}Co source. The interlayer spacing d{sub 002} of carbon fibers decreased after irradiation. The Young's modulus and density of the fibers increased with increasing dose. The tensile strength of fibers was found to increase at low dose and decrease at high dose. Additionally, Compton scattering effect caused by gamma-ray is proposed to be responsible for the structural and mechanical changes of fibers. The results indicated that gamma-ray irradiation was an effective method for improving the mechanical properties and graphitization degree of polyacrylonitrile based carbon fibers.

  4. Influence of metal-containing carbon fibers on the properties of carbon-filled plastics based on aromatic polyamide

    Science.gov (United States)

    Burya, A. I.; Safonova, A. M.; Rula, I. V.

    2012-07-01

    The influence of metal-containing carbon fibers on the thermal properties of carbon-filled phenylone-based plastics has been investigated. It has been shown that carbometallic fibers containing in their composition 20- 30 mass % of a finely dispersed metal (Co, Cu) are promising fillers of phenylone C-2 for making carbonfilled plastics working in frictional units of various machines and mechanisms.

  5. Deuterium trapping in carbon fiber composites exposed to D plasma

    Energy Technology Data Exchange (ETDEWEB)

    Airapetov, A. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Begrambekov, L., E-mail: lbb@plasma.mephi.r [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Brosset, C.; Gunn, J.P.; Grisolia, C. [Association EURATOM-CEA, CEA/DSM/DRFC Cadarache, 13108 St. Paul lez Durance (France); Kuzmin, A. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Loarer, T.; Lipa, M.; Monier-Garbet, P. [Association EURATOM-CEA, CEA/DSM/DRFC Cadarache, 13108 St. Paul lez Durance (France); Shigin, P. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Tsitrone, E. [Association EURATOM-CEA, CEA/DSM/DRFC Cadarache, 13108 St. Paul lez Durance (France); Zakharov, A. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation)

    2009-06-15

    Deuterium trapping in carbon fiber composite N11 and pyrolitic graphite PG99 irradiated with plasma ions and electrons was examined with thermal desorption spectrometry. It has been found that the deuterium trapping takes place even at ion and electron energies of about 10 eV. For equal ion fluences, the deuterium retention and probability of CD{sub 4} formation are higher for ion irradiation at lower ion flux. Peculiarities of the deuterium retention and CD{sub 4} formation are explained; driving forces and mechanisms of the D trapping are discussed.

  6. Laser ultrasound technology for fault detection on carbon fiber composites

    Science.gov (United States)

    Seyrkammer, Robert; Reitinger, Bernhard; Grün, Hubert; Sekelja, Jakov; Burgholzer, Peter

    2014-05-01

    The marching in of carbon fiber reinforced polymers (CFRPs) to mass production in the aeronautic and automotive industry requires reliable quality assurance methods. Laser ultrasound (LUS) is a promising nondestructive testing technique for sample inspection. The benefits compared to conventional ultrasound (US) testing are couplant free measurements and an easy access to complex shapes due to remote optical excitation and detection. Here the potential of LUS is present on composite test panels with relevant testing scenarios for industry. The results are evaluated in comparison to conventional ultrasound used in the aeronautic industry.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Structure and electrochemical properties of activated polyacrylonitrile based carbon fibers containing carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Jagannathan, Sudhakar; Chae, Han Gi; Jain, Rahul; Kumar, Satish [School of Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2008-12-01

    Solution spun polyacrylonitrile (PAN), PAN/multi-wall carbon nanotube (MWCNT), and PAN/single-wall carbon nanotube (SWCNT) fibers containing 5 wt.% carbon nanotubes were stabilized in air and activated using CO{sub 2} and KOH. The surface area as determined by nitrogen gas adsorption was an order of magnitude higher for KOH activated fibers as compared to the CO{sub 2} activated fibers. The specific capacitance of KOH activated PAN/SWCNT samples was as high as 250 F g{sup -1} in 6 M KOH electrolyte. Under the comparable KOH activation conditions, PAN and PAN/SWCNT fibers had comparable surface areas (BET surface area about 2200 m{sup 2} g{sup -1}) with pore size predominantly in the range of 1-5 nm, while surface area of PAN/MWCNT samples was significantly lower (BET surface area 970 m{sup 2} g{sup -1}). The highest capacitance and energy density was obtained for PAN/SWCNT samples, suggesting SWCNT advantage in charge storage. The capacitance behavior of these electrodes has also been tested in ionic liquids, and the energy density in ionic liquid is about twice the value obtained using KOH electrolyte. (author)

  12. 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.

  13. 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.

  14. 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.

  15. Thermal and electrical conductivities of carbon fibers and carbon nanotubes incorporated polyurethanes composites

    International Nuclear Information System (INIS)

    Single filler polyurethane composites with carbon fibers (CFs) and multi-walled carbon nanotubes (MWNTs) were prepared by melt mixing methods and its thermal as well as electrical resistivity characteristics were investigated. The influences of fillers and mixing methods on thermal and electrical conductivity of CF/- and MWNT/polyurethane composites were investigated and the result shows that the addition of carbon fillers improved the thermal conductivity of the polyurethane composites. Higher filler concentration results in better thermal conductivity because better formation of thermally conductive networks along polymer matrix to ensure the thermal was conducted through the matrix and the network along the polymer composites. The presence of carbon additives improves the electrical resistivity of the materials as well. The present study revealed the potential of carbon as agent for better thermal and electrical conductivities and their properties depend strongly on the dispersion and distribution of the fillers in the polymer matrix. (author)

  16. 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.

  17. 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.

  18. 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.

  19. Enhancement of Charpy impact value by electron beam irradiation of carbon fiber reinforced polymer

    International Nuclear Information System (INIS)

    Influences of electron beam irradiation on Charpy impact value of carbon fiber reinforced polymer (CFRP) have been investigated. The irradiation, which is one of short-time treatments, enhanced the Charpy impact value of CFRP. Furthermore, strengthening of carbon fiber, ductility enhancement of polymer and interface effects on impact test explains the impact value enhancement of CFRP. (author)

  20. 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 ...

  1. [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.

  2. 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...

  3. 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.

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

    International Nuclear Information System (INIS)

    Highlights: • A new chemical grafting method for carbon fibers was proposed. • The oxidation system adopts K2S2O8 and AgNO3. • 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-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

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

    OpenAIRE

    Arafat Shabaneh; Saad Girei; Punitha Arasu; Mohd Mahdi; Suraya Rashid; Suriati Paiman; Mohd Yaacob

    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...

  6. 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.

  7. TECHNICAL NOTE: Design and development of electromagnetic absorbers with carbon fiber composites and matching dielectric layers

    Science.gov (United States)

    Neo, C. P.; Varadan, V. K.

    2001-10-01

    Radar absorbing materials are designed and developed with carbon fibers and suitable matching layers. Complex permittivities of carbon fiber composite are predicted on the basis that the modulus of permittivity obeys a logarithmic law of mixtures and the dielectric loss tangents are related through a linear law of mixtures. Linear regression analysis performed on the data points provides the constants which are used to predict the effective permittivities of carbon fiber composite at different frequencies. Using the free space measurement system, complex permittivities of the lossy dielectric at different frequencies are obtained. These complex permittivities are used to predict the reflectivity of a thin lossy dielectric layer on carbon fiber composite substrate. The predicted results agree quite well with the measured data. It is interesting to note that the thin lossy dielectric layer, about 0.03 mm thick, has helped to reduce the reflectivity of the 5.2 mm thick carbon fiber composite considerably.

  8. Effects of EB irradiation on stress-strain curves for carbon fiber reinforced composite materials

    Science.gov (United States)

    Kobayashi, H.; Yamada, K.; Mizutani, A.; Uchida, N.; Tanaka, K.; Nishi, Yoshitake

    2004-02-01

    In order to evaluate influence of electron beam (EB) irradiation on elasticity and stress- strain curve of composite materials reinforced by carbon fiber (CF), carbon fiber reinforced polymer (CFRP) and carbon fiber reinforced graphite (C/C) were treated by EB irradiation of 0.3 MGy. Since the EB strengthening was mainly dominated by the ductility enhancements of carbon fiber and matrix of epoxy resin, EB irradiation enlarged fracture stress and enhanced fracture strain of CFRP. Furthermore, EB irradiation slightly enhanced bending elasticity of CFRP and largely enhanced the initial spring constant related to elasticity of C/C coil. Although the elasticity enhancement of carbon fibers did not largely contribute that of CFRP, that of treated graphite matrix in C/C mainly caused the C/C coil elasticity enhancement by EB irradiation. Such a new treatment is a dream-worthy technology for structural materials to be applied in the fields of future 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. 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.

  12. 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

  13. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Menchhofer, Paul A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Johnson, Joseph E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Lindahl, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    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.

  15. CARBON NANOTUBE CHOPPED FIBER FOR ENHANCIED PROPERTIES IN ADDITIVE MANUFACTURING

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

    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.

  16. 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.

  17. Research and Development of Carbon Nano fibers Modified Carbon Fiber%碳纳米纤维修饰碳纤维的研究及其进展

    Institute of Scientific and Technical Information of China (English)

    韩俊儒; 孟龙月; 潘海丽; 刘康恺; 金香梅

    2015-01-01

    综述了各种碳纤维的制备方法及其研究进展,特别对碳纳米管修饰碳纤维的研究进展进行了重点介绍,论述了化学气相沉淀法和接枝法制备碳纳米纤维/碳纤维复合材料增强体,对两种制备工艺的优缺点进行了阐述,以及对碳纳米纤维/碳纤维复合材料的研究前景作了简要展望。%The objective of this work is to provide a review on the preparation of various carbon fibers and its research progress.Especially focused on the carbon nanofibers modified carbon fibers and its research progress, the method of chemical vapor deposition and the grafted carbon nano fiber/carbon fiber reinforced composites was discussed, the advantages and disadvantages of the two kinds of preparation process were described, and research foreground of carbon nanofibers/carbon fibers composites was expected briefly.

  18. Development of silicon-based microelectrode array

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper introduces in details a kind of silicon-based microelectrode array. MEMS (micro-electromechanical system) technology is used in the fabrication of the microelectrode array, which is designed to perform signal recording and electrical stimulation for nerves in neural engineering. A simple fabrication process is developed. An improved model of microelectrodes is brought forward and successfully validated by the excellent match between circuit simulations and electrical measurements, including both magnitude and phase of microelectrode impedance. Compared with the simple one that is usually used, the improved model is believed to be an advance and more accurate. This modeling helps to improve the design of microelectrodes and understand the behavior of interface between electrode and cell. Furthermore, the microelectrode is proved to be a feasible tool for researches in neural engineering by successfully recording neural activities of sciatic nerve of a bullfrog.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, Robert Andrew; Pawelko, Robert James; Smolik, Galen Richard

    2001-05-01

    This report documents experiments and analyses that have been done at the Idaho National Engineering and Environmental Laboratory (INEEL) to measure the steam chemical reactivity of two types of carbon fiber composites, NS31 and NB31, proposed for use at the divertor strike points in an ITER-like tokamak. These materials are 3D CFCs constituted by a NOVOLTEX preform and densified by pyrocarbon infiltration and heat treatment. NS31 differs from NB31 in that the final infiltration was done with liquid silicon to reduce the porosity and enhance the thermal conductivity of the CFC. Our approach in this work was twofold: (1) physical characterization measurements of the specimens and (2) measurements of the chemical reactivity of specimens exposed to steam.

  4. 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.

