WorldWideScience

Sample records for carbon fiber sheet

  1. Carbon fiber reinforcements for sheet molding composites

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Soydan; Paulauskas, Felix L.

    2017-11-14

    A method of processing a carbon fiber tow includes the steps of providing a carbon fiber tow made of a plurality of carbon filaments, depositing a sizing composition at spaced-apart sizing sites along a length of the tow, leaving unsized interstitial regions of the tow, and cross-cutting the tow into a plurality of segments. Each segment includes at least a portion of one of the sizing sites and at least a portion of at least one of the unsized regions of the tow, the unsized region including and end portion of the segment.

  2. Experimental Study on RC Beams Strengthened with Carbon and Glass Fiber Sheets

    Directory of Open Access Journals (Sweden)

    Thaksin Thepchatri

    2009-05-01

    Full Text Available This study investigates the effects of the two types of fiber sheets, namely, carbon and glass fiber sheets, on the flexural behaviors of reinforced concrete (RC beams when they are bonded to the tension zones of the beams. A total of eight full-scale beams were tested in the experiments. The flexural strength and stiffness of RC beams were found to increase significantly after the installation of fiber sheets. An analytical model based on the principle of virtual work was developed to predict the load-deflection relationship of the hybrid beams. The paper also highlights the characteristics of debonding problem which limits the effective use of fiber materials.

  3. 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.

  4. 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.

  5. Flexible, Stretchable, and Rechargeable Fiber-Shaped Zinc-Air Battery Based on Cross-Stacked Carbon Nanotube Sheets.

    Science.gov (United States)

    Xu, Yifan; Zhang, Ye; Guo, Ziyang; Ren, Jing; Wang, Yonggang; Peng, Huisheng

    2015-12-14

    The fabrication of flexible, stretchable and rechargeable devices with a high energy density is critical for next-generation electronics. Herein, fiber-shaped Zn-air batteries, are realized for the first time by designing aligned, cross-stacked and porous carbon nanotube sheets simultaneously that behave as a gas diffusion layer, a catalyst layer, and a current collector. The combined remarkable electronic and mechanical properties of the aligned carbon nanotube sheets endow good electrochemical properties. They display excellent discharge and charge performances at a high current density of 2 A g(-1) . They are also flexible and stretchable, which is particularly promising to power portable and wearable electronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Hydroxyapatite growth on multiwall carbon nanotubes grown on titanium fibers from a titanium sheet

    KAUST Repository

    Chetibi, Loubna

    2013-09-27

    Nano-hydroxyapatite (HA) was grown on functionalized multiwalled carbon nanotubes (MWCNTs) deposited on TiO2 nanofibers (NFs) that were hydrothermally grown on Ti metal sheets. The HA was electrochemically grown on the MWCNTs/TiO2 porous layer. It was found that the HA grows on the MWCNTs/TiO2 NFs in the form of dense coating with nanorice grain-shaped. The incorporation of MWCNTs between HA and TiO2 NFs has led to higher adhesion strength as measured by micro-scratching test indicating the benefit of MWCNTs on the improving the bonding strength of HA layer. The obtained coatings exhibit excellent corrosion resistance in simulated body fluid. It is expected that this simple route for preparing the new HA/MWCNTs/TiO2/Ti-layered structure might be used not only in the biomedical field, but also in catalysis and biological sensing among others. © 2013 Springer Science+Business Media New York.

  7. A Novel Differential Time-of-Arrival Estimation Technique for Impact Localization on Carbon Fiber Laminate Sheets

    Directory of Open Access Journals (Sweden)

    Eugenio Marino Merlo

    2017-10-01

    Full Text Available Composite material structures are commonly used in many industrial sectors (aerospace, automotive, transportation, and can operate in harsh environments where impacts with other parts or debris may cause critical safety and functionality issues. This work presents a method for improving the accuracy of impact position determination using acoustic source triangulation schemes based on the data collected by piezoelectric sensors attached to the structure. A novel approach is used to estimate the Differential Time-of-Arrival (DToA between the impact response signals collected by a triplet of sensors, overcoming the limitations of classical methods that rely on amplitude thresholds calibrated for a specific sensor type. An experimental evaluation of the proposed technique was performed with specially made circular piezopolymer (PVDF sensors designed for Structural Health Monitoring (SHM applications, and compared with commercial piezoelectric SHM sensors of similar dimensions. Test impacts at low energies from 35 mJ to 600 mJ were generated in a laboratory by free-falling metal spheres on a 500 mm × 500 mm × 1.25 mm quasi-isotropic Carbon Fiber Reinforced Polymer (CFRP laminate plate. From the analysis of many impact signals, the resulting localization error was improved for all types of sensors and, in particular, for the circular PVDF sensor an average error of 20.3 mm and a standard deviation of 8.9 mm was obtained.

  8. Carbonized asphaltene-based carbon-carbon fiber composites

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-27

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

  9. Boron nitride converted carbon fiber

    Science.gov (United States)

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

    2016-04-05

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

  10. Chemically modified carbon fibers and their applications

    International Nuclear Information System (INIS)

    Ermolenko, I.N.; Lyubliner, I.P.; Gulko, N.V.

    1990-01-01

    This book gives a comprehensive review about chemically modified carbon fibers (e.g. by incorporation of other elements) and is structured as follows: 1. Types of carbon fibers, 2. Structure of carbon fibers, 3. Properties of carbon fibers, 4. The cellulose carbonization process, 5. Formation of element-carbon fiber materials, 6. Surface modification of carbon fibers, and 7. Applications of carbon fibers (e.g. adsorbents, catalysts, constituents of composites). (MM)

  11. Method of carbonizing polyacrylonitrile fibers

    Science.gov (United States)

    Cagliostro, D. E.; Lerner, N. R. (Inventor)

    1983-01-01

    This invention relates to a method of carbonizing polyacrylonitrile fibers by exposing the fibers at an elevated temperature to an oxidizing atmosphere; then exposing the oxidized fibers to an atmosphere of an inert gas such as nitrogen containing a carbonaceous material such as acetylene. The fibers are preferably treated with an organic compound, for example benzoic acid, before the exposure to an oxidizing atmosphere. The invention also relates to the resulting fibers. The treated fibers have enhanced tensile strength.

  12. Carbon fiber electrometer for dosimeter

    International Nuclear Information System (INIS)

    Piltingsrud, H.V.

    1976-01-01

    An electrometer for conventional pocket radiation dosimeters is disclosed in which the moving element of the electrometer is a carbon fiber. The fiber is spun from polyacrylonitrile homopolymer yarn and has a diameter of approximately 7 microns before carbonization. The polyacrylonitrile homopolymer fiber is conventionally preoxidized at approximately 270 0 C before conventional carbonization at approximately 1200 0 C. The resulting working fiber has a round cross sectional diameter of approximately 4 microns and a modulus of elasticity of approximately 15,000,000 psi. The fiber is mounted in a conventionally loop shaped electrometer frame by crimping the ends of the fiber into tabs on the frame. 2 claims, 5 figures

  13. Carbon fiber counting. [aircraft structures

    Science.gov (United States)

    Pride, R. A.

    1980-01-01

    A method was developed for characterizing the number and lengths of carbon fibers accidentally released by the burning of composite portions of civil aircraft structure in a jet fuel fire after an accident. Representative samplings of carbon fibers collected on transparent sticky film were counted from photographic enlargements with a computer aided technique which also provided fiber lengths.

  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. Carbon Fiber from Biomass

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-01

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

  17. 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.

  18. 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...

  19. Carbon fiber reinforced asphalt concrete

    International Nuclear Information System (INIS)

    Jahromi, Saeed G.

    2008-01-01

    Fibers are often used in the manufacture of other materials. For many years, they have been utilized extensively in numerous applications in civil engineering. Fiber-reinforcement refers to incorporating materials with desired properties within some other materials lacking those properties. Use of fibers is not a new phenomenon, as the technique of fiber-reinforced bitumen began early as 1950. In all industrialized countries today, nearly all concretes used in construction are reinforced. A multitude of fibers and fiber materials are being introduced in the market regularly. The present paper presents characteristics and properties of carbon fiber-reinforced asphalt mixtures, which improve the performance of pavements. To evaluate the effect of fiber contents on bituminous mixtures, laboratory investigations were carried out on the samples with and without fibers. During the course of this study, various tests were undertaken, applying Marshall Test indirect tensile test, creep test and resistance to fatigue cracking by using repeated load indirect tensile test. Carbon fiber exhibited consistency in results and as such it was observed that the addition of fiber does affect the properties of bituminous mixtures, i.e. an increase in its stability and decrease in the flow value as well as an increase in voids in the mix. Results indicate that fibers have the potential to resist structural distress in pavement, in the wake of growing traffic loads and thus improve fatigue by increasing resistance to cracks or permanent deformation. On the whole, the results show that the addition of carbon fiber will improve some of the mechanical properties like fatigue and deformation in the flexible pavement. (author)

  20. Mechanical behavior of fiber/matrix interfaces in CFRP sheets subjected to plastic deformation

    Directory of Open Access Journals (Sweden)

    Kamiya Ryuta

    2016-01-01

    Full Text Available The use of Carbon Fiber Reinforced Plastic (CFRP is increasing markedly, partially in the aviation industry, but it has been considered that CFRP sheets cannot be formed by press-forming techniques owing to the low ductility of CFRP. Since the mechanical characteristics of CFRP are dominated by the microscale structure, it is possible to improve its formability by optimizing the material structure. Therefore, to improve the formability, the interaction between the carbon fibers and the matrix must be clarified. In this study, microscale analyses were conducted by a finite-element model with cohesive zone elements.

  1. Multifunctional smart composites with integrated carbon nanotube yarn and sheet

    Science.gov (United States)

    Chauhan, Devika; Hou, Guangfeng; Ng, Vianessa; Chaudhary, Sumeet; Paine, Michael; Moinuddin, Khwaja; Rabiee, Massoud; Cahay, Marc; Lalley, Nicholas; Shanov, Vesselin; Mast, David; Liu, Yijun; Yin, Zhangzhang; Song, Yi; Schulz, Mark

    2017-04-01

    Multifunctional smart composites (MSCs) are materials that combine the good electrical and thermal conductivity, high tensile and shear strength, good impact toughness, and high stiffness properties of metals; the light weight and corrosion resistance properties of composites; and the sensing or actuation properties of smart materials. The basic concept for MSCs was first conceived by Daniel Inman and others about 25 years ago. Current laminated carbon and glass fiber polymeric composite materials have high tensile strength and are light in weight, but they still lack good electrical and thermal conductivity, and they are sensitive to delamination. Carbon nanotube yarn and sheets are lightweight, electrically and thermally conductive materials that can be integrated into laminated composite materials to form MSCs. This paper describes the manufacturing of high quality carbon nanotube yarn and sheet used to form MSCs, and integrating the nanotube yarn and sheet into composites at low volume fractions. Various up and coming technical applications of MSCs are discussed including composite toughening for impact and delamination resistance; structural health monitoring; and structural power conduction. The global carbon nanotube overall market size is estimated to grow from 2 Billion in 2015 to 5 Billion by 2020 at a CAGR of 20%. Nanotube yarn and sheet products are predicted to be used in aircraft, wind machines, automobiles, electric machines, textiles, acoustic attenuators, light absorption, electrical wire, sporting equipment, tires, athletic apparel, thermoelectric devices, biomedical devices, lightweight transformers, and electromagnets. In the future, due to the high maximum current density of nanotube conductors, nanotube electromagnetic devices may also become competitive with traditional smart materials in terms of power density.

  2. Methods of making carbon fiber from asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George; Bowen, III, Daniel E.

    2017-02-28

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

  3. Fabrication of Carbon Nanotube Polymer Actuator Using Nanofiber Sheet

    Science.gov (United States)

    Kato, Hayato; Shimizu, Akikazu; Sato, Taiga; Kushida, Masahito

    2017-11-01

    Carbon nanotube polymer actuators were developed using composite nanofiber sheets fabricated by multi-walled carbon nanotubes(MWCNTs) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Nanofiber sheets were fabricated by electrospinning method. The effect of flow rate and polymer concentration on nanofiber formation were verified for optimum condition for fabricating nanofiber sheets. We examined the properties of MWCNT/PVDF-HFP nanofiber sheets, as follows. Electrical conductivity and mechanical strength increased as the MWCNT weight ratio increased. We fabricated carbon nanotube polymer actuators using MWCNT/PVDF-HFP nanofiber sheets and succeeded in operating of our actuators.

  4. Elastoplastic properties of transversely isotropic sintered metal fiber sheets

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, T.F. [School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi’an 710072 (China); Chen, C.Q., E-mail: chencq@tsinghua.edu.cn [Department of Engineering Mechanics and Center for Nano and Micro Mechanics, AML, Tsinghua University, Beijing 100084 (China); Deng, Z.C. [School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi’an 710072 (China); State Key Laboratory of Structural Analysis of Industrial Equipment, Dalian University of Technology, Dalian 116024 (China)

    2016-04-26

    Sintering of layered metal fiber sheets produces a structured, tunable, paper-like material that holds promise for thermal and biomaterial applications. Particularly promising for these areas is a material system synthesized by the sequential-overlap method, which produces a networked, transversely isotropic open cell porous material. Engineering application of these materials has been limited due in part to uncertainty about their mechanical responses. Here, we present a comprehensive structural and mechanical characterization of these materials, and define a modeling framework suitable for engineering design. X-ray tomography revealed a layered structure with an isotropic fiber distribution within each layer. In-plane uniaxial compression and tension tests revealed a linear dependence of Young's modulus and yield strength upon relative fiber density. Out-of-plane tests, however, revealed much lower Young's modulus and strength, with quartic and cubic dependence upon relative density, respectively. Fiber fracture was the dominant mode of failure for tension within the “in-plane” directions of the fiber layers, and fiber decohesion was the dominant mode of failure for tension applied in the “out-of-plane” direction, normal to the layers. Models based upon dispersions of beams predicted both in-plane and out-of-plane elastoplastic properties as a function of the relative density of fibers. These models provide a foundation for mechanical design with and optimization of these materials for a broad range of potential applications.

  5. Molecular modeling of the microstructure evolution during carbon fiber processing

    Science.gov (United States)

    Desai, Saaketh; Li, Chunyu; Shen, Tongtong; Strachan, Alejandro

    2017-12-01

    The rational design of carbon fibers with desired properties requires quantitative relationships between the processing conditions, microstructure, and resulting properties. We developed a molecular model that combines kinetic Monte Carlo and molecular dynamics techniques to predict the microstructure evolution during the processes of carbonization and graphitization of polyacrylonitrile (PAN)-based carbon fibers. The model accurately predicts the cross-sectional microstructure of the fibers with the molecular structure of the stabilized PAN fibers and physics-based chemical reaction rates as the only inputs. The resulting structures exhibit key features observed in electron microcopy studies such as curved graphitic sheets and hairpin structures. In addition, computed X-ray diffraction patterns are in good agreement with experiments. We predict the transverse moduli of the resulting fibers between 1 GPa and 5 GPa, in good agreement with experimental results for high modulus fibers and slightly lower than those of high-strength fibers. The transverse modulus is governed by sliding between graphitic sheets, and the relatively low value for the predicted microstructures can be attributed to their perfect longitudinal texture. Finally, the simulations provide insight into the relationships between chemical kinetics and the final microstructure; we observe that high reaction rates result in porous structures with lower moduli.

  6. Mechanical properties of high performance carbon fibers

    International Nuclear Information System (INIS)

    Chen, K.J.

    1984-01-01

    Carbon fibers often show a variation in axial preferred orientation across the fiber diameter which leads to a modulus gradient and residual stress. Theoretical equations of the residual stresses in radial, hoop and longitudinal directions were derived from linear elasticity based on a perfect onion skin model. The high hoop compressive stress in the surface causes a flute-like structure in the fiber surface, and the radial stress within the fiber will induce microcracks within the fiber. Another model, based on parallel springs, was used to estimate the magnitude of the longitudinal stress which shows very good fit with the experimental data. The modulus gradient and residual strain in carbon fibers were measured by successively electrochemically milling away the fiber surface. Electrochemical etching was found to remove the carbon fiber surface very uniformly in contrast with air and wet oxidation. The moduli of most carbon fibers decreased after the outer layer of the fibers were removed. In general, type I carbon fibers with a skin/core heterogeneous structure show higher modulus gradient than those of type II and type A carbon fibers. Axial compressive residual stresses were very high for some higher modulus carbon fibers. SEM studies of the tensilely fracture surface of the single filament show, in general, type I carbon fiber failure initiates from interior voids while type II and type A fail by surface flaws

  7. Intermittent sizing on carbon fiber for composite application

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Jr, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Paulauskas, Felix L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ozcan, Soydan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Xiong, Fue [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grappe, Hippolyte A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    Intermittent sizing is a technique designed to improve the bonding of carbon fiber to a resin when manufacturing composite parts. The purpose of this technique is to improve Sheet Molding Composites (SMC) made of non-continuous carbon fibers while using regular material. At the end of the project, tests showed that improved mechanical properties have been achieved using this technique compared to conventional process. Mechanical properties have been improved by 110% for the peak tensile stress and by 60% for the modulus at the laboratory scale. In this project, Continental Structural Plastics and ORNL have worked to demonstrate the scalability and viability of commercialization of this technique.

  8. Carbon dioxide adsorption in graphene sheets

    Directory of Open Access Journals (Sweden)

    Ashish Kumar Mishra

    2011-09-01

    Full Text Available Control over the CO2 emission via automobiles and industrial exhaust in atmosphere, is one of the major concerns to render environmental friendly milieu. Adsorption can be considered to be one of the more promising methods, offering potential energy savings compared to absorbent systems. Different carbon nanostructures (activated carbon and carbon nanotubes have attracted attention as CO2 adsorbents due to their unique surface morphology. In the present work, we have demonstrated the CO2 adsorption capacity of graphene, prepared via hydrogen induced exfoliation of graphitic oxide at moderate temperatures. The CO2 adsorption study was performed using high pressure Sieverts apparatus and capacity was calculated by gas equation using van der Waals corrections. Physical adsorption of CO2 molecules in graphene was confirmed by FTIR study. Synthesis of graphene sheets via hydrogen exfoliation is possible at large scale and lower cost and higher adsorption capacity of as prepared graphene compared to other carbon nanostructures suggests its possible use as CO2 adsorbent for industrial application. Maximum adsorption capacity of 21.6 mmole/g was observed at 11 bar pressure and room temperature (25 ºC.

  9. Magneto-carbonization method for production of carbon fiber, and high performance carbon fibers made thereby

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Ozcan, Soydan; Eberle, Claude C.; Abdallah, Mohamed Gabr; Mackiewicz, Ludtka Gail; Ludtka, Gerard Michael; Paulauskas, Felix Leonard; Rivard, John Daniel Kennedy

    2017-08-08

    Method for the preparation of carbon fiber from fiber precursor, wherein the fiber precursor is subjected to a magnetic field of at least 3 Tesla during a carbonization process. The carbonization process is generally conducted at a temperature of at least 400.degree. C. and less than 2200.degree. C., wherein, in particular embodiments, the carbonization process includes a low temperature carbonization step conducted at a temperature of at least or above 400.degree. C. or 500.degree. C. and less than or up to 1000.degree. C., 1100.degree. C., or 1200.degree. C., followed by a high temperature carbonization step conducted at a temperature of at least or above 1200.degree. C. In particular embodiments, particularly in the case of a polyacrylonitrile (PAN) fiber precursor, the resulting carbon fiber may possess a minimum tensile strength of at least 600 ksi, a tensile modulus of at least 30 Msi, and an ultimate elongation of at least 1.5%.

  10. 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.

  11. Carbon fibers from SRC pitch

    Science.gov (United States)

    Greskovich, Eugene J.; Givens, Edwin N.

    1981-01-01

    This invention relates to an improved method of manufacturing carbon fibers from a coal derived pitch. The improvement resides in the use of a solvent refined coal which has been hydrotreated and subjected to solvent extraction whereby the hetero atom content in the resulting product is less than 4.0% by weight and the softening point is between about 100.degree.-250.degree. F.

  12. Storing Fluorine In Graphitelike Carbon Fibers

    Science.gov (United States)

    Hung, Ching-Cheh

    1995-01-01

    Fluorine stored in graphite or graphitelike carbon fibers for later release and/or use in chemical reactions. Storage in carbon fibers eliminates difficulty and risk of using high-pressure tanks and pipes to hold corrosive gas. Storage in carbon fibers makes fluorine more readily accessible than does storage as constituent of metal fluoride. Carbon fibers heated to release stored fluorine, which draws away to vessel where reacts with material to be fluorinated, possibly at temperature other than release temperature. Alternatively, material to be fluorinated mixed or otherwise placed in contact with fibers and entire mass heated to or beyond release temperature.

  13. The Spot Weldability of Carbon Steel Sheet

    Directory of Open Access Journals (Sweden)

    A. M. Al-Mukhtar

    2013-01-01

    Full Text Available The specimens of thickness 0.8 mm carbon steel number 1.8902 in a strip form were welded. The strips of lap joints and curved peeljoints configurations have been welded. The welding parameters such as weld current and weld time have been investigated. The relation between the weld area and the joint strength properties has been presented. The obtained results were showing that the weld joint strength and the molten area (weld nugget volume highly increase with the increasing of weld current. Therefore, the correlation between the maximum load (joint strength and area has been given. The reliable weldability under the tensile and shearing loading was considered. Therefore, the new limits of weldability have been presented to consider these two types of loading. Moreover, the experimental results were compared with the empirical relations that consider the sheet thickness only.

  14. Low Cost Carbon Fiber From Renewable Resources

    International Nuclear Information System (INIS)

    Compere, A.L.

    2001-01-01

    The Department of Energy Partnership for a New Generation of Vehicles has shown that, by lowering overall weight, the use of carbon fiber composites could dramatically decrease domestic vehicle fuel consumption. For the automotive industry to benefit from carbon fiber technology, fiber production will need to be substantially increased and fiber price decreased to$7/kg. To achieve this cost objective, alternate precursors to pitch and polyacrylonitrile (PAN) are being investigated as possible carbon fiber feedstocks. Additionally, sufficient fiber to provide 10 to 100 kg for each of the 13 million cars and light trucks produced annually in the U.S. will require an increase of 5 to 50-fold in worldwide carbon fiber production. High-volume, renewable or recycled materials, including lignin, cellulosic fibers, routinely recycled petrochemical fibers, and blends of these components, appear attractive because the cost of these materials is inherently both low and insensitive to changes in petroleum price. Current studies have shown that a number of recycled and renewable polymers can be incorporated into melt-spun fibers attractive as carbon fiber feedstocks. Highly extrudable lignin blends have attractive yields and can be readily carbonized and graphitized. Examination of the physical structure and properties of carbonized and graphitized fibers indicates the feasibility of use in transportation composite applications

  15. 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.

  16. Fabrication and Properties of Carbon Fibers

    Science.gov (United States)

    Huang, Xiaosong

    2009-01-01

    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.

  17. Patterned functional carbon fibers from polyethylene

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-01

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

  18. Carbon nanotube fiber terahertz polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, Ahmed [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Tsentalovich, Dmitri E.; Young, Colin C. [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Heimbeck, Martin S. [Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Everitt, Henry O. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Pasquali, Matteo [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2016-04-04

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼−30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2–1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

  19. Characterization of electrospun lignin based carbon fibers

    Science.gov (United States)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-01

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

  20. Surface analyses of carbon fibers produced from polyacrylonitrile fibers at low carbonization temperatures

    Science.gov (United States)

    Cagliostro, D. E.

    1983-01-01

    A process for producing carbon fibers from polyacrylonitrile at low carbonization temperatures was studied. The bulk and surface properties of fibers obtained after reaction with benzoic acid, air and carbonizing in nitrogen or a dilute acetylene atmosphere are discussed. All fiber products had different surface and internal compositions. Samples produced at temperatures up to 950 C and carbonized in nitrogen contained substantial quantities of nitrogen and oxygen at the surface. During carbonization, the surface nitrogen converted into two new forms, possibly nitrile and an azo or a new carbon-nitrogen bond. Samples carbonized in acetylene contained a carbon-rich surface stable to oxidation.

  1. Use of Carbon Nano-Fiber Foams as Strain Gauges to Detect Crack Propagation

    Science.gov (United States)

    2015-06-01

    capacitors [18]. Another example are recent attempts to use carbon fibers and carbon nanotubes to develop sensor devices. Sida Luo created aligned...ring caps made out of Ethlyene-Propylene • Super Glue (Cyanoacrylate, C5H5NO2) • One sheet of aluminum foil • AL5083 specimen (27.94 mm Length, 2.54

  2. 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.

  3. 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.

  4. The Feasibility of Modified Magnesia-Phosphate Cement as a Heat Resistant Adhesive for Strengthening Concrete with Carbon Sheets

    Directory of Open Access Journals (Sweden)

    Ailian Zhang

    2016-06-01

    Full Text Available External bonding of carbon fiber sheets has become a popular technique for strengthening concrete structures all over the world. Epoxy adhesive, which is used to bond the carbon fiber sheets and concrete, deteriorates rapidly when being exposed to high temperatures. This paper presents a high-temperature-resistant modified magnesia-phosphate cement (MPC with the compressive strength that does not decrease at the temperature of 600 °C. The bond properties of both the modified MPC and the epoxy adhesive between externally bonded carbon fiber sheets and concrete were evaluated by using a double-shear test method after exposure to elevating temperatures from 105 °C to 500 °C. The results showed that the bond strength of the modified MPC at room temperature (RT is much higher than that of the epoxy resin. Full carbonation with almost 0 MPa was detected for the epoxy sample after the exposure to 300 °C, while only 40% reduction of bond strength was tested for the modified MPC sample. Although the modified MPC specimens failed through interlaminar slip of fiber strips instead of complete debonding, the MPC specimens performed higher bond strength than epoxy resin at ambient temperature, and retained much higher bond strength at elevated temperatures. It could be concluded that it is feasible to strengthen concrete structural members with externally bonded carbon fiber sheets using the modified MPC instead of epoxy adhesive. Furthermore, the use of the modified MPC as the binder between carbon fiber sheets and concrete can be less expensive and an ecologically friendly alternative.

  5. Effects of fiber length on mechanical properties and fracture behavior of short carbon fiber reinforced geopolymer matrix composites

    International Nuclear Information System (INIS)

    Lin Tiesong; Jia Dechang; He Peigang; Wang Meirong; Liang Defu

    2008-01-01

    A kind of sheet-like carbon fiber preform was developed using short fibers (2, 7 and 12 mm, respectively) as starting materials and used to strengthen a geopolymer. Mechanical properties, fracture behavior, microstructure and toughening mechanisms of the as-prepared composites were investigated by three-point bending test, optical microscope and scanning electron microscopy. The results show that the short carbon fibers disperse uniformly in geopolymer matrix. The C f /geopolymer composites exhibit apparently improved mechanical properties and an obvious noncatastrophic failure behavior. The composite reinforced by the carbon fibers of 7 mm in length shows a maximum flexural strength as well as the highest work of facture, which are nearly 5 times and more than 2 orders higher than that of the geopolymer matrix, respectively. The predominant strengthening and toughening mechanisms are attributed to the apparent fiber bridging and pulling-out effect based on the weak fiber/matrix interface as well as the sheet-like carbon fiber preform

  6. Carbon composites composites with carbon fibers, nanofibers, and nanotubes

    CERN Document Server

    Chung, Deborah D L

    2017-01-01

    Carbon Composites: Composites with Carbon Fibers, Nanofibers, and Nanotubes, Second Edition, provides the reader with information on a wide range of carbon fiber composites, including polymer-matrix, metal-matrix, carbon-matrix, ceramic-matrix and cement-matrix composites. In contrast to other books on composites, this work emphasizes materials rather than mechanics. This emphasis reflects the key role of materials science and engineering in the development of composite materials. The applications focus of the book covers both the developing range of structural applications for carbon fiber composites, including military and civil aircraft, automobiles and construction, and non-structural applications, including electromagnetic shielding, sensing/monitoring, vibration damping, energy storage, energy generation, and deicing. In addition to these new application areas, new material in this updated edition includes coverage of cement-matrix composites, carbon nanofibers, carbon matrix precursors, fiber surface ...

  7. Fiber-Matrix Interphase Development in Carbon/Carbon Composites

    National Research Council Canada - National Science Library

    Rellick, G

    1998-01-01

    In carbon/carbon (C/C) composites-i.e., a composite in which a carbon matrix is reinforced with carbon fiber when the matrix is derived from a thermosetting resin, we always observe a distinct, highly graphitizable, and well-oriented...

  8. Method for the preparation of carbon fiber from polyolefin fiber precursor

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-11-28

    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.

  9. 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

  10. 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.

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

    Science.gov (United States)

    Tehrani, Mehran; Yari Boroujeni, Ayoub; Luhrs, Claudia; Phillips, Jonathan; Al-Haik, Marwan S

    2014-05-28

    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.

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

    Science.gov (United States)

    Tehrani, Mehran; Yari Boroujeni, Ayoub; Luhrs, Claudia; Phillips, Jonathan; Al-Haik, Marwan S.

    2014-01-01

    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. PMID:28788671

  13. A flexible tactile sensitive sheet using a hetero-core fiber optic sensor

    Science.gov (United States)

    Fujino, S.; Yamazaki, H.; Hosoki, A.; Watanabe, K.

    2014-05-01

    In this report, we have designed a tactile sensitive sheet based on a hetero-core fiber-optic sensor, which realize an areal sensing by using single sensor potion in one optical fiber line. Recently, flexible and wide-area tactile sensing technology is expected to applied to acquired biological information in living space and robot achieve long-term care services such as welfare and nursing-care and humanoid technology. A hetero-core fiber-optic sensor has several advantages such as thin and flexible transmission line, immunity to EMI. Additionally this sensor is sensitive to moderate bending actions with optical loss changes and is independent of temperature fluctuation. Thus, the hetero-core fiber-optic sensor can be suitable for areal tactile sensing. We measure pressure characteristic of the proposed sensitive sheet by changing the pressure position and pinching characteristic on the surface. The proposed tactile sensitive sheet shows monotonic responses on the whole sensitive sheet surface although different sensitivity by the position is observed at the sensitive sheet surface. Moreover, the tactile sensitive sheet could sufficiently detect the pinching motion. In addition, in order to realize the discrimination between pressure and pinch, we fabricated a doubled-over sensor using a set of tactile sensitive sheets, which has different kinds of silicon robbers as a sensitive sheet surface. In conclusion, the flexible material could be given to the tactile sensation which is attached under proposed sensitive sheet.

  14. Carbon fiber on polyimide ultra-microelectrodes

    Science.gov (United States)

    Gillis, Winthrop F.; Lissandrello, Charles A.; Shen, Jun; Pearre, Ben W.; Mertiri, Alket; Deku, Felix; Cogan, Stuart; Holinski, Bradley J.; Chew, Daniel J.; White, Alice E.; Otchy, Timothy M.; Gardner, Timothy J.

    2018-02-01

    Objective. Most preparations for making neural recordings degrade over time and eventually fail due to insertion trauma and reactive tissue response. The magnitudes of these responses are thought to be related to the electrode size (specifically, the cross-sectional area), the relative stiffness of the electrode, and the degree of tissue tolerance for the material. Flexible carbon fiber ultra-microelectrodes have a much smaller cross-section than traditional electrodes and low tissue reactivity, and thus may enable improved longevity of neural recordings in the central and peripheral nervous systems. Only two carbon fiber array designs have been described previously, each with limited channel densities due to limitations of the fabrication processes or interconnect strategies. Here, we describe a method for assembling carbon fiber electrodes on a flexible polyimide substrate that is expected to facilitate the construction of high-density recording and stimulating arrays. Approach. Individual carbon fibers were aligned using an alignment tool that was 3D-printed with sub-micron resolution using direct laser writing. Indium deposition on the carbon fibers, followed by low-temperature microsoldering, provided a robust and reliable method of electrical connection to the polyimide interconnect. Main results. Spontaneous multiunit activity and stimulation-evoked compound responses with SNR  >10 and  >120, respectively, were recorded from a small (125 µm) peripheral nerve. We also improved the typically poor charge injection capacity of small diameter carbon fibers by electrodepositing 100 nm-thick iridium oxide films, making the carbon fiber arrays usable for electrical stimulation as well as recording. Significance. Our innovations in fabrication technique pave the way for further miniaturization of carbon fiber ultra-microelectrode arrays. We believe these advances to be key steps to enable a shift from labor intensive, manual assembly to a more automated

  15. Thermal Transport Properties of Dry Spun Carbon Nanotube Sheets

    Directory of Open Access Journals (Sweden)

    Heath E. Misak

    2016-01-01

    Full Text Available The thermal properties of carbon nanotube- (CNT- sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an IR Camera. The heat flux of CNT-sheet was compared to that of copper, and it was found that the CNT-sheet has significantly higher specific heat transfer properties compared to those of copper. CNT-sheet is a potential candidate to replace copper in thermal transport applications where weight is a primary concern such as in the automobile, aircraft, and space industries.