  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

    2016-05-01

    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. 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 

  7. Enhanced electromagnetic properties of nickel nanoparticiles dispersed carbon fiber via electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeong Ju; Kim, Hyun Bin; Lee, Seung Jun; Kang, Phil Hyun [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2015-02-15

    Carbon fiber has received much attention owing to its properties, including a large surface-to-volume ratio, chemical and thermal stability, high thermal and electrical conductivity, and high mechanical strengths. In particular, magnetic nanopowder dispersed carbon fiber has been attractive in technological applications such as the electrochemical capacitor and electromagnetic wave shielding. In this study, the nickel-oxide-nanoparticle dispersed polyacrylonitrile (PAN) fibers were prepared through an electrospinning method. Electron beam irradiation was carried out with a 2.5 MeV beam energy to stabilize the materials. The samples were then heat treated for stabilization and carbonization. The nanofiber surface was analyzed using a field emission scanning electron microscope (FE-SEM). The crystal structures of the carbon matrix and nickel nanopowders were analysed using X-ray diffraction (XRD). In addition, the magnetic and electrical properties were analyzed using a vibrating sample magnetometer (VSM) and 4 point probe. As the irradiation dose increases, the density of the carbon fiber was increased. In addition, the electrical properties of the carbon fiber improved through electron beam irradiation. This is because the amorphous region of the carbon fiber decreases. This electron beam effect of PAN fibers containing nickel nanoparticles confirmed their potential as a high performance carbon material for various applications.

  8. 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.

  9. 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.

  10. Investigation of carbonized layer on surface of NaAlSi glass fibers

    International Nuclear Information System (INIS)

    There are presented and discussed experimental results about carbonate shell on the sodium rich alumosilicate (NaAlSi) glass fibers and carbonization in wet air atmosphere and water uptake kinetic of such fiber fabrics. The analyzes of water uptake kinetic by regression technique, leaching and heating of carbonized glass fabrics helped to separate stages of fast and slow processes between fiber and carbonate shell and air atmosphere. The shell contains mixture of trona and hydrated sodium carbonate. Heating converts both substances to sodium carbonate. The weight uptake after heating encounters two fast exponential processes associated with water absorption on the surface of carbonated shell and its diffusion into volume. The slow process associates with CO2 and H2O absorption from air, hydration and sodium carbonate conversion to trona

  11. Mechanical Properties, Surface Structure, and Morphology of Carbon Fibers Pre-heated for Liquid Aluminum Infiltration

    Science.gov (United States)

    Kachold, Franziska S.; Kozera, Rafal; Singer, Robert F.; Boczkowska, Anna

    2016-04-01

    To efficiently produce carbon fiber-reinforced aluminum on a large scale, we developed a special high-pressure die casting process. Pre-heating of the fibers is crucial for successful infiltration. In this paper, the influence of heating carried out in industrial conditions on the mechanical properties of the fibers was investigated. Therefore, polyacrylonitrile-based high-tensile carbon fiber textiles were heated by infrared emitters in an argon-rich atmosphere to temperatures between 450 and 1400 °C. Single fiber tensile tests revealed a decrease in tensile strength and strain at fracture. Young's modulus was not affected. Scanning electron microscopy identified cavities on the fiber surface as the reason for the decrease in mechanical properties. They were caused by the attack of atmospheric oxygen. The atomic structure of the fibers did not change at any temperature, as x-ray diffraction confirmed. Based on these data, the pre-heating for the casting process can be optimized.

  12. Literature Review of the Application of Conductive Carbon Fiber-graphite Concrete in floor heating

    OpenAIRE

    Xie xin; Zou Mengqiu

    2015-01-01

    The technical features of conductive carbon fiber-graphite concrete are reviewed in this paper, and its generation, development and the current technology condition are also introduced. According to the researches of conductive carbon fiber-graphite concrete material in recent years, the paper presents its application in all kinds of aspects especially floor heating engineering in which its advantages can be fully used. Finally, the paper summarized the developing trend of carbon ...

  13. 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.

  14. 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

  15. Use of nondestructive inspection and fiber optic sensing for damage characterization in carbon fiber fuselage structure

    Science.gov (United States)

    Neidigk, Stephen; Le, Jacqui; Roach, Dennis; Duvall, Randy; Rice, Tom

    2014-04-01

    To investigate a variety of nondestructive inspection technologies and assess impact damage characteristics in carbon fiber aircraft structure, the FAA Airworthiness Assurance Center, operated by Sandia National Labs, fabricated and impact tested two full-scale composite fuselage sections. The panels are representative of structure seen on advanced composite transport category aircraft and measured approximately 56"x76". The structural components consisted of a 16 ply skin, co-cured hat-section stringers, fastened shear ties and frames. The material used to fabricate the panels was T800 unidirectional pre-preg (BMS 8-276) and was processed in an autoclave. Simulated hail impact testing was conducted on the panels using a high velocity gas gun with 2.4" diameter ice balls in collaboration with the University of California San Diego (UCSD). Damage was mapped onto the surface of the panels using conventional, hand deployed ultrasonic inspection techniques, as well as more advanced ultrasonic and resonance scanning techniques. In addition to the simulated hail impact testing performed on the panels, 2" diameter steel tip impacts were used to produce representative impact damage which can occur during ground maintenance operations. The extent of impact damage ranges from less than 1 in2 to 55 in2 of interply delamination in the 16 ply skin. Substructure damage on the panels includes shear tie cracking and stringer flange disbonding. It was demonstrated that the fiber optic distributed strain sensing system is capable of detecting impact damage when bonded to the backside of the fuselage.

  16. 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.

  17. 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...

  18. 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

  19. 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.

  20. Mechanical Properties of Carbon Fiber-Reinforced Aluminum Manufactured by High-Pressure Die Casting

    Science.gov (United States)

    Kachold, Franziska; Singer, Robert

    2016-03-01

    Carbon fiber reinforced aluminum was produced by a specially adapted high-pressure die casting process. The MMC has a fiber volume fraction of 27%. Complete infiltration was achieved by preheating the bidirectional, PAN-based carbon fiber body with IR-emitters to temperatures of around 750 °C. The degradation of the fibers, due to attack of atmospheric oxygen at temperatures above 600 °C, was limited by heating them in argon-rich atmosphere. Additionally, the optimization of heating time and temperature prevented fiber degradation. Only the strength of the outer fibers is reduced by 40% at the most. The fibers in core of fiber body are nearly undamaged. In spite of successful manufacturing, the tensile strength of the MMC is below strength of the matrix material. Also unidirectional MMCs with a fiber volume fraction of 8% produced under the same conditions, lack of the reinforcing effect. Two main reasons for the unsatisfactory mechanical properties were identified: First, the fiber-free matrix, which covers the reinforced core, prevents effective load transfer from the matrix to the fibers. And second, the residual stresses in the fiber-free zones are as high as 100 MPa. This causes premature failure in the matrix. From this, it follows that the local reinforcement of an actual part is limited. The stress distribution caused by residual stresses and by loading needs to be known. In this way, the reinforcing phase can be placed and aligned accordingly. Otherwise delamination and premature failure might occur.

  1. Electrospinning of calcium carbonate fibers and their conversion to nanocrystalline hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Holopainen, Jani, E-mail: jani.holopainen@helsinki.fi; Santala, Eero; Heikkilä, Mikko; Ritala, Mikko

    2014-12-01

    Calcium carbonate (CaCO{sub 3}) fibers were prepared by electrospinning followed by annealing. Solutions consisting of calcium nitrate tetrahydrate (Ca(NO{sub 3}){sub 2}·4H{sub 2}O) and polyvinylpyrrolidone (PVP) dissolved in ethanol or 2-methoxyethanol were used for the fiber preparation. By varying the precursor concentrations in the electrospinning solutions CaCO{sub 3} fibers with average diameters from 140 to 290 nm were obtained. After calcination the fibers were identified as calcite by X-ray diffraction (XRD). The calcination process was studied in detail with high temperature X-ray diffraction (HTXRD) and thermogravimetric analysis (TGA). The initially weak fiber-to-substrate adhesion was improved by adding a strengthening CaCO{sub 3} layer by spin or dip coating Ca(NO{sub 3}){sub 2}/PVP precursor solution on the CaCO{sub 3} fibers followed by annealing of the gel formed inside the fiber layer. The CaCO{sub 3} fibers were converted to nanocrystalline hydroxyapatite (HA) fibers by treatment in a dilute phosphate solution. The resulting hydroxyapatite had a plate-like crystal structure with resemblance to bone mineral. The calcium carbonate and hydroxyapatite fibers are interesting materials for bone scaffolds and bioactive coatings. - Highlights: • Calcium carbonate fibers were prepared by electrospinning. • The electrospun fibers crystallized to calcite upon calcination at 500 °C. • Spin and dip coating methods were used to improve the adhesion of the CaCO{sub 3} fibers. • The CaCO{sub 3} fibers were converted to hydroxyapatite by treatment in phosphate solution. • The hydroxyapatite fibers consisted of plate-like nanocrystals.

  2. Fabrication and Characterization of a Pressure Sensor using a Pitch-based Carbon Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Sin; Kang, Bo Seon; Lee, Dong Weon [Chonnam National Univ., Gwangju (Korea, Republic of)

    2007-04-15

    This paper reports fabrication and characterization of a pressure sensor using a pitch-based carbon fiber. Pitch-based carbon fibers have been shown to exhibit the piezoresistive effect, in which the electric resistance of the carbon fiber changes under mechanical deformation. The main structure of pressure sensors was built by performing backside etching on a SOI wafer and creating a suspended square membrane on the front side. An AC electric field which causes dielectrophoresis was used for the alignment and deposition of a carbon fiber across the microscale gap between two electrodes on the membrane. The fabricated pressure sensors were tested by applying static pressure to the membrane and measuring the resistance change of the carbon fiber. The resistance change of carbon fibers clearly shows linear response to the applied pressure and the calculated sensitivities of pressure sensors are 0.25{approx}0.35 and 61.8 {omega}/k{omega}{center_dot}bar for thicker and thinner membrane, respectively. All these observations demonstrated the possibilities of carbon fiber-based pressure sensors.

  3. 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.

  4. 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 ...... 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....

  5. 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.

  6. 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. PMID:21074162

  7. 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.

  8. Method of improving adhesion of carbon fibers with a polymeric matrix

    Energy Technology Data Exchange (ETDEWEB)

    Vautard, Frederic; Ozcan, Soydan; Paulauskas, Felix Leonard

    2016-06-14

    A functionalized carbon fiber having covalently bound on its surface a partially cured epoxy or amine-containing sizing agent, wherein at least a portion of epoxide or amine groups in the sizing agent are available as uncrosslinked epoxide or amine groups, which corresponds to a curing degree of epoxide or amine groups of no more than about 0.6. Composites comprised of these functionalized carbon fibers embedded in a polymeric matrix are also described. Methods for producing the functionalized carbon fibers and composites thereof are also described.

  9. Carbon nanotube- and carbon fiber-reinforcement of ethylene-octene copolymer membranes for gas and vapor separation

    OpenAIRE

    Zuzana Sedláková; Gabriele Clarizia; Paola Bernardo; Johannes Carolus Jansen; Petr Slobodian; Petr Svoboda; Magda Kárászová; Karel Friess; Pavel Izak

    2014-01-01

    Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene)) with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs) and carbon fibers (CFs). Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane), aromatic compound (toluene), al...

  10. 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.)

  11. Surface modification of polyacrylonitrile-based carbon fiber and its interaction with imide

    Energy Technology Data Exchange (ETDEWEB)

    Xu Bing [Department of Polymer Science and Engineering, State Key Lab Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Wang Xiaoshu [Centre for Materials Analysis, Nanjing University, Nanjing 210093 (China); Lu Yun [Department of Polymer Science and Engineering, State Key Lab Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)]. E-mail: yunlu@nju.edu.cn

    2006-12-30

    In this work, sized polyacrylonitrile (PAN)-based carbon fibers were chemically modified with nitric acid and maleic anhydride (MA) in order to improve the interaction between carbon fiber surface and polyimide matrix. Bismaleimide (BMI) was selected as a model compound of polyimide to react with modified carbon fiber. The surface characteristic changing after modification and surface reaction was investigated by element analysis (EA), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and surface enhanced Raman scattering (SERS). The results indicated that the modification of carbon fiber surface with MA might follow the Diels Alder reaction mechanism. In the surface reaction between modified fibers and BMI, among the various surface functional groups, the hydroxyl group provided from phenolic hydroxyl group and bridged structure on carbon fiber may be the most effective group reacted with imide structure. The results may shed some light on the design of the appropriate surface structure, which could react with polyimide, and the manufacture of the carbon fiber-reinforced polyimide matrix composites.