  16. Polyacrylonitrile-based carbonized fibers and metal-carbonized fiber nanocomposites for thermal transport.

    Science.gov (United States)

    Ochanda, Fredrick; Atkinson, Ariel; Fey, Edmond O; Andala, Dickson; Jones, Wayne E

    2010-12-01

    This work examines the fabrication and thermal analysis of metal-carbon composite fibers prepared via an electrospinning process. The metal-carbon composite fibers of silver, copper, gold, and nickel were prepared by electrospinning of a composite solution of polyacrylonitrile (PAN) and metal precursor followed by heat treatment in air, nitrogen to 1000 degrees C and in 6% H2, respectively. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy dispersive spectroscopy (EDS) and Scanning thermal microscopy (SThM) were applied to characterize the metal-carbon fibers. TEM analysis showed a relatively uniform, contact-free distribution of the nanoparticles on the surface of the carbon fibers with size range of 3 nm-10 nm. Thermal analysis data showed an enhancement in the thermal conductivity of the nanomaterials when compared with the model PAN-based carbonized fibers. This was attributed to the incorporation of metal nanoparticles in the fiber matrix and on the surface.

  17. Carbon Fiber Damage in Accelerator Beam

    CERN Document Server

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

    2009-01-01

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

  18. Evaluation of Mechanical Property of Carbon Fiber/Polypropylene Composite According to Carbon Fiber Surface Treatment

    International Nuclear Information System (INIS)

    Han, Song Hee; Oh, Hyun Ju; Kim, Seong Su

    2013-01-01

    In this study, the mechanical properties of a carbon fiber/polypropylene composite were evaluated according to the carbon fiber surface treatment. Carbon fiber surface treatments such as silane coupling agents and plasma treatment were performed to enhance the interfacial strength between carbon fibers and polypropylene. The treated carbon fiber surface was characterized by XP S, Sem, and single-filament tensile test. The interlaminar shear strength (Ilks) of the composite with respect to the surface treatment was determined by a short beam shear test. The test results showed that the Ilks of the plasma-treated specimen increased with the treatment time. The Ilks of the specimen treated with a silane coupling agent after plasma treatment increased by 48.7% compared to that of the untreated specimen

  19. Carbon fiber production at low temperatures from polyacrylonitrile

    Science.gov (United States)

    Cagliostro, D. E.

    1980-01-01

    Recent safety considerations have sought to lower the electrical conductivity of carbon fibers. Carbon fibers produced from polyacrylonitrile at low carbonization temperatures (600-900 C) possess low electrical conductivity but do not possess adequate strength. Low-temperature processes are described which improve fiber strength but do not increase electrical conductivity substantially. The processes result in a carbon fiber with nearly twice the tensile strength compared to the old process. Process development and its effect on fiber properties are reported.

  20. Chitosan/polyurethane blended fiber sheets containing silver sulfadiazine for use as an antimicrobial wound dressing.

    Science.gov (United States)

    Lee, Sang Jin; Heo, Dong Nyoung; Moon, Ji-Hoi; Park, Ha Na; Ko, Wan-Kyu; Bae, Min Soo; Lee, Jung Bok; Park, Se Woong; Kim, Eun-Cheol; Lee, Chang Hoon; Jung, Bock-Young; Kwon, Il Keun

    2014-10-01

    Electrospun chitosan (CTS) nanofibers have been well known for use as a wound dressing in the biomedical field. Nevertheless, fatal bacterial infections are still a serious problem when CTS nanofibers are used for wound treatment. In this study, we designed a novel wound dressing based on blending the chitosan with polyurethane (CTS/PU) containing silver sulfadiazine (AgSD) in order to enhance both antibacterial activity and mechanical strength. This fiber sheet was produced using the electrospinning (ELSP) technique. The CTS/PU containing AgSD fiber sheet was characterized by energy-dispersive X-ray spectroscopy (EDX). The physicochemical properties of the CTS/PU/AgSD fiber sheets were also characterized by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The electrospun fibers were morphologically characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For an in vitro evaluation, the CTS/PU/AgSD fiber sheets were tested for their antibacterial activity against gram-negative Pseudomonas aeruginosa (P. aeruginosa), gram-positive Staphylococcus aureus (S. aureus) and Methicillin-resistant Staphylococcus aureus (MRSA). The results indicate that CTS/PU/AgSD fiber sheets have strong antimicrobial activity as displayed by inhibition of bacterial growth and prevention of infection during the healing process. These results indicate that this material would be good for use as a wound dressing material.

  1. Carbon Fiber Composite Materials for Automotive Applications

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Jr., Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mainka, Hendrik [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Volkswagen (VW) is internationally recognized for quantity and quality of world-wide vehicle production and the Oak Ridge National Laboratory (ORNL) is internationally recognized in materials research and development. With automotive production ramping up in the recently constructed VW Group of America facility in Chattanooga, Tennessee, ORNL and VW initiated discussions in 2012 concerning opportunities for collaboration around ORNL’s carbon fiber and composites programs. ORNL is conducting an internationally recognized program to develop and implement lower cost carbon fibers and composites for automotive and other “energy missions” for the US Department of Energy. Significant effort is ongoing in selecting, developing, and evaluating alternative precursors, developing and demonstrating advanced conversion techniques, and developing and tailoring surface treatment, sizings, and formatting fiber for specific composite matrices and end-use applications. ORNL already had North America’s most comprehensive suite of tools for carbon fiber research and development and established a semiproduction demonstration line referred to as the Carbon Fiber Technology Facility (CFTF) to facilitate implementation of low cost carbon fiber (LCCF) approaches in early 2013. ORNL and VW agreed to collaborate in a formal Cooperative Research and Development Agreement (NFE-12-03992) specifically focused on evaluating applicability of low cost carbon fiber products for potential vehicle components. The goal of the work outlined in this report was to develop and qualify uses for carbon fiber-reinforced structures in connection with civilian ground transportation. Significant progress was achieved in evaluating and understanding lignin-based precursor materials; however, availability of carbon fiber converted from lignin precursor combined with logistical issues associated with the Visa limitations for the VW participant resulted in significantly shortening of the collaboration

  2. 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.

  3. Coating for gasifiable carbon-graphite fibers

    Science.gov (United States)

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

    1982-01-01

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

  4. Viscoelastic properties and antimicrobial activity of cellulose fiber sheets impregnated with Ag nanoparticles.

    Science.gov (United States)

    Csóka, Levente; Božanić, Dušan K; Nagy, Veronika; Dimitrijević-Branković, Suzana; Luyt, Adriaan S; Grozdits, George; Djoković, Vladimir

    2012-10-01

    A silver nanoparticle colloid was prepared by a modified Tollens method using d-glucose as the reduction agent. The obtained nanoparticles were used for the modification of pine, linter and recycled cellulose fibers. Although the silver contents were relatively low (0.05-0.13 wt.%), the cellulose-sheets prepared from the modified fibers show improved mechanical and viscoelastic properties. The tensile index (strength) increased with up to 30% in comparison to the index of the sheets obtained from the untreated fibers. The influence of the nanoparticles on the viscoelastic properties of the cellulose sheets was investigated by dynamic mechanical analysis (DMA) in the temperature range from -120 to 20 °C and with a force frequency of 100 Hz. A broad relaxation transition positioned at -80 °C was observed in the loss modulus spectrum of all the cellulose sheets, while the Ag-modified sheets exhibited higher storage moduli values in the whole temperature range. The antimicrobial activity tests show that the pine, silver and recycled cellulose fiber sheets with silver nanoparticles can be successfully employed to prevent the viability and growth of the common pathogens Staphylococcus aureus, Escherichia coli and Candida albicans. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. 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.

  6. 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.

  7. Designing the Structure of Carbon Fibers for Optimal Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Soydan [ORNL; Vautard, Frederic [ORNL; Naskar, Amit K [ORNL

    2014-01-01

    Carbon fiber manufacturing follows generic processing steps: formation of thermoplastic fibers, stabilization, and carbonization. The final structures and end properties of the carbon fiber can differ significantly depending on the precursor chemistry and the associated processing sciences. Polyacrylonitrile (PAN) and mesophase pitch are the predominant precursors used in the production of carbon fibers. PAN-based carbon fibers consist of nanocrystalline graphitic domains typically 1.5 5 nm in size surrounded by amorphous carbon; in contrast, pitch-based carbon fibers are 10 50 nm crystallites with the graphitic (002) planes mostly aligned parallel to the fiber axis. It has been seen that the skin core structure of PAN-based carbon fibers plays a significant role in their mechanical properties. Designing a more homogenous carbon fiber microstructure by controlling the starting polymer and process parameters results in a different set of tensile strengths and elastic moduli. In this study the microstructural defect distribution (0.1 200 nm), measured by small-angle X-ray scattering, was shown to be directly related to the tensile strength of the carbon fibers. Here the formation of carbon structures from various polymer precursors is reviewed. Such a comprehensive understanding offers the opportunity to design carbon fiber microstructures with improved properties and to ultimately create new types of carbon fibers from alternative precursors at reduced cost.

  8. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-01

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

  9. [In vivo evaluation of carbon fiber posts].

    Science.gov (United States)

    Lai, V; Lugliè, P F; Chessa, G

    2002-05-01

    The use of carbon fiber posts allows morpho-functional restoration of endodontically treated teeth with an assembly of materials of a modulus of elasticity similar to that of dentin. The study clinically evaluated the percentage of survival of dental elements treated and reconstructed with endocanal carbon fiber posts. At the Dentistry Clinic of the University of Sassari 60 dental elements were selected from 46 subjects. The teeth, which had been treated endodontically with success for at least six months, were classified by parameters taken from the international literature and reconstructed using Tech 2000 carbon fiber posts and adhesive resinous systems recommended by the post manufacturer. The success rate was 98.4%. Almost half (49%) of the samples were single-rooted elements, 37.4% of the posts were 1.2 mm in diameter; in 78.3% the opposing contact was with a natural tooth; 100% of the elements had a type A dental structure. Third generation posts are a valid alternative to metallic posts and improve the prognosis of the treated element. The carbon fiber posts fixed with the composite, forming a single unit with the dental element, thus improving mid-term RESULTS. The technique is easy to use under clinical conditions and can be performed in a single session. So far, the method has provided promising clinical results, as this study demonstrated.

  10. Carbon stripper foils held in place with carbon fibers

    International Nuclear Information System (INIS)

    Jolivet, Connie S.; Miller, Shawn A.; Stoner, John O.; Ladd, Peter

    2008-01-01

    The Spallation Neutron Source (SNS) currently under construction at Oak Ridge National Laboratory, Oak Ridge, Tennessee, is planned to initially utilize carbon stripper foils having areal densities approximately 260 μg/cm 2 . The projected design requires that each foil be supported by only one fixed edge. For stability of the foil, additional support is to be provided by carbon fibers. The feasibility of manufacturing and shipping such mounted carbon foils produced by arc evaporation was studied using two prototypes. Production of the foils is described. Fibers were chosen for satisfactory mechanical strength consistent with minimal interference with the SNS beam. Mounting of the fibers, and packaging of the assemblies for shipping are described. Ten completed assemblies were shipped to SNS for further testing. Preliminary evaluation of the survivability of the foils in the SNS foil changer is described

  11. Interaction between carbon fibers and polymer sizing: Influence of fiber surface chemistry and sizing reactivity

    Science.gov (United States)

    Moosburger-Will, Judith; Bauer, Matthias; Laukmanis, Eva; Horny, Robert; Wetjen, Denise; Manske, Tamara; Schmidt-Stein, Felix; Töpker, Jochen; Horn, Siegfried

    2018-05-01

    Different aspects of the interaction of carbon fibers and epoxy-based polymer sizings are investigated, e.g. the wetting behavior, the strength of adhesion between fiber and sizing, and the thermal stability of the sizing layer. The influence of carbon fiber surface chemistry and sizing reactivity is investigated using fibers of different degree of anodic oxidation and sizings with different number of reactive epoxy groups per molecule. Wetting of the carbon fibers by the sizing dispersion is found to be specified by both, the degree of fiber activation and the sizing reactivity. In contrast, adhesion strength between fibers and sizing is dominated by the surface chemistry of the carbon fibers. Here, the number of surface oxygen groups seems to be the limiting factor. We also find that the sizing and the additional functionalities induced by anodic oxidation are removed by thermal treatment at 600 °C, leaving the carbon fiber in its original state after carbonization.

  12. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

  14. Plasma electrolytic polishing of metalized carbon fibers

    Directory of Open Access Journals (Sweden)

    Falko Böttger-Hiller

    2016-02-01

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

  15. Production of quasi-2D graphene nanosheets through the solvent exfoliation of pitch-based carbon fiber

    International Nuclear Information System (INIS)

    Yeon, Youngju; Lee, Jihoon; In, Insik; Lee, Mi Yeon; Kim, Sang Youl; Kim, Bongsoo; Park, Byoungnam

    2015-01-01

    Stable dispersion of quasi-2D graphene sheets with a concentration up to 1.27 mg mL −1 was prepared by sonication-assisted solvent exfoliation of pitch-based carbon fiber in N-methyl pyrrolidone with the mass yield of 2.32%. Prepared quasi-2D graphene sheets have multi-layered 2D plate-like morphology with rich inclusions of graphitic carbons, a low number of structural defects, and high dispersion stability in aprotic polar solvents, and facilitate the utilization of quasi-2D graphene sheets prepared from pitch-based carbon fiber for various electronic and structural applications. Thin films of quasi-2D graphene sheets prepared by vacuum filtration of the dispersion of quasi-2D graphene sheets demonstrated electrical conductivity up to 1.14 × 10 4 Ω/□ even without thermal treatment, which shows that pitch-based carbon fiber might be useful as the source of graphene-related nanomaterials. Because pitch-based carbon fiber could be prepared from petroleum pitch, a very cheap structural material for the pavement of asphalt roads, our approach might be promising for the mass production of quasi-2D graphene nanomaterials. (paper)

  16. Carbon Fiber Damage in Particle Beam

    CERN Document Server

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

    2011-01-01

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

  17. Carbon Nanotubes Growth on Graphite Fibers

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Lehoczky, S. L.; Muntele, I.; Ila, D.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Carbon nanotubes (CNT) were synthesized on graphite fibers by thermal Chemical Vapor Deposition (CVD). On the fiber surface, iron nanoparticles are coated and act as catalysts for CNT growth. The growth temperature ranges from 550 to 1000 C at an ambient pressure. Methane and hydrogen gases with methane contents of 10% to 100% are used for the CNT synthesis. At high growth temperatures (greater than 800 C), the rapid inter-diffusion of the transition metal iron on the graphite surface results in a rough fiber surface with no CNT grown on the surface. When the growth temperature is relatively low (650 - 800 C), CNT are fabricated on the graphite surface with catalytic particles on the nanotube top ends. Using micro Raman spectroscopy in the breath mode region, single-walled or multi-walled CNT can be determined, depending on methane concentrations.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

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

    International Nuclear Information System (INIS)

    An, Feng; Lu, Chunxiang; Li, Yonghong; Guo, Jinhai; Lu, Xiaoxuan; Lu, Huibin; He, Shuqing; Yang, Yu

    2012-01-01

    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 m 2 /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.

  20. 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.

  1. 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. © 2011 American Chemical Society

  2. Bending Properties of Sandwich Beams with Fiber Metal Laminate Face Sheet

    Directory of Open Access Journals (Sweden)

    Mostafa Sabzikar Boroujerdy1

    2013-01-01

    Full Text Available Sandwich structures are widely used in aerospace, high speed trains and marine applications because of lightweight and high in-plane and flexural stiffness. Sandwich structures consist of two thin face sheets and a core. Face sheets usually are made from highly stiff and highly strong materials; In general, the face sheets may be of different metal or composite layers. Both metal and composite face sheets have advantages and disadvantages, and searching for new materials with better properties is in progress. In this paper flexural behavior of a new generation sandwich beams with fiber metal laminate (FML face sheets were investigated experimentally. Three groups of specimens with different layer arrangements of face sheets consist of (Al/GE (0-90/GE(90-0/Al, (Al/GE(0-90/Al/GE(90-0 and (GE(0-90-0-90-90-0-90-0 and 40 kg/m3 polyurethane foam core were made and tested. The results show that sandwich beams with FML face sheets have better resistance against local loads, while composite faces are weak against intense loads. Also, FML faces are lighter than metal face sheets and have better connection to foam core. Also, a simple classical theory was used to predict the force-deflection behaviour of sandwich beams in elastic region. Good agreement between the experimental results and analytical prediction were obtained. Sandwich beams with FML face sheets have larger elastic region than beams with composite face sheets therefore agreement between the analytical and experimental results in these specimens are in larger area.

  3. Microwave conductance properties of aligned multiwall carbon nanotube textile sheets

    Science.gov (United States)

    Brown, Brian L.; Martinez, Patricia; Zakhidov, Anvar A.; Shaner, Eric A.; Lee, Mark

    2015-07-01

    Understanding the conductance properties of multi-walled carbon nanotube (MWNT) textile sheets in the microwave regime is essential for their potential use in high-speed and high-frequency applications. To expand current knowledge, complex high-frequency conductance measurements from 0.01 to 50 GHz and across temperatures from 4.2 K to 300 K and magnetic fields up to 2 T were made on textile sheets of highly aligned MWNTs with strand alignment oriented both parallel and perpendicular to the microwave electric field polarization. Sheets were drawn from 329 and 520 μm high MWNT forests that resulted in different DC resistance anisotropy. For all samples, the microwave conductance can be modeled approximately by a shunt capacitance in parallel with a frequency-independent conductance, but with no inductive contribution. This is consistent with diffusive Drude conduction as the primary transport mechanism up to 50 GHz. Further, it is found that the microwave conductance is essentially independent of both temperature and magnetic field.

  4. Microwave conductance properties of aligned multiwall carbon nanotube textile sheets

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Brian L. [Univ. of Texas, Dallas, TX (United States); Martinez, Patricia [Univ. of Texas, Dallas, TX (United States); Zakhidov, Anvar A. [Univ. of Texas, Dallas, TX (United States); Shaner, Eric A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Mark [Univ. of Texas, Dallas, TX (United States)

    2015-07-06

    Understanding the conductance properties of multi-walled carbon nanotube (MWNT) textile sheets in the microwave regime is essential for their potential use in high-speed and high-frequency applications. To expand current knowledge, complex high-frequency conductance measurements from 0.01 to 50 GHz and across temperatures from 4.2 K to 300 K and magnetic fields up to 2 T were made on textile sheets of highly aligned MWNTs with strand alignment oriented both parallel and perpendicular to the microwave electric field polarization. Sheets were drawn from 329 and 520 μm high MWNT forests that resulted in different DC resistance anisotropy. For all samples, the microwave conductance can be modeled approximately by a shunt capacitance in parallel with a frequency-independent conductance, but with no inductive contribution. Finally, this is consistent with diffusive Drude conduction as the primary transport mechanism up to 50 GHz. Further, it is found that the microwave conductance is essentially independent of both temperature and magnetic field.

  5. 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)

    Rahmanian, S.; Thean, K.S.; Suraya, A.R.; Shazed, M.A.; Mohd Salleh, M.A.; Yusoff, H.M.

    2013-01-01

    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.

  6. Embedded Aligned Carbon Nanotube Sheets for Strain and Damage sensing in Composite Structures

    Science.gov (United States)

    Aly, Karim Aly Abdelomoaty Elsayed

    The world demand for fiber reinforced composite materials has been steadily increasing because of the widespread adoption of this class of material in many markets. The automotive, aerospace, marine and energy sectors account for a large percentage of this grow. Outstanding fatigue performance, high specific stiffness and strength, and low density are among the most important properties that fiber reinforced polymer composites offer. Furthermore, their properties can be tailored to meet the specific needs of the final applications. However, this class of material is composed of multiple layers of inhomogeneous and anisotropic constituents, i.e. fibers and matrix. Therefore, this laminated nature make the composite material prone to intrinsic damage including interfacial debonding and delamination and their strength and failure are dependent on the fiber architecture and direction of the applied stresses. Consequently, it is of prime importance to monitor the health of these structures. New and improved methods for early detection of damage and structural health monitoring of composite materials may allow for enhanced reliability, lifetime and performance while minimizing maintenance time during a composite part's service life. Over the last few decades different non-destructive methods and materials have been investigated for use as strain sensors. Since the discovery of carbon nanotubes (CNTs), they have attracted much research interest due to their superior electrical, thermal and mechanical properties as well as their high aspect ratio. In this context, CNTs have been used in the recent years to enable sensing capabilities. In this dissertation, the usage of CNTs for performing strain and damage sensing in composites is evaluated. This was enabled by embedding aligned sheets of two millimeters long, interconnected CNTs into laminated structures that were then subjected to different forms of mechanical loading. The localization of the CNT sheets inside the host

  7. Microstructure and mechanical properties of carbon fiber reinforced ...

    Indian Academy of Sciences (India)

    68

    Microstructure and mechanical properties of carbon fiber reinforced alumina composites fabricated from sol. CHAOYANG FAN, QINGSONG MA* and KUANHONG ZENG. Science and Technology on Advanced Ceramic Fibers &Composites Laboratory, National University of Defense Technology,. Changsha 410073, PR ...

  8. Intercalation of Carbon Nanotube Fibers to Improve their Conductivity

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to increase the electrical conductivity of fibers made up of carbon nanotubes by intercalation with bromine. We further expect that the resulting fibers...

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

    Science.gov (United States)

    Song, Weimin; Yin, Jian

    2016-01-01

    Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored. PMID:28773824

  10. 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).

  11. Effect of heat treatment on carbon fiber surface properties and fibers/epoxy interfacial adhesion

    International Nuclear Information System (INIS)

    Dai Zhishuang; Zhang Baoyan; Shi Fenghui; Li Min; Zhang Zuoguang; Gu Yizhuo

    2011-01-01

    Carbon fiber surface properties are likely to change during the molding process of carbon fiber reinforced matrix composite, and these changes could affect the infiltration and adhesion between carbon fiber and resin. T300B fiber was heat treated referring to the curing process of high-performance carbon fiber reinforced epoxy matrix composites. By means of X-ray photoelectron spectroscopy (XPS), activated carbon atoms can be detected, which are defined as the carbon atoms conjunction with oxygen and nitrogen. Surface chemistry analysis shows that the content of activated carbon atoms on treated carbon fiber surface, especially those connect with the hydroxyl decreases with the increasing heat treatment temperature. Inverse gas chromatography (IGC) analysis reveals that the dispersive surface energy γ S d increases and the polar surface energy γ S sp decreases as the heat treatment temperature increases to 200. Contact angle between carbon fiber and epoxy E51 resin, which is studied by dynamic contact angle test (DCAT) increases with the increasing heat treatment temperature, indicating the worse wettability comparing with the untreated fiber. Moreover, micro-droplet test shows that the interfacial shear strength (IFSS) of the treated carbon fiber/epoxy is lower than that of the untreated T300B fiber which is attributed to the decrement of the content of reactive functional groups including hydrogen group and epoxy group.

  12. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material, Phase I

    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...

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

    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...

  14. Development of a Portable Sensitive Equipment Decontamination System. Volume 2: Activated Carbon Fiber Wipe

    Science.gov (United States)

    2010-05-01

    Spent Activated carbon fiber fabric: Rationale—the JSSED and JPID ORD require that the process or system must not permit any residual health hazards...approved 2001): Standard Test Method for Stiffness of Nonwoven Fabrics Using the Cantilever Test • ASTM D 6829-02: Standard Test Method for...experimental flow sheet and Figure 9 is a photograph of the experimental setup. Stainless Steel Screen 5um Teflon• Membrane Filter Packing A •* Outlet

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

    Science.gov (United States)

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

    2014-01-07

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

  16. Co-deposition of carbon dots and reduced graphene oxide nanosheets on carbon-fiber microelectrode surface for selective detection of dopamine

    Science.gov (United States)

    Fang, Jian; Xie, Zhigang; Wallace, Gordon; Wang, Xungai

    2017-08-01

    In this work, carbon dots (CD) decorated graphene oxide (GO) nanosheets were electrochemically reduced and deposited onto carbon fiber (CF) to fabricate microelectrodes for highly sensitive and selective dopamine (DA) detection, in the presence of ascorbic acid (AA) and uric acid (UA). The results have shown that surface modification considerably increases the electrocatalytic activity of the carbon fiber microelectrode. Due to possible aggregation of the rGO sheets during deposition, modifying the microelectrode surface with rGO sheets alone cannot achieve the selectivity required for simultaneous detection of DA, AA and UA. Through attaching CD onto GO sheets, the rGO + CD/CF microelectrode performance was significantly improved. The existence of CD on GO sheets can effectively avoid inter-layer stacking of the rGO sheets and provide increased surface area for neurotransmitter-electrode interaction enhancement. The CD can also increase the charge storage capacity of GO sheets. This is the first report on applying both CD and rGO for surface modification of carbon fiber microelectrode. The rGO + CD/CF microelectrode has achieved a linear DA detection concentration range of 0.1-100 μM, with a detection limit of 0.02 μM. The sensitivity of the microelectrode towards DA was as high as 6.5 nA/μM, which is significantly higher than previously reported carbon fiber microelectrodes. The highly sensitive all-carbon based microelectrodes should find use in a number of biomedical applications, such as neurotransmitter detection, neural signal recording and cell physiology studies.

  17. Carbon Fiber Reinforced, Zero CME Composites, Phase I

    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...

  18. Poor fluorinated graphene sheets carboxymethylcellulose polymer composite mode locker for erbium doped fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Chengbo, E-mail: mouc1@aston.ac.uk, E-mail: a.rozhin@aston.ac.uk; Turitsyn, Sergei; Rozhin, Aleksey, E-mail: mouc1@aston.ac.uk, E-mail: a.rozhin@aston.ac.uk [Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham B4 7ET (United Kingdom); Arif, Raz [Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham B4 7ET (United Kingdom); Physics Department, Faculty of Science, University of Sulaimani, Sulaimani, Kurdistan Region (Iraq); Lobach, Anatoly S.; Spitsina, Nataliya G. [Institute of Problems of Chemical Physics RAS, Ac. Semenov Av. 1, Chernogolovka, Moscow Region 142432 (Russian Federation); Khudyakov, Dmitry V. [Institute of Problems of Chemical Physics RAS, Ac. Semenov Av. 1, Chernogolovka, Moscow Region 142432 (Russian Federation); Physics Instrumentation Center of the Institute of General Physics A.M. Prokhorov Russian Academy of Sciences, Troitsk, Moscow Region 142190 (Russian Federation); Kazakov, Valery A. [Keldysh Center, Onezhskaya 8, Moscow 125438 (Russian Federation)

    2015-02-09

    We report poor fluorinated graphene sheets produced by thermal exfoliation embedding in carboxymethylcellulose polymer composite (GCMC) as an efficient mode locker for erbium doped fiber laser. Two GCMC mode lockers with different concentration have been fabricated. The GCMC based mode locked fiber laser shows stable soliton output pulse shaping with repetition rate of 28.5 MHz and output power of 5.5 mW was achieved with the high concentration GCMC, while a slightly higher output power of 6.9 mW was obtained using the low concentration GCMC mode locker.

  19. Contrastive study of anodic oxidation on carbon fibers and graphite fibers

    International Nuclear Information System (INIS)

    Liu Xin; Yang Changling; Lu Yonggen

    2012-01-01

    Anodic oxidation of polyacrylonitrile (PAN) graphite fibers was investigated in comparison with that of carbon fibers. The mechanical and interfacial properties of the treated fibers along with their surface structures were studied with X-ray photoelectron spectroscopy, atomic force microscope, contact angle analyzer, tensile strength instrument and Raman spectrometer. The results show that the graphite fibers were inactive during anodic oxidation for the higher graphitic carbon, while the carbon fibers were active and the surface oxygen content got saturated soon. The dynamics of anodic oxidation for the fibers can be described by a homogenous thickness reduction model, which indicated that the kinetic constant of anodic oxidation for the graphite fibers was only one sixth of that for the carbon fibers. Surface roughness contributed to the improvement on fiber/matrix adhesion as well as the surface oxygen content. The achievement of the surface treatment was proved by Raman spectroscopy mapping the stress of the fiber inside an epoxy resin droplet. The increase of interfacial shear strength from the untreated graphite fibers to the anodized graphite fibers was 160% (from 65 to 170 MPa), much higher than 70% that from untreated carbon fibers to the anodized ones (from 135 to 230 MPa).

  20. Contrastive study of anodic oxidation on carbon fibers and graphite fibers

    Science.gov (United States)

    Liu, Xin; Yang, Changling; Lu, Yonggen

    2012-03-01

    Anodic oxidation of polyacrylonitrile (PAN) graphite fibers was investigated in comparison with that of carbon fibers. The mechanical and interfacial properties of the treated fibers along with their surface structures were studied with X-ray photoelectron spectroscopy, atomic force microscope, contact angle analyzer, tensile strength instrument and Raman spectrometer. The results show that the graphite fibers were inactive during anodic oxidation for the higher graphitic carbon, while the carbon fibers were active and the surface oxygen content got saturated soon. The dynamics of anodic oxidation for the fibers can be described by a homogenous thickness reduction model, which indicated that the kinetic constant of anodic oxidation for the graphite fibers was only one sixth of that for the carbon fibers. Surface roughness contributed to the improvement on fiber/matrix adhesion as well as the surface oxygen content. The achievement of the surface treatment was proved by Raman spectroscopy mapping the stress of the fiber inside an epoxy resin droplet. The increase of interfacial shear strength from the untreated graphite fibers to the anodized graphite fibers was 160% (from 65 to 170 MPa), much higher than 70% that from untreated carbon fibers to the anodized ones (from 135 to 230 MPa).

  1. 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.

  2. Reinforcement of RC structure by carbon fibers

    Directory of Open Access Journals (Sweden)

    Kissi B.

    2016-01-01

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

  3. The quantitative representation of fiber-and sheet-texture in metals of cubic system

    International Nuclear Information System (INIS)

    Kim, H.J.; Kim, S.C.; Chun, B.C.; Lee, C.Y.

    1983-01-01

    This is the first article of a series dealing with studies on the quantitative representation of fiber-and sheet-type textures in metals of cubic crystal system. Texture measurements by neutron diffraction method are analyzed using Bunge's series expansion method and the effect of series truncation is studied for samples of various texture sharpness. The present article describes two computer programs, TXFIB and TXSHT, develped for the analysis of the respective fiber-and sheet-type texture. Using these computer programs, the orientation distribution function can be expanded in the series of generalized spherical harmonics up to 58th term from 6 experimental pole figures as input. Estimations of various errors involved in the texture analysis and texture sharpness index are also included in the programs. (Author)

  4. Two-step sulfonation process for the conversion of polymer fibers to carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Bryan E.; Patton, Jasson T.; Hukkanen, Eric J.; Bernius, Mark T.

    2017-11-14

    Disclosed herein are processes for preparing carbon fibers, comprising: sulfonating a polymer fiber with a sulfonating agent that is fuming sulfuric acid, sulfuric acid, chlorosulfonic acid, or a combination thereof; treating the sulfonated polymer with a heated solvent, wherein the temperature of the heated solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 501-3000.degree. C. Carbon fibers prepared according to these methods are also disclosed herein.

  5. Effect of sizing on carbon fiber surface properties and fibers/epoxy interfacial adhesion

    International Nuclear Information System (INIS)

    Dai Zhishuang; Shi Fenghui; Zhang Baoyan; Li Min; Zhang Zuoguang

    2011-01-01

    This paper aims to study effect of sizing on surface properties of carbon fiber and the fiber/epoxy interfacial adhesion by comparing sized and desized T300B and T700SC carbon fibers. By means of X-ray photoelectron spectroscopy (XPS), activated carbon atoms can be detected, which are defined as the carbon atoms conjunction with oxygen and nitrogen. Surface chemistry analysis shows that the desized carbon fibers present less concentration of activated carbon, especially those connect with the hydroxyl and epoxy groups. Inverse gas chromatography (IGC) analysis reveals that the desized carbon fibers have larger dispersive surface energy γ S D and smaller polar component γ S SP than the commercial sized ones. Moreover, micro-droplet test shows that the interfacial shear strength (IFSS) of the desized carbon fiber/epoxy is higher than those of the T300B and T700SC. Variations of the IFSS for both the sized and desized carbon fibers correspond to γ S D /γ S tendency of the fiber surface, however the work of adhesion does not reveal close correlation with IFSS trend for different fiber/epoxy systems.