  12. Textile electrodes woven by carbon nanotube-graphene hybrid fibers for flexible electrochemical capacitors

    Science.gov (United States)

    Cheng, Huhu; Dong, Zelin; Hu, Chuangang; Zhao, Yang; Hu, Yue; Qu, Liangti; Chen, Nan; Dai, Liming

    2013-03-01

    Functional graphene-based fibers are promising as new types of flexible building blocks for the construction of wearable architectures and devices. Unique one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene (CNT/G) hybrid fibers with a large surface area and high electrical conductivity have been achieved by pre-intercalating graphene fibers with Fe3O4 nanoparticles for subsequent CVD growth of CNTs. The CNT/G hybrid fibers can be further woven into textile electrodes for the construction of flexible supercapacitors with a high tolerance to the repeated bending cycles. Various other applications, such as catalysis, separation, and adsorption, can be envisioned for the CNT/G hybrid fibers.Functional graphene-based fibers are promising as new types of flexible building blocks for the construction of wearable architectures and devices. Unique one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene (CNT/G) hybrid fibers with a large surface area and high electrical conductivity have been achieved by pre-intercalating graphene fibers with Fe3O4 nanoparticles for subsequent CVD growth of CNTs. The CNT/G hybrid fibers can be further woven into textile electrodes for the construction of flexible supercapacitors with a high tolerance to the repeated bending cycles. Various other applications, such as catalysis, separation, and adsorption, can be envisioned for the CNT/G hybrid fibers. Electronic supplementary information (ESI) available: Electrochemical measurement of graphene fibers. See DOI: 10.1039/c3nr00320e

  13. 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.

  14. 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.

  15. Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.

    Science.gov (United States)

    Ummadi, Jyothir Ganesh; Downs, Corey J; Joshi, Vrushali S; Ferracane, Jack L; Koley, Dipankar

    2016-03-15

    Solid-state ion-selective electrodes are used as scanning electrochemical microscope (SECM) probes because of their inherent fast response time and ease of miniaturization. In this study, we report the development of a solid-state, low-poly(vinyl chloride), carbon-based calcium ion-selective microelectrode (Ca(2+)-ISME), 25 μm in diameter, capable of performing an amperometric approach curve and serving as a potentiometric sensor. The Ca(2+)-ISME has a broad linear response range of 5 μM to 200 mM with a near Nernstian slope of 28 mV/log[a(Ca(2+))]. The calculated detection limit for Ca(2+)-ISME is 1 μM. The selectivity coefficients of this Ca(2+)-ISME are log K(Ca(2+),A) = -5.88, -5.54, and -6.31 for Mg(2+), Na(+), and K(+), respectively. We used this new type of Ca(2+)-ISME as an SECM probe to quantitatively map the chemical microenvironment produced by a model substrate, bioactive glass (BAG). In acidic conditions (pH 4.5), BAG was found to increase the calcium ion concentration from 0.7 mM ([Ca(2+)] in artificial saliva) to 1.4 mM at 20 μm above the surface. In addition, a solid-state dual SECM pH probe was used to correlate the release of calcium ions with the change in local pH. Three-dimensional pH and calcium ion distribution mapping were also obtained by using these solid-state probes. The quantitative mapping of pH and Ca(2+) above the BAG elucidates the effectiveness of BAG in neutralizing and releasing calcium ions in acidic conditions. PMID:26861499

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. Rheological and LASER additives for higher efficiency in producing poly(acrylonitrile)-based carbon fibers

    OpenAIRE

    Herbert, Christian

    2016-01-01

    This work is based on the NRW Ziel2 ‘Megacarbon’ project which aims for the more resource efficient production of carbon fibers (CF) for the automotive market. In cooperation with the Dralon GmbH in Dormagen a CF precursor with properties at least equal to the industry reference fiber Bluestar was developed and used in fiber spinning experiments. For the improvement of the spinning process a hyperbranched, rheological additive was synthesized for the decrease of dynamic viscosity over a broad...

  2. High-resolution Brillouin analysis in a carbon-fiber-composite unmanned aerial vehicle model wing

    Science.gov (United States)

    Stern, Yonatan; London, Yosef; Preter, Eyal; Antman, Yair; Shlomi, Orel; Silbiger, Maayan; Adler, Gadi; Zadok, Avi

    2016-05-01

    Standard optical fibers are successfully embedded within a model wing of an unmanned aerial vehicle, constructed of carbon fiber and epoxy, during its production. Time-gated Brillouin optical correlation domain analysis along the embedded optical fibers is performed with a spatial resolution of 4 cm. Tests were carried out using a portable measurement setup prototype. The results represent an important step towards applications of high-resolution Brillouin analysis outside the research laboratory.

  3. 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

  4. Thermal oxidation induced degradation of carbon fiber reinforced composites and carbon nanotube sheet enhanced fiber/matrix interface for high temperature aerospace structural applications

    Science.gov (United States)

    Haque, Mohammad Hamidul

    Recent increase in the use of carbon fiber reinforced polymer matrix composite, especially for high temperature applications in aerospace primary and secondary structures along with wind energy and automotive industries, have generated new challenges to predict its failure mechanisms and service life. This dissertation reports the experimental study of a unidirectional carbon fiber reinforced bismaleimide (BMI) composites (CFRC), an excellent candidate for high temperature aerospace components, undergoing thermal oxidation at 260 °C in air for over 3000 hours. The key focus of the work is to investigate the mechanical properties of the carbon fiber BMI composite subjected to thermal aging in three key aspects - first, studying its bulk flexural properties (in macro scale), second, characterizing the crack propagation along the fiber direction, representing the interfacial bonding strength between fiber and matrix (in micro scale), and third, introducing nano-structured materials to modify the interface (in nano scale) between the carbon fiber and BMI resin and mechanical characterization to study its influence on mitigating the aging effect. Under the first category, weight loss and flexural properties have been monitored as the oxidation propagates through the fiber/matrix interface. Dynamic mechanical analysis and micro-computed tomography analysis have been performed to analyze the aging effects. In the second category, the long-term effects of thermal oxidation on the delamination (between the composite plies) and debonding (between fiber and matrix) type fracture toughness have been characterized by preparing two distinct types of double cantilever beam specimens. Digital image correlation has been used to determine the deformation field and strain distribution around the crack propagation path. Finally the resin system and the fiber/matrix interface have been modified using nanomaterials to mitigate the degradations caused by oxidation. Nanoclay modified

  5. Research of fiber carbon dioxide sensing system based laser absorption spectrum

    Science.gov (United States)

    Wei, Yubin; Zhang, Tingting; Li, Yanfang; Zhao, Yanjie; Wang, Chang; Liu, Tongyu

    2012-02-01

    Carbon dioxide is one of the important gas need to be detected in coal mine safety. In the mine limited ventilation environment, Concentration of carbon dioxide directly affects the health of coal miners. Carbon dioxide is also one of important signature Gas in spontaneous combustion forecasting of coal goaf area, it is important to accurately detect concentration of carbon dioxide in coal goaf area. This paper proposed a fiber carbon dioxide online sensing system based on tunable diode laser spectroscopy. The system used laser absorption spectroscopy and optical fiber sensors combined, and a near-infrared wavelength 1608nm fiber-coupled distributed feedback laser (DFB) as a light source and a 7cm length gas cell, to achieve a high sensitivity concentration detection of carbon dioxide gas. The technical specifications of sensing system can basically meet the need of mine safety.

  6. Three-dimensional carbon fibers and method and apparatus for their production

    Science.gov (United States)

    Muradov, Nazim Z.

    2012-02-21

    This invention relates to novel three-dimensional (3D) carbon fibers which are original (or primary) carbon fibers (OCF) with secondary carbon filaments (SCF) grown thereon, and, if desired, tertiary carbon filaments (TCF) are grown from the surface of SCF forming a filamentous carbon network with high surface area. The methods and apparatus are provided for growing SCF on the OCF by thermal decomposition of carbonaceous gases (CG) over the hot surface of the OCF without use of metal-based catalysts. The thickness and length of SCF can be controlled by varying operational conditions of the process, e.g., the nature of CG, temperature, residence time, etc. The optional activation step enables one to produce 3D activated carbon fibers with high surface area. The method and apparatus are provided for growing TCF on the SCF by thermal decomposition of carbonaceous gases over the hot surface of the SCF using metal catalyst particles.

  7. Stretchable Micro-Electrode Array

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, M; Hamilton, J; Polla, D; Rose, K; Wilson, T; Krulevitch, P

    2002-03-08

    This paper focuses on the design consideration, fabrication processes and preliminary testing of the stretchable micro-electrode array. We are developing an implantable, stretchable micro-electrode array using polymer-based microfabrication techniques. The device will serve as the interface between an electronic imaging system and the human eye, directly stimulating retinal neurons via thin film conducting traces and electroplated electrodes. The metal features are embedded within a thin ({approx}50 micron) substrate fabricated using poly (dimethylsiloxane) (PDMS), a biocompatible elastomeric material that has very low water permeability. The conformable nature of PDMS is critical for ensuring uniform contact with the curved surface of the retina. To fabricate the device, we developed unique processes for metalizing PDMS to produce robust traces capable of maintaining conductivity when stretched (5%, SD 1.5), and for selectively passivating the conductive elements. An in situ measurement of residual strain in the PDMS during curing reveals a tensile strain of 10%, explaining the stretchable nature of the thin metalized devices.

  8. 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...

  9. 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.

  10. 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...

  11. 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.

  12. Self-Sensing Properties of Alkali Activated Blast Furnace Slag (BFS Composites Reinforced with Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Pedro Garcés

    2013-10-01

    Full Text Available In recent years, several researchers have shown the good performance of alkali activated slag cement and concretes. Besides their good mechanical properties and durability, this type of cement is a good alternative to Portland cements if sustainability is considered. Moreover, multifunctional cement composites have been developed in the last decades for their functional applications (self-sensing, EMI shielding, self-heating, etc.. In this study, the strain and damage sensing possible application of carbon fiber reinforced alkali activated slag pastes has been evaluated. Cement pastes with 0, 0.29 and 0.58 vol % carbon fiber addition were prepared. Both carbon fiber dosages showed sensing properties. For strain sensing, function gage factors of up to 661 were calculated for compressive cycles. Furthermore, all composites with carbon fibers suffered a sudden increase in their resistivity when internal damages began, prior to any external signal of damage. Hence, this material may be suitable as strain or damage sensor.

  13. Evaluation of Tensile Strength of Unresin Continuous Carbon Fiber Cables as Tensile Reinforcement for Concrete Structures

    OpenAIRE

    Ohta, Toshiaki; Djamaluddin, Rudy; Seo, SungTag; Sajima, Takao; Harada, Koji

    2002-01-01

    As a tensile reinforcement of a concrete structure member, tensile strength of Unresin Continuous Carbon Fiber (UCCF) cables should be stated clearly. It has been reported that, through direct tensile test, tensile capacity of UCCF cables ranged from 30%

  14. 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.

  15. 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.

  16. 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.

  17. 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%.

  18. Enrichment of ventilation air methane (VAM) with carbon fiber composites.

    Science.gov (United States)

    Bae, Jun-Seok; Su, Shi; Yu, Xin Xiang

    2014-05-20

    Treatment of ventilation air methane (VAM) with cost-effective technologies has been an ongoing challenge due to its high volumetric flow rate with low and variable methane concentrations. In this work, honeycomb monolithic carbon fiber composites were developed and employed to capture VAM with a large-scale test unit at various conditions such as VAM concentration, ventilation air (VA) flow rate, temperature, and purging fluids. Regardless of inlet VAM concentrations, methane was captured at almost 100%. To regenerate the composites, the initial vacuum swing followed by combined temperature and vacuum swing adsorption (TVSA) was applied. It was found that initial vacuum swing is a control step for the final methane concentration having 5 or 11 times the VAM enrichment by one-step adsorption, which is, to our knowledge, the best performance achieved in VAM enrichment technologies worldwide. Five-time enriched VAM can be utilized as a principle fuel for lean burn turbine. Also, it can be further enriched by second step adsorption to more than 25% which then can be used for commercially available gas engines. In this way, the final product can be out of the methane explosive range (5-15%). PMID:24787090

  19. Carbon Fiber Strand Tensile Failure Dynamic Event Characterization

    Science.gov (United States)

    Johnson, Kenneth L.; Reeder, James

    2016-01-01

    There are few if any clear, visual, and detailed images of carbon fiber strand failures under tension useful for determining mechanisms, sequences of events, different types of failure modes, etc. available to researchers. This makes discussion of physics of failure difficult. It was also desired to find out whether the test article-to-test rig interface (grip) played a part in some failures. These failures have nothing to do with stress rupture failure, thus representing a source of waste for the larger 13-00912 investigation into that specific failure type. Being able to identify or mitigate any competing failure modes would improve the value of the 13-00912 test data. The beginnings of the solution to these problems lay in obtaining images of strand failures useful for understanding physics of failure and the events leading up to failure. Necessary steps include identifying imaging techniques that result in useful data, using those techniques to home in on where in a strand and when in the sequence of events one should obtain imaging data.

  20. 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.

  1. 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.

  2. 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...

  3. The friction and wear properties of Polypropylene composite filled with carbon fiber and Polyamide 6

    OpenAIRE

    Li, Jian; Kao-Walter, Sharon

    2014-01-01

    Carbon fiber composites were prepared in order to study the influence of fillers (polyamide 6; PA6) on the tensile and tribological properties of polypropylene (PP) composites. Tensile fracture mechanism was discussed based on the tensile testresults. Tribological tests were conducted on a Mobile Remote Handler-3 (MRH-3) friction and wear tester using a block-on-ring arrangement. It was observed that the carbon fiber (CF) played a main role in the tensile-resistant and wear-resistant properti...

  4. 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.

  5. Nomex-derived activated carbon fibers as electrode materials in carbon based supercapacitors

    Science.gov (United States)

    Leitner, K.; Lerf, A.; Winter, M.; Besenhard, J. O.; Villar-Rodil, S.; Suárez-García, F.; Martínez-Alonso, A.; Tascón, J. M. D.

    Electrochemical characterization has been carried out for electrodes prepared of several activated carbon fiber samples derived from poly (m-phenylene isophthalamide) (Nomex) in an aqueous solution. Depending on the burn-off due to activation the BET surface area of the carbons was in the order of 1300-2800 m 2 g -1, providing an extensive network of micropores. Their capability as active material for supercapacitors was evaluated by using cyclic voltammetry and impedance spectroscopy. Values for the capacitance of 175 F g -1 in sulfuric acid were obtained. Further on, it was observed that the specific capacitance and the performance of the electrode increase significantly with increasing burn-off degree. We believe that this fact can be attributed to the increase of surface area and porosity with increasing burn-off.

  6. 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.

  7. 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.

  8. Thermal management of a Li-ion battery using carbon fiber-PCM composites

    International Nuclear Information System (INIS)

    A combination of latent and sensible heat capabilities has made phase change materials (PCMs) very useful in a variety of heat transfer applications. The main purpose of using the phase change material in lithium-ion (Li-ion) battery thermal management systems (BTMs) is to mitigate the excessive temperature rise in the cells and to create uniform temperature distribution within the battery pack. In this work, carbon fibers were added to a PCM to enhance its heat transfer potentials. Various strategies were adopted to manage temperature distribution around a single AA-battery-like simulator. The effects of carbon fiber size and weight percent within the PCM on thermal performance were studied. Experimental results have indicated that a mixture of PCM with 2-mm-long carbon fibers and mass percentage of 0.46% showed the best thermal performance for which the maximum temperature rise in the battery simulator can be reduced by up to 45%. - Graphical abstract: The schematic of the experimental setup and data acquisition system (1-power source 2-container 3-battery module 4-thermocouples 5-temperature indicator 6-data acquisition system). - Highlights: • Thermal performance of a Li-ion battery simulator is studied in the presence of PCM. • The effect of carbon fiber on heat transfer enhancement is examined. • Better thermal management can be achieved by the presence of carbon fiber in PCM. • Both carbon fiber mass fraction and length play crucial role in thermal management

  9. 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.

  10. Self-diagnosis of structures strengthened with hybrid carbon-fiber-reinforced polymer sheets

    Science.gov (United States)

    Wu, Z. S.; Yang, C. Q.; Harada, T.; Ye, L. P.

    2005-06-01

    The correlation of mechanical and electrical properties of concrete beams strengthened with hybrid carbon-fiber-reinforced polymer (HCFRP) sheets is studied in this paper. Two types of concrete beams, with and without reinforcing bars, are strengthened with externally bonded HCFRP sheets, which have a self-structural health monitoring function due to the electrical conduction and piezoresistivity of carbon fibers. Parameters investigated include the volume fractions and types of carbon fibers. According to the investigation, it is found that the hybridization of uniaxial HCFRP sheets with several different types of carbon fibers is a viable method for enhancing the mechanical properties and obtaining a built-in damage detection function for concrete structures. The changes in electrical resistance during low strain ranges before the rupture of carbon fibers are generally smaller than 1%. Nevertheless, after the gradual ruptures of carbon fibers, the electrical resistance increases remarkably with the strain in a step-wise manner. For the specimens without reinforcing bars, the electrical behaviors are not stable, especially during the low strain ranges. However, the electrical behaviors of the specimens with reinforcing bars are relatively stable, and the whole range of self-sensing function of the HCFRP-strengthened RC structures has realized the conceptual design of the HCFRP sensing models and is confirmed by the experimental investigations. The relationships between the strain/load and the change in electrical resistance show the potential self-monitoring capacity of HCFRP reinforcements used for strengthening concrete structures.

  11. Synthesis and characterization of carbon nano fibers for its application in the adsorption of toxic gases

    International Nuclear Information System (INIS)

    The production of carbon nano fibers (CNF's) by diverse techniques as the electric arc, laser ablation, or chemical deposition in vapor phase, among other, they have been so far used from final of the 90's. However, the synthesis method by discharge Glow arc of alternating current and high frequency developed by Pacheco and collaborators, is a once alternative for its obtaining. In the plasma Application Laboratory (LAP) of the National Institute of Nuclear Research (INlN) it was designed and manufactured a reactor of alternating current and high frequency that produces a Glow arc able to synthesize carbon nano fibers. Its were carried out nano fibers synthesis with different catalysts to different proportions and with distinct conditions of vacuum pressure and methane flow until obtaining the best nano fibers samples and for it, this nano structures were characterized by Scanning and Transmission Electron Microscopy, X-ray Diffraction, Raman spectrometry and EDS spectrometry. Once found the optimal conditions for the nano fibers production its were contaminated with NO2 toxic gas and it was determined if they present adsorption, for it was used the thermal gravimetric analysis technique. This work is divided in three parts, in the first one, conformed by the chapters 1, at the 3, they are considered the foundations of the carbon nano fibers, their history, their characteristics, growth mechanisms, synthesis techniques, the thermal gravimetric analysis principles and the adsorption properties of the nano fibers. In the second part, consistent of the chapters 4 and 5, the methodology of synthesis and characterization of the nano fibers is provided. Finally, in third part its were carried out the activation energy calculation, the adsorption of the CNF's is analyzed and the conclusions are carried out. The present study evaluates the adsorption of environmental gas pollutants as the nitrogen oxides on carbon nano fibers at environmental or near conditions. Also, they

  12. Surface structural evolvement in the conversion of polyacrylonitrile precursors to carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Xin, E-mail: qx3023@nimte.ac.cn; Zou, Ruifen; OuYang, Qin; Wang, Xuefei; Zhang, Yonggang

    2015-02-01

    Highlights: • The characteristic striated topography of PAN precursors resulted from the wet spinning process could pass down to carbon fibers. • The ridges and grooves monitored became much more well-defined after the thermo-oxidation. • Both the depth and the width of longitudinal grooves decreased after the carbonization. • Carbon, nitrogen, oxygen and silicon were the governing elements on the fiber surface. - Abstract: Surface structural evolvement in the conversion of polyacrylonitrile (PAN) precursors to carbon fibers was investigated through scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). SEM results showed that the characteristic striated topography of PAN precursors resulted from the wet spinning process could pass down to carbon fibers. The fiber diameter gradually decreased from 11.3 μm to 5.5 μm and the corresponding density increased from 1.18 g/cm{sup 3} to 1.80 g/cm{sup 3} in the conversion of PAN precursors to carbon fibers. The ridges and grooves monitored by AFM became much more well-defined after the thermo-oxidation. However, the original longitudinal grooves were destroyed and both the depth and the width of longitudinal grooves decreased after the carbonization. XPS results revealed that carbon, nitrogen, oxygen and silicon were the governing elements on the fiber surface. The −C−C functional groups was the dominant groups and the relative contents of −C=O and −COO groups gradually increased in the process of thermo-oxidation and carbonization.

  13. 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.

  14. 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.

  15. Sizing and characterization of carbon fibers with aqueous water-dispersible polymeric interphases

    OpenAIRE

    Broyles, Norman S.

    1996-01-01

    Composite durability can be influenced by varying the properties of the fiber/matrix interphase region. One method to modifY the properties of this interphase is through the application of a sizing to the carbon fiber. Recent work at Virginia Tech has shown that polymer-modified interphases can lead to increases by as much as two orders of magnitude in notched fatigue lifetime. In the present work, an apparatus was constructed to uniformly coat carbon fiber tow with water-solub...

  16. Complementary methods for nondestructive testing of composite materials reinforced with carbon woven fibers

    Science.gov (United States)

    Steigmann, R.; Iftimie, N.; Sturm, R.; Vizureanu, P.; Savin, A.

    2015-11-01

    This paper presents complementary methods used in nondestructive evaluation (NDE) of composite materials reinforced with carbon woven fibers as two electromagnetic methods using sensor with orthogonal coils and sensor with metamaterials lens as well as ultrasound phased array method and Fiber Bragg gratings embedded instead of a carbon fiber for better health monitoring. The samples were impacted with low energy in order to study delamination influence. The electromagnetic behavior of composite was simulated by finite- difference time-domain (FDTD) software, showing a very good concordance with electromagnetic nondestructive evaluation tests.

  17. Dense Z-pinches by carbon fiber pinch and by conductive thin film linear compression

    International Nuclear Information System (INIS)

    Dense Z-pinch plasmas are created by two different ways and are examined experimentally. A stable plasma column existing for about 20 ns has been created in the carbon fiber pinch driven by a pulsed power generator. Any significant differences in emitted soft X-ray intensity from the plasma are not observed between fiber pinches of carbon fiber with nickel or copper coating and without any coating material. Techninal difficulties in handling thin foil metal liner for linear compression experiments are overcome by proposing a conductive thin film deposited on the surface of discharge tube wall as a compression liner. Uniform cyclindrical compression of the thin film liner has been confirmed

  18. 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.

  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. 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.

  1. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi;

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...... with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described...

  2. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  3. Voltammetric microelectrodes for biocorrosion studies

    Energy Technology Data Exchange (ETDEWEB)

    Xu, K.; Dexter, S.C.; Luther, G.W. III [Univ. of Delaware, Lewes, DE (United States). Coll. of Marine Studies

    1998-10-01

    Understanding various biocorrosion mechanisms requires direct measurement of chemical concentrations and profiles within thin biofilms or discrete biodeposits. A gold-based mercury microelectrode was developed for simultaneous measurement of dissolved O{sub 2}, Mn, Fe, S(-II), and low pH using square wave voltammetry. It was constructed by electroreducing Hg(II) on a gold wire of 25-{micro}m diameter encased in glass. By mounting the electrode on a computerized micromanipulator, vertical microprofiles of the key redox species were measured with 10-{micro}m depth resolution across marine biofilms formed on metal coupons. Various interfering factors and experimental parameters of the voltammetric measurements were reviewed. Results revealed the heterogeneous nature of the biofilm and complex microbially mediated heavy metal (Mn and Fe) cycles within the film system. Data interpretation provided further insight into the mechanism of microbiologically influenced metal corrosion.