  6. Evaluation of Sustainable Structural Concrete Using Recycled Aggregate and Aramid Fiber Sheet

    Directory of Open Access Journals (Sweden)

    Y. S. Cho

    2016-01-01

    Full Text Available The purpose of this study was to evaluate the flexural performance of recycled aggregate RC beam reinforced with aramid fiber sheets. Compressive strength of concrete using recycled aggregate is generally similar or slightly lower than normal concrete. To improve the compressive strength, aramid fiber sheets have been used in this study. This study examines the structural behavior of concrete beams prepared with recycled aggregate and strengthened aramid fiber sheets at varying locations. One concrete beam as a control specimen, that is prepared with 30 percent recycled aggregate and 70 percent natural aggregate, has been tested, and 3 more strengthened beams (bottom, bottom and sides, bottom and both ends with U-shaped strengthened beams are tested. The ultimate loads have increased by 38.01%, 39.88%, and 100.79% for bottom, bottom and sides, bottom and both ends with U-shaped strengthened beams. The ductility ratios are 2.75~6.20 for strengthened beams. The experimental results showed that the strengthening system with U-shaped band controls the premature debonding and provides a more ductile failure mode than the strengthening system without U-shaped bands. It can be found that the ultimate strength of H40-RGA30-BS specimen based on load-deflection curves shows most promising result. The experimental results are compared with the analytical results of nonlinear flexural behaviors for strengthened reinforced recycled aggregate concrete beam.

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

    International Nuclear Information System (INIS)

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

    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.

  8. 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.

  9. 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.

  10. Research on application of carbon fiber heating material in clothing

    Science.gov (United States)

    Yang, Huanhong

    2017-08-01

    With the development of society, the way of keeping warm clothing is also developing. Carbon fiber has the advantages of high efficiency, safety, mobility and comfort. As a heating element, it has good application prospect. In this paper, the main technology, application issues and design method of carbon fiber heating garment are analyzed, and the key problems in industrialization are also put forward.

  11. Structure and growth process of vapor-grown carbon fibers

    Science.gov (United States)

    Koyama, T.; Endo, M.

    1983-01-01

    The structure, effect of heat, and growth process of vapor-grown carbon fibers are investigated. The growth process of the carbon fibers could be divided into three stages; nucleation, elongation, and thickening processes. Also, a multi-layered structure can be produced as well as graphitization.

  12. Graphene fiber: a new trend in carbon fibers

    OpenAIRE

    Zhen Xu; Chao Gao

    2015-01-01

    New fibers with increased strength and rich functionalities have been untiringly pursued by materials researchers. In recent years, graphene fiber has arisen as a new carbonaceous fiber with high expectations in terms of mechanical and functional performance. In this review, we elucidated the concept of sprouted graphene fibers, including strategies for their fabrication and their basic structural attributes. We examine the rapid advances in the promotion of mechanical/functional properties o...

  13. Tribological dry sliding behavior of chopped carbon fiber reinforced polyetheretherketone

    Science.gov (United States)

    Chumaevskii, A. V.; Ivanov, A. N.; Filippov, A. V.; Rubtsov, V. E.; Kolubaev, E. A.

    2017-12-01

    Tribological tests on 3D printed pure polyetheretherketone and carbon fiber reinforced polyetheretherketone samples were carried out. The negative effect of carbon fiber sticking out of the matrix on wear and sliding process stability was revealed. These fibers may be too long and oriented to the worn surface in a manner that prevents their removal by wear so that the worn surface becomes irregular and the sliding process instable.

  14. 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.

  15. Electrophoretic deposition of carbon nanotubes on a carbon fiber surface with different index graphitization

    International Nuclear Information System (INIS)

    Almeida, E.C.; Baldan, M.R.; Ferreira, N.G.; Edwards, E.R.

    2009-01-01

    Full text: The purpose of this work is to examine the electrophoretic deposition of carbon nanotubes powder on carbon fibers, produced at different heat treatments temperatures. Besides, a systematic study of the effects of graphitization index from substrate on the structure and morphology of CNTs has been available. Carbon fibers were produced from polyacrylonitrile at three different heat treatments temperatures, 1000, 1500 and 2000 deg C. The carbon fibers microstructure or its graphitization index may be controlled by the heat treatments temperatures. The electrophoretic deposition of carbon nanotubes was obtained with the powder of carbon nanotubes dispersed in water by ultrasonication to obtain dispersions of 0.05 mg/mL. The carbon fibers were immersed in the nanotube dispersion, and a positive potential of 10 V/cm was applied. Morphology and microstructure of carbon nanotubes on carbon fibers were obtained by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.

    2016-12-27

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    Graphical abstract: Carbon nanotube/carbon fiber hybrid fiber was proposed by the treatment with hydrogen peroxide and concentrated nitric acid combined with electrophoretic deposition process. - Highlights: • Carbon nanotube coated carbon fiber was prepared by two methods. • Uniform and dense CNTs network formed by oxidative treatments combined with EPD. • Pretreatment of the CF is beneficial to EPD of CNTs on carbon fiber surface. • CNTs enhanced the surface activity and wettability of carbon fibers. • CNTs have contributed to the interfacial properties of composite. - Abstract: 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

  18. Bioconversion of Waste Fiber Sludge to Bacterial Nanocellulose and Use for Reinforcement of CTMP Paper Sheets

    Directory of Open Access Journals (Sweden)

    Genqiang Chen

    2017-09-01

    Full Text Available Utilization of bacterial nanocellulose (BNC for large-scale applications is restricted by low productivity in static cultures and by the high cost of the medium. Fiber sludge, a waste stream from pulp and paper mills, was enzymatically hydrolyzed to sugar, which was used for the production of BNC by the submerged cultivation of Komagataeibacter xylinus. Compared with a synthetic glucose-based medium, the productivity of purified BNC from the fiber sludge hydrolysate using shake-flasks was enhanced from 0.11 to 0.17 g/(L × d, although the average viscometric degree of polymerization (DPv decreased from 6760 to 6050. The cultivation conditions used in stirred-tank reactors (STRs, including the stirring speed, the airflow, and the pH, were also investigated. Using STRs, the BNC productivity in fiber-sludge medium was increased to 0.32 g/(L × d and the DPv was increased to 6650. BNC produced from the fiber sludge hydrolysate was used as an additive in papermaking based on the chemithermomechanical pulp (CTMP of birch. The introduction of BNC resulted in a significant enhancement of the mechanical strength of the paper sheets. With 10% (w/w BNC in the CTMP/BNC mixture, the tear resistance was enhanced by 140%. SEM images showed that the BNC cross-linked and covered the surface of the CTMP fibers, resulting in enhanced mechanical strength.

  19. Extended-length fiber optic carbon dioxide monitoring

    Science.gov (United States)

    Delgado-Alonso, Jesus; Lieberman, Robert A.

    2013-05-01

    This paper discusses the design and performance of fiber optic distributed intrinsic sensors for dissolved carbon dioxide, based on the use optical fibers fabricated so that their entire lengths are chemically sensitive. These fibers use a polymer-clad, silica-core structure where the cladding undergoes a large, reversible, change in optical absorbance in the presence of CO2. The local "cladding loss" induced by this change is thus a direct indication of the carbon dioxide concentration in any section of the fiber. To create these fibers, have developed a carbon dioxide-permeable polymer material that adheres well to glass, is physically robust, has a refractive index lower than fused silica, and acts as excellent hosts for a unique colorimetric indicator system that respond to CO2. We have used this proprietary material to produce carbon-dioxide sensitive fibers up to 50 meters long, using commercial optical fiber fabrication techniques. The sensors have shown a measurement range of dissolved CO2 of 0 to 1,450 mg/l (0 to 100% CO2 saturation), limit of detection of 0.3 mg/l and precision of 1.0 mg/l in the 0 to 50 mg/l dissolved CO2 range, when a 5 meter-long sensor fiber segment is used. Maximum fiber length, minimum detectable concentration, and spatial resolution can be adjusted by adjusting indicator concentration and fiber design.

  20. EVALUATION OF MICROMECHANICAL PROPERTIES OF CARBON FIBER FABRIC USING NANOINDETATION

    Directory of Open Access Journals (Sweden)

    Pavel Klapálek

    2017-11-01

    Full Text Available This paper is focused mainly on nanoindentation of carbon fibers. Fibers are in form of carbon fiber fabric that is used in larger research that is focused on reinforcing beams made of glued laminated timber. Knowledge of this material on macro and micro level will help to understand its behavior in this specific type of use. Nanoindentation is method used in this paper to obtain material characteristics on micro level such as hardness and modulus of elasticity. Samples of the carbon fiber fabric had to be prepared for this specific testing method by polishing samples of carbon fabric attached in epoxy resin. In particular, it was found that the indentation hardness of the fibers ranges around 3.65 GPa and modulus of elasticity ranges around 26 GPa.

  1. Modification of carbon fiber surfaces via grafting with Meldrum's acid

    Science.gov (United States)

    Cuiqin, Fang; Jinxian, Wu; Julin, Wang; Tao, Zhang

    2015-11-01

    The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated in this work. The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid to create carboxylic functionalized surfaces. The surface functionalization effect was detected with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The XPS results showed that the relative content of carboxylic groups on carbon fiber surfaces was increased from initial 1.41% to 7.84%, however, that of carbonyl groups was decreased from 23.11% to 13.28% after grafting reaction. The SEM, AFM and TGA results indicated that the surfaces of carbon fibers neither etched nor generated coating. The tensile strength of carbon fibers was preserved after grafting reaction according to single fiber tensile strength tests. The fibers were well combined with matrix and the maximal interlaminar shear strength (ILSS) of carbon fiber/epoxy resin composites was sharply increased approximately 74% after functionalization. The effects of acetic acid and sonication on the degree of the surface functionalization were also studied.

  2. Plasma polymerized thin coating as a protective layer of carbon nanotubes grafted on carbon fibers

    International Nuclear Information System (INIS)

    Einig, A; Magga, Y; Bai, J B; Rumeau, P; Desrousseaux, S

    2013-01-01

    Nanoparticles addition is widely studied to improve properties of carbon fiber reinforced composites. Here, hybrid carbon fiber results from grafting of carbon nanotubes (CNT) by Chemical Vapor Deposition (CVD) on the carbon fiber for mechanical reinforcement and conductive properties. Both tows and woven fabrics made of the hybrid fibers are added to the matrix for composite processing. However handling hybrid fibers may induce unwilling health risk due to eventual CNT release and a protective layer is required. A thin coating layer is deposited homogeneously by low pressure plasma polymerization of an organic monomer without modifying the morphology and the organization of grafted CNTs. The polymeric layer effect on the electrical behavior of hybrid fiber is assessed by conductivity measurements. Its influence on the mechanical properties is also studied regarding the interface adhesion between fiber and matrix. The protective role of layer is demonstrated by means of friction constraints applied to the hybrid fiber.

  3. Surface structure and adsorption properties of ultrafine porous carbon fibers

    International Nuclear Information System (INIS)

    Song Xiaofeng; Wang Ce; Zhang Dejiang

    2009-01-01

    Ultrafine porous carbon fibers (UPCFs) were successfully synthesized by chemical activation of electrospun polyacrylonitrile fibers. In the current approach, potassium hydroxide was adopted as activation reagent. UPCFs were systematically evaluated by scanning electron microscope and nitrogen adsorption. The mass ratio of potassium hydroxide to preoxidized fibers, activation temperature and activation time are crucial for producing high quality UPCFs. The relationships between porous structure and process parameters are explored. UPCFs were applied as adsorbent for nitrogen monoxide to be compared with commercial porous carbon fibers.

  4. Radiation processing for carbon fiber-reinforced polytetrafluoroethylene composite materials

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Udagawa, Akira; Morita, Yousuke

    2001-01-01

    The present work is an attempt to evaluate the performance of the fiber composites with crosslinked polytetrafluoroethylene (PTFE) as a polymer matrix by radiation. The uni-directional carbon fiber-reinforced composites were fabricated with PTFE fine powder impregnation method and then crosslinked by electron beams irradiation under selective conditions. The carbon fiber-reinforced crosslinked PTFE composites show good mechanical properties compared with crosslinked PTFE. The radiation resistance of crosslinked PTFE composites is improved more than that of crosslinked resin without fiber. (author)

  5. Carbon Fiber Manufacturing Facility Siting and Policy Considerations: International Comparison

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Jeffrey J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Booth, Samuel [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-06-21

    Carbon fiber is increasingly used in a wide variety of applications due largely to its superior material properties such as high strength-to-weight ratio. The current global carbon fiber manufacturing industry is predominately located in China, Europe, Japan, and the United States. The carbon fiber market is expected to expand significantly through 2024 and to require additional manufacturing capacity to meet demand. Carbon fiber manufacturing facilities can offer significant economic development and employment opportunities as exemplified by the $1 billion investment and 500 jobs expected at a new Toray plant in Moore, South Carolina. Though the market is expected to expand, it is unclear where new manufacturing facilities will locate to meet demand. This uncertainty stems from the lack of research evaluating how different nations with significant carbon fiber manufacturing capacity compare as it relates to certain manufacturing facility siting factors such as costs of labor and energy as well as policy directed at supporting carbon fiber development, domestic deployment, and exports. This report fills these gaps by evaluating the top carbon fiber manufacturing countries, including China, European Union countries, Japan, Mexico, South Korea, Taiwan, and the United States. The report documents how the United States compares to these countries based on a range of manufacturing siting considerations and existing policies related to carbon fiber. It concludes with a discussion of various policy options the United States could adopt to both (1) increase the competitiveness of the United States as it relates to attracting new carbon fiber manufacturing and (2) foster broader end-use markets for deployment.

  6. 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.

  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. Enhanced thermal conductivity of carbon fiber/phenolic resin composites by the introduction of carbon nanotubes

    Science.gov (United States)

    Kim, Y. A.; Kamio, S.; Tajiri, T.; Hayashi, T.; Song, S. M.; Endo, M.; Terrones, M.; Dresselhaus, M. S.

    2007-02-01

    The authors report a significant enhancement in the thermal conductivity of a conventional carbon fiber/phenolic resin composite system when adding highly crystalline multiwalled carbon nanotubes. They demonstrate that 7wt% of carbon nanotubes dispersed homogeneously in a phenolic resin acted as an effective thermal bridge between adjacent carbon fibers and resulted in an enhancement of the thermal conductivity (e.g., from 250to393W/mK). These results indicate that highly crystalline carbon nanotubes can be used as a multifunctional filler to enhance simultaneously the mechanical and thermal properties of the carbon fiber/phenolic resin composites.

  10. A Comparative study of two RVE modelling methods for chopped carbon fiber SMC

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhangxing; Li, Yi; Shao, Yimin; Huang, Tianyu; Xu, Hongyi; Li, Yang; Chen, Wei; Zeng, Danielle; Avery, Katherine; Kang, HongTae; Su, Xuming

    2017-04-06

    To achieve vehicle light-weighting, the chopped carbon fiber sheet molding compound (SMC) is identified as a promising material to replace metals. However, there are no effective tools and methods to predict the mechanical property of the chopped carbon fiber SMC due to the high complexity in microstructure features and the anisotropic properties. In this paper, the Representative Volume Element (RVE) approach is used to model the SMC microstructure. Two modeling methods, the Voronoi diagram-based method and the chip packing method, are developed for material RVE property prediction. The two methods are compared in terms of the predicted elastic modulus and the predicted results are validated using the Digital Image Correlation (DIC) tensile test results. Furthermore, the advantages and shortcomings of these two methods are discussed in terms of the required input information and the convenience of use in the integrated processing-microstructure-property analysis.

  11. Multifunctional Next Generation Carbon Nanotube Super Fibers

    National Research Council Canada - National Science Library

    Ait-Haddou, Hassan

    2005-01-01

    The goal of this program was to produce continuous strong CNT-based fibers. The production of continuous fibers was met and we have matched 2/3 of the strength of what has been previously reported with CNT-PAN fibers...

  12. Design of Low Cost, Highly Adsorbent Activated Carbon Fibers

    National Research Council Canada - National Science Library

    Mangun, Christian

    2003-01-01

    .... EKOS has developed a novel activated carbon fiber - (ACF) that combines the low cost and durability of GAC with tailored pore size and pore surface chemistry for improved defense against chemical agents...

  13. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-01

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

  15. Radiation processing for PTFE composite reinforced with carbon fiber

    International Nuclear Information System (INIS)

    Akihiro Oshima; Akira Udagawa; Yousuke Morita

    1999-01-01

    The present work is an attempt to evaluate the performance of crosslinked PTFE as a polymer matrix for carbon fiber-reinforced composite materials. The carbon fiber-reinforced PTFE pre-composite, which is laminated with PTFE fine powder, is crosslinked by electron beam irradiation. Mechanical and frictional properties of the crosslinked PTFE composite obtained are higher than those of PTFE resin. The crosslinked PTFE composite with high mechanical and radiation resistant performance is obtained by radiation crosslinking process

  16. 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.

  17. 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.

  18. 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.

  19. Micro-Scale Mechanical Testing of Non-Woven Carbon Nanotube Sheets and Yarns

    Science.gov (United States)

    Magargee, J.; Morestin, F.; Cao, J.; Jones, J. S.

    2013-01-01

    Non-woven carbon nanotube (CNT) sheets and yarns were tested using a novel micro-scale mechanical testing system. CNT sheets were observed to delaminate during uniaxial testing using an adbesive gripping method, resulting from a higher proportion of load bearing in the outer sheets versus internal sheets and an apparently low interlaminar shear strength. In response to this, a new spool-grip method was used to alleviate non-uniform through-thickness stresses, circumvent premature delamination, and allow the sheet material to sustain a 72% increase in measured tensile strength. Furthermore, tension tests of CNT yarns showed that the yarn-structure was approximaiely 7 times stronger than the sheet structure, owing to a higher degree of CNT alignment in the test direction.

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

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo

    2014-01-01

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

  1. Standard Test Method for Gel Time of Carbon Fiber-Epoxy Prepreg

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 This test method covers the determination of gel time of carbon fiber-epoxy tape and sheet. The test method is suitable for the measurement of gel time of resin systems having either high or low viscosity. 1.2 The values stated in SI units are to be regarded as standard. The values in parentheses are for reference only. 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.

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

    International Nuclear Information System (INIS)

    Agnihotri, Prabhat Kamal; Kar, Kamal K; Basu, Sumit

    2012-01-01

    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)

  3. 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.

  4. 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 × 10 6 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. (paper)

  6. Advanced stabilization of PAN fibers for fabrication of carbon fibers by e-beam irradiation

    International Nuclear Information System (INIS)

    Jeun, Joon Pyo; Kim, Du Young; Shin, Hye Kyoung; Kang, Phil Hyun; Park, Jung Ki

    2012-01-01

    In recent years, the carbon fiber industry has been growing rapidly to meet the demand from efferent industries such as aerospace, military, turbine blades, light weight cylinders and pressure vessels. Generally, carbon fibers are manufactured by a controlled pyrolysis of stabilized precursor fiber such as polyacrylonitrile (PAN). In the stabilization step, the linear PAN molecules are first converted to cyclic structure. However, cyclization is a very complicated process and there are still differences of opinion on the reaction mechanisms. Photo-induced crosslinking and stabilization of PAN via ion beam, X-ray, gamma ray and UV irradiation has been reported in the literature. However, the process required a long stabilization time. In this work, a new and highly effective method of pretreatment PAN precursor fiber was described. The effect of the e-beam on the stabilization process of the fibers was investigated using differential scanning calorimeter (DSC) and X-ray diffraction (XRD) measurement

  7. Carbon Fiber Reinforced Polymer with Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance

    Directory of Open Access Journals (Sweden)

    Gerald Artner

    2017-01-01

    Full Text Available A carbon fiber reinforced polymer (CFRP laminate, with the top layer consisting of shredded fibers, is proposed and manufactured. The shredded fibers are aligned randomly on the surface to achieve a more isotropic conductivity, as is desired in antenna applications. Moreover, fiber shreds can be recycled from carbon fiber composites. Conductivity, permittivity, and permeability are obtained with the Nicolson-Ross-Weir method from material samples measured inside rectangular waveguides in the frequency range of 4 to 6 GHz. The decrease in material anisotropy results in negligible influence on antennas. This is shown by measuring the proposed CFRP as ground plane material for both a narrowband wire monopole antenna for 5.9 GHz and an ultrawideband conical monopole antenna for 1–10 GHz. For comparison, all measurements are repeated with a twill-weave CFRP.

  8. Carbon fiber/SiC composite for reduced activation

    International Nuclear Information System (INIS)

    Noda, T.; Araki, H.; Abe, F.; Okada, M.

    1991-01-01

    A carbon fiber/SiC composite fabricated by a chemical vapor infiltration process at 1173-1623 K was studied to develop a low-activation material. A high-purity composite was obtained with the total amount of impurities less than 0.02 wt%. The microstructure and the mechanical properties using a bend test were examined. A composite with woven carbon yarn showed both high strength and toughness. Further, the induced activity of the material was evaluated by calculations simulating fusion neutron irradiation. The carbon fiber/SiC composite shows an excellent low-activation behavior. (orig.)

  9. 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

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

    International Nuclear Information System (INIS)

    Rahmanian, S.; Suraya, A.R.; Shazed, M.A.; Zahari, R.; Zainudin, E.S.

    2014-01-01

    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)

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

    Science.gov (United States)

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

    2012-08-01

    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, 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.

  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. Processes for preparing carbon fibers using gaseous sulfur trioxide

    Science.gov (United States)

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

    2016-01-05

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

  14. Modeling the Role of Bulk and Surface Characteristics of Carbon Fiber on Thermal Conductance across the Carbon Fiber/Matrix Interface (Postprint)

    Science.gov (United States)

    2015-11-09

    energy exchange is investigated in terms of interface thermal conductance across the carbon fiber and the matrix. 15. SUBJECT TERMS BMI resin ; carbon ... carbon features. KEYWORDS: carbon fibers, BMI resin , molecular dynamics, interfaces, thermal conductance 1. INTRODUCTION Today, laser technology is...the near-surface region of carbon fiber to a much larger scale than what is reported to date); (b) model high-temperature BMI monomeric resins

  15. Energy Absorption in Chopped Carbon Fiber Compression Molded Composites

    International Nuclear Information System (INIS)

    Starbuck, J.M.

    2001-01-01

    In passenger vehicles the ability to absorb energy due to impact and be survivable for the occupant is called the ''crashworthiness'' of the structure. To identify and quantify the energy absorbing mechanisms in candidate automotive composite materials, test methodologies were developed for conducting progressive crush tests on composite plate specimens. The test method development and experimental set-up focused on isolating the damage modes associated with the frond formation that occurs in dynamic testing of composite tubes. Quasi-static progressive crush tests were performed on composite plates manufactured from chopped carbon fiber with an epoxy resin system using compression molding techniques. The carbon fiber was Toray T700 and the epoxy resin was YLA RS-35. The effect of various material and test parameters on energy absorption was evaluated by varying the following parameters during testing: fiber volume fraction, fiber length, fiber tow size, specimen width, profile radius, and profile constraint condition. It was demonstrated during testing that the use of a roller constraint directed the crushing process and the load deflection curves were similar to progressive crushing of tubes. Of all the parameters evaluated, the fiber length appeared to be the most critical material parameter, with shorter fibers having a higher specific energy absorption than longer fibers. The combination of material parameters that yielded the highest energy absorbing material was identified

  16. Comparison of sizing effect of T700 grade carbon fiber on interfacial properties of fiber/BMI and fiber/epoxy

    International Nuclear Information System (INIS)

    Yao Lirui; Li Min; Wu Qing; Dai Zhishuang; Gu Yizhuo; Li Yanxia; Zhang Zuoguang

    2012-01-01

    Highlights: ► Carbon fiber sizings can react itself and with resin at high temperature. ► Sizings improve IFSS of carbon fiber/epoxy, but reduce that of BMI matrix. ► IFSS of carbon fiber/epoxy is larger than corresponding carbon fiber/BMI. ► Partially desized carbon fiber shows the effect of polymeric sizing component. ► The results are helpful for optimizing sizing agent of carbon fiber composites. - Abstract: This paper aims to study impact of sizing agents on interfacial properties of two T700 grade high strength carbon fibers with bismaleimide (BMI) and epoxy (EP) resin matrix. The fiber surface roughness and chemical properties are analyzed for sized, desized, and partially desized carbon fibers, using atom force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. FTIR analysis indicates that the sizing agents are chemically reactive, and they can react with BMI and EP at high temperatures. The micro-droplet tests exhibit that the desized carbon fibers have lower interfacial strengths with EP than the sized fibers, however, for BMI matrix, opposite trend is revealed. This is consistent with the chemical reactions of the sizing agents with the EP and BMI resins, in which sufficient reactions are observed for the sizing/EP mixture, while only partial reactions are probed for the sizing/BMI mixture. Interestingly, un-extracted epoxy type sizing particles are observed on partially desized carbon fiber surface, which significantly improves the interfacial adhesion with EP matrix.

  17. Design aid for shear strengthening of reinforced concrete T-joints using carbon fiber reinforced plastic composites

    Science.gov (United States)

    Gergely, Ioan

    The research presented in the present work focuses on the shear strengthening of beam column joints using carbon fiber composites, a material considered in seismic retrofit in recent years more than any other new material. These composites, or fiber reinforced polymers, offer huge advantages over structural steel reinforced concrete or timber. A few of these advantages are the superior resistance to corrosion, high stiffness to weight and strength to weight ratios, and the ability to control the material's behavior by selecting the orientation of the fibers. The design and field application research on reinforced concrete cap beam-column joints includes analytical investigations using pushover analysis; design of carbon fiber layout, experimental tests and field applications. Several beam column joints have been tested recently with design variables as the type of composite system, fiber orientation and the width of carbon fiber sheets. The surface preparation has been found to be critical for the bond between concrete and composite material, which is the most important factor in joint shear strengthening. The final goal of this thesis is to develop design aids for retrofitting reinforced concrete beam column joints. Two bridge bents were tested on the Interstate-15 corridor. One bent was tested in the as-is condition. Carbon fiber reinforced plastic composite sheets were used to externally reinforce the second bridge bent. By applying the composite, the displacement ductility has been doubled, and the bent overall lateral load capacity has been increased as well. The finite element model (using DRAIN-2DX) was calibrated to model the actual stiffness of the supports. The results were similar to the experimental findings.

  18. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    Science.gov (United States)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  19. Carbon Fiber Mirror for a CubeSat Telescope

    Science.gov (United States)

    Kim, Young-Soo; Jang, Jeong Gyun; Kim, Jihun; Nam, Uk Won

    2017-08-01

    Telescope mirrors made by carbon fibers have been increasingly used especially for space applications, and they may replace the traditional glass mirrors. Glass mirrors are easy to fabricate, but needed to be carefully handled as they are brittle. Other materials have also been considered for telescope mirrors, such as metals, plastics, and liquids even. However glass and glass ceramics are still commonly and dominantly used.Carbon fiber has mainly been used for mechanical supports like truss structure and telescope tubes, as it is stiff and light-weight. It can also be a good material for telescope mirrors, as it has additional merits of non-brittle and very low thermal expansion. Therefore, carbon fiber mirror would be suitable for space telescopes which should endure the harsh vibration conditions during launch.A light-weight telescope made by carbon fiber has been designed for a small satellite which would have much less weight than conventional ones. In this poster, mirror materials are reviewed, and a design of carbon fiber telescope is presented and discussed.

  20. Phonon dispersions in graphene sheet and single-walled carbon ...

    Indian Academy of Sciences (India)

    Abstract. In the present research paper, phonons in graphene sheet have been calculated by constructing a dynamical matrix using the force constants derived from the second-generation reactive empirical bond order potential by Brenner and co-workers. Our results are comparable to inelastic X-ray scattering as well as ...

  1. INCREASING STAMPING FORMABILITY OF LOW-CARBON COLD ROLLED THIN STEEL SHEETS

    Directory of Open Access Journals (Sweden)

    I. Tatarkina

    2015-12-01

    Full Text Available The use of surfactant (épila was studied as a method for improving the cold-formability of steel sheets. The factors of the resulting effect were analyzed. Application of épila significantly reduces the surface roughness and decreases the stress concentrates. Epilam fills pores and microcracks, displaces moisture and gases, thereby reducing metal embrittlement. The application of épila pro-vides the highest category of drawing the low carbon sheet steel 08kp.

  2. Electromagnetic configurable architectures for assessment of Carbon Fiber Reinforced Plastics

    Directory of Open Access Journals (Sweden)

    Steigmann Rozina

    2017-01-01

    Full Text Available Carbon Fiber Reinforced Plastics are used in most wide domains due their low density, lack of mechanical fatigue phenomena and high strength–to weight ratio. From electromagnetic point of view, Carbon Fiber Reinforced Plastics structure represents an inhomogeneous structure of electric conductive fibers embedded into a dielectric material, thus an electromagnetic configurable architecture can be used to evaluate above mentioned defects. The paper proposes a special sensor, send receiver type and the obtaining of electromagnetic image by post-processing each coil signals in each point of scanning, using a sub-encoding image reconstruction algorithm and super-resolution procedures. The layout of fibers can be detected interrogating only diagonal reception coils.

  3. Measurement of population inversions and gain in carbon fiber plasmas

    International Nuclear Information System (INIS)

    Milchberg, H.; Skinner, C.H.; Suckewer, S.; Voorhees, D.

    1985-10-01

    A CO 2 laser (approx.0.5 kJ energy, 70 nsec pulse width) was focussed onto the end of an axially oriented, thick (35 to 350 μ) carbon fiber with or without a magnetic field present along the laser-fiber axis. We present evidence for axial-to-transverse enhancement of the CVI 182A (n = 3 → 2) transition, which is correlated with the appearance of a population inversion between levels n = 3 and 2. For the B = 0 kG, zero field case, the maximum gain-length product of kl approx. =3 (k approx. =6 cm -1 ) was measured for a carbon fiber coated with a thin layer of aluminum (for additional radiation cooling). The results are interpreted in terms of fast recombination due mostly to thermal conduction from the plasma to the cold fiber core

  4. 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.

  5. DFT calculation for adatom adsorption on graphene sheet as a prototype of carbon nanotube functionalization

    International Nuclear Information System (INIS)

    Ishii, A; Yamamoto, M; Asano, H; Fujiwara, K

    2008-01-01

    DFT calculation of various atomic species on graphene sheet is investigated as prototypes for formation of nano-structures on carbon nanotube (CNT) wall. We investigate computationally adsorption energies and adsorption sites on graphene sheet for a lot of atomic species including transition metals, noble metals, nitrogen and oxygen, using the DFT calculation as a prototype for CNT. The suitable atomic species can be chosen as each application from those results. The calculated results show us that Mo and Ru are bounded strongly on graphene sheet with large diffusion barrier energy. On the other hand, some atomic species has large binding energies with small diffusion barrier energies

  6. Modification of polyacrylonitrile carbon fibers by highfluence ion irradiation

    Science.gov (United States)

    Andrianova, N. N.; Borisov, A. M.; Kazakov, V. A.; Mashkova, E. S.; Ovchinnikov, M. A.; Savushkina, S. V.; Chernenko, N. M.

    2017-12-01

    The Raman spectroscopy has been used to analyse ion-induced modifications of carbon PAN-fiber shell due to 10-30 keV Ar+ high fluence ion irradiation at normal and oblique incidence in the temperature range from RT to 400 °C. It has shown that formed in ion-induced processes of amorphization, recrystallization and crimping the modifications of PAN-fiber shell are characterized by the presence of the amorphous phase with the A peak in the Raman spectra and the increased intensity of the D peak relative to the G peak in comparison with non-irradiated fiber. Amorphous phase in the PAN-fiber shell is the highest in case of amorphization and the least at the crimping. The increased intensity of the D peak in the Raman spectra and the G peak shift towards higher frequencies during recrystallization and crimping indicates ion-induced nanostructuring of the PAN- fiber shell.

  7. 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)

    2017-01-01

    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.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    Heitbrink, William A.; Lo, Li-Ming

    2015-01-01

    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 8 and 2.8 × 10 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

  10. 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.

  11. Carbon nano tubes embedded in polymer nano fibers

    International Nuclear Information System (INIS)

    Dror, Y.; Kedem, S.; Khalfin, R.L.; Paz, Y.; Cohenl, Y.; Salalha, Y.; Yarin, A.L.; Zussman, A.

    2004-01-01

    Full Text: The electro spinning process was used successfully to embed Multi-walled carbon nano tubes (MWCNTs) and single-walled carbon nano tubes (SWCNTs) in a matrix of poly(ethylene oxide) (PEO) forming composite nano fibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphphilic alternating copolymer of styrene and sodium maleate. MWNT dispersion was achieved by ionic and nonionic surfactants. The distribution and conformation of the nano tubes in the nano fibers were studied by transmission electron microscopy (TEM). Oxygen plasma etching was used to expose the nano tubes within the nano fibers to facilitate direct observation. Nano tube alignment within the nano fibers was shown to depend strongly on the quality of the initial dispersions. Well-dispersed and separated nano tubes were embedded in a straight and aligned form while entangled non-separated nano tubes were incorporated as dense aggregates. X-ray diffraction demonstrated a high degree of orientation of the PEO crystals in the electro spun nano fibers with embedded SWCNTs, whereas incorporation of MVCNTs had a detrimental effect on the polymer orientation. Composite polymer nano fibers containing dispersed phases of nanometric TiO 2 particles and MWCNTs were also prepared electro spinning. In this case, the polymer matrix was poly(acrylonitrile) (PAN). The morphology and possible applications of these composite nano fibers will be discussed

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

    Science.gov (United States)

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

    2016-09-06

    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.

  13. Multiscale modeling of PVDF matrix carbon fiber composites

    Science.gov (United States)

    Greminger, Michael; Haghiashtiani, Ghazaleh

    2017-06-01

    Self-sensing carbon fiber reinforced composites have the potential to enable structural health monitoring that is inherent to the composite material rather than requiring external or embedded sensors. It has been demonstrated that a self-sensing carbon fiber reinforced polymer composite can be created by using the piezoelectric polymer polyvinylidene difluoride (PVDF) as the matrix material and using a Kevlar layer to separate two carbon fiber layers. In this configuration, the electrically conductive carbon fiber layers act as electrodes and the Kevlar layer acts as a dielectric to prevent the electrical shorting of the carbon fiber layers. This composite material has been characterized experimentally for its effective d 33 and d 31 piezoelectric coefficients. However, for design purposes, it is desirable to obtain a predictive model of the effective piezoelectric coefficients for the final smart composite material. Also, the inverse problem can be solved to determine the degree of polarization obtained in the PVDF material during polarization by comparing the effective d 33 and d 31 values obtained in experiment to those predicted by the finite element model. In this study, a multiscale micromechanics and coupled piezoelectric-mechanical finite element modeling approach is introduced to predict the mechanical and piezoelectric performance of a plain weave carbon fiber reinforced PVDF composite. The modeling results show good agreement with the experimental results for the mechanical and electrical properties of the composite. In addition, the degree of polarization of the PVDF component of the composite is predicted using this multiscale modeling approach and shows that there is opportunity to drastically improve the smart composite’s performance by improving the polarization procedure.

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

    Science.gov (United States)

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

    2002-01-15

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

  15. Plasma exposure tests of a carbon fiber/epoxy composite

    International Nuclear Information System (INIS)

    Schneider, T.; Rome, J.

    1988-07-01

    An experiment was conducted to test the exposure of a vacuum chamber made of a carbon fiber/epoxy composite to a plasma environment. In previous tests this material(CE 339, made by Ferro Corp.) has shown good vacuum properties and has also demonstrated the capability to withstand high energy electron beams in tests at the Naval Research Laboratory. Based on these promising results, the Torsatron Group at Auburn University conducted plasma exposure tests on a section of carbon fiber/epoxy composite pipe furnished by Oak Ridge National Laboratory. 1 ref, 2 figs

  16. 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.

  17. 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.

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

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites...

  19. Electrical conductivity of short carbon fibers and carbon black-reinforced chloroprene rubber

    International Nuclear Information System (INIS)

    Khoshniat, A. R.; MirAli, M.; Hemmati, M.; Afshar Taromi, F.; Katbab, A.

    2002-01-01

    Elastomers and plastics are intrinsically insulating materials, but by addition of some conductive particles such as conductive carbon black, carbon fibers and metals, they can change to conductive form. Conductivity of these composites are due to formation of the lattices of conductive filler particles in polymer chains. In this report, conductivity of chloroprene rubber filled with carbon black and carbon fibers as a function of temperature and pressure are studied. Electrical conductivity of chloroprene in a function of temperature and pressure are studied. Electrical conductivity of chloroprene in the presence of carbon black with proper mixing conditions increases to the conductivity level of semiconductors and even in the presence of carbon fibers it increases to the level of a conductor material. Meanwhile, the sensitivity of this compound to heat and pressure rises. Thus these composites have found various applications in the manufacture of heat and pressure sensitive sensors

  20. Carbon Nanotube (CNT) and Carbon Fiber Reinforced SiC Optical Components, Phase I

    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...

  1. Evaluation of long carbon fiber reinforced concrete to mitigate earthquake damage of infrastructure components.

    Science.gov (United States)

    2013-06-01

    The proposed study involves investigating long carbon fiber reinforced concrete as a method of mitigating earthquake damage to : bridges and other infrastructure components. Long carbon fiber reinforced concrete has demonstrated significant resistanc...

  2. Modification of powdered activated carbon for the production of carbon nano fibers (CNFs)

    International Nuclear Information System (INIS)

    Ahmed, Y.M.; Al-Mamun, A.; Muyibi, S.A.; Al-Khatib, M.F.R.; Jameel, A.T.; Al-Saadi, M.A.

    2009-01-01

    Full text: In the present work, powdered activated carbon (PAC) was modified and used for the production of carbon nano fibers (CNFs). The modification of PAC was done by the impregnation of nickel on the surface of the activated carbon using the wet impregnation method. Variable weight percentage ratios of the catalyst (nickel) ratio were used. The nano fibers were synthesized on the surface of modified PAC by using the Chemical Vapor Deposition (CVD) method at a temperature of ∼680 degree Celsius for one hour in the presence of acetylene as a carbon source. FESEM, TEM, and TGA were used for the characterization of the product. (author)

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

    International Nuclear Information System (INIS)

    Valdivia B, M.

    2005-01-01

    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. Evaluation of the Potential Health Hazards Associated with the Machining of Carbon Fiber Composites.

    Science.gov (United States)

    1987-01-01

    RESOLU11ON TESI CF-i NAII(IN , LUP I&NA U 10 CV) OIICEILE CUP1 EVALUATION OF THE POTENTIAL HEALTH HAZARDS ASSOCIATED WITH THE MACHINING OF CARBON FIBER...tailored to a wide variety of applications through variations in their chemistry (4). ,,. II. HEALTH AND SAFETY HAZARDS Carbon Fibers Carbon fibers are...considered biologically inert, as evidenced by their introduction into the human body as surgical implants. It is not the chemistry of carbon fibers

  5. High Per?formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

    OpenAIRE

    Zequine, Camila; Ranaweera, C. K.; Wang, Z.; Singh, Sweta; Tripathi, Prashant; Srivastava, O. N.; Gupta, Bipin Kumar; Ramasamy, K.; Kahol, P. K.; Dvornic, P. R.; Gupta, Ram K.

    2016-01-01

    High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4?A/g with energy density of 54?Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stabilit...

  6. 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.

  7. Adsorption performance of silver-loaded activated carbon fibers

    Directory of Open Access Journals (Sweden)

    Yan Xue-Feng

    2018-01-01

    Full Text Available Silver-loaded activated carbon fiber is prepared, and its adsorption performance is studied experimentally using five methylene blue solutions with different concentrations under three different temperature conditions. The adsorption tests show that fibers adsorption increase as the increase of temperature, and there is an optimal value for solution concentration, beyond which its adsorption will de-crease. Fibers isothermal adsorption to methylene blue is different from those by the monolayer adsorption by Langmuir model and the multilayer adsorption by Freundlich model. Through the analysis of thermodynamic parameters, Gibbs free energy, standard entropy, and standard enthalpy, it is found that the fibers adsorption to methylene blue is an exothermic process of physical adsorption.

  8. Correlation Between Shear Punch and Tensile Strength for Low-Carbon Steel and Stainless Steel Sheets

    Science.gov (United States)

    Mahmudi, R.; Sadeghi, M.

    2013-02-01

    The deformation behavior of AISI 1015 low-carbon steel, and AISI 304 stainless steel sheets was investigated by uniaxial tension and the shear punch test (SPT). Both materials were cold rolled to an 80% thickness reduction and subsequently annealed in the temperature range 25-850 °C to produce a wide range of yield and ultimate strength levels. The correlations between shear punch and tensile yield and ultimate stresses were established empirically. Different linear relationships having different slopes and intercepts were found for the low-carbon and stainless steel sheets, and the possible parameters affecting the correlation were discussed. It was shown that, within limits, yield and tensile strength of thin steel sheets can be predicted from the shear data obtained by the easy-to-perform SPT.

  9. 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.

  10. Chemical recycling of carbon fibers reinforced epoxy resin composites in oxygen in supercritical water

    International Nuclear Information System (INIS)

    Bai, Yongping; Wang, Zhi; Feng, Liqun

    2010-01-01

    The carbon fibers in carbon fibers reinforced epoxy resin composites were recovered in oxygen in supercritical water at 30 ± 1 MPa and 440 ± 10 o C. The microstructure of the recovered carbon fibers was observed using scanning electron microscopy (SEM) and atom force microscopy (AFM). The results revealed that the clean carbon fibers were recovered and had higher tensile strength relative to the virgin carbon fibers when the decomposition rate was above 85 wt.%, although the recovered carbon fibers have clean surface, the epoxy resin on the surface of the recovered carbon fibers was readily observed. As the decomposition rate increased to above 96 wt.%, no epoxy resin was observed on the surface of the carbon fibers and the oxidation of the recovered carbon fibers was readily measured by X-ray photoelectron spectroscopy (XPS) analysis. The carbon fibers were ideally recovered and have original strength when the decomposition rates were between 94 and 97 wt.%. This study clearly showed the oxygen in supercritical water is a promising way for recycling the carbon fibers in carbon fibers reinforced resin composites.

  11. Characterization of porous carbon fibers and related materials

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, E.L. Jr. [Univ. of Tennessee, Knoxville, TN (United States)

    1996-07-15

    This program was geared to support the Fossil Energy Material Sciences Program with respect to several areas of interest in efficient production and utilization of energy. Carbon molecular sieves have great potential for economically purifying gases; i.e. removal of carbon dioxide from natural gas without having to resort to cryogenic techniques. Microporous carbons can be tailored to serve as adsorbents for natural gas in on-board storage in automotive applications, avoiding high pressures and heavy storage tanks. This program is a laboratory study to evaluate production methodologies and activation processes to produce porous carbons for specific applications. The Carbon Materials Technology Group of Oak Ridge National Laboratory (ORNL) is engaged in developmental programs to produce activated carbon fibers (ACF) for applications in fixed beds and/or flowing reactors engineering applications.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. 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.

  14. Polyethersulfone flat sheet and hollow fiber membranes from solutions in ionic liquids

    KAUST Repository

    Kim, Dooli

    2017-06-10

    We fabricated flat-sheet and hollow fiber membranes from polyethersulfone (PES) solutions in two ionic liquids: 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP) and 1,3-dimethylimidazolium dimethyl phosphate ([MMIM]DMP). The solvents are non-volatile and less toxic than organic solvents, such as dimethylformamide (DMF). The membranes morphologies were compared with those of membranes prepared from solutions in DMF, using electron microscopy. Water permeance, solute rejection and mechanical strengths were evaluated. Membranes were applied to DNA separation. While membranes based on PES were successfully prepared, polysulfone (PSf) does not dissolve in the same ionic liquids. The discrepancy between PES and PSf could not be explained using classical Flory-Huggins theory, which does not consider the coulombic contributions in ionic liquids. The differences in solubility could be understood, by applying density functional theory to estimate the interaction energy between the different polymers and solvents. The theoretical results were supported by experimental measurements of intrinsic viscosity and dynamic light scattering (DLS).

  15. Preparation and characterization of carbon nanofibrous/hydroxyapatite sheets for bone tissue engineering.

    Science.gov (United States)

    Abd El-Aziz, A M; El Backly, Rania M; Taha, Nahla A; El-Maghraby, Azza; Kandil, Sherif H

    2017-07-01

    Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects require some sort of scaffold to do so. In the current study we proposed a method to obtain a carbon nanofibrous/Hydroxyapatite (HA) bioactive scaffold. The carbon nanofibrous (CNF) nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of poly acrylonitrile "PAN" and subsequent stabilization and carbonization processes. The CNFs sheets were functionalized by both hydroxyapatite (HA) and bovine serum albumin (BSA). The HA was added to the electrospun solution, but in case of (BSA), it was adsorbed after the carbonization process. The changes in the properties taking place in the precursor sheets were investigated using the characterization methods (SEM, FT-IR, TGA and EDX). The prepared materials were tested for biocompatibility via subcutaneous implantation in New Zealand white rabbits. We successfully prepared biocompatible functionalized sheets, which have been modified with HA or HA and BSA. The sheets that were functionalized by both HA and BSA are more biocompatible with fewer inflammatory cells of (neutrophils and lymphocytes) than ones with only HA over the period of 3weeks. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

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

  17. Preparation of carbon fiber unsaturated sizing agent for enhancing interfacial strength of carbon fiber/vinyl ester resin composite

    Science.gov (United States)

    Jiao, Weiwei; Cai, Yemeng; Liu, Wenbo; Yang, Fan; Jiang, Long; Jiao, Weicheng; Wang, Rongguo

    2018-05-01

    The practical application of carbon fiber (CF) reinforced vinyl ester resin (VE) composite was hampered seriously by the poor interfacial adhesion property. In this work, a novel unsaturated sizing agent was designed and prepared to improve the interfacial strength by covalently bonding CF with VE matrix. The main component of the sizing agent, N-(4‧4-diaminodiphenyl methane)-2-hydroxypropyl methacrylate (DMHM), was synthesized and confirmed by FTIR and NMR. XPS results of sized carbon fiber (SCF) showed that DMHM has adhered to desized fiber surface and reacted with some active functional groups on the surface. The SCF was characterized by high surface roughness and surface energy (especially the polar component), which means better wettability by VE. As a result, the interface shear strength and interlaminar shear strength of SCF/VE composite were enhanced by 96.56% and 66.07% respectively compared with CF/VE composite, benefited mainly from the strong and tough interphase.

  18. The usage of carbon fiber reinforcement polymer and glass fiber reinforcement polymer for retrofit technology building

    Science.gov (United States)

    Tarigan, Johannes; Meka, Randi; Nursyamsi

    2018-03-01

    Fiber Reinforcement Polymer has been used as a material technology since the 1970s in Europe. Fiber Reinforcement Polymer can reinforce the structure externally, and used in many types of buildings like beams, columns, and slabs. It has high tensile strength. Fiber Reinforcement Polymer also has high rigidity and strength. The profile of Fiber Reinforcement Polymer is thin and light, installation is simple to conduct. One of Fiber Reinforcement Polymer material is Carbon Fiber Reinforcement Polymer and Glass Fiber Reinforcement Polymer. These materials is tested when it is installed on concrete cylinders, to obtain the comparison of compressive strength CFRP and GFRP. The dimension of concrete is diameter of 15 cm and height of 30 cm. It is amounted to 15 and divided into three groups. The test is performed until it collapsed to obtain maximum load. The results of research using CFRP and GFRP have shown the significant enhancement in compressive strength. CFRP can increase the compressive strength of 26.89%, and GFRP of 14.89%. For the comparison of two materials, CFRP is more strengthening than GFRP regarding increasing compressive strength. The usage of CFRP and GFRP can increase the loading capacity.

  19. Feeding Single-Walled Carbon Nanotubes or Graphene to Silkworms for Reinforced Silk Fibers.

    Science.gov (United States)

    Wang, Qi; Wang, Chunya; Zhang, Mingchao; Jian, Muqiang; Zhang, Yingying

    2016-10-12

    Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance. The possibility of creating tougher silks attracts particular research interest. Carbon nanotubes and graphene are widely studied for their use as reinforcement. In this work, we report mechanically enhanced silk directly collected by feeding Bombyx mori larval silkworms with single-walled carbon nanotubes (SWNTs) and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers, whereas the others went into the excrement of silkworms. Spectroscopy study indicated that nanocarbon additions hindered the conformation transition of silk fibroin from random coil and α-helix to β-sheet, which may contribute to increased elongation at break and toughness modules. We further investigated the pyrolysis of modified silk, and a highly developed graphitic structure with obviously enhanced electrical conductivity was obtained through the introduction of SWNTs and graphene. The successful generation of these SWNT- or graphene-embedded silks by in vivo feeding is expected to open up possibilities for the large-scale production of high-strength silk fibers.

  20. Low temperature stabilization process for production of carbon fiber having structural order

    Science.gov (United States)

    Rios, Orlando; McGuire, Michael Alan; More, Karren Leslie; Tenhaeff, Wyatt Evan; Menchhofer, Paul A.; Paulauskas, Felix Leonard

    2017-08-15

    A method for producing a carbon fiber, the method comprising: (i) subjecting a continuous carbon fiber precursor having a polymeric matrix in which strength-enhancing particles are incorporated to a stabilization process during which the carbon fiber precursor is heated to within a temperature range ranging from the glass transition temperature to no less than 20.degree. C. below the glass transition temperature of the polymeric matrix, wherein the maximum temperature employed in the stabilization process is below 400.degree. C., for a processing time within said temperature range of at least 1 hour in the presence of oxygen and in the presence of a magnetic field of at least 1 Tesla, while said carbon fiber precursor is held under an applied axial tension; and (ii) subjecting the stabilized carbon fiber precursor, following step (i), to a carbonization process. The stabilized carbon fiber precursor, resulting carbon fiber, and articles made thereof are also described.

  1. 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.

  2. Mechanical properties of continuously spun fibers of carbon nanotubes.

    Science.gov (United States)

    Motta, Marcelo; Li, Ya-Li; Kinloch, Ian; Windle, Alan

    2005-08-01

    We report on the mechanical properties of fibers consisting of pure carbon nanotube fibers directly spun from an aerogel formed during synthesis by chemical vapor deposition. The continuous withdrawal of product from the gas phase imparts a high commercial potential to the process, either for the production of particularly strong fibers or for the economic production of bulk quantities of carbon nanotubes. Tensile tests were performed on fibers produced from the dissociation of three different hydrocarbons, namely, ethanol, ethylene glycol, and hexane, with a range of iron (catalyst) concentrations. The conditions were chosen to lie within the range known to enable satisfactory continuous spinning, the iron concentration being varied within this range. Increasing proportions of single wall nanotubes were found as the iron concentration was decreased, conditions which also produced fibers of best strength and stiffness. The maximum tensile strength obtained was 1.46 GPa (equivalent to 0.70 N/tex assuming a density of 2.1 g/cm(3)). The experiments indicate that significant improvements in the mechanical properties can be accomplished by optimizing the process conditions.

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

    International Nuclear Information System (INIS)

    Yuan Hua; Wang Chengguo; Zhang Shan; Lin Xue

    2012-01-01

    Highlights: ► We used very simple and effective modification method to treat PAN-based carbon fiber by liquid oxidation and coupling agent. ► Carbon fiber surface functional groups were analyzed by LRS and XPS. ► Proper treatment of carbon fiber can prove an effective way to increase composite's performance. ► Carbon fiber surface modifications by oxidation and APS could strengthen fiber activity and enlarge surface area as well as its roughness. - Abstract: In this work, polyacrylonitrile (PAN)-based carbon fiber were chemically modified with H 2 SO 4 , KClO 3 and silane coupling agent (γ-aminopropyltriethoxysilane, APS), and carbon fiber reinforced phenolic matrix composites were prepared. The structural and surface characteristics of the carbon fiber were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman scattering (LRS) and Fourier transform infrared spectroscopy (FTIR). Single fiber mechanical properties, specific surface area, composite impact properties and interfacial shear strength (ILSS) were researched to indicate the effects of surface modification on fibers and the interaction between modified fiber surface and phenolic matrix. The results showed that carbon fiber surface modification by oxidation and APS can strengthen fiber surface chemical activity and enlarge the fiber surface area as well as its roughness. When carbon fiber (CF) is oxidized treatment, the oxygen content as well as the O/C ratio will be obviously increased. Oxygen functional groups increase with oxidation time increasing. Carbon fiber treated with APS will make C-O-R content increase and O-C=O content decrease due to surface reaction. Proper treatment of carbon fiber with acid and silane coupling agent prove an effective way to increase the interfacial adhesion and improve the mechanical and outdoor performance of the resulting fiber/resin composites.

  4. Increased Tensile Strength of Carbon Nanotube Yarns and Sheets through Chemical Modification and Electron Beam Irradiation

    Science.gov (United States)

    Miller, Sandi G.; Williams, Tiffany S.; Baker, James S.; Sola, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S.; Wilmoth, Nathan G.; Gaier, James; Chen, Michelle; Meador, Michael A.

    2014-01-01

    The inherent strength of individual carbon nanotubes offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of carbon nanotube (CNT) forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading; and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated to macro-scale CNT forms where bulk material strength is limited by inter-tube electrostatic attraction and slippage. The focus of this work was to assess post processing of CNT sheet and yarn to improve the macro-scale strength of these material forms. Both small molecule functionalization and e-beam irradiation was evaluated as a means to enhance tensile strength and Youngs modulus of the bulk CNT material. Mechanical testing results revealed a tensile strength increase in CNT sheets by 57 when functionalized, while an additional 48 increase in tensile strength was observed when functionalized sheets were irradiated; compared to unfunctionalized sheets. Similarly, small molecule functionalization increased yarn tensile strength up to 25, whereas irradiation of the functionalized yarns pushed the tensile strength to 88 beyond that of the baseline yarn.

  5. Computer Modeling of Carbon Metabolism Enables Biofuel Engineering (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2011-09-01

    In an effort to reduce the cost of biofuels, the National Renewable Energy Laboratory (NREL) has merged biochemistry with modern computing and mathematics. The result is a model of carbon metabolism that will help researchers understand and engineer the process of photosynthesis for optimal biofuel production.

  6. 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.

  7. Electron beam irradiation effects on carbon fiber reinforced PEEK composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Hagiwara, Miyuki; Odajima, Tosikazu; Sakai, Hideo; Nakakura, Toshiyuki; Masutani, Masahiro.

    1987-03-01

    Carbon fiber(CF) reinforced composites, using polyarylether-sulfone (PES) or polyarylether-ether-ketone (PEEK) as matrix material, were prepared and their electron beam irradiation effects were studied on the basis of changes in mechanical and dynamic viscoelastic properties and observation of fracture surfaces. The flexural strength of PES-CF composite decreased to 70 % of the initial strength after the irradiation of 3 MGy and 40 % after 15 MGy. The change in the profile of stress-strain (S-S) curves and fractographic observation by electron microscopy indicated that this composite irradiated with over 3 MGy was fractured by delamination caused by to the degradation of matrix polymer. The mechanical properties of PEEK-CF composite were scarcely decreased even after irradiated up to 180 MGy and this composite showed very high radiation resistance. The change in the profile of S-S curves and fractographic observation showed that this composite fractured due to destruction of fiber in the dose range less than 180 MGy, indicating that PEEK was excellent matrix material used in high radiation field. PEEK-PES-CF composite which was composed of the carbon fibers coated with PES solution showed less radiation resistance compared with PEEK-CF composite; the flexural strength decreased to 85 % of the initial value after the irradiation with 90 MGy. It was revealed from the changes in the profile of S-S curve that the specimen irradiated over 120 MGy was fractured due to not only fiber destruction but delamination. Deterioration mechanism of PEEK-PES-CF composite was studied by dynamic viscoelastic measurements in connection with the damage on matrix-fiber interface. It was suggested that the deterioration in mechanical properties of this composite was caused by the degradation of PES that coated on the surface of the carbon fibers. (author)

  8. An Experimental Study on Concrete Flat Slabs Prestressed with Carbon Fibre Reinforced Polymer Sheets

    Directory of Open Access Journals (Sweden)

    Yin Shen

    2015-01-01

    Full Text Available Carbon fibre reinforced polymer (CFRP is currently used to reinforce buildings in civil engineering in the common forms of sheets, while the utilization efficiency of a CFRP materials greatly decreased when the CFRP material is directly bonded to the structure because of the lack of the effect of the exertion of a prestress. A paper spool-inspired anchoring method is proposed to overcome the shearing problem in the anchoring system through the friction between layers. Anchoring and jack-up tensioning devices for CFRP sheets are also designed and produced. A prestress is successfully applied to single and multiple CFRP sheets (80% tensioning strength is achieved, thus verifying the tensioning effect of the prestress. Based on these results, prestressed concrete flat slabs were designed with pretensioned CFRP sheets. The corresponding mechanical properties of the concrete flat slabs are tested to verify the feasibility of using CFRP sheets to apply a prestress. The results show that the uniformity of the fibre stress during the tensioning of the CFRP sheet is the key to the success of the application of the prestress.

  9. Thermal conductivity of freestanding single wall carbon nanotube sheet by Raman spectroscopy.

    Science.gov (United States)

    Sahoo, Satyaprakash; Chitturi, Venkateswara Rao; Agarwal, Radhe; Jiang, Jin-Wu; Katiyar, Ram S

    2014-11-26

    Thermal properties of single wall carbon nanotube sheets (SWCNT-sheets) are of significant importance in the area of thermal management, as an isolated SWCNT possesses high thermal conductivity of the value about 3000 W m(-1) K(-1). Here we report an indirect method of estimating the thermal conductivity of a nanometer thick suspended SWCNT-sheet by employing the Raman scattering technique. Tube diameter size is examined by the transmissions electron microscopy study. The Raman analysis of the radial breathing modes predicts narrow diameter size distribution with achiral (armchair) symmetry of the constituent SWCNTs. From the first order temperature coefficient of the A1g mode of the G band along with the laser power dependent frequency shifting of this mode, the thermal conductivity of the suspended SWCNT-sheet is estimated to be about ∼18.3 W m(-1) K(-1). Our theoretical study shows that the thermal conductivity of the SWCNT-sheet has contributions simultaneously from the intratube and intertube thermal transport. The intertube thermal conductivity (with contributions from the van der Waals interaction) is merely around 0.7 W m(-1) K(-1), which is three orders smaller than the intratube thermal conductivity, leading to an abrupt decrease in the thermal conductivity of the SWCNT-sheet as compared to the reported value for isolated SWCNT.

  10. Electrical characterization and microwave application of polyacrylonitrile/carbon nanotube-based carbon fibers

    Science.gov (United States)

    Sano, Eiichi; Watanuki, Takehito; Ikebe, Masayuki; Fugetsu, Bunshi

    2017-09-01

    The addition of carbon nanotubes (CNTs) in polyacrylonitrile (PAN) precursor is an effective way to increase the electrical conductivity of derived carbon fibers. The electrical conductivity of 4.9 × 104 S/m for a PAN-based carbon fiber at room temperature increases to 9.4 × 104 S/m by adding 0.5 wt % CNTs. The measured conductivity for both PAN/CNT- and PAN-based carbon fibers monotonically increases as the temperature increases from 10 and 300 K. An attempt to explain the measured temperature dependences of electrical conductivities by various carrier transport models showed that a simple two-carrier model can give reasonable electron and hole mobility. A monopole antenna fabricated with PAN/CNT-based carbon fibers shows a gain of 2.3 dBi at 2.4 GHz, which is only 0.2 dB smaller than that of a reference (Cu-wire) monopole antenna. This result suggests the possibility of using PAN/CNT-based carbon fibers as antenna elements.

  11. 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...... CNT nanoreinforcement into the matrix and/or the sizing of carbon fiber/reinforced composites ensures strong increase of the composite strength. The effect of secondary CNTs reinforcement is strongest when some small addition of CNTs in the polymer matrix is complemented by the fiber sizing with high...... multiscale computational (FE) models of the carbon/polymer composite with varied CNT distributions have been developed and employed to study the effect of the secondary CNT reinforcement, its distribution and content on the strength and fracture behavior of the composites. It is shown that adding secondary...

  12. The effect of fiber oxidation on the friction and wear behaviors of short-cut carbon fiber/polyimide composites

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available Pitch-based short-cut carbon fibers were treated by HNO3 oxidation, thereafter the treated (CFN and untreated carbon fibers (CF were incorporated into polyimide (PI matrix to form composites. The carbon fibers before and after treatment were examined by Fourier Transform Infrared Spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS and scanning electron microscope (SEM. The friction and wear behaviors of PI composites sliding against GCr15 steel rings were evaluated on an M-2000 model ring-on-block test rig, which revealed that small incorporation of carbon fibers can decrease the friction coefficient and improve the wear resistance of PI composites, and that the reinforcement effect of treated carbon fibers was better than that of the untreated ones. It was found that the optimum content of carbon fibers is 15 wt% when a thin and continuous transfer film was formed on the counterpart surface during the friction process. With further increasing content of carbon fibers, the friction coefficient increased and the wear resistance reduced owing to the drop out of carbon fibers from PI matrix. Besides, the friction coefficient of the PI composites decreased and the wear resistance improved with increasing load, while for the pure PI, its wear resistance decreased drastically owing to the micro-melting and mechanical deterioration caused by friction heat under a higher load.

  13. Textile fibers coated with carbon nanotubes for smart clothing applications

    Science.gov (United States)

    Lepak, Sandra; Lalek, Bartłomiej; Janczak, Daniel; Dybowska-Sarapuk, Łucja; Krzemiński, Jakub; Jakubowska, Małgorzata; Łekawa-Raus, Agnieszka

    2017-08-01

    Carbon nanomaterials: graphene, fullerenes and in particular carbon nanotubes (CNTs) are extremely interesting and extraordinary materials. It is mostly thanks to theirs unusual electrical and mechanical properties. Carbon nanotubes are increasingly examined to enable its usage in many fields of science and technology. It has been reported that there is a high possibility to use CNTs in electronics, optics, material engineering, biology or medicine. However, this material still interests and inspire scientists around the world and the list of different CNTs applications is constantly expanding. In this paper we are presenting a study on the possibility of application carbon nanotubes as a textile fiber coating for smart clothing applications. Various suspensions and pastes containing CNTs have been prepared as a possible coating onto textile fibers. Different application techniques have also been tested. Those techniques included painting with nanotube suspension, spray coating of suspensions and immersion. Following textile fibers were subject to tests: cotton, silk, polyester, polyamide and wool. Obtained composites materials were then characterized electrically by measuring the electrical resistance.

  14. Single Carbon Fibers with a Macroscopic-Thickness, 3D Highly Porous Carbon Nanotube Coating.

    Science.gov (United States)

    Zou, Mingchu; Zhao, Wenqi; Wu, Huaisheng; Zhang, Hui; Xu, Wenjing; Yang, Liusi; Wu, Shiting; Wang, Yunsong; Chen, Yijun; Xu, Lu; Cao, Anyuan

    2018-02-19

    Carbon fiber (CF) grafted with a layer of carbon nanotubes (CNTs) plays an important role in composite materials and other fields; to date, the applications of CNTs@CF multiscale fibers are severely hindered by the limited amount of CNTs grafted on individual CFs and the weak interfacial binding force. Here, monolithic CNTs@CF fibers consisting of a 3D highly porous CNT sponge layer with macroscopic-thickness (up to several millimeters), which is directly grown on a single CF, are fabricated. Mechanical tests reveal high sponge-CF interfacial strength owing to the presence of a thin transitional layer, which completely inhibits the CF slippage from the matrix upon fracture in CNTs@CF fiber-epoxy composites. The porous conductive CNTs@CF hybrid fibers also act as a template for introducing active materials (pseudopolymers and oxides), and a solid-state fiber-shaped supercapacitor and a fiber-type lithium-ion battery with high performances are demonstrated. These CNTs@CF fibers with macroscopic CNT layer thickness have many potential applications in areas such as hierarchically reinforced composites and flexible energy-storage textiles. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 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.

  16. 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.

  17. Carbon chloride-core fibers for soliton mediated supercontinuum generation.

    Science.gov (United States)

    Chemnitz, Mario; Gaida, Christian; Gebhardt, Martin; Stutzki, Fabian; Kobelke, Jens; Tünnermann, Andreas; Limpert, Jens; Schmidt, Markus A

    2018-02-05

    We report on soliton-fission mediated infrared supercontinuum generation in liquid-core step-index fibers using highly transparent carbon chlorides (CCl 4 , C 2 Cl 4 ). By developing models for the refractive index dispersions and nonlinear response functions, dispersion engineering and pumping with an ultrafast thulium fiber laser (300 fs) at 1.92 μm, distinct soliton fission and dispersive wave generation was observed, particularly in the case of tetrachloroethylene (C 2 Cl 4 ). The measured results match simulations of both the generalized and a hybrid nonlinear Schrödinger equation, with the latter resembling the characteristics of non-instantaneous medium via a static potential term and representing a simulation tool with substantially reduced complexity. We show that C 2 Cl 4 has the potential for observing non-instantaneous soliton dynamics along meters of liquid-core fiber opening a feasible route for directly observing hybrid soliton dynamics.

  18. 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.