  4. A Study of Atmospheric Plasma Treatment on Surface Energetics of Carbon Fibers

    International Nuclear Information System (INIS)

    In this study, the atmospheric plasma treatment with He/O2 was conducted to modify the surface chemistry of carbon fibers. The effects of plasma treatment parameters on the surface energetics of carbon fibers were experimentally investigated with respect to gas flow ratio, power intensity, and treatment time. Surface characteristics of the carbon fibers were determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Fourier transform infrared (FT-IR), Zeta-potential, and contact angle measurements. The results indicated that oxygen plasma treatment led to a large amount of reactive functional groups onto the fiber surface, and these groups can form together as physical intermolecular bonding to improve the surface wettability with a hydrophilic polymer matrix

  5. 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.

  6. 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.

  7. 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.

  8. Formation and chemical reactivity of carbon fibers prepared by defluorination of graphite fluoride

    Science.gov (United States)

    Hung, Ching-Cheh

    1994-01-01

    Defluorination of graphite fluoride (CFX) by heating to temperatures of 250 to 450 C in chemically reactive environments was studied. This is a new and possibly inexpensive process to produce new carbon-based materials. For example, CF 0.68 fibers, made from P-100 carbon fibers, can be defluorinated in BrH2C-CH = CH-CH2Br (1,4-dibromo-2butene) heated to 370 C, and graphitized to produce fibers with an unusually high modulus and a graphite layer structure that is healed and cross-linked. Conversely, a sulfur-doped, visibly soft carbon fiber was produced by defluorinating CF 0.9 fibers, made from P-25, in sulfur (S) vapor at 370 C and then heating to 660 C in nitrogen (N2). Furthermore, defluorination of the CF 0.68 fibers in bromine (Br2) produced fragile, structurally damaged carbon fibers. Heating these fragile fibers to 1100 C in N2 caused further structural damage, whereas heating to 150 C in bromoform (CHBr3) and then to 1100 C in N2 healed the structural defects. The defluorination product of CFX, tentatively called activated graphite, has the composition and molecular structure of graphite, but is chemically more reactive. Activated graphite is a scavenger of manganese (Mn), and can be intercalated with magnesium (Mg). Also, it can easily collect large amounts of an alloy made from copper (Cu) and type 304 stainless steel to form a composite. Finally, there are indications that activated graphite can wet metals or ceramics, thereby forming stronger composites with them than the pristine carbon fibers can form.

  9. 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.)

  10. 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.

  11. Electrochemical Fabrication and Electrocatalytic Properties of Nanostructured Mesoporous Platinum Microelectrodes

    Institute of Scientific and Technical Information of China (English)

    Mengyan NIE; Joanne M. Elliott

    2005-01-01

    Electrodeposition from a lyotropic liquid crystal template medium was used to produce nanostructured platinum microelectrodes with high specific surface area and high mass transport efficiency. Compared to polished and conventional platinized microelectrodes, well-ordered nanostructured platinum microelectrodes exhibited enhanced electrocatalytic properties for oxygen and ascorbic acid, whilst well-ordered nanostructured platinum microelectrodes offered improved electrocatalytic properties for oxygen reduction compared to disordered nanostructured platinum microelectrodes.

  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. Sulfur-impregnated activated carbon fiber cloth as a binder-free cathode for rechargeable Li-S batteries.

    Science.gov (United States)

    Elazari, Ran; Salitra, Gregory; Garsuch, Arnd; Panchenko, Alexander; Aurbach, Doron

    2011-12-15

    A route for the preparation of binder-free sulfur-carbon cathodes is developed for lithium sulfur batteries. The method is based on the impregnation of elemental sulfur into the micropores of activated carbon fibers. These electrodes demonstrate good electrochemical performance at high current density attributed to the uniform dispersion of sulfur inside the carbon fiber. PMID:22052740

  14. 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.

  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. PMID:27322344

  16. 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.

  17. 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.

  18. 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.

  19. Fiber

    Science.gov (United States)

    Diet - fiber; Roughage; Bulk ... Dietary fiber adds bulk to your diet. Because it makes you feel full faster, it can help with ... Elsevier Saunders; 2016:chap 213. National Research Council. ... Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids ( ...

  20. Excellent Adhesion of Carbon Fibers to Polyurethane Matrix and Substantial Improvement of the Mechanical Properties of Polyurethane

    OpenAIRE

    Seydibeyoglu, M. Ozgur

    2011-01-01

    In this study, polyurethane-carbon fiber composites were prepared with excellent interface with perfect adhesion of carbon fibers with the polyurethane matrix. The polyurethane was thermoplastic polyurethane and the carbon fiber was polyacrylonitrile based with 7 micron meter thickness. The composites were prepared with solvent casting technique. The composite materials were characterized with tensile testing, dynamic mechanical analysis, scanning electron microscope, and thermogravimetric an...

  1. 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.

  2. pH and electrical actuation of single walled carbon nanotube/chitosan composite fibers

    Science.gov (United States)

    Ozarkar, Sukrut; Jassal, Manjeet; Agrawal, Ashwini K.

    2008-10-01

    In the present study, an attempt has been made to utilize the pH responsive nature of chitosan to produce fibers which can respond to an applied electric voltage. Single walled carbon nanotubes (SWCNTs) have been used for reinforcing the chitosan fibers. But the SWCNTs are associated with their own challenges of aggregation which have been solved in this study by suitable functionalization. Electron microscopy and Raman spectroscopy was used to investigate the dispersions. The functionalized SWCNTs showed improved dispersion in chitosan. The SWCNT/chitosan composite fibers were successfully solution spun and heat-set to give stable fibers of 50 ± 2 µm. The composite fibers exhibited a significant increase in the mechanical properties. The tenacity of the composite fibers reinforced with functionalized SWCNTs increased from 96 to 226 MPa with an increase in SWCNT content from 0 to 0.2 wt%. The strong interaction of carboxylic functional groups of functionalized SWCNTs with the chitosan matrix may be responsible for the improved dispersion and considerable enhancement of the mechanical properties. Further, the stability of the fibers towards the pH switching environment has also been investigated, along with the response to an applied electric voltage. Composite fibers prepared using 0.1 wt% of functionalized carbon nanotubes were observed to exhibit a stable response with high magnitude of strain and high strain rate.

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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. PMID:24758290

  13. The carbon fiber development for uranium centrifuges: a Brazilian cooperative research

    International Nuclear Information System (INIS)

    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)

  14. 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...

  15. 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

  16. Failure Mechanisms of a Gold Microelectrode in Bioelectronics Applications

    Directory of Open Access Journals (Sweden)

    Jonghun Kim

    2015-01-01

    Full Text Available The generation, growth, and collapse of tiny bubbles are inevitable for a microelectrode working in aqueous environment, thus resulting in physical damages on the microelectrode. The failure mechanisms of a microelectrode induced by tiny bubble collapsing are investigated by generating tiny hydrogen bubbles on a gold microelectrode through deionized water electrolysis. The surface of the microelectrode is modified with a thiol-functionalized arginine-glycine-aspartic acid peptide to generate perfectly spherical bubbles in proximity of the surface. The failure of an Au microelectrode is governed by two damage mechanisms, depending on the thickness of the microelectrode: a water-hammer pressure due to the violent collapse of a single large bubble, formed through merging of small bubbles, for ultrathin Au microelectrodes of 40–60 nm in thickness, and an energy accumulation resulting from the repetitive collapse of tiny bubbles for thick Au microelectrodes of 100–120 nm.

  17. 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.

  18. Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

    Directory of Open Access Journals (Sweden)

    Yue Lian-yong

    2016-01-01

    Full Text Available Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made part of the jet fracture. The carbon fiber reinforced rubber composite armour has good defence ablity especially when the nature rubber plate hybrid 15% volume percentage carbonfiber and the obliquity angle is 68°. The hybrid fiber reinforced rubber composite armour can be used as a new kind of light protective armour.

  19. 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.

  20. 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.

  1. Poly(lactic acid)/Carbon Nanotube Fibers as Novel Platforms for Glucose Biosensors

    OpenAIRE

    Valtencir Zucolotto; Eliton Souto Medeiros; Luiz Henrique Capparelli Mattoso; Juliano Elvis Oliveira

    2012-01-01

    The focus of this paper is the development and investigation of properties of new nanostructured architecture for biosensors applications. Highly porous nanocomposite fibers were developed for use as active materials in biosensors. The nanocomposites comprised poly(lactic acid)(PLA)/multi-walled carbon nanotube (MWCNT) fibers obtained via solution-blow spinning onto indium tin oxide (ITO) electrodes. The electrocatalytic properties of nanocomposite-modified ITO electrodes were investigated to...

  2. Removal of cyanobacteria toxins from drinking water by adsorption on activated carbon fibers

    OpenAIRE

    Eden Cavalcanti de Albuquerque Júnior; Manoel Orlando Alvarez Méndez; Aparecido dos Reis Coutinho; Telma Teixeira Franco

    2008-01-01

    Natural fibers from macadamia nut shell, dried coconut shell endocarp, unripe coconut mesocarp, sugarcane bagasse and pine wood residue were used to prepare activated carbon fibers (ACF) with potential application for removing microcystins. The ACF from pine wood and sugar cane bagasse were used to remove [D-Leucine¹]MCYST-LR from water. After 10 minutes of contact time, more than 98% of toxin was removed by the ACF. The microcystin adsorption monolayer, q m, in the ACF recovered 200 and 161 ...

  3. 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 ...

  4. 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...

  5. 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.

  6. 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

  7. Nano-carbon black and carbon fiber as conductive materials for the diagnosing of the damage of concrete beam

    OpenAIRE

    Yining Ding; Zhipei Chen; Zhibo Han; Yulin Zhang; Torgal, Fernando Pacheco

    2013-01-01

    The nano-carbon black (NCB) and carbon fiber (CF) as electric conductive materials were added into the concrete. The effect of the NCB and CF on the mechanical properties and on the fractional change in resistance (FCR) of concrete was investigated. The relationships among the FCR, the strain of initial geometrical neutral axis (IGNA) and the beam damage degree were developed. The results showed that the relationship between the FCR and IGNA strain can be described by the First Or...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Syed Mohd Saufi

    2002-11-01

    Full Text Available This paper reports the development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane. Nitrogen was used as an inert gas during pyrolysis of the PAN hollow fiber membrane into carbon membrane. PAN membranes were pyrolyzed at temperature ranging from 500oC to 800oC for 30 minutes of thermal soak time. Scanning Electron Microscope (SEM, Fourier Transform Infrared Spectroscopy (FTIR and gas sorption analysis were applied to characterize the PAN based carbon membrane. Pyrolysis temperature was found to significantly change the structure and properties of carbon membrane. FTIR results concluded that the carbon yield still could be increased by pyrolyzing PAN membranes at temperature higher than 800oC since the existence of other functional group instead of CH group. Gas adsorption analysis showed that the average pore diameter increased up to 800oC.

  14. Crystalline and tensile properties of carbon nanotube and graphene reinforced polyamide 12 fibers

    Science.gov (United States)

    Chatterjee, S.; Nüesch, F. A.; Chu, B. T. T.

    2013-02-01

    The influence of carbon nanotubes (CNTs) and graphene nanoplatelets (GnPs) on the structure and mechanical properties of polyamide 12 (PA12) fibers was investigated. As seen from wide-angle X-ray diffraction analysis the crystallinity index increases with incorporation of nanofillers due to nucleation effects. Marked improvement was noted for mechanical properties of the composites with increase in elastic modulus, yield stress and strength of the fibers. The most significant improvement of a factor of 4 could be observed for elastic modulus with the inclusion of 0.5 wt.% GnP. A comparative study was made between the fibers reinforced with CNTs and GnPs.

  15. Iosipesco shear resistance in composites of carbon and glass fiber with epoxi resin

    Directory of Open Access Journals (Sweden)

    Vanderlei O. Gonçalves

    2009-01-01

    Full Text Available The main aim of the present work was the determination of the shear modulus (G12 and the maximum shear strength (ô12 using the Iosipescu Shear Test. Tests were carried out on two types of composites, carbon fiber/epoxy and glass fiber/epoxy, used in the aerospace industry, and also a molded epoxy resin matrix. The results indicate the effective contribution of fiber reinforcements to the shear strength (ô12 and shear modulus (G12 compared to the no reinforcement polymer matrix.

  16. Clothing polymer fibers with well-aligned and high-aspect ratio carbon nanotubes

    Science.gov (United States)

    Sun, Gengzhi; Zheng, Lianxi; An, Jia; Pan, Yongzheng; Zhou, Jinyuan; Zhan, Zhaoyao; Pang, John H. L.; Chua, Chee Kai; Leong, Kah Fai; Li, Lin

    2013-03-01

    It is believed that the crucial step towards preparation of electrical conductive polymer-carbon nanotube (CNT) composites is dispersing CNTs with a high length-to-diameter aspect ratio in a well-aligned manner. However, this process is extremely challenging when dealing with long and entangled CNTs. Here in this study, a new approach is demonstrated to fabricate conductive polymer-CNT composite fibers without involving any dispersion process. Well-aligned CNT films were firstly drawn from CNT arrays, and then directly coated on polycaprolactone fibers to form polymer-CNT composite fibers. The conductivity of these composite fibers can be as high as 285 S m-1 with only 2.5 wt% CNT loading, and reach 1549 S m-1 when CNT loading is 13.4 wt%. As-prepared composite fibers also exhibit 82% retention of conductivity at a strain of 7%, and have improved mechanical properties.It is believed that the crucial step towards preparation of electrical conductive polymer-carbon nanotube (CNT) composites is dispersing CNTs with a high length-to-diameter aspect ratio in a well-aligned manner. However, this process is extremely challenging when dealing with long and entangled CNTs. Here in this study, a new approach is demonstrated to fabricate conductive polymer-CNT composite fibers without involving any dispersion process. Well-aligned CNT films were firstly drawn from CNT arrays, and then directly coated on polycaprolactone fibers to form polymer-CNT composite fibers. The conductivity of these composite fibers can be as high as 285 S m-1 with only 2.5 wt% CNT loading, and reach 1549 S m-1 when CNT loading is 13.4 wt%. As-prepared composite fibers also exhibit 82% retention of conductivity at a strain of 7%, and have improved mechanical properties. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34208e

  17. 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. PMID:22372914

  18. 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.

  19. 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.

  20. 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.

  1. Alignment of carbon nanotubes and reinforcing effects in nylon-6 polymer composite fibers

    International Nuclear Information System (INIS)

    Alignment of pristine carbon nanotubes (P-CNTs) and fluorinated carbon nanotubes (F-CNTs) in nylon-6 polymer composite fibers (PCFs) has been achieved using a single-screw extrusion method. CNTs have been used as filler reinforcements to enhance the mechanical and thermal properties of nylon-6 composite fibers. The composites were fabricated by dry mixing nylon-6 polymer powder with the CNTs as the first step, then followed by the melt extrusion process of fiber materials in a single-screw extruder. The extruded fibers were stretched to their maxima and stabilized using a godet set-up. Finally, fibers were wound on a Wayne filament winder machine and tested for their tensile and thermal properties. The tests have shown a remarkable change in mechanical and thermal properties of nylon-6 polymer fibers with the addition of 0.5 wt% F-CNTs and 1.0 wt% of P-CNTs. To draw a comparison between the improvements achieved, the same process has been repeated with neat nylon-6 polymer. As a result, tensile strength has been increased by 230% for PCFs made with 0.5% F-CNTs and 1% P-CNTs as additives. These fibers have been further characterized by DSC, Raman spectroscopy and SEM which confirm the alignment of CNTs and interfacial bonding to nylon-6 polymer matrix

  2. Alignment of carbon nanotubes and reinforcing effects in nylon-6 polymer composite fibers.

    Science.gov (United States)

    Rangari, Vijaya K; Yousuf, Mohammed; Jeelani, Shaik; Pulikkathara, Merlyn X; Khabashesku, Valery N

    2008-06-18

    Alignment of pristine carbon nanotubes (P-CNTs) and fluorinated carbon nanotubes (F-CNTs) in nylon-6 polymer composite fibers (PCFs) has been achieved using a single-screw extrusion method. CNTs have been used as filler reinforcements to enhance the mechanical and thermal properties of nylon-6 composite fibers. The composites were fabricated by dry mixing nylon-6 polymer powder with the CNTs as the first step, then followed by the melt extrusion process of fiber materials in a single-screw extruder. The extruded fibers were stretched to their maxima and stabilized using a godet set-up. Finally, fibers were wound on a Wayne filament winder machine and tested for their tensile and thermal properties. The tests have shown a remarkable change in mechanical and thermal properties of nylon-6 polymer fibers with the addition of 0.5 wt% F-CNTs and 1.0 wt% of P-CNTs. To draw a comparison between the improvements achieved, the same process has been repeated with neat nylon-6 polymer. As a result, tensile strength has been increased by 230% for PCFs made with 0.5% F-CNTs and 1% P-CNTs as additives. These fibers have been further characterized by DSC, Raman spectroscopy and SEM which confirm the alignment of CNTs and interfacial bonding to nylon-6 polymer matrix. PMID:21825828

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Enhanced mechanical strength and electrical conductivity of carbon-nanotube/TiC hybrid fibers

    Science.gov (United States)

    Yi, Qinghua; Dai, Xiao; Zhao, Jie; Sun, Yinghui; Lou, Yanhui; Su, Xiaodong; Li, Qingwen; Sun, Baoquan; Zheng, Honghe; Shen, Mingrong; Wang, Qinghua; Zou, Guifu

    2013-07-01

    We report the synthesis of carbon nanotube/TiC hybrid fibers using a polymer-assisted chemical solution approach. Ti metal ions are bound to aqueous polyethyleneimine (PEI) to form precursor solution. Amphiphilic PEI with Ti easily permeates the CNT fibers. Upon annealing in a controlled atmosphere, a homogeneous TiC network is formed in the CNT fibers. The obtained CNT/TiC hybrid fibers show prominent enhancement in mechanical strength and electrical conductivity. The tensile strength and conductivity of CNT/TiC fibers can be improved to 0.67 GPa and 1650 S cm-1 at room temperature, respectively. More importantly, a tensile modulus as high as 420 GPa has been achieved for the CNT/TiC fibers. Analysis shows that the cross-linking matrix of hard TiC plays a significant role in the improvement of mechanical strength. Furthermore, the electrons are transported in the CNT/TiC fiber by a three dimensional hopping mechanism.We report the synthesis of carbon nanotube/TiC hybrid fibers using a polymer-assisted chemical solution approach. Ti metal ions are bound to aqueous polyethyleneimine (PEI) to form precursor solution. Amphiphilic PEI with Ti easily permeates the CNT fibers. Upon annealing in a controlled atmosphere, a homogeneous TiC network is formed in the CNT fibers. The obtained CNT/TiC hybrid fibers show prominent enhancement in mechanical strength and electrical conductivity. The tensile strength and conductivity of CNT/TiC fibers can be improved to 0.67 GPa and 1650 S cm-1 at room temperature, respectively. More importantly, a tensile modulus as high as 420 GPa has been achieved for the CNT/TiC fibers. Analysis shows that the cross-linking matrix of hard TiC plays a significant role in the improvement of mechanical strength. Furthermore, the electrons are transported in the CNT/TiC fiber by a three dimensional hopping mechanism. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01857a

  9. Corrosion detection of steel reinforced concrete using combined carbon fiber and fiber Bragg grating active thermal probe

    Science.gov (United States)

    Li, Weijie; Ho, Siu Chun Michael; Song, Gangbing

    2016-04-01

    Steel reinforcement corrosion is one of the dominant causes for structural deterioration for reinforced concrete structures. This paper presents a novel corrosion detection technique using an active thermal probe. The technique takes advantage of the fact that corrosion products have poor thermal conductivity, which will impede heat propagation generated from the active thermal probe. At the same time, the active thermal probe records the temperature response. The presence of corrosion products can thus be detected by analyzing the temperature response after the injection of heat at the reinforcement-concrete interface. The feasibility of the proposed technique was firstly analyzed through analytical modeling and finite element simulation. The active thermal probe consisted of carbon fiber strands to generate heat and a fiber optic Bragg grating (FBG) temperature sensor. Carbon fiber strands are used due to their corrosion resistance. Wet-dry cycle accelerated corrosion experiments were performed to study the effect of corrosion products on the temperature response of the reinforced concrete sample. Results suggest a high correlation between corrosion severity and magnitude of the temperature response. The technique has the merits of high accuracy, high efficiency in measurement and excellent embeddability.

  10. Modeling the Tensile Strength of Carbon Fiber - Reinforced Ceramic - Matrix Composites Under Multiple Fatigue Loading

    Science.gov (United States)

    Li, Longbiao

    2016-06-01

    An analytical method has been developed to investigate the effect of interface wear on the tensile strength of carbon fiber - reinforced ceramic - matrix composites (CMCs) under multiple fatigue loading. The Budiansky - Hutchinson - Evans shear - lag model was used to describe the micro stress field of the damaged composite considering fibers failure and the difference existed in the new and original interface debonded region. The statistical matrix multicracking model and fracture mechanics interface debonding criterion were used to determine the matrix crack spacing and interface debonded length. The interface shear stress degradation model and fibers strength degradation model have been adopted to analyze the interface wear effect on the tensile strength of the composite subjected to multiple fatigue loading. Under tensile loading, the fibers failure probabilities were determined by combining the interface wear model and fibers failure model based on the assumption that the fiber strength is subjected to two - parameter Weibull distribution and the loads carried by broken and intact fibers satisfy the Global Load Sharing criterion. The composite can no longer support the applied load when the total loads supported by broken and intact fibers approach its maximum value. The conditions of a single matrix crack and matrix multicrackings for tensile strength corresponding to multiple fatigue peak stress levels and different cycle number have been analyzed.

  11. Band-type microelectrodes for amperometric immunoassays.

    Science.gov (United States)

    Lee, Ga-Yeon; Chang, Young Wook; Ko, Hyuk; Kang, Min-Jung; Pyun, Jae-Chul

    2016-07-20

    A band-type microelectrode was made using a parylene-N film as a passivation layer. A circular-type, mm-scale electrode with the same diameter as the band-type microelectrode was also made with an electrode area that was 5000 times larger than the band-type microelectrode. By comparing the amperometric signals of 3,5,3',5'-tetramethylbenzidine (TMB) samples at different optical density (OD) values, the band-type microelectrode was determined to be 9 times more sensitive than the circular-type electrode. The properties of the circular-type and the band-type electrodes (e.g., the shape of their cyclic voltammograms, the type of diffusion layer used, and the diffusion layer thickness per unit electrode area) were characterized according to their electrode area using the COMSOL Multiphysics software. From these simulations, the band-type electrode was estimated to have the conventional microelectrode properties, even when the electrode area was 100 times larger than a conventional circular-type electrode. These results show that both the geometry and the area of an electrode can influence the properties of the electrode. Finally, amperometric analysis based on a band-type electrode was applied to commercial ELISA kits to analyze human hepatitis B surface antigen (hHBsAg) and human immunodeficiency virus (HIV) antibodies. PMID:27251855

  12. Nanostructural evolution during emission of CsI-coated carbon fiber cathodes

    Science.gov (United States)

    Drummy, Lawrence F.; Apt, Scott; Shiffler, Don; Golby, Ken; LaCour, Matt; Maruyama, Benji; Vaia, Richard A.