  19. System to continuously produce carbon fiber via microwave assisted plasma processing

    Science.gov (United States)

    White, Terry L [Knoxville, TN; Paulauskas, Felix L [Knoxville, TN; Bigelow, Timothy S [Knoxville, TN

    2010-11-02

    A system to continuously produce fully carbonized or graphitized carbon fibers using microwave-assisted plasma (MAP) processing comprises an elongated chamber in which a microwave plasma is excited in a selected gas atmosphere. Fiber is drawn continuously through the chamber, entering and exiting through openings designed to minimize in-leakage of air. There is a gradient of microwave power within the chamber with generally higher power near where the fiber exits and lower power near where the fiber enters. Polyacrylonitrile (PAN), pitch, or any other suitable organic/polymeric precursor fibers can be used as a feedstock for the inventive system. Oxidized or partially oxidized PAN or pitch or other polymeric fiber precursors are run continuously through a MAP reactor in an inert, non-oxidizing atmosphere to heat the fibers, drive off the unwanted elements such as oxygen, nitrogen, and hydrogen, and produce carbon or graphite fibers faster than conventionally produced carbon fibers.

  20. 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.

  1. Production of activated carbon from cellulosic fibers for environment protection

    International Nuclear Information System (INIS)

    Le Coq, L.; Faur, C.; Le Cloirec, P.; Phan Ngoc, H.

    2005-01-01

    Activated carbon fibers (ACF) have received an increasing attention in recent years as an adsorbent for purifying polluted gaseous and aqueous streams. Their preparation, characterization and application have been reported in many studies [1], which show that the porosity of ACF is dependent on activation conditions, as temperature, time or gas. ACF provide adsorption rates 2 to 50 times higher than Granular Activated Carbon [2], because of their low diameter (∼10 m) providing a larger external surface area in contact with the fluid compared with that of granules. Furthermore, their potential for the removal of various pollutants from water was demonstrated towards micro-organics like phenols [3], pesticides or dyes [4]. Generally, fibrous activated carbons are produced from natural or synthetic precursors by carbonization at 600-1000 C followed by an activation step by CO 2 oe steam at higher temperature [2]. Another way to produce the fibrous activated carbons is chemical activation with H 3 PO 4 , HNO 3 , KOH...[5]. Different types of synthetic or natural fibers have been used as precursors of fibrous activated carbons since 1970: polyacrylonitrile (PAN), polyphenol, rayon, cellulose phosphate, pitch, etc. Each of them has its own applications and limitations. The synthetic fibers being generally expensive, it would be interesting to find out low-cost precursors from local material resources. This work is a part of a research exchange program between the Vietnamese National Center of Natural Sciences and Technology (Vietnam) and the Ecole des Mines de Nantes (Gepea, France), with the aim to find some economical solutions for water treatment. Fibrous activated carbons are produced from natural cellulose fibers, namely jute and coconut fibers, which are abundant in Vietnam as well as in other tropical countries, have a low ash content and a low cost in comparison with synthetic fibers. Two methods are compared to produce activated carbons: 1) a physical

  2. 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.

  3. 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.

  4. 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.

  5. Removing nickel from nickel-coated carbon fibers

    Science.gov (United States)

    Hardianto, A.; Hertleer, C.; De Mey, G.; Van Langenhove, L.

    2017-10-01

    Conductive fibers/yarns are one of the most important materials for smart textiles because of their electrically conductive functionality combined with flexibility and light weight. They can be applied in many fields such as the medical sector, electronics, sensors and even as thermoelectric generators. Temperature sensors, for example, can be made using the thermocouple or thermopile principle which usually uses two different metal wires that can produce a temperature-dependent voltage. However, if metal wires are inserted into a textile structure, they will decrease the flexibility properties of the textile product. Nickel-coated Carbon Fiber (NiCF), a conductive textile yarn, has a potential use as a textile-based thermopile if we can create an alternating region of carbon and nickel along the fiber which in turn it can be used for substituting the metallic thermopile. The idea was to remove nickel from NiCF in order to obtain a yarn that contains alternating zones of carbon and nickel. Due to no literature reporting on how to remove nickel from NiCF, in this paper we investigated some chemicals to remove nickel from NiCF.

  6. 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.

  7. Interfacial studies on the O3 modified carbon fiber-reinforced polyamide 6 composites

    International Nuclear Information System (INIS)

    Li, J.

    2008-01-01

    In this work, O 3 modification method was used for the surface treatment of polyacrylonitrile (PAN)-based carbon fiber. The surface characteristics of carbon fibers were characterized by X-ray photoelectron spectroscopy (XPS). The interfacial properties of carbon fiber-reinforced polyamide 6 (CF/PA6) composites were investigated by means of the single fiber pull-out tests. As a result, it was found that IFSS values of the composites with O 3 treated carbon fiber are increased by 60% compared to that without treatment. XPS results show that O 3 treatment increases the amount of carboxyl groups on carbon fiber surface, thus the interfacial adhesion between carbon fiber and PA6 matrix is effectively promoted

  8. Tensile Properties and Fracture Behavior of Different Carbon Nanotube-Grafted Polyacrylonitrile-Based Carbon Fibers

    Science.gov (United States)

    Naito, Kimiyoshi

    2014-11-01

    The tensile properties and fracture behavior of different carbon nanotube (CNT)-grafted polyacrylonitrile-based (T1000GB) single carbon fibers were investigated. Grafting of CNTs was achieved via chemical vapor deposition (CVD). When Fe(C5H5)2 (also applied via CVD) was used as the catalyst, the tensile strength and Weibull modulus of the carbon fibers were improved, possibly due to the growth of dense CNT networks on the carbon fibers, which may have led to a reduction in the number of strength-limiting defects. Separately, at lower concentrations of an Fe(NO3)3·9H2O catalyst in ethanol, which was applied via dipping, the tensile strength of CNT-grafted fibers was nearly identical to that of the as-received fibers, although the Weibull modulus was higher. For higher concentrations of the Fe(NO3)3·9H2O catalyst, however, the tensile strength and the Weibull modulus were lower than those for the as-received material. Although the density of the CNT network increased with the concentration of the Fe(NO3)3·9H2O catalyst in the ethanol solution, heating of the ethanolic Fe(NO3)3·9H2O catalyst solution generated nitric acid (HNO3) due to decomposition, which damaged the fiber surfaces, resulting in an increase in the number of flaws and consequently a reduction in the tensile strength. Therefore, the tensile strength and Weibull modulus of CNT-grafted carbon fibers vary due to the combination of these effects and as a function of the catalyst concentration.

  9. Aligned carbon nanotube-silicon sheets: a novel nano-architecture for flexible lithium ion battery electrodes.

    Science.gov (United States)

    Fu, Kun; Yildiz, Ozkan; Bhanushali, Hardik; Wang, Yongxin; Stano, Kelly; Xue, Leigang; Zhang, Xiangwu; Bradford, Philip D

    2013-09-25

    Aligned carbon nanotube sheets provide an engineered scaffold for the deposition of a silicon active material for lithium ion battery anodes. The sheets are low-density, allowing uniform deposition of silicon thin films while the alignment allows unconstrained volumetric expansion of the silicon, facilitating stable cycling performance. The flat sheet morphology is desirable for battery construction. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

    Minke, Christine; Kunz, Ulrich; Turek, Thomas

    2017-02-01

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

  11. Carbon-graphite component for an electrochemical cell and method for making the component

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, R.C. Jr.

    1987-06-02

    A method is described for making a carbon-graphite component suited for use in an electrochemical cell, comprising: forming a precursor sheet structure consisting essentially of a mixture of cellulose fibers, purified graphite particles and a carbonizable, thermosetting resin wherein the cellulose fibers support and position the purified graphite particles; heating the sheet structure to a first temperature range to carbonize the cellulose fibers and thermosetting resin wherein the carbonized resin bonds the carbonized cellulose fibers and graphite particles together; and heating the sheet structure to a second, higher temperature range to graphitize the carbonized cellulose fibers and resin.

  12. 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.

  13. Fiber-optic anemometer based on single-walled carbon nanotube coated tilted fiber Bragg grating.

    Science.gov (United States)

    Zhang, Yang; Wang, Fang; Liu, Zigeng; Duan, Zhihui; Cui, Wenli; Han, Jie; Gu, Yiying; Wu, Zhenlin; Jing, Zhenguo; Sun, Changsen; Peng, Wei

    2017-10-02

    In this work, a novel and simple optical fiber hot-wire anemometer based on single-walled carbon nanotubes (SWCNTs) coated tilted fiber Bragg grating (TFBG) is proposed and demonstrated. For the hot-wire wind speed sensor design, TFBG is an ideal in-fiber sensing structure due to its unique features. It is utilized as both light coupling and temperature sensing element without using any geometry-modified or uncommon fiber, which simplifies the sensor structure. To further enhance the thermal conversion capability, SWCNTs are coated on the surface of the TFBG instead of traditional metallic materials, which have excellent thermal characteristics. When a laser light is pumped into the sensor, the pump light propagating in the core will be easily coupled into cladding of the fiber via the TFBG and strongly absorbed by the SWCNTs thin film. This absorption acts like a hot-wire raising the local temperature of the fiber, which is accurately detected by the TFBG resonance shift. In the experiments, the sensor's performances were investigated and controlled by adjusting the inherent angle of the TFBG, the thickness of SWCNTs film, and the input power of the pump laser. It was demonstrated that the developed anemometer exhibited significant light absorption efficiency up to 93%, and the maximum temperature of the local area on the fiber was heated up to 146.1°C under the relatively low pump power of 97.76 mW. The sensitivity of -0.3667 nm/(m/s) at wind speed of 1.0 m/s was measured with the selected 12° TFBG and 1.6 μm film.

  14. Differences in plankton community structure and carbon cycling along a climate gradient from the Greenland Ice Sheet to offshore waters

    DEFF Research Database (Denmark)

    Arendt, K.E.; Nielsen, Torkel Gissel; Rysgaard, S.

    . Protozooplankton accounts for 20-38% of the carbon turnover in the offshore and inland areas. However, protozooplankton like copepods has low ability to turn over the primary production close to the Ice Sheet. Increased run of from the Greenland Ice Sheet due to global warming could displace the existing climate...

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-06-21

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

  17. Hibiscus fiber carbon for fuel cell device material

    International Nuclear Information System (INIS)

    Nanik Indayaningsih; Anne Zulfia; Dedi Priadi; Suprapedi

    2010-01-01

    The objective of this research is carbon of hibiscus fibers for the application as basic material of fuel cell device. The carbon is made using a pyrolysis process in inert gas (nitrogen) for 1 hour at temperature of 500 °C, 700 °C and 900 °C. The X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Impedance-Capacitance-Resistance-meter are used to find out the microstructure, morphology and electrical properties respectively. The results of the experiment showed that the carbon had a structure of amorphous, and as the semiconductor material the electrical conductivity was 5 x 10 -5 S.cm -1 to 4.9 x 10 -5 S.cm -1 increasing in accordance with the pyrolysis temperature. The morphology resembled to plaited mats constructed by porous fibers having width of 50 µm to 300 µm, thickness of 25 µm to 35 µm, and the porous size of 0.5 µm to 5 µm. This morphology enables carbon to be applied as a candidate for a basic material of the Proton Exchange Membrane Fuel Cell. (author)

  18. 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.

  19. The prospect of carbon fiber implants in radiotherapy

    Science.gov (United States)

    Xiao‐bin, Tang; Chang‐ran, Geng; Da, Chen

    2012-01-01

    Because of their superior characteristics, carbonaceous materials, which are still at their early stage of development, have garnered significant interest. Because of their low atomic number, carbonaceous orthopedic implants possess radiation properties similar to biological tissues and, therefore, they are more suitable to patients in need of radiotherapy. The effects of stainless steel, titanium, and carbon plates on radiation dose distributions were investigated in this work using Monte Carlo simulations and TLD measurements for 6 MV photon beams. It is found that carbon plates will neither increase the incident surface dose, nor lead to the decrease of exit surface dose (the effect of a second build‐up). Carbon fiber orthopedic implants have a good prospect for radiotherapy patients because they have minimal perturbation effects on the radiotherapy dose distribution. PACS number: 87.55.K‐,87.55.Gh, 87.55.ne PMID:22766953

  20. The thinnest molecular separation sheet by graphene gates of single-walled carbon nanohorns.

    Science.gov (United States)

    Ohba, Tomonori

    2014-11-25

    Graphene is possibly the thinnest membrane that could be used as a molecular separation gate. Several techniques including absorption, cryogenic distillation, adsorption, and membrane separation have been adopted for constructing separation systems. Molecular separation using graphene as the membrane has been studied because large area synthesis of graphene is possible by chemical vapor deposition. Control of the gate sizes is necessary to achieve high separation performances in graphene membranes. The separation of molecules and ions using graphene and graphene oxide layers could be achieved by the intrinsic defects and defect donation of graphene. However, the controllability of the graphene gates is still under debate because gate size control at the picometer level is inevitable for the fabrication of the thinnest graphene membranes. In this paper, the controlled gate size in the graphene sheets in single-walled carbon nanohorns (NHs) is studied and the molecular separation ability of the graphene sheets is assessed by molecular probing with CO2, O2, N2, CH4, and SF6. Graphene sheets in NHs with different sized gates of 310, 370, and >500 pm were prepared and assessed by molecular probing. The 310 pm-gates in the graphene sheets could separate the molecules tested, whereas weak separation properties were observed for 370 pm-gates. The amount of CO2 that penetrated the 310 pm-gates was more than 35 times larger than that of CH4. These results were supported by molecular dynamics simulations of the penetration of molecules through 300, 400, and 700 pm-gates in graphene sheets. Therefore, a gas separation membrane using a 340-pm-thick graphene sheet has high potential. These findings provide unambiguous evidence of the importance of graphene gates on the picometer level. Control of the gates is the primary challenge for high-performance separation membranes made of graphene.

  1. Gel Spun PAN/CNT Based Carbon Fibers with Honey-Comb Cross-Section

    Science.gov (United States)

    2013-11-13

    include nano composite fibers with thermal conductivity in the range of 2 – 15 W/m/k. Details of the unpublished work of the honey -comb fiber are...GEL SPUN PAN/CNT BASED CARBON FIBERS WITH HONEY - COMB CROSS-SECTION SATISH KUMAR GEORGIA TECH RESEARCH CORPORATION 11/13/2013 Final Report...TABLE of CONTENTS Content Page Executive Summary 1-2 Low Density carbon fibers with honey -comb structure 3-15

  2. Bonded carbon or ceramic fiber composite filter vent for radioactive waste

    Science.gov (United States)

    Brassell, Gilbert W.; Brugger, Ronald P.

    1985-02-19

    Carbon bonded carbon fiber composites as well as ceramic or carbon bonded ceramic fiber composites are very useful as filters which can separate particulate matter from gas streams entraining the same. These filters have particular application to the filtering of radioactive particles, e.g., they can act as vents for containers of radioactive waste material.

  3. 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.

  4. Mechanical Properties of Low-Density SiC-Coated Carbon-Bonded Carbon Fiber Composites

    Czech Academy of Sciences Publication Activity Database

    Ahmed, A. S.; Chlup, Zdeněk; Dlouhý, Ivo; Rawlings, R. D.; Boccaccini, A. R.

    2012-01-01

    Roč. 9, č. 2 (2012), s. 401-412 ISSN 1546-542X R&D Projects: GA ČR GA101/09/1821 Institutional research plan: CEZ:AV0Z20410507 Keywords : SiC coating * Carbon bonded * Carbon Fiber Composites * Fracture Toughness Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.153, year: 2012

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

    Directory of Open Access Journals (Sweden)

    Jossano Saldanha Marcuzzo

    2013-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Jossano Saldanha Marcuzzo

    2012-01-01

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

  7. Novel multifunctional composites based on carbon nanotube sheets and yarns: Synthesis, fabrication, properties and applications

    Science.gov (United States)

    Lepro Chavez, Xavier N.

    Multiwalled carbon nanotube (MWNT) aligned sheets directly drawn from forests and derived yarns have recently attracted wide attention because of their exhibited mechanical, electronic, photonic and optical properties. Unfortunately, the supply of drawable forests is currently limited since the set of experimental conditions required to obtain adequate forest morphology is rather narrow, thus restricting the advance towards large scale applications. This work starts by addressing this issue by showing that the correct preparation of alternative substrates, such as thin metallic sheets, can produce the forest morphology required for solid-state drawability and increase the attainable surface for forest harvesting without further enlargement of the currently used chemical vapor deposition (CVD) reactor chamber. Also, it explores suitable ways to quantify the alignment of MWNTs in forests and by comparing them with spinnable ones, provides a range of alignment distribution where forest drawability can be reasonably expected. Next, this work presents procedures that can add functionality to the MWNT free-standing sheets without strongly affecting their mechanical integrity, nanotube alignment or individual morphology. Proved examples, such as free-standing sheets of catalytic-active, highly capacity (39 F/g), aligned nitrogen-doped MWNTs and silicon-based ceramic conformationally coated MWNTs that can be easily twisted into yarns, are examined in different chapters. Moreover, we show that MWNT sheets can be used for templating materials other than carbon into nanostructured arrays by preparing sheets of aligned silicon oxide nanotubes. Similar to MWNT sheets, these nanotube based materials can be used as host to confine functional unspinnable materials (up to 95 wt.%) by twisting them together into biscrolled yarns, suitable for applications as superconductors, lithium-ion batteries, fuel cells catalysts and photocatalysis. Such biscrolled yarns have a twist

  8. 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.

  9. Modification of carbon fiber surfaces via grafting with Meldrum's acid

    Energy Technology Data Exchange (ETDEWEB)

    Cuiqin, Fang; Jinxian, Wu [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Julin, Wang, E-mail: wjl@mail.buct.edu.cn [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Tao, Zhang [Beijing Institute of Ancient Architecture, Beijing 100050 (China)

    2015-11-30

    Graphical abstract: - Highlights: • The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated. • The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid. • The relative content of carboxylic groups on carbon fiber surfaces was increased. • The surfaces of carbon fibers neither etched nor generated coating. • Tensile strength of carbon fibers was preserved after grafting reaction. - Abstract: The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated in this work. The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid to create carboxylic functionalized surfaces. The surface functionalization effect was detected with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The XPS results showed that the relative content of carboxylic groups on carbon fiber surfaces was increased from initial 1.41% to 7.84%, however, that of carbonyl groups was decreased from 23.11% to 13.28% after grafting reaction. The SEM, AFM and TGA results indicated that the surfaces of carbon fibers neither etched nor generated coating. The tensile strength of carbon fibers was preserved after grafting reaction according to single fiber tensile strength tests. The fibers were well combined with matrix and the maximal interlaminar shear strength (ILSS) of carbon fiber/epoxy resin composites was sharply increased approximately 74% after functionalization. The effects of acetic acid and sonication on the degree of the surface functionalization were also studied.

  10. Modification of carbon fiber surfaces via grafting with Meldrum's acid

    International Nuclear Information System (INIS)

    Cuiqin, Fang; Jinxian, Wu; Julin, Wang; Tao, Zhang

    2015-01-01

    Graphical abstract: - Highlights: • The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated. • The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid. • The relative content of carboxylic groups on carbon fiber surfaces was increased. • The surfaces of carbon fibers neither etched nor generated coating. • Tensile strength of carbon fibers was preserved after grafting reaction. - Abstract: The mechanism of Meldrum's acid modifying carbon fiber surfaces was investigated in this work. The existing carbonyl groups of carbon fibers were grafted with Meldrum's acid to create carboxylic functionalized surfaces. The surface functionalization effect was detected with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The XPS results showed that the relative content of carboxylic groups on carbon fiber surfaces was increased from initial 1.41% to 7.84%, however, that of carbonyl groups was decreased from 23.11% to 13.28% after grafting reaction. The SEM, AFM and TGA results indicated that the surfaces of carbon fibers neither etched nor generated coating. The tensile strength of carbon fibers was preserved after grafting reaction according to single fiber tensile strength tests. The fibers were well combined with matrix and the maximal interlaminar shear strength (ILSS) of carbon fiber/epoxy resin composites was sharply increased approximately 74% after functionalization. The effects of acetic acid and sonication on the degree of the surface functionalization were also studied.

  11. 77 FR 73978 - Foreign-Trade Zone 148-Knoxville, TN, Toho Tenax America, Inc. (Carbon Fiber Manufacturing...

    Science.gov (United States)

    2012-12-12

    ... manufacture carbon fiber for export and oxidized polyacrylonitrile fiber (Board Order 1868, 77 FR 69435, 11/19/2012). Board Order 1868 did not include authority to manufacture carbon fiber for the U.S. market; the...--Knoxville, TN, Toho Tenax America, Inc. (Carbon Fiber Manufacturing Authority), Opening of Comment Period on...

  12. Nonlinear Finite Elements Analysis of Reinforced Concrete Columns Strengthened With Carbon Fiber Reinforced Polymer (CFRP

    Directory of Open Access Journals (Sweden)

    Mazen Dewan Abdulla

    2018-02-01

    Full Text Available This paper presents the results of a study to have better understanding of structural behavior of the reinforced concrete (RC column wrapped by carbon fiber reinforced polymer (CFRP sheets. In this study, 3D F.E model has been presented using ANSYS computer program (Release 16.0 to analyze reinforced concrete columns strengthened with CFRP composites , to evaluate the gain in performance (strength and ductility due to strengthening, and to study the effect of the most important parameters such as: compressive strength of concrete, modulus of elasticity of CFRP and corner radius of square columns. Three dimensional eight-node brick element (SOLID65 was used to represent the concrete, three dimensional spar element (LINK180 represented the steel and using a three dimensional shell element (SHELL41 to represent the CFRP composites. The present study has a comparison between the analytical results from the ANSYS finite element analysis with experimental data. The results of the study show that, external bonded CFRP sheets are very effective in enhancing the axial strength and ductility of the concrete columns. Inspection of

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

    International Nuclear Information System (INIS)

    Potapov, A.M.

    2015-01-01

    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

  14. Carbon nanotube fiber mats for microbial fuel cell electrodes.

    Science.gov (United States)

    Delord, Brigitte; Neri, Wilfrid; Bertaux, Karen; Derre, Alain; Ly, Isabelle; Mano, Nicolas; Poulin, Philippe

    2017-11-01

    Novel carbon nanotube based electrodes of microbial fuel cells (MFC) have been developed. MFC is a promising technology for the wastewater treatment and the production of electrical energy from redox reactions of natural substrates. Performances of such bio-electrochemical systems depend critically on the structure and properties of the electrodes. The presently developed materials are made by weaving fibers solely comprised of carbon nanotubes. They exhibit a large scale porosity controlled by the weaving process. This porosity allows an easy colonization by electroactive bacteria. In addition, the fibers display a nanostructuration that promotes excellent growth and adhesion of the bacteria at the surface of the electrodes. This unique combination of large scale porosity and nanostructuration allows the present electrodes to perform better than carbon reference. When used as anode in a bioelectrochemical reactor in presence of Geobacter sulfurreducens bacteria, the present electrodes show a maximal current density of about 7.5mA/cm 2 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. High resolution transmission electron microscopic study of nanoporous carbon consisting of curved single graphite sheets

    International Nuclear Information System (INIS)

    Bourgeois, L.N.; Bursill, L.A.

    1997-01-01

    A high resolution transmission electron microscopic study of a nanoporous carbon rich in curved graphite monolayers is presented. Observations of very thin regions. including the effect of tilting the specimen with respect to the electron beam, are reported. The initiation of single sheet material on an oriented graphite substrate is also observed. When combined with image simulations and independent measurements of the density (1.37g cm -3 ) and sp 3 /sp 2 +sp 2 bonding fraction (0.16), these observations suggest that this material is a two phase mixture containing a relatively low density aggregation of essentially capped single shells like squat nanotubes and polyhedra, plus a relatively dense 'amorphous' carbon structure which may be described using a random-Schwarzite model. Some negatively-curved sheets were also identified in the low density phase. Finally, some discussion is offered regarding the growth mechanisms responsible for this nanoporous carbon and its relationship with the structures of amorphous carbons across a broad range of densities, porosities and sp 3 /sp 2 +sp 3 bonding fractions

  16. High resolution transmission electron microscopic study of nanoporous carbon consisting of curved single graphite sheets

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, L.N.; Bursill, L.A.

    1997-12-31

    A high resolution transmission electron microscopic study of a nanoporous carbon rich in curved graphite monolayers is presented. Observations of very thin regions. including the effect of tilting the specimen with respect to the electron beam, are reported. The initiation of single sheet material on an oriented graphite substrate is also observed. When combined with image simulations and independent measurements of the density (1.37g cm {sup -3}) and sp{sup 3}/sp{sup 2}+sp{sup 2} bonding fraction (0.16), these observations suggest that this material is a two phase mixture containing a relatively low density aggregation of essentially capped single shells like squat nanotubes and polyhedra, plus a relatively dense `amorphous` carbon structure which may be described using a random-Schwarzite model. Some negatively-curved sheets were also identified in the low density phase. Finally, some discussion is offered regarding the growth mechanisms responsible for this nanoporous carbon and its relationship with the structures of amorphous carbons across a broad range of densities, porosities and sp{sup 3}/sp{sup 2}+sp{sup 3} bonding fractions. 29 refs., 8 figs., 2 tabs.

  17. Influence of fiber orientation on the inherent acoustic nonlinearity in carbon fiber reinforced composites.

    Science.gov (United States)

    Chakrapani, Sunil Kishore; Barnard, Daniel J; Dayal, Vinay

    2015-02-01

    This paper presents the study of non-classical nonlinear response of fiber-reinforced composites. Nonlinear elastic wave methods such as nonlinear resonant ultrasound spectroscopy (NRUS) and nonlinear wave modulation spectroscopy have been used earlier to detect damages in several materials. It was observed that applying these techniques to composites materials becomes difficult due to the significant inherent baseline nonlinearity. Understanding the non-classical nonlinear nature of the composites plays a vital role in implementing nonlinear acoustic techniques for material characterization as well as qualitative nondestructive testing of composites. Since fiber reinforced composites are orthotropic in nature, the baseline response variation with fiber orientation is very important. This work explores the nature of the inherent nonlinearity by performing nonlinear resonant spectroscopy (NRS) in intact unidirectional carbon/epoxy samples with different fiber orientations with respect to major axis of the sample. Factors such as frequency shifts, modal damping ratio, and higher harmonics were analyzed to explore the non-classical nonlinear nature of these materials. Conclusions were drawn based on the experimental observations.

  18. A Chemical Template for Synthesis of Molecular Sheets of Calcium Carbonate

    Science.gov (United States)

    Rianasari, Ina; Benyettou, Farah; Sharma, Sudhir Kumar; Blanton, Thomas; Kirmizialtin, Serdal; Jagannathan, Ramesh

    2016-05-01

    Inspired by the discovery of graphene and its unique properties, we focused our research to develop a scheme to create nacre like lamellar structures of molecular sheets of CaCO3 interleaved with an organic material, namely carbon. We developed a facile, chemical template technique, using a formulation of poly(acrylic) acid (PAA) and calcium acetate to create lamellar stacks of single crystal sheets of CaCO3, with a nominal thickness of 17 Å, the same as a unit-cell dimension for calcite (c-axis = 17.062 Å), interleaved with amorphous carbon with a nominal thickness of 8 Å. The strong binding affinity between carboxylate anions and calcium cations in the formulation was used as a molecular template to guide CaCO3 crystallization. Computational modeling of the FTIR spectra showed good agreement with experimental data and confirmed that calcium ions are bridged between polymer chains, resulting in a net-like polymer structure. The process readily lends itself to explore the feasibility of creating molecular sheets of other important inorganic materials and potentially find applications in many fields such as super capacitors and “low k di-electric” systems.

  19. Analysis of the Microstructure and Oxidation Behavior of Some Commercial Carbon Fibers

    International Nuclear Information System (INIS)

    Kim, Dae Ho; Kim, Bohye; Yang, Kap Seung; Im, Hun Kook; Bang, Yun Hyuk; Kim, Sung Ryong

    2011-01-01

    The relationship between the microstructure, mechanical properties, and oxidation behavior of pitch-, polyacrylonitrile (PAN)-, and Rayon-based carbon fibers (CFs) has been studied in detail. Three types of carbon fiber were exposed to isothermal oxidation in air and the weight change was measured by thermogravimetric analyzer (TGA) apparatus. After activation energy was gained according to the conversion at reacting temperature, the value of specific surface area and the surface morphology was compared, and the reaction mechanism of oxidation affecting development of pores of carbon fibers was examined. This study will lead to a new insight into the relationship between the microstructure and mechanical properties of carbon fibers

  20. 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.

  1. RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E; Eric Skidmore, E

    2008-12-12

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

  2. Round Robin Tests to Determine Fiber Content of Carbon Fiber-Reinforced Thermoplastic Composites by Combustion and Thermogravimetry

    Directory of Open Access Journals (Sweden)

    Masahiro Funabashi

    2017-01-01

    Full Text Available To propose methods to determine the fiber content of carbon fiber-reinforced plastics (CFRP for the International Organization for Standardization, the fiber contents of CFRP with polyamide-6 were measured using a combustion method based on ISO 14127 and a thermogravimetry method based on the modified ISO 9924-3 under a round robin test managed by the Polymer Subcommittee of the Industrial Technology Cooperative Promotion Committee in Japan. In the combustion method, the fiber contents of the CFRTP (~0.3 g were determined by the mass of carbon fiber remaining after burning (ISO 14127. The fiber contents in weight of the CFRTP with 8, 9, or 10 plies were determined to be 55.720%, 61.088%, or 65.326%, respectively, by 17 research institutes. In the thermogravimetry method, the fiber contents of the CFRTP (~10 mg were determined by the mass of carbon fiber remaining after heating it to 600°C in nitrogen gas using thermogravimetry apparatus (modified ISO 9924-3. The fiber contents of the CFRTP with 8, 9, or 10 plies were determined to be 56.908%, 61.579%, or 64.819%, respectively, by 8 research institutes. It was confirmed that thermogravimetry method was as accurate as the combustion method based on ISO 14127.

  3. Mechanical Reinforcement of Epoxy Composites with Carbon Fibers and HDPE

    Science.gov (United States)

    He, R.; Chang, Q.; Huang, X.; Li, J.

    2018-01-01

    Silanized carbon fibers (CFs) and a high-density polyethylene with amino terminal groups (HDPE) were introduced into epoxy resins to fabricate high-performance composites. A. mechanical characterization of the composites was performed to investigate the effect of CFs in cured epoxy/HDPE systems. The composites revealed a noticeable improvement in the tensile strength, elongation at break, flexural strength, and impact strength in comparison with those of neat epoxy and cured epoxy/HDPE systems. SEM micrographs showed that the toughening effect could be explained by yield deformations, phase separation, and microcracking.

  4. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    International Nuclear Information System (INIS)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-01-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  5. Thin-Sheet zinc-coated and carbon steels laser welding

    International Nuclear Information System (INIS)

    Pecas, P.; Gouveia, H.; Quintino, L.

    1998-01-01

    This paper describes the results of a research on CO 2 laser welding of thin-sheet carbon steels (Zinc-coated and uncoated), at several thicknesses combinations. Laser welding has an high potential to be applied on sub-assemblies welding before forming to the automotive industry-tailored blanks. The welding process is studied through the analysis of parameters optimization, metallurgical quality and induced distortions by the welding process. The clamping system and the gas protection system developed are fully described. These systems allow the minimization of common thin-sheet laser welding defects like misalignment, and zinc-coated laser welding defects like porous and zinc ventilation. The laser welding quality is accessed by DIN 8563 standard, and by tensile, microhardness and corrosion test. (Author) 8 refs

  6. Carbon nanotubes/carbon fiber hybrid material: a super support material for sludge biofilms.

    Science.gov (United States)

    Liu, Qijie; Dai, Guangze; Bao, Yanling

    2017-07-16

    Carbon fiber (CF) is widely used as a sludge biofilm support material for wastewater treatment. Carbon nanotubes/carbon fiber (CNTs/CF) hybrid material was prepared by ultrasonically assisted electrophoretic deposition (EPD). CF supports (CF without handling, CF oxidized by nitric acid, CNTs/CF hybrid material) were evaluated by sludge immobilization tests, bacterial cell adsorption tests and Derjaguin -Landau -Verwey -Overbeek (DLVO) theory. We found that the CNTs/CF hybrid material has a high capacity for adsorbing activated sludge, nitrifying bacterial sludge and pure strains (Escherichia coli and Staphylococcus aureus). CNTs deposited on CF surface easily wound around the curved surface of bacterial cell which resulted in capturing more bacterial cells. DLVO theory indicated the lowest total interaction energy of CNTs/CF hybrid material, which resulted in the highest bacteria cell adsorption velocity. Experiments and DLVO theory results proved that CNTs/CF hybrid material is a super support material for sludge biofilms.