    2010-06-01

    Carbon-based nanofiber and microfiber cathodes exhibit very low voltages for the onset of electron emission, and thus provide exciting opportunities for applications ranging from high power microwave sources to field emission displays. CsI coatings have been experimentally shown to lower the work function for emission from the fiber tips, although little is known about the microstructure of the fibers themselves in their as-received state, after coating with CsI, or after being subjected to high voltage cycling. Longitudinal cross sections of the original, unused CsI-coated fibers produced by focused ion beam lift-out revealed a nanostructured graphitic core surrounded by an amorphous carbon shell with submicron sized islands of crystalline CsI on the outer surface. Aberration-corrected high resolution electron microscopy (HREM) of the fiber core achieved 0.10 nm resolution, with the graphite (200) clearly visible in digital fast Fourier transformations of the 2-4 nm highly ordered graphitic domains. As the cathode fibers are cycled at high voltage, HREM demonstrates that the graphitic ordering of the core increases with the number of cycles, however the structure and thickness of the amorphous carbon layer remains unchanged. These results are consistent with micro-Raman measurements of the fiber disordered/graphitic (D/G) band ratios. After high voltage cycling, a uniform ˜100 nm film at the fiber tip was evident in both bright field transmission electron microscopy (TEM) and high angle annular dark field scanning TEM (STEM). Low-dose electron diffraction techniques confirmed the amorphous nature of this film, and STEM with elemental mapping via x-ray energy dispersive spectroscopy indicates this layer is composed of CsIO. The oxidative evolution of tip composition and morphology due to impurities in the chamber, along with increased graphitization of the fiber core, contributes to changes in emission behavior with cycling.

  13. Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

    OpenAIRE

    Singh, B. P.; Veena Choudhary; Parveen Saini; Mathur, R.B.

    2012-01-01

    In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs) carbon fiber (CF) fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz). The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE) from −29.4 dB for CF/epoxy-composite to −51.1 dB for CF-MWCNT/epoxy multiscale comp...

  14. Comparative Study of Fiber Bragg Gratings and Fiber Polarimetric Sensors for Structural Health Monitoring of Carbon Composites

    Directory of Open Access Journals (Sweden)

    Massimo Olivero

    2014-01-01

    Full Text Available A comparative study is presented between Bragg grating (FBG and polarimetric sensors (PS, two of the most promising fiber optic sensing techniques for the structural health monitoring of smart materials based on carbon fiber composites. The paper describes the realization of a test plate equipped with both types of sensors and reports the characterization under static and dynamic conditions, highlighting pros and cons of both technologies. The FBG setup achieves 1.15 ± 0.0016 pm/kg static load response and reproduces dynamic excitation with 0.1% frequency uncertainty; the PS system exhibits a sensitivity of 1.74 ± 0.001 mV/kg and reproduces dynamic excitation with 0.5% frequency uncertainty. It is shown that the PS technology is a good and cheap alternative to FBG for vibration-monitoring of small structures at high frequency.

  15. Fiber Optic Chemical Nanosensors Based on Engineered Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    M. Consales

    2008-01-01

    Full Text Available In this contribution, a review of the development of high-performance optochemical nanosensors based on the integration of carbon nanotubes with the optical fiber technology is presented. The paper first provide an overview of the amazing features of carbon nanotubes and their exploitation as highly adsorbent nanoscale materials for gas sensing applications. Successively, the attention is focused on the operating principle, fabrication, and characterization of fiber optic chemosensors in the Fabry-Perot type reflectometric configuration, realized by means of the deposition of a thin layer of single-walled carbon nanotubes (SWCNTs upon the distal end of standard silica optical fibers. This is followed by an extensive review of the excellent sensing capabilities of the realized SWCNTs-based chemical nanosensors against volatile organic compounds and other pollutants in different environments (air and water and operating conditions (room temperature and cryogenic temperatures. The experimental results reported here reveal that ppm and sub-ppm chemical detection limits, low response times, as well as fast and complete recovery of the sensor responses have been obtained in most of the investigated cases. This evidences the great potentialities of the proposed photonic nanosensors based on SWCNTs to be successfully employed for practical environmental monitoring applications both in liquid and vapor phase as well as for space. Furthermore, the use of novel SWCNTs-based composites as sensitive fiber coatings is proposed to enhance the sensing performance and to improve the adhesion of carbon nanotubes to the fiber surface. Finally, new advanced sensing configurations based on the use of hollow-core optical fibers coated and partially filled by carbon nanotubes are also presented.

  16. Advances in electrospun carbon fiber-based electrochemical sensing platforms for bioanalytical applications.

    Science.gov (United States)

    Mao, Xianwen; Tian, Wenda; Hatton, T Alan; Rutledge, Gregory C

    2016-02-01

    Electrochemical sensing is an efficient and inexpensive method for detection of a range of chemicals of biological, clinical, and environmental interest. Carbon materials-based electrodes are commonly employed for the development of electrochemical sensors because of their low cost, biocompatibility, and facile electron transfer kinetics. Electrospun carbon fibers (ECFs), prepared by electrospinning of a polymeric precursor and subsequent thermal treatment, have emerged as promising carbon systems for biosensing applications since the electrochemical properties of these carbon fibers can be easily modified by processing conditions and post-treatment. This review addresses recent progress in the use of ECFs for sensor fabrication and analyte detection. We focus on the modification strategies of ECFs and identification of the key components that impart the bioelectroanalytical activities, and point out the future challenges that must be addressed in order to advance the fundamental understanding of the ECF electrochemistry and to realize the practical applications of ECF-based sensing devices. PMID:26650731

  17. Advances in electrospun carbon fiber-based electrochemical sensing platforms for bioanalytical applications.

    Science.gov (United States)

    Mao, Xianwen; Tian, Wenda; Hatton, T Alan; Rutledge, Gregory C

    2016-02-01

    Electrochemical sensing is an efficient and inexpensive method for detection of a range of chemicals of biological, clinical, and environmental interest. Carbon materials-based electrodes are commonly employed for the development of electrochemical sensors because of their low cost, biocompatibility, and facile electron transfer kinetics. Electrospun carbon fibers (ECFs), prepared by electrospinning of a polymeric precursor and subsequent thermal treatment, have emerged as promising carbon systems for biosensing applications since the electrochemical properties of these carbon fibers can be easily modified by processing conditions and post-treatment. This review addresses recent progress in the use of ECFs for sensor fabrication and analyte detection. We focus on the modification strategies of ECFs and identification of the key components that impart the bioelectroanalytical activities, and point out the future challenges that must be addressed in order to advance the fundamental understanding of the ECF electrochemistry and to realize the practical applications of ECF-based sensing devices.

  18. Clinical evaluation of carbon fiber reinforced carbon endodontic post, glass fiber reinforced post with cast post and core: A one year comparative clinical study

    Directory of Open Access Journals (Sweden)

    Preethi G

    2008-01-01

    Full Text Available Aim: Restoring endodontically treated teeth is one of the major treatments provided by the dental practitioner. Selection and proper use of restorative materials continues to be a source of frustration for many clinicians. There is controversy surrounding the most suitable choice of restorative material and the placement method that will result in the highest probability of successful treatment. This clinical study compares two different varieties of fiber posts and one cast post and core in terms of mobility of crown margin under finger pressure, recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and periodontal pathology requiring crown removal over the period of 12months as evaluated by clinical and radiographical examination. Materials and Methods: 30 root canal treated, single rooted maxillary anterior teeth of 25 patients in the age range of 18-60 years where a post retained crown was indicated were selected for the study between January 2007 and August 2007; and prepared in a standard clinical manner. It was divided into 3 groups of 10 teeth in each group. After post space preparation, the Carbon fiber and Glass fiber reinforced posts were cemented with Scotch bond multipurpose plus bonding agent and RelyX adhesive resin cement in the first and second groups respectively. The Cast post and cores were cemented with Zinc Phosphate cement in the third group. Following post- cementation, the preparation was further refined and a rubber base impression was taken for metal-ceramic crowns which was cemented with Zinc Phosphate cement. A baseline periapical radiograph was taken once each crown was cemented. All patients were evaluated after one week (baseline, 3 months, 6 months and one year for following characteristics mobility of crown margin under finger pressure, recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and

  19. Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers

    Science.gov (United States)

    Song, Li; Toth, Geza; Wei, Jinquan; Liu, Zheng; Gao, Wei; Ci, Lijie; Vajtai, Robert; Endo, Morinobu; Ajayan, Pulickel M.

    2012-01-01

    We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5-20 µm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 105 S m - 1 and over 1 × 105 A cm - 2 in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers.

  20. Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers

    International Nuclear Information System (INIS)

    We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5–20 µm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 105 S m−1 and over 1 × 105 A cm−2 in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers.

  1. Gradient distribution of radial structure of PAN-based carbon fiber treated by high temperature

    Institute of Scientific and Technical Information of China (English)

    Haitao Wang; Yu Wang; Ting Li; Shuai Wu; Lianghua Xu

    2014-01-01

    High-performance graphite fibers were prepared and analyzed. The gradient distribution of radial structure of PAN-based carbon fibers was characterized by two different Raman test methods (incident laser beam perpendicular to and parallel to the fiber axis) and studied by the distribution of graphitization degree. Meanwhile difference between the two Raman test methods was used to describe the orientation of the graphite crystallite along the fiber axis. The results showed that the radial structure of PAN-based carbon fiber presented different gradient distribution states at different heat treatment temperatures, and the graphitization degree in the skin region changed more rapidly compared with the core region since the skin region was more affected by temperature which resulted in the obvious difference between skin and core structures. The difference of graphitization degree (Δg) characterized by two different Raman test methods increased with heat treatment temperature, indicating that the high temperature treatment (HTT) promoted further stacking of graphite crystallite, and the orientation degree of the graphite crystallite along the fiber axis was continuously increased.

  2. Aspects regarding wearing behaviour in case of aluminium composite materials reinforced with carbon fibers

    Science.gov (United States)

    Caliman, R.

    2016-08-01

    This paper presents a study regarding wear comportment of sintered composite materials obtained by mixture of aluminium with short carbon fibers. The necessity to satisfying more and more the specific functions during design of high performance structures leads to perform multi-materials such as reinforced composite parts. The wear tests were made on three different orientations of fibers on a standard machine of tribology, pin disk type. Counter-disk was made of cast iron with a superficial hardness of 92 HB. The wear rate and friction coefficient decreased exponentially with time of friction and reached a stationary value. This behaviour was attributed to the development of a lubricating film on the friction surface. To conduct this work was performed measurements on samples from the Al matrix composites and carbon fiber 43%, wear mechanism was investigated by scanning electron microscopy. In addition to fiber orientation, the tribological behaviour of metal matrix composites reinforced with fiber is influenced by the interfacial reaction of fiber-matrix. The characteristics and the dimensions of the interface depend on the cycle of temperature and time at which the material has been subjected during the manufacturing process and thereafter.

  3. Deformation behavior of FRP-metal composites locally reinforced with carbon fibers

    Science.gov (United States)

    Scholze, M.; Kolonko, A.; Lindner, T.; Lampke, T.; Helbig, F.

    2016-03-01

    This study investigates variations of hybrid laminates, consisting of one aluminum sheet and a unidirectional glass fiber (GF) reinforced polyamide 6 (PA6) basic structure with partial carbon fiber (CF) reinforcement. To create these heterogeneous FRP laminates, it is necessary to design and produce semi-finished textile-based products. Moreover, a warp knitting machine in conjunction with a warp thread offset unit was used to generate bionic inspired compounds. By the variation of stacking prior to the consolidation process of the hybrid laminate, an oriented CF reinforcement at the top and middle layer of the FRP is realized. In both cases the GFRP layer prevents contact between the aluminum and carbon fibers. In so doing, the high strength of carbon fibers can be transferred to the hybrid laminate in load directions with an active prevention of contact corrosion. The interface strength between thermoplastic and metal component was improved by a thermal spray coating on the aluminum sheet. Because of the high surface roughness and porosity, mechanical interlock was used to provide high interface strength without bonding agents between both components. The resulting mechanical properties of the hybrid laminates are evaluated by three point bending tests in different load directions. The effect of local fiber orientation and layer positioning on failure and deformation mechanism is additionally investigated by digital image correlation (DIC).