  7. Flexural properties of polyethylene, glass and carbon fiber-reinforced resin composites for prosthetic frameworks.

    Science.gov (United States)

    Maruo, Yukinori; Nishigawa, Goro; Irie, Masao; Yoshihara, Kumiko; Minagi, Shogo

    2015-01-01

    High flexural properties are needed for fixed partial denture or implant prosthesis to resist susceptibility to failures caused by occlusal overload. The aim of this investigation was to clarify the effects of four different kinds of fibers on the flexural properties of fiber-reinforced composites. Polyethylene fiber, glass fiber and two types of carbon fibers were used for reinforcement. Seven groups of specimens, 2 × 2 × 25 mm, were prepared (n = 10 per group). Four groups of resin composite specimens were reinforced with polyethylene, glass or one type of carbon fiber. The remaining three groups served as controls, with each group comprising one brand of resin composite without any fiber. After 24-h water storage in 37°C distilled water, the flexural properties of each specimen were examined with static three-point flexural test at a crosshead speed of 0.5 mm/min. Compared to the control without any fiber, glass and carbon fibers significantly increased the flexural strength (p glass fiber (p glass fibers (p > 0.05). Fibers could, therefore, improve the flexural properties of resin composite and carbon fibers in longitudinal form yielded the better effects for reinforcement.

  8. Investigating the efficiency of using the carbon fiber polymer on beam–column connection

    Directory of Open Access Journals (Sweden)

    Mahmoud M. Eldeeb

    2016-03-01

    Full Text Available Due to the huge amount of energy induced from earthquakes, such natural hazards usually represent the most significant threat on existing and new buildings. Recently, a lot of considerable efforts were dedicated to design buildings capable of withstanding earthquakes' ground motions by utilizing lateral resisting elements, such as reinforced concrete shear walls, cores, frames, and steel bracing. Contrasting the experience gained from the previously designed guidelines and provisions for lateral resisting systems, recent studies illustrated that the existence of lateral resisting system in low-rise buildings is essential in order to resist ground motions. As such, some endeavors are directed to reinforce old buildings against seismic loads. This paper focuses on investigating the efficiency of using Carbon Fiber Polymer (CFRP sheets on the behavior of beam–column connections considering a cantilever beam with concentrated load at its free end. In addition, to complement the published data, finite element model using the computer package ANSYS was used. The additional beam–column connections in this study are classified in 4 groups (A, B, C, and D depending on the percentage of reinforcement at the bottom and top of the beam (%As. The efficiency of using CFRP was concluded; the CFRP sheet improves or decreases the efficiency of beam–column connection depending on %As in the beam. The paper investigates the influence of boundary condition, columns as hinged supports, and the efficiency of using CFRP. It is concluded that the CFRP sheet improves or decreases the efficiency of beam–column connection depending on %As in the beam.

  9. Plasma-grafting polymerization on carbon fibers and its effect on their composite properties

    Science.gov (United States)

    Zhang, Huanxia; Li, Wei

    2015-11-01

    Interfacial adhesion between matrix and fibers plays a crucial role in controlling the performance of composites. Carbon fibers have the major constraint of chemical interness and hence have limited adhesion with the matrix. Surface treatment of fibers is the best solution to this problem. In this work, carbon fibers were activated by plasma and grafting polymerization. The grafting ratio of polymerization was obtained by acid-base titration. The chemical and physical changes induced by the treatments on carbon fiber surface was examined using contact angle measurements, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. The interfacial adhesion of CF/EP (carbon fiber/epoxy) composites were analyzed by a single fiber composite (SFC) for filament fragmentation test. Experimental results show that the grafting rate was not only the function of the plasma-treat time but also the concentration of the grafting polymerization. The oxygen-containing groups (such as Csbnd O, Cdbnd O, and Osbnd Cdbnd O) and the interfacial shear strength (IFSS) of the plasma-grafting carbon fiber increased more significantly than the carbon fiber without plasma treatment grafted with MAH. This demonstrates that the surfaces of the carbon fiber samples are more active, hydrophilic, and rough after plasma-grafting treatments using a DBD operating in ambient argon mixture with oxygen. With DBD (dielectric barrier discharges) operating in ambient argon mixture with oxygen, the more active, hydrophilic, and rough surface was obtained by the plasma-grafting treatments.

  10. High efficient and continuous surface modification of carbon fibers with improved tensile strength and interfacial adhesion

    Science.gov (United States)

    Sun, Jingfeng; Zhao, Feng; Yao, Yue; Jin, Zhen; Liu, Xu; Huang, Yudong

    2017-08-01

    Most of the surface modification technologies for carbon fibers, no matter in laboratory scale or for commercial manufacture, are accompanied by a simultaneous decrease in tensile strength. In this paper, a feasible and high efficient strategy for carbon fiber treatment which could obviously improve both tensile strength and interfacial adhesion was proposed. Continuously moving carbon fibers were treated with atmospheric helium plasma for 1 min, followed by a 5 min pyrolytic carbon deposition using ethanol as precursor at 800 °C. The effects of the new approach were characterized by SEM, AFM, nanoindentation, XPS, Raman, wettability analysis, single fiber tensile strength testing and single fiber pull-out testing. After modification, pyrolytic carbon coating was deposited on the fiber surface uniformly, and the roughness and surface energy increased significantly. The single fiber tensile testing results indicate that the resulting fiber strength increased 15.7%, rising from 3.13 to 3.62 GPa. Meanwhile, the interfacial shear strength of its epoxy composites increased from 65.3 to 83.5 MPa. The comparative studies of carbon fibers modified with commercial anodic oxidation and sizing were also carried out. The results demonstrate that the new method can be utilized in the carbon fiber manufacture process and is more efficient than the traditional approaches.

  11. Production of Low Cost Carbon-Fiber through Energy Optimization of Stabilization Process

    Directory of Open Access Journals (Sweden)

    Gelayol Golkarnarenji

    2018-03-01

    Full Text Available To produce high quality and low cost carbon fiber-based composites, the optimization of the production process of carbon fiber and its properties is one of the main keys. The stabilization process is the most important step in carbon fiber production that consumes a large amount of energy and its optimization can reduce the cost to a large extent. In this study, two intelligent optimization techniques, namely Support Vector Regression (SVR and Artificial Neural Network (ANN, were studied and compared, with a limited dataset obtained to predict physical property (density of oxidative stabilized PAN fiber (OPF in the second zone of a stabilization oven within a carbon fiber production line. The results were then used to optimize the energy consumption in the process. The case study can be beneficial to chemical industries involving carbon fiber manufacturing, for assessing and optimizing different stabilization process conditions at large.

  12. 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.

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

    International Nuclear Information System (INIS)

    Fang, Cuiqin; Wang, Julin; Zhang, Tao

    2014-01-01

    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

  14. Structural analysis of alanine tripeptide with antiparallel and parallel beta-sheet structures in relation to the analysis of mixed beta-sheet structures in Samia cynthia ricini silk protein fiber using solid-state NMR spectroscopy.

    Science.gov (United States)

    Asakura, Tetsuo; Okonogi, Michi; Nakazawa, Yasumoto; Yamauchi, Kazuo

    2006-05-10

    The structural analysis of natural protein fibers with mixed parallel and antiparallel beta-sheet structures by solid-state NMR is reported. To obtain NMR parameters that can characterize these beta-sheet structures, (13)C solid-state NMR experiments were performed on two alanine tripeptide samples: one with 100% parallel beta-sheet structure and the other with 100% antiparallel beta-sheet structure. All (13)C resonances of the tripeptides could be assigned by a comparison of the methyl (13)C resonances of Ala(3) with different [3-(13)C]Ala labeling schemes and also by a series of RFDR (radio frequency driven recoupling) spectra observed by changing mixing times. Two (13)C resonances observed for each Ala residue could be assigned to two nonequivalent molecules per unit cell. Differences in the (13)C chemical shifts and (13)C spin-lattice relaxation times (T(1)) were observed between the two beta-sheet structures. Especially, about 3 times longer T(1) values were obtained for parallel beta-sheet structure as compared to those of antiparallel beta-sheet structure, which could be explicable by the difference in the hydrogen-bond networks of both structures. This very large difference in T(1) becomes a good measure to differentiate between parallel or antiparallel beta-sheet structures. These differences in the NMR parameters found for the tripeptides may be applied to assign the parallel and antiparallel beta-sheet (13)C resonances in the asymmetric and broad methyl spectra of [3-(13)C]Ala silk protein fiber of a wild silkworm, Samia cynthia ricini.

  15. Composite carbon foam electrode

    Science.gov (United States)

    Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

    1997-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

  16. Carbon Nanotubes Growth by CVD on Graphite Fibers

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Cochrane, J. C.; Lehoczky, S. L.; Muntele, I.; Ila, D.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Due to the superior electrical and mechanical properties of carbon nanotubes (CNT), synthesizing CNT on various substances for electronics devices and reinforced composites have been engaged in many efforts for applications. This presentation will illustrate CNT synthesized on graphite fibers by thermal CVD. On the fiber surface, iron nanoparticles as catalysts for CNT growth are coated. The growth temperature ranges from 600 to 1000 C and the pressure ranges from 100 Torr to one atmosphere. Methane and hydrogen gases with methane content of 10% to 100% are used for the CNT synthesis. At high growth temperatures (greater than or equal to 900 C), the rapid inter-diffusion of the transition metal iron on the graphite surface results in the rough fiber surface without any CNT grown on it. When the growth temperature is relative low (650-800 C), CNT with catalytic particles on the nanotube top ends are fabricated on the graphite surface. (Methane and hydrogen gases with methane content of 10% to 100% are used for the CNT synthesis.) (By measuring the samples) Using micro Raman spectroscopy in the breath mode region, single-walled or multi-walled CNT (MWCNT), depending on growth concentrations, are found. Morphology, length and diameter of these MWCNT are determined by scanning electron microscopy and Raman spectroscopy. The detailed results of syntheses and characterizations will be discussed in the presentation.

  17. Growth of carbon fibres, sheets and tubes on diamond films under high power plasma etching conditions

    International Nuclear Information System (INIS)

    Villalpando, I.; John, P.; Wilson, J. I. B.

    2017-01-01

    The application of diamond as a plasma facing material for fusion reactors can be limited by unknown reactions between diamond and the chamber materials transported by the plasma. Transformation of diamond to other structures can cause problems such as contamination of the plasma with loose particles or retention of gases. We have seen that diamond thin films are eroded under hydrogen plasma etching, but if silicon is present the growth of various carbon structures on diamond films is observed. We have produced carbon with different morphologies on diamond films including fibres, sheets with flower-like shapes and tubes and proposed growth mechanisms based on the results of scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Sample surfaces contain silicon and are oxidised having COO and CO groups as seen by XP S analysis. Raman analyses revealed a spectrum typical for graphite combined with that from diamond that remains on the surface after hydrogen bombardment. The results of this sturdy show the experimental conditions in which carbon fibres, sheets and tubes are produced under high-power hydrogen etching of diamond films and open the possibility to other applications such as catalysts, sensors and the production of electrodes. (Author)

  18. Growth of carbon fibres, sheets and tubes on diamond films under high power plasma etching conditions

    Energy Technology Data Exchange (ETDEWEB)

    Villalpando, I. [Centro de Investigacion de los Recursos Naturales, Antigua Normal Rural, Salaices, Lopez, Chihuahua (Mexico); John, P.; Wilson, J. I. B., E-mail: isaelav@hotmail.com [School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14-4AS (United Kingdom)

    2017-11-01

    The application of diamond as a plasma facing material for fusion reactors can be limited by unknown reactions between diamond and the chamber materials transported by the plasma. Transformation of diamond to other structures can cause problems such as contamination of the plasma with loose particles or retention of gases. We have seen that diamond thin films are eroded under hydrogen plasma etching, but if silicon is present the growth of various carbon structures on diamond films is observed. We have produced carbon with different morphologies on diamond films including fibres, sheets with flower-like shapes and tubes and proposed growth mechanisms based on the results of scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Sample surfaces contain silicon and are oxidised having COO and CO groups as seen by XP S analysis. Raman analyses revealed a spectrum typical for graphite combined with that from diamond that remains on the surface after hydrogen bombardment. The results of this sturdy show the experimental conditions in which carbon fibres, sheets and tubes are produced under high-power hydrogen etching of diamond films and open the possibility to other applications such as catalysts, sensors and the production of electrodes. (Author)

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

    Directory of Open Access Journals (Sweden)

    L. A. Spagnolo JR

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

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

    Science.gov (United States)

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

    2015-12-29

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

  1. Thermoacoustic excitation of sonar projector plates by free-standing carbon nanotube sheets

    International Nuclear Information System (INIS)

    Aliev, Ali E; Mayo, Nathanael K; Baughman, Ray H; Avirovik, Dragan; Priya, Shashank; Zarnetske, Michael R; Blottman, John B

    2014-01-01

    Carbon nanotubes (CNT) generate smooth-spectra sound over a wide frequency range (1–10 5  Hz) by means of thermoacoustics (TA). The protective encapsulation of CNT sheets in inert gases between rigid vibrating plates provides resonant features in the TA sound projector. The vibrational modes of plates and the compliance of the soft sealing spacers between those plates are studied with the aim of creating efficient, tunable underwater sound generation at relatively low frequencies, 10 Hz–10 kHz. (paper)

  2. 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.

  3. Glycolysis of carbon fiber-epoxy unidirectional mat catalysed by sodium hydroxide

    Science.gov (United States)

    Zaini, Mariana Binti Mohd; Badri, Khairiah Haji

    2014-09-01

    This study was conducted to recycle carbon fibre-epoxy (CFRP) composite in woven sheet/ mat form. The CFRP was recycled through glycolysis with polyethlyene glycol (PEG 200) as the solvent. The CFRP was loaded into the solvent at a ratio of 4:1 (w/w). PEG200 was diluted with water to a ratio of 80:20 (v/v). This reaction was catalysed by sodium hydroxide (NaOH) solution with varying concentrations at 1.5, 1.7 and 1.9% (w/v). The glycolysis was conducted at 180-190 °C. The recovered CF (rCF) was analysed using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) while the degraded solution was analysed using FTIR and the epoxy content was determined. The FTIR spectrum of the rCF exhibited the disappearance of the COC peak belonged to epoxy and supported by the SEM micrographs that showed clear rCF. On the other hand, the analysed filtrate detected the disappearance of oxygen peak element in the EDX spectrum for all rCF samples. This gave an indication that the epoxy resin has been removed from the surface of the carbon fiber.

  4. Glycolysis of carbon fiber-epoxy unidirectional mat catalysed by sodium hydroxide

    International Nuclear Information System (INIS)

    Zaini, Mariana Binti Mohd; Badri, Khairiah Haji

    2014-01-01

    This study was conducted to recycle carbon fibre-epoxy (CFRP) composite in woven sheet/ mat form. The CFRP was recycled through glycolysis with polyethlyene glycol (PEG 200) as the solvent. The CFRP was loaded into the solvent at a ratio of 4:1 (w/w). PEG200 was diluted with water to a ratio of 80:20 (v/v). This reaction was catalysed by sodium hydroxide (NaOH) solution with varying concentrations at 1.5, 1.7 and 1.9% (w/v). The glycolysis was conducted at 180-190 °C. The recovered CF (rCF) was analysed using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) while the degraded solution was analysed using FTIR and the epoxy content was determined. The FTIR spectrum of the rCF exhibited the disappearance of the COC peak belonged to epoxy and supported by the SEM micrographs that showed clear rCF. On the other hand, the analysed filtrate detected the disappearance of oxygen peak element in the EDX spectrum for all rCF samples. This gave an indication that the epoxy resin has been removed from the surface of the carbon fiber

  5. Mechanical Properties of Domestic T700 Grade Carbon Fibers/QY9611 BMI Matrix Composites

    Directory of Open Access Journals (Sweden)

    LI Guoli

    2017-04-01

    Full Text Available The morphologies,surface energies and surface chemical properties of the domestic T700 grade carbon fiber and the T700S carbon fiber were characterized by using scanning electronic microscopy (SEM, inverse gas chromatography(IGC and X-ray photoelectron spectroscopy (XPSrespectively.The mechanical properties of the two carbon fibers/QY9611 composites were also discussed. The results indicate that the surface properties of carbon fibers have an important influence on the interfacial properties of composites. The interfacial properties of domestic T700 grade carbon fibers/QY9611 composite at room temperature/dry conditions are superior to T700S/QY9611 composite. The toughness of domestic T700 grade carbon fibers/QY9611composite is outstanding as well. The value of CAI has reached the level of foreign advanced composite IM7/5250-4. After hydrothermal treatment,the interfacial strength of domestic T700 grade carbon fibers/QY9611 composite is equal to that of T700S/QY9611 composite. It shows that domestic T700 grade carbon fibers/QY9611 composite has good hydrothermal-resistant properties.

  6. 21 CFR 878.3500 - Polytetrafluoroethylene with carbon fibers composite implant material.

    Science.gov (United States)

    2010-04-01

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

  7. Conduction noise absorption by fiber-reinforced epoxy composites with carbon nanotubes

    International Nuclear Information System (INIS)

    Lee, Ok Hyoung; Kim, Sung-Soo; Lim, Yun-Soo

    2011-01-01

    Nearly all electronic equipment is susceptible to malfunction as a result of electromagnetic interference. In this study, glass fiber, and carbon fiber as a type reinforcement and epoxy as a matrix material were used to fabricate composite materials. In an attempt to increase the conduction noise absorption, carbon nanotubes were grown on the surface of glass fibers and carbon fibers. A microstrip line with characteristic impedance of 50 Ω in connection with network analyzer was used to measure the conduction noise absorption. In comparing a glass fiber/epoxy composite with a GF-CNT/Ep composite, it was demonstrated that the CNTs significantly influence the noise absorption property mainly due to increase in electric conductivity. In the carbon fiber composites, however, the effectiveness of CNTs on the degree of electric conductivity is negligible, resulting in a small change in reflection and transmission of an electromagnetic wave. - Research Highlights: → In this study, glass fiber and carbon fiber as a type reinforcement and epoxy as a matrix material were used to fabricate composite materials. In an attempt to increase the conduction noise absorption, carbon nanotubes (CNTs) were grown on the surface of glass fibers and carbon fibers. A microstrip line with characteristic impedance of 50 Ω in connection with network analyzer was used to measure the conduction noise absorption. → In comparing a glass fiber/epoxy composite with a GF-CNT/Ep composite, it was demonstrated that the CNTs significantly influence the noise absorption property mainly due to increase in electric conductivity. In the carbon fiber composites, however, the effectiveness of CNTs on the degree of electric conductivity is negligible, resulting in a small change in reflection and transmission of an electromagnetic wave.

  8. The Study on the Mechanical Properties of Multi-walled Carbon Nanotube/Polypropylene Fibers

    Science.gov (United States)

    Youssefi, Mostafa; Safaie, Banafsheh

    2018-01-01

    Polypropylene (PP) is an important semicrystalline polymer with various applications. Polypropylene fibers containing 1 wt% of multi-walled carbon nanotube was spun using a conventional melt spinning apparatus. The produced fibers were drawn with varying levels of draw ratio. The mechanical properties of the composites were studied. Tensile strength and modulus of the composite fibers were increased with the increase in draw ratio. Molecular orientation and helical content of the composite fibers were increased after drawing. To conclude, tensile properties and molecular orientation of the composite fibers were higher than those of neat polypropylene fibers with the same draw ratio.

  9. A Silicon detector system on carbon fiber support at small radius

    International Nuclear Information System (INIS)

    Johnson, Marvin E.

    2004-01-01

    The design of a silicon detector for a p(bar p) collider experiment will be described. The detector uses a carbon fiber support structure with sensors positioned at small radius with respect to the beam. A brief overview of the mechanical design is given. The emphasis is on the electrical characteristics of the detector. General principles involved in grounding systems with carbon fiber structures will be covered. The electrical characteristics of the carbon fiber support structure will be presented. Test results imply that carbon fiber must be regarded as a conductor for the frequency region of interest of 10 to 100 MHz. No distinction is found between carbon fiber and copper. Performance results on noise due to pick-up through the low mass fine pitch cables carrying the analogue signals and floating metal is discussed

  10. 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.

  11. Experimental Research on Tensile Process of Carbon Fiber Composite Materials Basing on Acoustic Emission

    Science.gov (United States)

    Liu, Yanlei; Wang, Bing; Li, Weizhong; Yu, Bing; Xia, Fuyong

    With the extensive application of carbon fiber composite materials in the region of high-pressure vessel and aerospace, the related material damage mechanism analysis and integrality detecting is also massively being carried out which is more complex than the sole material. Acoustic emission technique can monitor the tensile process of carbon fiber composite laminate. And the acoustic emission signals by tensile specimens of different winding angles were investigated. Different angles in specimen's layers of carbon fiber had different mechanical properties and failure mechanisms. The results show that there were different signal characteristics from carbon fiber in different stages. Analysis on experimental data showed that acoustic emission testing technique can determine the process of different internal activities in carbon fiber composite laminate.

  12. Strongly Coupled Molybdenum Carbide on Carbon Sheets as a Bifunctional Electrocatalyst for Overall Water Splitting.

    Science.gov (United States)

    Wang, Hao; Cao, Yingjie; Sun, Cheng; Zou, Guifu; Huang, Jianwen; Kuai, Xiaoxiao; Zhao, Jianqing; Gao, Lijun

    2017-09-22

    High-performance and affordable electrocatalysts from earth-abundant elements are desirably pursued for water splitting involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Here, a bifunctional electrocatalyst of highly crystalline Mo 2 C nanoparticles supported on carbon sheets (Mo 2 C/CS) was designed toward overall water splitting. Owing to the highly active catalytic nature of Mo 2 C nanoparticles, the high surface area of carbon sheets and efficient charge transfer in the strongly coupled composite, the designed catalysts show excellent bifunctional behavior with an onset potential of -60 mV for HER and an overpotential of 320 mV to achieve a current density of 10 mA cm -2 for OER in 1 m KOH while maintaining robust stability. Moreover, the electrolysis cell using the catalyst only requires a low cell voltage of 1.73 V to achieve a current density of 10 mA cm -2 and maintains the activity for more than 100 h when employing the Mo 2 C/CS catalyst as both anode and cathode electrodes. Such high performance makes Mo 2 C/CS a promising electrocatalyst for practical hydrogen production from water splitting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Effect of doping of multi-walled carbon nanotubes on phenolic based carbon fiber reinforced nanocomposites

    International Nuclear Information System (INIS)

    Saeed, Sadaf; Hakeem, Saira; Faheem, Muhammad; Alvi, Rashid Ahmed; Farooq, Khawar; Hussain, Syed Tajammul; Ahmad, Shahid Nisar

    2013-01-01

    We report on the effect of multi-walled carbon nanotubes (MWCNTs) on different properties of phenolic resin. A low content of MWCNTs (∼ 0.05 wt%) was mixed in phenolic resin and a stable dispersion was achieved by ultrasonication, followed by melt mixing. After curing the characterization of these composites was done by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infra-red spectroscopy (FTIR). The thermal and ablative properties of carbon fiber reinforced MWCNTs-phenolic nanocomposites were also studied. The addition of MWCNTs showed improvement in thermal stability and ablation properties.

  14. Effect of doping of multi-walled carbon nanotubes on phenolic based carbon fiber reinforced nanocomposites

    Science.gov (United States)

    Saeed, Sadaf; Hakeem, Saira; Faheem, Muhammad; Alvi, Rashid Ahmed; Farooq, Khawar; Tajammul Hussain, Syed; Nisar Ahmad, Shahid

    2013-06-01

    We report on the effect of multi-walled carbon nanotubes (MWCNTs) on different properties of phenolic resin. A low content of MWCNTs (~ 0.05 wt%) was mixed in phenolic resin and a stable dispersion was achieved by ultrasonication, followed by melt mixing. After curing the characterization of these composites was done by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infra-red spectroscopy (FTIR). The thermal and ablative properties of carbon fiber reinforced MWCNTs-phenolic nanocomposites were also studied. The addition of MWCNTs showed improvement in thermal stability and ablation properties.

  15. Carbon nanofibers grown on activated carbon fiber fabrics as electrode of supercapacitors

    International Nuclear Information System (INIS)

    Ko, T-H; Hung, K-H; Tzeng, S-S; Shen, J-W; Hung, C-H

    2007-01-01

    Carbon nanofibers (CNFs) were grown directly on activated carbon fiber fabric (ACFF), which was then used as the electrode of supercapacitors. Cyclic voltammetry and ac impedance were used to characterize the electrochemical properties of ACFF and CNF/ACFF electrodes in both aqueous and organic electrolytes. ACFF electrodes show higher specific capacitance than CNF/ACFF electrodes due to larger specific surface area. However, the spaces formed between the CNFs in the CNF/ACFF electrodes are more easily accessed than the slit-type pores of ACFF, and much higher electrical-double layer capacitance was obtained for CNF/ACFF electrodes

  16. XPS analysis of the carbon fibers surface modified via HMDSO to carbon nanotube growth

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, L.D.R.; Gomes, M.C.B.; Trava-Airoldi, V.J.; Corat, E.J.; Lugo, D.C. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

    2016-07-01

    Full text: Carbon fibers (CF) have been widely used to reinforce structural composites. Due to their strength-to-weight properties, CF composites are finding increased structural uses in areas such as aerospace, aeronautical, automobile and others. The strength of the fiber-resin interface bond has been found to be the limiting factor to the mechanical properties of CF-epoxy materials, due to their non-polar nature that limit the affinity of CF to bind chemically to any matrix. The growth of carbon nanotubes (CNTs) on the surface of CF is a promising approach for improving mechanical, electrical and thermal properties of structural composites. However growing CNTs on CF presents some obstacles, such as diffusion of metal catalyst particles on CF, uneven CNT growth and loss of mechanical properties of CF. To avoid the diffusion of catalyst particles we modified the CF surface with hexamethyldisiloxane (HMDSO) at low temperature (400 °C), also preventing the loss of mechanical properties and allowing uniform CNTs growth. We deposited CNTs via floating catalyst method, with ferrocene providing the catalyst particle and the oxidative dehydrogenation reaction of acetylene providing the carbon. The CF surface modification was analyzed via X-ray photoelectron spectroscopy (XPS) and CNTs growth via scanning electron microscopy with field emission gun. The XPS analysis showed that HMDSO promotes the binding of oxygen to carbon and silicon present on CF surface, the chemical modification of the surface of the CF enables the uniform growth of carbon nanotubes. (author)

  17. XPS analysis of the carbon fibers surface modified via HMDSO to carbon nanotube growth

    International Nuclear Information System (INIS)

    Cardoso, L.D.R.; Gomes, M.C.B.; Trava-Airoldi, V.J.; Corat, E.J.; Lugo, D.C.

    2016-01-01

    Full text: Carbon fibers (CF) have been widely used to reinforce structural composites. Due to their strength-to-weight properties, CF composites are finding increased structural uses in areas such as aerospace, aeronautical, automobile and others. The strength of the fiber-resin interface bond has been found to be the limiting factor to the mechanical properties of CF-epoxy materials, due to their non-polar nature that limit the affinity of CF to bind chemically to any matrix. The growth of carbon nanotubes (CNTs) on the surface of CF is a promising approach for improving mechanical, electrical and thermal properties of structural composites. However growing CNTs on CF presents some obstacles, such as diffusion of metal catalyst particles on CF, uneven CNT growth and loss of mechanical properties of CF. To avoid the diffusion of catalyst particles we modified the CF surface with hexamethyldisiloxane (HMDSO) at low temperature (400 °C), also preventing the loss of mechanical properties and allowing uniform CNTs growth. We deposited CNTs via floating catalyst method, with ferrocene providing the catalyst particle and the oxidative dehydrogenation reaction of acetylene providing the carbon. The CF surface modification was analyzed via X-ray photoelectron spectroscopy (XPS) and CNTs growth via scanning electron microscopy with field emission gun. The XPS analysis showed that HMDSO promotes the binding of oxygen to carbon and silicon present on CF surface, the chemical modification of the surface of the CF enables the uniform growth of carbon nanotubes. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-06

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

  19. Experimental Investigation on Micro-Welding of Thin Stainless Steel Sheet by Fiber Laser

    OpenAIRE

    Mohd I.S. Ismail; Yasuhiro Okamoto; Akira Okada; Yoshiyuki Uno

    2011-01-01

    Problem statement: The miniaturization of components plays an important role for manufacturing in electrical and electronic industries. Therefore, the joining technology of thin metal sheets has been strongly required. Laser welding with micro-beam and high-speed scanning is a promising solution in micro-welding, because it has high-potential advantages in welding heat sensitive components with precise control of heat input and minimal thermal distortion. Approach: In this study, the characte...

  20. 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.

  1. Electrochromic fiber-shaped supercapacitors.

    Science.gov (United States)

    Chen, Xuli; Lin, Huijuan; Deng, Jue; Zhang, Ye; Sun, Xuemei; Chen, Peining; Fang, Xin; Zhang, Zhitao; Guan, Guozhen; Peng, Huisheng

    2014-12-23

    An electrochromic fiber-shaped super-capacitor is developed by winding aligned carbon nanotube/polyaniline composite sheets on an elastic fiber. The fiber-shaped supercapacitors demonstrate rapid and reversible chromatic transitions under different working states, which can be directly observed by the naked eye. They are also stretchable and flexible, and are woven into textiles to display designed signals in addition to storing energy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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.

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

    International Nuclear Information System (INIS)

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

    2001-01-01

    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. 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.

  5. Carbon fiber reinforced hierarchical orthogrid stiffened cylinder: Fabrication and testing

    Science.gov (United States)

    Wu, Hao; Lai, Changlian; Sun, Fangfang; Li, Ming; Ji, Bin; Wei, Weiyi; Liu, Debo; Zhang, Xi; Fan, Hualin

    2018-04-01

    To get strong, stiff and light cylindrical shell, carbon fiber reinforced hierarchical orthogrid stiffened cylinders are designed and fabricated. The cylinder is stiffened by two-scale orthogrid. The primary orthogrid has thick and high ribs and contains several sub-orthogrid cells whose rib is much thinner and lower. The primary orthogrid stiffens the bending rigidity of the cylinder to resist the global instability while the sub-orthogrid stiffens the bending rigidity of the skin enclosed by the primary orthogrid to resist local buckling. The cylinder is fabricated by filament winding method based on a silicone rubber mandrel with hierarchical grooves. Axial compression tests are performed to reveal the failure modes. With hierarchical stiffeners, the cylinder fails at skin fracture and has high specific strength. The cylinder will fail at end crushing if the end of the cylinder is not thickened. Global instability and local buckling are well restricted by the hierarchical stiffeners.

  6. 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.

  7. Carbon fiber composites application in ITER plasma facing components

    International Nuclear Information System (INIS)

    Barabash, V.; Federici, G.; Matera, R.; Akiba, M.; Nakamura, K.; Bonal, J.P.; Pacher, H.D.; Roedig, M.; Vieider, G.; Wu, C.H.

    1998-01-01

    Carbon fiber composites (CFCs) are one of the candidate armour materials for the plasma facing components of the international thermonuclear experimental reactor (ITER). For the present reference design, CFC has been selected as armour for the divertor target near the plasma strike point mainly because of unique resistance to high normal and off-normal heat loads. It does not melt under disruptions and might have higher erosion lifetime in comparison with other possible armour materials. Issues related to CFC application in ITER are described in this paper. They include erosion lifetime, tritium codeposition with eroded material and possible methods for the removal of the codeposited layers, neutron irradiation effect, development of joining technologies with heat sink materials, and thermomechanical performance. The status of the development of new advanced CFCs for ITER application is also described. Finally, the remaining R and D needs are critically discussed. (orig.)

  8. Carbon fiber composites application in ITER plasma facing components

    Science.gov (United States)

    Barabash, V.; Akiba, M.; Bonal, J. P.; Federici, G.; Matera, R.; Nakamura, K.; Pacher, H. D.; Rödig, M.; Vieider, G.; Wu, C. H.

    1998-10-01

    Carbon Fiber Composites (CFCs) are one of the candidate armour materials for the plasma facing components of the International Thermonuclear Experimental Reactor (ITER). For the present reference design, CFC has been selected as armour for the divertor target near the plasma strike point mainly because of unique resistance to high normal and off-normal heat loads. It does not melt under disruptions and might have higher erosion lifetime in comparison with other possible armour materials. Issues related to CFC application in ITER are described in this paper. They include erosion lifetime, tritium codeposition with eroded material and possible methods for the removal of the codeposited layers, neutron irradiation effect, development of joining technologies with heat sink materials, and thermomechanical performance. The status of the development of new advanced CFCs for ITER application is also described. Finally, the remaining R&D needs are critically discussed.

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

    Science.gov (United States)

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

    2014-01-01

    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. PMID:24786100

  10. 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.