  4. Fabrication of a low density carbon fiber foam and its characterization as a strain gauge

    OpenAIRE

    Claudia C. Luhrs; Daskam, Chris D.; Edwin Gonzalez; Jonathan Phillips

    2014-01-01

    Samples of carbon nano-fiber foam (CFF), essentially a 3D solid mat of intertwined nanofibers of pure carbon, were grown using the Constrained Formation of Fibrous Nanostructures (CoFFiN) process in a steel mold at 550 °C from a palladium particle catalysts exposed to fuel rich mixtures of ethylene and oxygen. The resulting material was studied using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), Surface area analysis (BET), and Thermogravimetric Analysis (TGA). Tra...

  5. Carbonic anhydrase immobilized on hollow fiber membranes using glutaraldehyde activated chitosan for artificial lung applications

    OpenAIRE

    Kimmel, J. D.; Arazawa, D. T.; Ye, S.-H.; Shankarraman, V; Wagner, W. R.; Federspiel, W. J.

    2013-01-01

    Extracorporeal CO2 removal from circulating blood is a promising therapeutic modality for the treatment of acute respiratory failure. The enzyme carbonic anhydrase accelerates CO2 removal within gas exchange devices by locally catalyzing HCO3− into gaseous CO2 within the blood. In this work, we covalently immobilized carbonic anhydrase on the surface of polypropylene hollow fiber membranes using glutaraldehyde activated chitosan tethering to amplify the density of reactive amine functional gr...

  6. Surface modification of carbon fibers by a polyether sulfone emulsion sizing for increased interfacial adhesion with polyether sulfone

    Science.gov (United States)

    Yuan, Haojie; Zhang, Shouchun; Lu, Chunxiang

    2014-10-01

    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.

  7. Multiscale model of heat dissipation mechanisms during field emission from carbon nanotube fibers

    Science.gov (United States)

    Cahay, M.; Zhu, W.; Fairchild, S.; Murray, P. T.; Back, T. C.; Gruen, G. J.

    2016-01-01

    A multiscale model of field emission (FE) from carbon nanotube fibers (CNFs) is developed, which takes into account Joule heating within the fiber and radiative cooling and the Nottingham effect at the tip of the individual carbon nanotubes (CNTs) in the array located at the fiber tip. The model predicts the fraction of CNTs being destroyed as a function of the applied external electric field and reproduces many experimental features observed in some recently investigated CNFs, such as order of magnitude of the emission current (mA range), low turn on electric field (fraction of V/μm), deviation from pure Fowler-Nordheim behavior at large applied electric field, hysteresis of the FE characteristics, and a spatial variation of the temperature along the CNF axis with a maximum close to its tip of a few hundred °C.

  8. Multiscale model of heat dissipation mechanisms during field emission from carbon nanotube fibers

    Energy Technology Data Exchange (ETDEWEB)

    Cahay, M.; Zhu, W. [Spintronics and Vacuum Nanoelectronics Laboratory, University of Cincinnati, Cincinnati, Ohio 45221 (United States); Fairchild, S. [Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, Ohio 45433 (United States); Murray, P. T.; Back, T. C. [Research Institute, University of Dayton, Dayton, Ohio 45469-0170 (United States); Center of Excellence for Thin Film Research and Surface Engineering, University of Dayton, Dayton, Ohio 45469-0170 (United States); Gruen, G. J. [Research Institute, University of Dayton, Dayton, Ohio 45469-0170 (United States)

    2016-01-18

    A multiscale model of field emission (FE) from carbon nanotube fibers (CNFs) is developed, which takes into account Joule heating within the fiber and radiative cooling and the Nottingham effect at the tip of the individual carbon nanotubes (CNTs) in the array located at the fiber tip. The model predicts the fraction of CNTs being destroyed as a function of the applied external electric field and reproduces many experimental features observed in some recently investigated CNFs, such as order of magnitude of the emission current (mA range), low turn on electric field (fraction of V/μm), deviation from pure Fowler-Nordheim behavior at large applied electric field, hysteresis of the FE characteristics, and a spatial variation of the temperature along the CNF axis with a maximum close to its tip of a few hundred  °C.

  9. COPPER/CARBON CORE SHELL NANOPARTICLES AS ADDITIVE FOR NATURAL FIBER/WOOD PLASTIC BLENDS

    Directory of Open Access Journals (Sweden)

    Qinglin Wu,

    2012-06-01

    Full Text Available Copper/carbon core/shell nanoparticles (CCCSNs recently have been introduced as an industrial material. In this paper, composites based on high density polyethylene (HDPE, bamboo fiber, CCCSNs, and coupling agent (MAPE were prepared by melt compounding. The influence of CCCSN content on the resulting composites’ mechanical, biological resistance, and thermal properties was investigated. It was found that CCCSNs within the carbon black matrix were processed well with bamboo fiber-plastic blends through mixing and injection molding. The materials enhanced composite strength and modulus-related properties. Composites with CCCSNs and natural fibers reduced heat capacity and thermal diffusivity. Composites with CCCSN materials also enhanced termite and mold performance. Thus, the material can be used as additive for plastics and other polymers to modify strength properties, biological resistance (e.g., mold and stain, and thermal conductivity properties.

  10. Multiscale model of heat dissipation mechanisms during field emission from carbon nanotube fibers

    International Nuclear Information System (INIS)

    A multiscale model of field emission (FE) from carbon nanotube fibers (CNFs) is developed, which takes into account Joule heating within the fiber and radiative cooling and the Nottingham effect at the tip of the individual carbon nanotubes (CNTs) in the array located at the fiber tip. The model predicts the fraction of CNTs being destroyed as a function of the applied external electric field and reproduces many experimental features observed in some recently investigated CNFs, such as order of magnitude of the emission current (mA range), low turn on electric field (fraction of V/μm), deviation from pure Fowler-Nordheim behavior at large applied electric field, hysteresis of the FE characteristics, and a spatial variation of the temperature along the CNF axis with a maximum close to its tip of a few hundred  °C

  11. Application of diffusion barriers to the refractory fibers of tungsten, columbium, carbon and aluminum oxide

    Science.gov (United States)

    Douglas, F. C.; Paradis, E. L.; Veltri, R. D.

    1973-01-01

    A radio frequency powered ion-plating system was used to plate protective layers of refractory oxides and carbide onto high strength fiber substrates. Subsequent overplating of these combinations with nickel and titanium was made to determine the effectiveness of such barrier layers in preventing diffusion of the overcoat metal into the fibers with consequent loss of fiber strength. Four substrates, five coatings, and two metal matrix materials were employed for a total of forty material combinations. The substrates were tungsten, niobium, NASA-Hough carbon, and Tyco sapphire. The diffusion-barrier coatings were aluminum oxide, yttrium oxide, titanium carbide, tungsten carbide with 14% cobalt addition, and zirconium carbide. The metal matrix materials were IN 600 nickel and Ti 6/4 titanium. Adhesion of the coatings to all substrates was good except for the NASA-Hough carbon, where flaking off of the oxide coatings in particular was observed.

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

    Directory of Open Access Journals (Sweden)

    Arafat Shabaneh

    2015-05-01

    Full Text Available 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 sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%, the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s towards ethanol.

  13. Woven Glass Fiber Composites with Aligned Carbon Nanotube Sheet Interlayers

    OpenAIRE

    Hardik Bhanushali; Philip D. Bradford

    2016-01-01

    This investigation describes the design, fabrication, and testing of woven glass fiber reinforced epoxy matrix laminates with aligned CNT sheets integrated between plies in order to improve the matrix dominated through thickness properties such as the interlaminar fracture toughness at ply interfaces. Using aligned CNT sheets allows for a concentration of millimeter long CNTs at the most likely point of laminate failure. Mode I and Mode II interlaminar fracture toughness of various CNT modifi...

  14. Effect of particle size and distribution of the sizing agent on the carbon fibers surface and interfacial shear strength (IFSS) of its composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.L. [Open Project of State Key Laboratory Breeding Base for Mining Disaster Prevention and Control, Shandong University of Science and Technology (China); School of Materials Science and Engineering, Shandong University of Science and Technology, 266590 Qingdao (China); Liu, Y. [School of Materials Science and Engineering, Shandong University of Science and Technology, 266590 Qingdao (China); Huang, Y.D., E-mail: rlzhit@126.com [School of Chemical Engineering and Technology, State Key laboratory of Urban Water Resource and Environment Department of Applied Chemistry, Harbin Institute of Technology, 150001 Harbin (China); Liu, L. [School of Chemical Engineering and Technology, State Key laboratory of Urban Water Resource and Environment Department of Applied Chemistry, Harbin Institute of Technology, 150001 Harbin (China)

    2013-12-15

    Effect of particle size and distribution of the sizing agent on the performance of carbon fiber and carbon fiber composites has been investigated. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize carbon fiber surface topographies. At the same time, the single fiber strength and Weibull distribution were also studied in order to investigate the effect of coatings on the fibers. The interfacial shear strength and hygrothermal aging of the carbon fiber/epoxy resin composites were also measured. The results indicated that the particle size and distribution is important for improving the surface of carbon fibers and its composites performance. Different particle size and distribution of sizing agent has different contribution to the wetting performance of carbon fibers. The fibers sized with P-2 had higher value of IFSS and better hygrothermal aging resistant properties.

  15. Size Classification of Chopped Carbon Fibers in the Composite Materials Manufacturing

    Directory of Open Access Journals (Sweden)

    А.S. Dovbysh

    2010-01-01

    Full Text Available Information synthesis of the learning decision support system for automation of the chopped carbon fibers size control used for the matrix filling within the manufacturing of composite materials based on polytetrafluoroethylene is considered. To improve the reliability of recognition learning algorithm with the optimization of the precision control is proposed.

  16. Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments

    NARCIS (Netherlands)

    Rubio-Bollinger, G.; Castellanos-Gomez, A.; Bilan, S.; Zotti, L.A.; Arroyo, C.R.; Agraït, N.; Cuevas, J.

    2012-01-01

    We fabricate and characterize carbon-fiber tips for their use in combined scanning tunneling and force microscopy based on piezoelectric quartz tuning fork force sensors. An electrochemical fabrication procedure to etch the tips is used to yield reproducible sub-100-nm apex. We also study electron t

  17. Rotor losses in laminated magnets and an anisotropic carbon fiber sleeve

    NARCIS (Netherlands)

    Van der Geest, M.; Wolmarans, J.J.; Polinder, H.; Ferreira, J.A.; Zeilstra, D.

    2012-01-01

    High speed fault tolerant permanent magnet machines have strong asynchronous airgap harmonics, making them susceptible to rotor eddy-current losses. These losses can be reduced by using novel high resistivity materials like plastic bonded magnets and carbon fiber reinforced retaining sleeves. This p

  18. Carbon Fiber-gold/mercury Dual-electrode Detection for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A carbon fiber-gold/mercury dual-electrode for capillary electrophoresis is constructed. Cysteine, glutathione, ascorbic acid and uric acid can be detected simultaneously and selectively at the dual-electrode, respectively. The capillary electrophoresis / dual-electrode detection system has been used to determine these compounds in human blood samples.

  19. Size Classification of Chopped Carbon Fibers in the Composite Materials Manufacturing

    OpenAIRE

    А.S. Dovbysh; А.F. Budnik; N.І. Andriienko

    2010-01-01

    Information synthesis of the learning decision support system for automation of the chopped carbon fibers size control used for the matrix filling within the manufacturing of composite materials based on polytetrafluoroethylene is considered. To improve the reliability of recognition learning algorithm with the optimization of the precision control is proposed.

  20. Extracting Information from Conventional AE Features for Fatigue Onset Damage Detection in Carbon Fiber Composites

    DEFF Research Database (Denmark)

    Unnthorsson, Runar; Pontoppidan, Niels Henrik Bohl; Jonsson, Magnus Thor

    2005-01-01

    We have analyzed simple data fusion and preprocessing methods on Acoustic Emission measurements of prosthetic feet made of carbon fiber reinforced composites. This paper presents the initial research steps; aiming at reducing the time spent on the fatigue test. With a simple single feature...