  11. Measurement of defects in carbon fiber reinforced polymer drilled

    Directory of Open Access Journals (Sweden)

    Pascual Víctor

    2017-01-01

    Full Text Available Increasingly, fiber-reinforced materials are more widely used because of their good mechanical properties. It is usual to join pieces of these materials through screws and rivets, for which it is necessary to make a hole in the piece, usually by drilling. One of the problems of use CFRP resides in the appearance of defects due to the machining. The main defect to be taken into account is the delamination. Delamination implies poor tolerance when assembling parts, reducing the structural integrity of the part, and areas with high wear, as a series of stresses arise when mounting the screws. Much has been published about delamination and the factors that influence its appearance, so we are not going to focus on it. The present study aims to quantify and measure the defects associated with the drilling of compounds reinforced with carbon fibers, in relation to the cutting parameters used in each case. For this purpose, an optical measurement system and a posterior digital image processing will be used through Deltec Vision software.

  12. Influencing Mechanism of Electrochemical Treatment on Preparation of CNTs-grafted on Carbon Fibers

    Directory of Open Access Journals (Sweden)

    SONG Lei

    2017-11-01

    Full Text Available Based on electrochemical anodic oxidation, an innovative technique was developed to efficiently obtain the uniform catalyst coating on continuous carbon fibers. Through systematic investigation on the effect of electrochemical modified strength on the physical and chemical characteristics of carbon fiber surface, catalyst particles and the morphology of CNTs-grafted carbon fibers, tensile strength of multi-scale reinforcement and the interlaminar shear strength of its reinforced composites, the electrochemical modification process on carbon fibre surface was optimized. The results show that the morphology and distribution of catalyst particles not only affect the morphology of CNTs deposited on the surface of carbon fibres,but also affect the mechanical properties of multi-scale reinforcement and its reinforced composites of CNTs-grafted carbon fibers.

  13. Microfluidic Actuation of Carbon Nanotube Fibers for Neural Recordings

    Science.gov (United States)

    Vercosa, Daniel G.

    Implantable devices to record and stimulate neural circuits have led to breakthroughs in neuroscience; however, technologies capable of electrical recording at the cellular level typically rely on rigid metals that poorly match the mechanical properties of soft brain tissue. As a result these electrodes often cause extensive acute and chronic injury, leading to short electrode lifetime. Recently, flexible electrodes such as Carbon Nanotube fibers (CNTf) have emerged as an attractive alternative to conventional electrodes and studies have shown that these flexible electrodes reduce neuro-inflammation and increase the quality and longevity of neural recordings. Insertion of these new compliant electrodes, however, remains challenge. The stiffening agents necessary to make the electrodes rigid enough to be inserted increases device footprint, which exacerbates brain damage during implantation. To overcome this challenge we have developed a novel technology to precisely implant and actuate high-performance, flexible carbon nanotube fiber (CNTf) microelectrodes without using a stiffening agents or shuttles. Instead, our technology uses drag forces within a microfluidic device to drive electrodes into tissue while minimizing the amount of fluid that is ejected into the tissue. In vitro experiments in brain phantoms, show that microfluidic actuated CNTf can be implanted at least 4.5 mm depth with 30 microm precision, while keeping the total volume of fluid ejected below 0.1 microL. As proof of concept, we inserted CNTfs in the small cnidarian Hydra littoralis and observed compound action potentials corresponding to contractions and in agreement with the literature. Additionally, brain slices extracted from transgenic mice were used to show that our device can be used to record spontaneous and light evoked activity from the cortex and deep brain regions such as the thalamic reticular nucleus (TRN). Overall our microfluidic actuation technology provides a platform for

  14. Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

    International Nuclear Information System (INIS)

    Méjean, Chloé; Pometcu, Laura; Benzerga, Ratiba; Sharaiha, Ala; Le Paven-Thivet, Claire; Badard, Mathieu; Pouliguen, Philippe

    2017-01-01

    Highlights: • Carbon fibers loaded epoxy foam composites are proposed as microwave absorbers. • Dielectric properties (ε′, tanδ) of composites increase with carbon fibers content and length. • S 11 coefficient of a pyramidal prototype was characterized in anechoic chamber. • Epoxy prototype shows better absorption performance than commercial absorber. • S 11 of the prototype is lower than −30 dB (4–18 GHz) at normal and oblique incidences. - Abstract: This paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber.

  15. 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.

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

    International Nuclear Information System (INIS)

    Lee, Yeong Ju; Kim, Hyun Bin; Lee, Seung Jun; Kang, Phil Hyun

    2015-01-01

    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

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

    International Nuclear Information System (INIS)

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

    2017-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Xiaomin [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Carbon Fiber Engineering Research Center, School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Zhu, Bo, E-mail: zhubo@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Carbon Fiber Engineering Research Center, School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Cai, Xun, E-mail: caixunzh@sdu.edu.cn [School of Computer Science and Technology, Shandong University, Jinan 250101 (China); Liu, Jianjun [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Carbon Fiber Engineering Research Center, School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Qiao, Kun [Carbon Fiber Engineering Research Center, School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Yu, Junwei [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061 (China); Carbon Fiber Engineering Research Center, School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)

    2017-04-15

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

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

    Directory of Open Access Journals (Sweden)

    A. G. Gaikwad

    2012-06-01

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

  20. Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

    Energy Technology Data Exchange (ETDEWEB)

    Méjean, Chloé; Pometcu, Laura [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Benzerga, Ratiba, E-mail: ratiba.benzerga@univ-rennes1.fr [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Sharaiha, Ala; Le Paven-Thivet, Claire; Badard, Mathieu [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Pouliguen, Philippe [Département Recherche et Innovation Scientifique de la Direction Générale de l’Armement, 7-9 rue des Mathurins, 92221 Bagneux (France)

    2017-06-15

    Highlights: • Carbon fibers loaded epoxy foam composites are proposed as microwave absorbers. • Dielectric properties (ε′, tanδ) of composites increase with carbon fibers content and length. • S{sub 11} coefficient of a pyramidal prototype was characterized in anechoic chamber. • Epoxy prototype shows better absorption performance than commercial absorber. • S{sub 11} of the prototype is lower than −30 dB (4–18 GHz) at normal and oblique incidences. - Abstract: This paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber.

  1. Nitrogen-enriched carbon sheets derived from egg white by using expanded perlite template and its high-performance supercapacitors.

    Science.gov (United States)

    Chen, Jiucun; Liu, Yinqin; Li, Wenjun; Xu, Liqun; Yang, Huan; Li, Chang Ming

    2015-08-28

    Nitrogen-enriched carbon sheets were synthesized using egg white as a unique carbon source and expanded perlite as a novel template. The as-prepared material was further used as an electrode material for super capacitor applications, demonstrating excellent super capacitance with a maximum gravimetric specific capacitance of 302 F g(−1) at 0.5 A g(−1) in a 3-electrode setup for a sample carbonized at 850 °C and activated for 6 h. Moreover, the carbon sheet-based capacitor with 2-symmetric electrodes showed an excellent cycle life (2% loss at 0.1 A g(−1) after 10 000 cycles). The excellent performance may be attributed to the combination of the 3D carbon structure and the highly concentrated doped nitrogen component from the natural egg source for superior pseudocapacitance.

  2. Nitrogen-enriched carbon sheets derived from egg white by using expanded perlite template and its high-performance supercapacitors

    Science.gov (United States)

    Chen, Jiucun; Liu, Yinqin; Li, Wenjun; Xu, Liqun; Yang, Huan; Li, Chang Ming

    2015-08-01

    Nitrogen-enriched carbon sheets were synthesized using egg white as a unique carbon source and expanded perlite as a novel template. The as-prepared material was further used as an electrode material for supercapacitor applications, demonstrating excellent supercapacitance with a maximum gravimetric specific capacitance of 302 F g-1 at 0.5 A g-1 in a 3-electrode setup for a sample carbonized at 850 °C and activated for 6 h. Moreover, the carbon sheet-based capacitor with 2-symmetric electrodes showed an excellent cycle life (2% loss at 0.1 A g-1 after 10 000 cycles). The excellent performance may be attributed to the combination of the 3D carbon structure and the highly concentrated doped nitrogen component from the natural egg source for superior pseudocapacitance.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. Evaluation of carbon fiber surface treated by chemical and cold plasma processes

    Directory of Open Access Journals (Sweden)

    Liliana Burakowski Nohara

    2005-09-01

    Full Text Available Sized PAN-based carbon fibers were treated with hydrochloric and nitric acids, as well as argon and oxygen cold plasmas, and the changes on their surfaces evaluated. The physicochemical properties and morphological changes were investigated by atomic force microscopy (AFM, scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, tensile strength tests and Raman spectroscopy. The nitric acid treatment was found to cause the most significant chemical changes on the carbon fiber surface, introducing the largest number of chemical groups and augmenting the roughness. The oxygen plasma treatments caused ablation of the carbon fiber surface, removing carbon atoms such as CO and CO2 molecules. In addition, the argon plasma treatment eliminated defects on the fiber surface, reducing the size of critical flaws and thus increasing the fiber's tensile strength.

  8. 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.

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

    OpenAIRE

    Kerrouche, Abdelfateh; Boyle, William J.O.; Sun, Tong; Grattan, Kenneth T. V.; Schmidt, Jacob Wittrup; Täljsten, Björn

    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 (60 mm) optical fiber network and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures and in tests were subjected to strain through a series of cycles of pulling tests, with applied forces of up to 30 kN. The results show that effective strain measurements can be obtained from the diffe...

  10. 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...

  11. New generation fiber reinforced polymer composites incorporating carbon nanotubes

    Science.gov (United States)

    Soliman, Eslam

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    Park, Chang Sin; Kang, Bo Seon; Lee, Dong Weon

    2007-01-01

    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∼0.35 and 61.8 Ω/kΩ·bar for thicker and thinner membrane, respectively. All these observations demonstrated the possibilities of carbon fiber-based pressure sensors

  14. Eggplant-derived microporous carbon sheets: towards mass production of efficient bifunctional oxygen electrocatalysts at low cost for rechargeable Zn-air batteries.

    Science.gov (United States)

    Li, Bing; Geng, Dongsheng; Lee, Xinjing Shannon; Ge, Xiaoming; Chai, Jianwei; Wang, Zhijuan; Zhang, Jie; Liu, Zhaolin; Hor, T S Andy; Zong, Yun

    2015-05-25

    We report 2D microporous carbon sheets with high surface area, derived from eggplant via simple carbonization and KOH activation, as low cost yet efficient bifunctional catalysts for high performance rechargeable zinc-air batteries.

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

    Science.gov (United States)

    Kachold, Franziska; Singer, Robert

    2016-08-01

    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.

  16. 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.

  17. Tunable color parallel tandem organic light emitting devices with carbon nanotube and metallic sheet interlayers

    International Nuclear Information System (INIS)

    Oliva, Jorge; Desirena, Haggeo; De la Rosa, Elder; Papadimitratos, Alexios; Zakhidov, Anvar A.

    2015-01-01

    Parallel tandem organic light emitting devices (OLEDs) were fabricated with transparent multiwall carbon nanotube sheets (MWCNT) and thin metal films (Al, Ag) as interlayers. In parallel monolithic tandem architecture, the MWCNT (or metallic films) interlayers are an active electrode which injects similar charges into subunits. In the case of parallel tandems with common anode (C.A.) of this study, holes are injected into top and bottom subunits from the common interlayer electrode; whereas in the configuration of common cathode (C.C.), electrons are injected into the top and bottom subunits. Both subunits of the tandem can thus be monolithically connected functionally in an active structure in which each subunit can be electrically addressed separately. Our tandem OLEDs have a polymer as emitter in the bottom subunit and a small molecule emitter in the top subunit. We also compared the performance of the parallel tandem with that of in series and the additional advantages of the parallel architecture over the in-series were: tunable chromaticity, lower voltage operation, and higher brightness. Finally, we demonstrate that processing of the MWCNT sheets as a common anode in parallel tandems is an easy and low cost process, since their integration as electrodes in OLEDs is achieved by simple dry lamination process

  18. 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....

  19. Growth, structure, and optical properties of carbon-reinforced silica fibers

    International Nuclear Information System (INIS)

    Zhang, Z. J.; Ajayan, P. M.; Ramanath, G.; Vacik, J.; Xu, Y. H.

    2001-01-01

    We report the synthesis of carbon-reinforced silica fibers by methane exposure of metallocene-treated oxidized-Si(001) substrates at 1100 degree C. The SiO 2 cap layer transforms into silica fibers reinforced by glassy carbon in the core during methane exposure. High-resolution electron microscopy and spatially resolved spectroscopy measurements of the fibers reveal an amorphous structure without a hollow, and domains of glassy carbon embedded at the fiber core. The carbon-reinforced fibers are optically transparent and have an optical band gap of ≅3.1 eV. These fibers are organized in radial patterns that vary for different metallocene species. On nickelocene-treated substrates, the fibers originate from the circumference of the circular templates and grow outwards, forming radial patterns. On ferrocene-treated substrates, randomly oriented fibers grow within as well as slightly outside the perimeter of the templates, forming wreath-like patterns. Aligned growth of such fibers could be useful for fabricating optoelectronics devices and reinforced composites. [copyright] 2001 American Institute of Physics

  20. Experimental lumbar spine fusion with novel tantalum-coated carbon fiber implant

    DEFF Research Database (Denmark)

    Ding, Ming

    2007-01-01

    the possibility of coating a biocompatible metal layer on top of the carbon fiber material, to improve its biological performance. Tantalum was chosen because of its bone compatibility, based on our previous studies. A novel spinal fusion cage was fabricated by applying a thin tantalum coating on the surface......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...

  1. Aerogel to simulate delamination and porosity defects in carbon-fiber reinforced polymer composites

    Science.gov (United States)

    Juarez, Peter; Leckey, Cara A. C.

    2018-04-01

    Representative defect standards are essential for the validation and calibration of new and existing inspection techniques. However, commonly used methods of simulating delaminations in carbon-fiber reinforced polymer (CFRP) composites do not accurately represent the behavior of the real-world defects for several widely-used NDE techniques. For instance, it is common practice to create a delamination standard by inserting Polytetrafluoroethylene (PTFE) in between ply layers. However, PTFE can transmit more ultrasonic energy than actual delaminations, leading to an unrealistic representation of the defect inspection. PTFE can also deform/wrinkle during the curing process and has a thermal effusivity two orders of magnitude higher than air (almost equal to that of a CFRP). It is therefore not effective in simulating a delamination for thermography. Currently there is also no standard practice for producing or representing a known porosity in composites. This paper presents a novel method of creating delamination and porosity standards using aerogel. Insertion of thin sheets of solid aerogel between ply layers during layup is shown to produce air-gap-like delaminations creating realistic ultrasonic and thermographic inspection responses. Furthermore, it is shown that depositing controlled amounts of aerogel powder can represent porosity. Micrograph data verifies the structural integrity of the aerogel through the composite curing process. This paper presents data from multiple NDE methods, including X-ray computed tomography, immersion ultrasound, and flash thermography to the effectiveness of aerogel as a delamination and porosity simulant.

  2. Sunlight Absorption on the Greenland Ice Sheet Experiment (SAGE) - Tracing black carbon from emissions to deposition

    Science.gov (United States)

    Polashenski, C.; Soja, A. J.; Thomas, J. L.; Dibb, J. E.; Choi, H. D.; Flanner, M.; Bergin, M.; Casey, K.; Chen, J.; Courville, Z.; Lai, A.; Schauer, J. J.; Shafer, M. M.; Ward, J. L.

    2016-12-01

    The SAGE project seeks to understand the impact of light absorbing impurities on the Greenland Ice Sheet (GrIS). In general, the project has found that black carbon and dust concentrations in snow were low in the dry snow zones of the GrIS during 2012-2014 and that their concentrations do not appear to be trending relative to observations of these concentrations in snow over recent decades. We provide a revised analysis of MODIS albedo trends on the GrIS using new collection 6 data. These indicate that observed albedo of dry snow is not substantially trending. Sensor drift which had been present in collection 5 data has been substantially removed and the observed albedo of dry snow on the GrIS is now showing near zero trend. Episodic enhancements in BC deposition are, however, found in specific layers in our extensive snow pit observations. These peak enhancements include concentrations of up to 40 ng/g BC and would have reduced the albedo of the snow by 0.01-0.02. If timed correctly, the deposition of such a layer could be an important factor in initiating a melt-albedo feedback. Here we present an overview of synthesis work seeking to trace the formation of such a layer back to emission sources and call attention to multiple presentations making up the project. Collectively, the work traces a specific enhanced deposition event occurring on the northwest region of the ice sheet in early August 2013 to source fires in Canada. We summarize the multi-modal approach including remote sensing of aerosols, atmospheric trajectory modeling, chemical transport modeling, and coupled Earth system modeling. The emission, transport, and deposition of the enhanced event is observed and predicted by these tools and we find general agreement between these several modes of sensing and predicting. Further investigations explore other events where BC was emitted and even transported over the ice sheet but did not cause deposition events, resulting in no BC signature in the snow. We

  3. 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.

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

    International Nuclear Information System (INIS)

    Xu Bing; Wang Xiaoshu; Lu Yun

    2006-01-01

    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

  5. Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuwei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Liquan [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Ma, Lichun; Qi, Meiwei; Yu, Jiali [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-10-15

    Highlights: • Carbon fibers are grafted with phenyl amine group via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 73%. • Tensile strength of the carbon fibers does not decrease distinctly. • Using water as the reaction medium can avoid pollution from organic solvents. • Grafting via aryl diazonium reaction in one step can improve modification efficiency. - Abstract: Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction “on water” to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction “on water” could be a facile green platform to functionalize carbon fibers for many interesting applications.

  6. Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

    International Nuclear Information System (INIS)

    Wang, Yuwei; Meng, Linghui; Fan, Liquan; Ma, Lichun; Qi, Meiwei; Yu, Jiali; Huang, Yudong

    2014-01-01

    Highlights: • Carbon fibers are grafted with phenyl amine group via aryl diazonium reaction. • Interfacial shear strength of the carbon fibers increases by 73%. • Tensile strength of the carbon fibers does not decrease distinctly. • Using water as the reaction medium can avoid pollution from organic solvents. • Grafting via aryl diazonium reaction in one step can improve modification efficiency. - Abstract: Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction “on water” to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction “on water” could be a facile green platform to functionalize carbon fibers for many interesting applications

  7. N-type thermoelectric recycled carbon fibre sheet with electrochemically deposited Bi{sub 2}Te{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Pang, E.J.X. [Division of Materials, Mechanics and Structures, The University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Pickering, S.J., E-mail: stephen.pickering@nottingham.ac.uk [Division of Materials, Mechanics and Structures, The University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Chan, A. [Division of Materials, Mechanics and Structures, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan (Malaysia); Wong, K.H. [Division of Materials, Mechanics and Structures, The University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Lau, P.L. [Division of Materials, Mechanics and Structures, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan (Malaysia)

    2012-09-15

    An N-type thermoelectric recycled carbon fibre sheet with bismuth telluride coating has been successfully synthesised through an electro-deposition technique. The Seebeck coefficient and electrical properties of the combined recycled carbon fibre sheet and bismuth telluride films are reported. Classification of the crystal structure, surface morphology and the elemental composition of the resulting deposits are methodically characterised by XRD, SEM and EDX. Cyclic voltammetry is also carried out in nitric acid solutions to investigate the right range of deposition potential. The synthesis N-type thermoelectric sheet has a highest attainable Seebeck coefficient of -54 {mu}V K{sup -1} and an electrical resistivity of 8.9 Multiplication-Sign 10{sup -5} Ohm-Sign m. The results show slight differences in morphologies and thermoelectric properties for the films deposited at varying deposition potential. The increase in thermoelectrical properties of the recycled carbon fibre is in line with the development of using coated recycled fibre for thermoelectrical applications. - Graphical abstract: SEM image of an N-type thermoelectric recycled carbon fibre sheet with Bi{sub 2}Te{sub 3} coatings. Highlights: Black-Right-Pointing-Pointer N-type thermoelectric sheet is synthesis through the electrodeposition of Bi{sub 2}Te{sub 3}. Black-Right-Pointing-Pointer Bi{sub 2}Te{sub 3} composition can be controlled by varying the deposition voltage. Black-Right-Pointing-Pointer Seebeck coefficient and electrical properties of the combined sheet were reported. Black-Right-Pointing-Pointer Material characterisations of the deposits are done using XRD, SEM and EDX.

  8. Carbon Fiber Reinforced Carbon-Al-Cu Composite for Friction Material.

    Science.gov (United States)

    Cui, Lihui; Luo, Ruiying; Ma, Denghao

    2018-03-31

    A carbon/carbon-Al-Cu composite reinforced with carbon fiber 2.5D-polyacrylonitrile-based preforms was fabricated using the pressureless infiltration technique. The Al-Cu alloy liquids were successfully infiltrated into the C/C composites at high temperature and under vacuum. The mechanical and metallographic properties, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS) of the C/C-Al-Cu composites were analyzed. The results showed that the bending property of the C/C-Al-Cu composites was 189 MPa, whereas that of the pure carbon slide material was only 85 MPa. The compressive strength of C/C-Al-Cu was 213 MPa, whereas that of the pure carbon slide material was only 102 MPa. The resistivity of C/C-Al-Cu was only 1.94 μΩm, which was lower than that of the pure carbon slide material (29.5 μΩm). This finding can be attributed to the "network conduction" structure. Excellent wettability was observed between Al and the carbon matrix at high temperature due to the existence of Al₄C₃. The friction coefficients of the C/C, C/C-Al-Cu, and pure carbon slide composites were 0.152, 0.175, and 0.121, respectively. The wear rate of the C/C-Al-Cu composites reached a minimum value of 2.56 × 10 -7 mm³/Nm. The C/C-Al-Cu composite can be appropriately used as railway current collectors for locomotives.

  9. 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

  10. Carbon aerogel composites prepared by ambient drying and using oxidized polyacrylonitrile fibers as reinforcements.

    Science.gov (United States)

    Feng, Junzong; Zhang, Changrui; Feng, Jian; Jiang, Yonggang; Zhao, Nan

    2011-12-01

    Carbon fiber-reinforced carbon aerogel composites (C/CAs) for thermal insulators were prepared by copyrolysis of resorcinol-formaldehyde (RF) aerogels reinforced by oxidized polyacrylonitrile (PAN) fiber felts. The RF aerogel composites were obtained by impregnating PAN fiber felts with RF sols, then aging, ethanol exchanging, and drying at ambient pressure. Upon carbonization, the PAN fibers shrink with the RF aerogels, thus reducing the difference of shrinkage rates between the fiber reinforcements and the aerogel matrices, and resulting in C/CAs without any obvious cracks. The three point bend strength of the C/CAs is 7.1 ± 1.7 MPa, and the thermal conductivity is 0.328 W m(-1) K(-1) at 300 °C in air. These composites can be used as high-temperature thermal insulators (in inert atmospheres or vacuum) or supports for phase change materials in thermal protection system. © 2011 American Chemical Society

  11. Multifunctional Flexible Composites Based on Continuous Carbon Nanotube Fiber

    Science.gov (United States)

    2014-07-28

    different amounts of CNTs [23]. We wrap the graphene fiber with highly aligned CNT film (Fig. 14a). After the hybrid fibers were densified with ethanol ...multifunctional composites fibers [28] and accessing of large polymer chains to enhance fiber mechanical properties [29]. 2.14 Electromechanical...emitters, solid-phase microextraction and catalysis . Different from graphene- based aerogels (GBAs) and membranes (GBMs), GBFs have demonstrated

  12. [Study on the skin-core evolvement of carbon fibers as a function of heat treatment temperature by Raman spectroscopy].

    Science.gov (United States)

    Liu, Fu-jie; Fan, Li-dong; Wang, Hao-jing; Zhu, Zhen-ping

    2008-08-01

    The skin-core evolvement of the carbon fibers was studied as a function of heat-treatment temperature though the analysis of Raman spectroscopy of the carbon fibers surface and core. It was found that the change of the Raman spectra of the carbon fibers core was similar to that on the surface with the increase in heat-treatment temperature. At 1600 degrees C, the Rs and Rc values were almost equal, indicating that the degrees of the graphitization of the carbon fibers surface and core were almost uniform. The Rs and Rc values decreased dramatically with the increase in heat-treatment temperature, and Rs decreased more. At 2800 degrees C, the Rs value came to 0.429, lowered 77.2%, while the Rc value then came to 1.101, lowered 38.7% only. It implied that the graphitization degree of the carbon fibers was enhanced with increasing the heat treatment temperature, and that of carbon fibers surface was enhanced more. The graphite characters of the carbon of the carbon fibers surface were different from that of the carbon fibers core. The former is close to soft carbon, which is easy to graphitize, while the latter is close to hard carbon, which is difficult to graphitize, and it may be resin carbon Skin-core structure gene Rsc (= Rs/Rc) which denoted the skin-core degree of the carbon fibers was first brought forward and adopted. The Rsc value is between 0 and 1. When the Rsc value is equal to 1, the carbon fibers are homogenous. When the Rsc value is close to zero, there are serious skin-core structures in the carbon fibers. The Rsc value reduced linearly with the increase in heat-treatment temperature, indicating that the homogeneous degrees of the carbon fibers decreased and the skin-core degrees of the carbon fibers increased. The crystallite size of the carbon fibers surface and core increased gradually with the increase in heat-treatment temperature, but the surface's increased more quickly, indicating that the carbon of the carbon fibers surface was easier to

  13. Obtaining of Fibers and granules of carbon for the Immobilization of Enzymes

    International Nuclear Information System (INIS)

    Malagon M, Martha L; Rico R, Yolanda Rico R; Lopez de, Helda A; Caicedo M, Luis Alfonso

    2002-01-01

    Fibers and pellets of carbon were prepared from coal tar. The tar was filtrated and stabilized in a nitrogen atmosphere at 330 degrades Celsius. Extrusion and pellets prepared the fibers by injection on water. Lactase was immobilized by adsorption process. Pellets were better support than fibers, because produced lower pressure drop and upper enzyme retention. Pellets showed the following characteristics: density 2,407 g/cm3, porosity 81,69% and diameter 3 mm

  14. 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.; hide

    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.

  15. 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

  16. Post-tensioned carbon fiber composite cable (CFCC), Little Pond Bridge, Route 302, Fryeburg, Maine.

    Science.gov (United States)

    2013-02-01

    Corrosion of reinforcing steel in concrete has been a constant and expensive maintenance problem which : is exacerbated by Maines coastal environment, harsh winters, and the use of chlorides on the roads and : bridges. Carbon fiber products are in...

  17. Cooperative research and the carbon fiber development for application in uranium centrifuges project

    International Nuclear Information System (INIS)

    Queiroz, Paulo Cesar Beltrao; Zouain, Desiree Moraes

    2009-01-01

    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 fibre-based engineering properties make it a valuable supply for high technological products, such as uranium ultracentrifuge. There is no production of such fibers in Brazil. Its trade is subject to international market restrictions due to carbon fibers' dual applications. The Centro Tecnologico da Marinha em Sao Paulo (CTMSP), the Universidade de Campinas (UNICAMP), the Universidade de Sao Paulo (USP), the RADICIFIBRAS Company, and the Financiadora de Estudos e Projetos (FINEP), which is responsible for the project financial support, established a partnership aiming the development of a domestic polyacrylonitrile (Pan)-based carbon fiber industry. Such alliances or technological partnerships are best known in developed countries, such as USA and Japan, as Cooperative Research or Research Joint Ventures (RJV). (author)

  18. Assessing Toxicity of Obscurant Grade Pan-Based Carbon Fiber Aquatic Species Chronic Tests

    National Research Council Canada - National Science Library

    Chester, N. A; Haley, M. V; Kumas, C. W; Checkai, R. T

    2004-01-01

    ...). Use of polyacrylonitrile (PAN)-based carbon fiber in the module will provide user-capability for delivering large area obscurant screens in the millimeter wave-range of the electromagnetic spectrum while maintaining...

  19. 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...

  20. 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.

  1. 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.

  2. Electroadsorption desalination with carbon nanotube/PAN-based carbon fiber felt composites as electrodes.

    Science.gov (United States)

    Liu, Yang; Zhou, Junbo

    2014-01-01

    The chemical vapor deposition method is used to prepare CNT (carbon nanotube)/PCF (PAN-based carbon fiber felt) composite electrodes in this paper, with the surface morphology of CNT/PCF composites and electroadsorption desalination performance being studied. Results show such electrode materials with three-dimensional network nanostructures having a larger specific surface area and narrower micropore distribution, with a huge number of reactive groups covering the surface. Compared with PCF electrodes, CNT/PCF can allow for a higher adsorption and desorption rate but lower energy consumption; meanwhile, under the condition of the same voltage change, the CNT/PCF electrodes are provided with a better desalination effect. The study also found that the higher the original concentration of the solution, the greater the adsorption capacity and the lower the adsorption rate. At the same time, the higher the solution's pH, the better the desalting; the smaller the ions' radius, the greater the amount of adsorption.

  3. Neutron irradiation studies on low density pan fiber based carbon/carbon composites

    Science.gov (United States)

    Venugopalan, Ramani; Sathiyamoorthy, D.; Acharya, R.; Tyagi, A. K.

    2010-09-01

    Carbon has been extensively used in nuclear reactors and there has been growing interest to develop carbon-based materials for high-temperature nuclear and fusion reactors. Carbon-carbon composite materials as against conventional graphite material are now being looked into as the promising materials for the high temperature reactor due their ability to have high thermal conductivity and high thermal resistance. Research on the development of such materials and their irradiation stability studies are scant. In the present investigations carbon-carbon composite has been developed using polyacrylonitrile (PAN) fiber. Two samples denoted as Sample-1 and Sample-2 have been prepared by impregnation using phenolic resin at pressure of 30 bar for time duration 10 h and 20 h respectively, and they have been irradiated by neutrons. The samples were irradiated in a flux of 10 12 n/cm 2/s at temperature of 40 °C. The fluence was 2.52 × 10 16 n/cm 2. These samples have been characterized by XRD and Raman spectroscopy before and after neutron irradiation. DSC studies have also been carried out to quantify the stored energy release behavior due to irradiation. The XRD analysis of the irradiated and unirradiated samples indicates that the irradiated samples show the tendency to get ordered structure, which was inferred from the Raman spectroscopy. The stored energy with respect to the fluence level was obtained from the DSC. The stored energy from these carbon composites is very less compared to irradiated graphite under ambient conditions.

  4. Measurements of black carbon and its impact over Southwest Greenland Ice Sheet from 2016 to 2017.

    Science.gov (United States)

    Cintron, I.; Leidman, S. Z.; Rennermalm, A. K.; Mazurek, M.

    2017-12-01

    Black carbon (BC) is recognized as the second most important anthropogenic atmospheric warming species, only after carbon dioxide (CO2), since its radiative forcing has been estimated to +0.4 W m-2. Light absorbing aerosols, such as BC, have a significant impact on snow reflectivity decline, which contributes to the accelerated melting seen in recent years in the region. In Greenland, the ice sheet mass loss has tripled since the mid 1950s in concert with sharply lowered albedo and increased absorption of solar radiation enhancing surface melt. Presence of BC is likely to enhance solar absorption, yet the impact is not well understood partly due to scarce availability of direct measurements of BC in the Greenland accumulation zone. Here, we are investigating how much of the change in the observed snowmelt in the southwest GrIS can be attributed to deposition of light absorbing aerosols, such as BC. To this end we collected snow samples at different depths, in five different sites on the southwest GrIS and applied the Snow, Ice, and Aerosol Radiative (SNICAR) model. Finally, results from BC mass annual concentration distribution and mixing state using the Single Particle Soot Photometer (SP2) will be discussed.

  5. Repair of reinforced concrete beams using carbon fiber reinforced polymer

    Directory of Open Access Journals (Sweden)

    Karzad Abdul Saboor

    2017-01-01

    Full Text Available This research paper is part of an ongoing research on the behaviour of Reinforced Concrete (RC beams retrofitted with Externally Bonded Carbon Fiber Reinforced Polymer (EB-CFRP. A total of 5 large-scale rectangular beams, previously damaged due to shear loading, were repaired and strengthened with EB-CFRP and tested in this study. The major cracks of the damaged beams were injected with epoxy and the beams were wrapped with 2 layers of EB-CFRP discrete strips with 100mm width and 150mm center to center spacing. The beams were instrumented and tested to failure under three points loading in simply supported configuration. The measured test parameters were the beams deflection, maximum load, and the strain in the FRP strips. The failure mode was also observed. The results showed that applying EB-FRP strips increased the shear strength significantly relative to the original shear capacity of the beam. The results demonstrate that the application of EB-FRP strips used in this study is an effective repair method that can be used to repair and strengthen damaged beams.

  6. 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%).

  7. 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.

  8. Supercritical Regeneration of an Activated Carbon Fiber Exhausted with Phenol

    Directory of Open Access Journals (Sweden)

    M. Jesus Sanchez-Montero

    2018-01-01

    Full Text Available The properties of supercritical CO2 (SCCO2 and supercritical water (SCW turn them into fluids with a great ability to remove organic adsorbates retained on solids. These properties were used herein to regenerate an activated carbon fiber (ACF saturated with a pollutant usually contained in wastewater and drinking water, phenol. Severe regeneration conditions, up to 225 bar and 400 °C, had to be employed in SCCO2 regeneration to break the strong interaction established between phenol and the ACF. Under suitable conditions (regeneration temperature, time, and pressure, and flow of SCCO2 the adsorption capacity of the exhausted ACF was completely recovered, and even slightly increased. Most of the retained phenol was removed by thermal desorption, but the extra percentage removed by extraction allowed SCCO2 regeneration to be significantly more efficient than the classical thermal regeneration methods. SCCO2 regeneration and SCW regeneration were also compared for the first time. The use of SCW slightly improved regeneration, although SCW pressure was thrice SCCO2 pressure. The pathways that controlled SCW regeneration were also investigated.

  9. SU-F-T-424: Mitigation of Increased Surface Dose When Treating Through A Carbon Fiber Couch Top

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E; Misgina, F [University of Kentucky, Lexington, KY (United States)

    2016-06-15

    Purpose: To study the effect of the Varian carbon fiber couch top on surface dose for patients being treated using single PA beams in the supine position and to identify simple methods for surface dose reduction. Methods: Measurements of surface dose were obtained in Solid Water phantoms using both a parallel plate ionization chamber (PTW Advanced Markus) and EBT2 Radiochromic films for both 6 and 10MV photons. All measurements were referenced to a depth considered a typical for PA Spine fields. Techniques used to reduce the surface dose included introducing an air standoff using Styrofoam sheets to suspend the phantom surface above the couch top and by adding a thin high Z scattering foil on the table surface. Surface doses were evaluated for typical field sizes, standoff heights, and various scattering materials. Comparisons were made to the surface dose obtainable when treating through a Varian Mylar covered tennis racket style couch top. Results: Dependence on typical spine field sizes was relatively minor. Dependence on air gap was much more significant. Surface doses decreased exponentially with increases in air standoff distance. Surface doses were reduced by approximately 50% for an air gap of 10cm and 40% for a 15cm air gap. Surface doses were reduced by an additional 15% by the addition of a 1mm Tin scattering foil. Conclusion: Using simple techniques, it is possible to reduce the surface dose when treating single PA fields through the Varian carbon fiber couch top. Surface doses can be reduced to levels observed when treating though transparent Mylar tops by adding about 15 cm of air gap. Further reductions are possible by adding thin scattering foils, such as Tin or Lead, on the couch surface. This is a low cost approach to reduce surface dose when using the Varian carbon fiber couch top.

  10. SU-F-T-424: Mitigation of Increased Surface Dose When Treating Through A Carbon Fiber Couch Top

    International Nuclear Information System (INIS)

    Johnson, E; Misgina, F

    2016-01-01

    Purpose: To study the effect of the Varian carbon fiber couch top on surface dose for patients being treated using single PA beams in the supine position and to identify simple methods for surface dose reduction. Methods: Measurements of surface dose were obtained in Solid Water phantoms using both a parallel plate ionization chamber (PTW Advanced Markus) and EBT2 Radiochromic films for both 6 and 10MV photons. All measurements were referenced to a depth considered a typical for PA Spine fields. Techniques used to reduce the surface dose included introducing an air standoff using Styrofoam sheets to suspend the phantom surface above the couch top and by adding a thin high Z scattering foil on the table surface. Surface doses were evaluated for typical field sizes, standoff heights, and various scattering materials. Comparisons were made to the surface dose obtainable when treating through a Varian Mylar covered tennis racket style couch top. Results: Dependence on typical spine field sizes was relatively minor. Dependence on air gap was much more significant. Surface doses decreased exponentially with increases in air standoff distance. Surface doses were reduced by approximately 50% for an air gap of 10cm and 40% for a 15cm air gap. Surface doses were reduced by an additional 15% by the addition of a 1mm Tin scattering foil. Conclusion: Using simple techniques, it is possible to reduce the surface dose when treating single PA fields through the Varian carbon fiber couch top. Surface doses can be reduced to levels observed when treating though transparent Mylar tops by adding about 15 cm of air gap. Further reductions are possible by adding thin scattering foils, such as Tin or Lead, on the couch surface. This is a low cost approach to reduce surface dose when using the Varian carbon fiber couch top.

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

    Directory of Open Access Journals (Sweden)

    Zhiqian Yang

    2015-10-01

    Full Text Available A composite fiber based on carbon nanotube (CNT and poly(vinyl alcohol (PVA was prepared by melt-spinning. Structural features and the mechanical performances of the PVA/CNT composite fiber were investigated as a function of draw condition. Initial moduli and tensile strengths of the drawn composite fibers are much higher than those of undrawn composite fiber. It is identified from XRD and 2D XRD that the composite fiber exhibits enhanced crystallinity and orientation degree with increasing the draw ratio. Accordingly, finger-like pores distributed along the axial direction homogeneous on the melt-spinning PVA fiber surface. After dry and hot-drawn, the hydrophobicity of PVA/CNT composites fiber decreased gradually.

  12. Surface Properties of PAN-based Carbon Fibers Modified by Electrochemical Oxidization in Organic Electrolyte Systems

    Directory of Open Access Journals (Sweden)

    WU Bo

    2016-09-01

    Full Text Available PAN-based carbon fibers were modified by electrochemical oxidization using fatty alcohol polyoxyethylene ether phosphate (O3P, triethanolamine (TEOA and fatty alcohol polyoxyethylene ether ammonium phosphate (O3PNH4 as organic electrolyte respectively. Titration analysis, single fiber fracture strength measurement and field emission scanning electron microscopy (FE-SEM were used to evaluate the content of acidic functional group on the surface, mechanical properties and surface morphology of carbon fiber. The optimum process of electrochemical treatment obtained is at 50℃ for 2min and O3PNH4 (5%, mass fraction as the electrolyte with current density of 2A/g. In addition, the surface properties of modified carbon fibers were characterized by X-ray photoelectron spectroscopy (XPS and single fiber contact angle test. The results show that the hydrophilic acidic functional groups on the surface of carbon fiber which can enhance the surface energy are increased by the electrochemical oxidation using O3PNH4 as electrolyte, almost without any weakening to the mechanical properties of carbon fiber.

  13. Evaluation of ionic liquid epoxy carbon fiber composites in a cryogenic environment

    Science.gov (United States)

    Lyne, Christopher T.; Henry, Christopher R.; Kaukler, William F.; Grugel, R. N.

    2018-03-01

    A novel ionic liquid epoxy (ILE) was used to fabricate carbon fiber composite discs which were then subjected to biaxial strain testing in liquid nitrogen. The ILE composite showed a greater strain-to-failure at cryogenic temperatures when compared to a commercial epoxy. This result is likely an effect, as shown in micrographs, of the strong ILE bonding with the carbon fibers as well as it exhibiting plastic deformation at the fracture surface.

  14. Transition layers formation on the boundaries carbon fiber-copper dependence on the active additions

    International Nuclear Information System (INIS)

    Wlosinski, W.; Pietrzak, K.

    1993-01-01

    The basic problem connected with fabrication of carbon fiber-copper composites is to overcome the problem of low wettability of carbon fiber by copper. One of the possible solutions of that problem is to use the copper doped with active metals. The investigation results of transition layer forming on the phase boundary in the system have been discussed in respect of the kind and content of active elements added to the copper. 5 refs, 5 figs, 5 tabs

  15. Research on mechanical properties of carbon fiber /polyamide reinforced PP composites

    Science.gov (United States)

    Chen, Xinghui; Yu, Qiang; Liu, Lixia; Ji, Wenhua; Yang, Li; Fan, Dongli

    2017-10-01

    The polyamide composites reinforced by carbon fiber/polypropylene are produced by injection molding processing. The flow abilities and mechanical properties of the CF/PA/PP composite materials are studied by the fusion index instrument and the universal testing machine. The results show that with the content of carbon fiber/polyamide increase, the impact breaking strength and the tensile property of the composite materials increase, which is instructive to the actual injection production of polypropylene products.

  16. Fiber Strength Utilization in Carbon/Carbon Composites: Part 2. Extended Studies With Pitch- and PAN-Based Fibers

    National Research Council Canada - National Science Library

    Zaldivar, R

    1998-01-01

    ...) composites as a function of heat treatment temperature (HTT) have been extended beyond the original group of DuPont pitch-based E-series fibers to include additional pitch and PAN-based fibers...

  17. 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.

  18. Adsorption of heavy metals onto activated carbons derived from polyacrylonitrile fiber.

    Science.gov (United States)

    Zaini, Muhammad Abbas Ahmad; Amano, Yoshimasa; Machida, Motoi

    2010-08-15

    The aim of this research is to produce activated carbons derived from polyacrylonitrile (PAN) fiber and to examine their feasibility of removing heavy metals from aqueous solution. Thermogravimetric analysis was used to identify the suitable conditions for preparing oxidized fiber and coke as activated carbon precursors. Steam and CO(2) were used to activate the precursors. Activated carbons were characterized by their pore texture, elemental compositions and surface functionalities. Batch adsorption and desorption studies were carried out to determine the metal-binding ability of activated carbons. Two commercial activated carbon fibers (ACFs), i.e., A-20 and W10-W, were employed to compare the removal performance of PAN derived activated carbons. Influence of oxidation treatment of PAN fiber prior to steam activation was also explored and discussed. Results indicated that steam produced a higher surface area but a lower resultant yield as compared to CO(2). Also, precursors activated by steam showed a greater removal performance. For both activation methods, fiber displayed a better metal-binding ability than coke. A small nitrogen loss from PAN fiber as a result of oxidation treatment assisted a greater removal of Cu(II) and Pb(II), but the interaction to Cu(II) was found stronger. It is proposed that the formation of cyclized structure by oxidation treatment minimized the nitrogen loss during steam activation, hence increased the uptake performance. Copyright 2010 Elsevier B.V. All rights reserved.

  19. Effect of different dispersants in compressive strength of carbon fiber cementitious composites

    Science.gov (United States)

    Lestari, Yulinda; Bahri, Saiful; Sugiarti, Eni; Ramadhan, Gilang; Akbar, Ari Yustisia; Martides, Erie; Khaerudini, Deni S.

    2013-09-01

    Carbon Fiber Cementitious Composites (CFCC) is one of the most important materials in smart concrete applications. CFCC should be able to have the piezoresistivity properties where its resistivity changes when there is applied a stress/strain. It must also have the compressive strength qualification. One of the important additives in carbon fiber cementitious composites is dispersant. Dispersion of carbon fiber is one of the key problems in fabricating piezoresistive carbon fiber cementitious composites. In this research, the uses of dispersants are methylcellulose, mixture of defoamer and methylcellulose and superplasticizer based polycarboxylate. The preparation of composite samples is similar as in the mortar technique according to the ASTM C 109/109M standard. The additives material are PAN type carbon fibers, methylcellulose, defoamer and superplasticizer (as water reducer and dispersant). The experimental testing conducts the compressive strength and resistivity at various curing time, i.e. 3, 7 and 28 days. The results obtained that the highest compressive strength value in is for the mortar using superplasticizer based polycarboxylate dispersant. This also shown that the distribution of carbon fiber with superplasticizer is more effective, since not reacting with the cementitious material which was different from the methylcellulose that creates the cement hydration reaction. The research also found that the CFCC require the proper water cement ratio otherwise the compressive strength becomes lower.

  20. High Per formance and Flexible Supercapacitors based on Carbonized Bamboo Fibers for Wide Temperature Applications

    Science.gov (United States)

    Zequine, Camila; Ranaweera, C. K.; Wang, Z.; Singh, Sweta; Tripathi, Prashant; Srivastava, O. N.; Gupta, Bipin Kumar; Ramasamy, K.; Kahol, P. K.; Dvornic, P. R.; Gupta, Ram K.

    2016-08-01

    High performance carbonized bamboo fibers were synthesized for a wide range of temperature dependent energy storage applications. The structural and electrochemical properties of the carbonized bamboo fibers were studied for flexible supercapacitor applications. The galvanostatic charge-discharge studies on carbonized fibers exhibited specific capacity of ~510F/g at 0.4 A/g with energy density of 54 Wh/kg. Interestingly, the carbonized bamboo fibers displayed excellent charge storage stability without any appreciable degradation in charge storage capacity over 5,000 charge-discharge cycles. The symmetrical supercapacitor device fabricated using these carbonized bamboo fibers exhibited an areal capacitance of ~1.55 F/cm2 at room temperature. In addition to high charge storage capacity and cyclic stability, the device showed excellent flexibility without any degradation to charge storage capacity on bending the electrode. The performance of the supercapacitor device exhibited ~65% improvement at 70 °C compare to that at 10 °C. Our studies suggest that carbonized bamboo fibers are promising candidates for stable, high performance and flexible supercapacitor devices.

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

    International Nuclear Information System (INIS)

    Juanico L, J.A.

    2004-01-01

    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 NO 2 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

  2. Measurement of characteristic impedance of silicon fiber sheet based readout strip panel for RPC detector in INO

    Science.gov (United States)

    Singh, M. K.; Kumar, A.; Marimuthu, N.; Singh, V.; Subrahmanyam, V. S.

    2017-01-01

    The India-based Neutrino Observatory (INO) is a mega science project of India, which is going to use about 30,000 Resistive Plate Chambers (RPC) as active detector elements for the study of atmoshpheric neutrino oscillations. Each RPC detector will consist of two orthogonally placed readout strip panel for picking the signals generated in the gas chamber. The area of RPC detector in INO-ICAL (Iron Calorimeter) experiment will be 2 m × 2 m, therefore the dimensions of readout strip panel should also be 2 m × 2 m. To get undistorted signals pass through the readout strip panel to front-end electronics, their characteristic impedance should be matched with each other. In the present paper, we describe the need and search of new dielectric material for the fabrication of flame resistant, waterproof and flexible readout strip panel. We will also describe the measurement of characteristic impedance of Plastic Honeycomb (PH) based readout strip panel and Silicon Fiber Sheet (SFS) based readout strip panel in a comparative way, and its variation under loading and with time. Based on this study, we found that a 5 mm thick SFS-based readout strip panel has a minimum signal reflection at 49.5 ohm characteristic impedance value. Our study shows that SFS is a good dielectric material for the purpose.

  3. Removal of antibiotics in sponge membrane bioreactors treating hospital wastewater: Comparison between hollow fiber and flat sheet membrane systems.

    Science.gov (United States)

    Nguyen, Thanh-Tin; Bui, Xuan-Thanh; Luu, Vinh-Phuc; Nguyen, Phuoc-Dan; Guo, Wenshan; Ngo, Huu-Hao

    2017-09-01

    Hollow fiber (HF) and flat sheet (FS) Sponge MBRs were operated at 10-20 LMH flux treating hospital wastewater. Simultaneous nitrification denitrification (SND) occurred considerably with TN removal rate of 0.011-0.020mg TN mgVSS -1 d -1 . Furthermore, there was a remarkable removal of antibiotics in both Sponge MBRs, namely Norfloxacin (93-99% (FS); 62-86% (HF)), Ofloxacin (73-93% (FS); 68-93% (HF)), Ciprofloxacin (76-93% (FS); 54-70% (HF)), Tetracycline (approximately 100% for both FS and HF) and Trimethoprim (60-97% (FS); 47-93% (HF). Whereas there was a quite high removal efficiency of Erythromycin in Sponge MBRs, with 67-78% (FS) and 22-48% (HF). Moreover, a slightly higher removal of antibiotics in FS than in HF achieved, with the removal rate being of 0.67-32.40 and 0.44-30.42µgmgVSS -1 d -1 , respectively. In addition, a significant reduction of membrane fouling of 2-50 times was achieved in HF-Sponge MBR for the flux range. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Qian, Xin; Zou, Ruifen; OuYang, Qin; Wang, Xuefei; Zhang, Yonggang

    2015-01-01

    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 3 to 1.80 g/cm 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

  5. 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.

  6. 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.

  7. 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.

  8. Large and stable emission current from synthesized carbon nanotube/fiber network

    International Nuclear Information System (INIS)

    Di, Yunsong; Xiao, Mei; Zhang, Xiaobing; Wang, Qilong; Li, Chen; Lei, Wei; Cui, Yunkang

    2014-01-01

    In order to obtain a large and stable electron field emission current, the carbon nanotubes have been synthesized on carbon fibers by cold wall chemical vapor deposition method. In the hierarchical nanostructures, carbon fibers are entangled together to form a conductive network, it could provide excellent electron transmission and adhesion property between electrode and emitters, dispersed clusters of carbon nanotubes with smaller diameters have been synthesized on the top of carbon fibers as field emitters, this kind of emitter distribution could alleviate electrostatic shielding effect and protect emitters from being wholly destroyed. Field emission properties of this kind of carbon nanotube/fiber network have been tested, up to 30 mA emission current at an applied electric field of 6.4 V/μm was emitted from as-prepared hierarchical nanostructures. Small current degradation at large emission current output by DC power operation indicated that carbon nanotube/fiber network could be a promising candidate for field emission electron source

  9. Electrochemical surface functionalization of carbon fibers for chemical affinity improvement with epoxy resins

    Science.gov (United States)

    Kainourgios, Panayiotis; Kartsonakis, Ioannis A.; Dragatogiannis, Dimitrios A.; Koumoulos, Elias P.; Goulis, Panagiotis; Charitidis, Costas A.

    2017-09-01

    The purpose of this study is to increase the wetting properties of carbon fibers in order to improve the adhesion force between the fiber and the polymer matrix. Commercial carbon fibers were surface functionalized through cyclic voltammetry together with potentiostatic conditions in aqueous electrolyte solutions of H2SO4, in the presence of acrylic acid, methacrylic acid, acrylonitrile and N-vinylpyrrolidone monomers. The anodic and cathodic peaks were correlated with oxide formation and their partial reduction, respectively. The produced surface modified carbon fibers were wetted with epoxy resin so that to produce dumbbell type composites for tensile strength testing. The nature of oxygen containing groups on the fibers surface was determined by Fourier-transform infrared and Raman spectroscopy. Moreover, the wetting properties of the treated carbon fibers were evaluated via contact angle measurements whereas the morphology of the coated fibers was investigated via scanning electron microscopy. Finally, the mechanical performance of the composites was evaluated by means of tensile testing and strength measurements.

  10. Study on adsorption of activated carbon fiber to background-level xenon in air by the method of 133Xe tracer

    International Nuclear Information System (INIS)

    Zhang Haitao; Wang Yalong; Zhang Lixing; Wang Xuhui; Zhang Xiaolin

    2001-01-01

    The adsorption behaviors of the different activated carbon fibers to ultra-trace xenon in air are studied using the method of 133 Xe as tracer. The efficiency equation of adsorption columns are determined. The comparison of adsorptive capacity between activated carbon fibers and activated carbon indicates that activated carbon fibers are better than activated carbon under low temperature

  11. Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction “on water”

    Science.gov (United States)

    Wang, Yuwei; Meng, Linghui; Fan, Liquan; Ma, Lichun; Qi, Meiwei; Yu, Jiali; Huang, Yudong

    2014-10-01

    Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction "on water" to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction "on water" could be a facile green platform to functionalize carbon fibers for many interesting applications.

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

    International Nuclear Information System (INIS)

    Park, Soo Jin; Chang, Yong Hwan; Moon, Cheol Whan; Suh, Dong Hack; Im, Seung Soon; Kim, Yeong Cheol

    2010-01-01

    In this study, the atmospheric plasma treatment with He/O 2 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

  13. Preparation and characterization of photocatalytic carbon dots-sensitized electrospun titania nanostructured fibers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haopeng [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhu, Yihua, E-mail: yhzhu@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Cao, Huimin; Yang, Xiaoling; Li, Chunzhong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► The TiO{sub 2}-CDs nanostructured fibers are fabricated by using APS combining the electrospinning TiO{sub 2} nanostructured fibers and CDs. ► The CD can work as a photosensitizer in the degradation of rhodamine B under visible light irradiation. ► The TiO{sub 2}-CDs nanostructured fibers exhibit enhanced photocatalytic efficiency and can be easily handled and recycled. -- Abstract: The carbon dots (CDs) are new functional carbon-aceous materials. Compared to conventional dye molecules and semiconductor quantum dots, CDs are superior in chemical inertness and low toxicity. The TiO{sub 2}-CDs nanostructured fibers were fabricated by combining the electrospinning technique and reflux method. Compared with the pure TiO{sub 2} nanostructured fibers and P25, the TiO{sub 2}-CDs nanostructured fibers exhibited enhanced photocatalytic efficiency of photodegradation of rhodamine B (RhB) under visible light irradiation. The enhanced photocatalytic activity of TiO{sub 2}-CDs nanostructured fibers could be attributed to the presence of CDs embedded in TiO{sub 2} nanostructured fibers. The CD can work as a photosensitizer in the degradation. Furthermore, the TiO{sub 2}-CDs nanostructured fibers could be easily handled and recycled due to their one-dimensional nanostructural property.

  14. Green synthesis of nitrogen-doped graphitic carbon sheets with use of Prunus persica for supercapacitor applications

    Science.gov (United States)

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel; Perumal, Suguna; Lee, Yong Rok

    2017-01-01

    Nitrogen-doped graphitic carbon sheets (N-GCSs) were prepared from the extract of unripe Prunus persica fruit by a direct hydrothermal method. The synthesized N-GCSs were examined by high resolution transmission electron microscopy (HRTEM), nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy. HRTEM showed that the synthesized carbon sheets were graphitic with lattice fringes and an inter-layer distance of 0.36 nm. Doping with the nitrogen moiety present over the synthesized GCSs was confirmed by XPS, FT-IR spectroscopy, and energy dispersive X-ray spectroscopy elemental mapping. The fruit extract associated with hydrothermal-carbonization method is economical and eco-friendly with a single step process. The resulting carbon sheets could be modified and are promising candidates for nano-electronic applications, including supercapacitors. The synthesized N-GCSs-2 provided a high specific capacitance of 176 F g-1 at a current density of 0.1 A g-1. This electrode material has excellent cyclic stability, even after 2000 cycles of charge-discharge at a current density of 0.5 A g-1.

  15. Further investigation on boric acid catalytic graphitization of polyacrylonitrile carbon fibers: Mechanism and mechanical properties

    International Nuclear Information System (INIS)

    Wen, Ya; Lu, Yonggen; Xiao, Hao; Qin, Xianying

    2012-01-01

    Highlights: ► The modulus of carbon fiber was improved by boric acid at the temperature range of 1500–2900 °C. ► 2300 °C is a key temperature degree from which the boron began to benefit fiber strength. ► The fiber strength was affected by the boron reaction and related to the boron states. -- Abstract: Catalytic graphitization of polyacrylonitrile based carbon fibers by boric acid doping was studied and the dependence of fiber tensile strength on the boron content and temperature was discussed. It was found that there existed a key temperature point for the boron to take effect. When the fibers were modified with 7.0 wt.% boric acid solution, with increasing temperature, the tensile strength was lower than that of the unmodified ones below 2300 °C, but a reverse thing happened above 2300 °C. Moreover, when being heated at 2500 °C, the modified fibers showed an increasing tensile modulus and strength with increasing boron content till maximums of 404 GPa and 2.46 GPa, 26% and 16% higher than those of unmodified ones. The mechanical properties of the fibers were affected by the interaction of carbon and boron, and also related with boron states. The decomposition of boron acid and its interaction with carbon brought defects on fiber surface, degrading the mechanical properties below 1300 °C. With further heat treatment, the boron diffused into the fibers and divided into two states: substitutional and interstitial. At a temperature over 2300 °C with an appreciate boron content, the substitutional would be formed predominantly, which removed the structural defects and relaxed the distortions, so as to benefit the mechanical properties.

  16. 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.

  17. Carbon fiber intramedullary nails reduce artifact in postoperative advanced imaging

    International Nuclear Information System (INIS)

    Zimel, Melissa N.; Hwang, Sinchun; Riedel, Elyn R.; Healey, John H.

    2015-01-01

    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.)

  18. Particulate Photocatalyst Sheets Based on Carbon Conductor Layer for Efficient Z-Scheme Pure-Water Splitting at Ambient Pressure.

    Science.gov (United States)

    Wang, Qian; Hisatomi, Takashi; Suzuki, Yohichi; Pan, Zhenhua; Seo, Jeongsuk; Katayama, Masao; Minegishi, Tsutomu; Nishiyama, Hiroshi; Takata, Tsuyoshi; Seki, Kazuhiko; Kudo, Akihiko; Yamada, Taro; Domen, Kazunari

    2017-02-01

    Development of sunlight-driven water splitting systems with high efficiency, scalability, and cost-competitiveness is a central issue for mass production of solar hydrogen as a renewable and storable energy carrier. Photocatalyst sheets comprising a particulate hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) embedded in a conductive thin film can realize efficient and scalable solar hydrogen production using Z-scheme water splitting. However, the use of expensive precious metal thin films that also promote reverse reactions is a major obstacle to developing a cost-effective process at ambient pressure. In this study, we present a standalone particulate photocatalyst sheet based on an earth-abundant, relatively inert, and conductive carbon film for efficient Z-scheme water splitting at ambient pressure. A SrTiO 3 :La,Rh/C/BiVO 4 :Mo sheet is shown to achieve unassisted pure-water (pH 6.8) splitting with a solar-to-hydrogen energy conversion efficiency (STH) of 1.2% at 331 K and 10 kPa, while retaining 80% of this efficiency at 91 kPa. The STH value of 1.0% is the highest among Z-scheme pure water splitting operating at ambient pressure. The working mechanism of the photocatalyst sheet is discussed on the basis of band diagram simulation. In addition, the photocatalyst sheet split pure water more efficiently than conventional powder suspension systems and photoelectrochemical parallel cells because H + and OH - concentration overpotentials and an IR drop between the HEP and OEP were effectively suppressed. The proposed carbon-based photocatalyst sheet, which can be used at ambient pressure, is an important alternative to (photo)electrochemical systems for practical solar hydrogen production.

  19. Polyacrylonitrile Fibers Anchored Cobalt/Graphene Sheet Nanocomposite: A Low-Cost, High-Performance and Reusable Catalyst for Hydrogen Generation.

    Science.gov (United States)

    Zhang, Fei; Huang, Guoji; Hou, Chengyi; Wang, Hongzhi; Zhang, Qinghong; Li, Yaogang

    2016-06-01

    Cobalt and its composites are known to be active and inexpensive catalysts in sodium borohydride (NaBH4) hydrolysis to generate clean and renewable hydrogen energy. A novel fiber catalyst, cobalt/graphene sheet nanocomposite anchored on polyacrylonitrile fibers (Co/GRs-PANFs), which can be easily recycled and used in any reactor with different shapes, were synthesized by anchoring cobalt/graphene (Co/GRs) on polyacrylonitrile fibers coated with graphene (GRs-PANFs) at low temperature. The unique structure design effectively prevents the inter-sheet restacking of Co/GRs and fully exploits the large surface area of novel hybrid material for generate hydrogen. And the extra electron transfer path supplied by GRs on the surface of GRs-PANFs can also enhance their catalysis performances. The catalytic activity of the catalyst was investigated by the hydrolysis of NaBH4 in aqueous solution with GRs-PANFs. GRs powders and Co powders were used as control groups. It was found that both GRs and fiber contributed to the hydrogen generation rate of Co/GRs-PANFs (3222 mL x min(-1) x g(-1)), which is much higher than that of cobalt powders (915 mL x min(-1) x g(-1)) and Co/GRs (995 mL x min(-1) x g(-1)). The improved hydrogen generation rate, low cost and uncomplicated recycling make the Co/GRs-PANFs promising candidate as catalysts for hydrogen generation.

  20. Effects of carbon fiber surface characteristics on interfacial bonding of epoxy resin composite subjected to hygrothermal treatments

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    Qian, Xin; Zou, Ruifen; OuYang, Qin; Wang, Xuefei; Zhang, Yonggang

    2015-02-01

    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/cm3 to 1.80 g/cm3 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 sbnd Csbnd C functional groups was the dominant groups and the relative contents of sbnd Cdbnd O and sbnd COO groups gradually increased in the process of thermo-oxidation and carbonization.

  2. Quantifying Black Carbon Deposition Over the Greenland Ice Sheet from Forest Fires in Canada

    Science.gov (United States)

    Thomas, J. L.; Polashenski, C. M.; Soja, Amber J.; Marelle, L.; Casey, K. A.; Choi, H. D.; Raut, J.-C.; Wiedinmyer, C.; Emmons, L. K.; Fast, J. D.; hide

    2017-01-01

    Black carbon (BC) concentrations observed in 22 snowpits sampled in the northwest sector of the Greenland ice sheet in April 2014 have allowed us to identify a strong and widespread BC aerosol deposition event, which was dated to have accumulated in the pits from two snow storms between 27 July and 2 August 2013. This event comprises a significant portion (57 on average across all pits) of total BC deposition over 10 months (July 2013 to April 2014). Here we link this deposition event to forest fires burning in Canada during summer 2013 using modeling and remote sensing tools. Aerosols were detected by both the Cloud-Aerosol Lidar with Orthogonal Polarization (on board CALIPSO) and Moderate Resolution Imaging Spectroradiometer (Aqua) instruments during transport between Canada and Greenland. We use high-resolution regional chemical transport modeling (WRF-Chem) combined with high-resolution fire emissions (FINNv1.5) to study aerosol emissions, transport, and deposition during this event. The model captures the timing of the BC deposition event and shows that fires in Canada were the main source of deposited BC. However, the model underpredicts BC deposition compared to measurements at all sites by a factor of 2100. Underprediction of modeled BC deposition originates from uncertainties in fire emissions and model treatment of wet removal of aerosols. Improvements in model descriptions of precipitation scavenging and emissions from wildfires are needed to correctly predict deposition, which is critical for determining the climate impacts of aerosols that originate from fires.

  3. Quantifying black carbon deposition over the Greenland ice sheet from forest fires in Canada

    Science.gov (United States)

    Thomas, J. L.; Polashenski, C. M.; Soja, A. J.; Marelle, L.; Casey, K. A.; Choi, H. D.; Raut, J.-C.; Wiedinmyer, C.; Emmons, L. K.; Fast, J. D.; Pelon, J.; Law, K. S.; Flanner, M. G.; Dibb, J. E.

    2017-08-01

    Black carbon (BC) concentrations observed in 22 snowpits sampled in the northwest sector of the Greenland ice sheet in April 2014 have allowed us to identify a strong and widespread BC aerosol deposition event, which was dated to have accumulated in the pits from two snow storms between 27 July and 2 August 2013. This event comprises a significant portion (57% on average across all pits) of total BC deposition over 10 months (July 2013 to April 2014). Here we link this deposition event to forest fires burning in Canada during summer 2013 using modeling and remote sensing tools. Aerosols were detected by both the Cloud-Aerosol Lidar with Orthogonal Polarization (on board CALIPSO) and Moderate Resolution Imaging Spectroradiometer (Aqua) instruments during transport between Canada and Greenland. We use high-resolution regional chemical transport modeling (WRF-Chem) combined with high-resolution fire emissions (FINNv1.5) to study aerosol emissions, transport, and deposition during this event. The model captures the timing of the BC deposition event and shows that fires in Canada were the main source of deposited BC. However, the model underpredicts BC deposition compared to measurements at all sites by a factor of 2-100. Underprediction of modeled BC deposition originates from uncertainties in fire emissions and model treatment of wet removal of aerosols. Improvements in model descriptions of precipitation scavenging and emissions from wildfires are needed to correctly predict deposition, which is critical for determining the climate impacts of aerosols that originate from fires.

  4. Average Frequency – RA Value for Reinforced Concrete Beam Strengthened with Carbon Fibre Sheet

    Directory of Open Access Journals (Sweden)

    Mohamad M. Z.

    2016-01-01

    Full Text Available Acoustic Emission (AE is one of the tools that can be used to detect the crack and to classify the type of the crack of reinforced concrete (RC structure. Dislocation or movement of the material inside the RC may release the transient elastic wave. In this situation, AE plays important role whereby it can be used to capture the transient elastic wave and convert it into AE parameters such as amplitude, count, rise time and duration. Certain parameter can be used directly to evaluate the crack behavior. But in certain cases, the AE parameter needs to add and calculate by using related formula in order to observe the behavior of the crack. Using analysis of average frequency and RA value, the crack can be classified into tensile or shear cracks. In this study, seven phases of increasing static load were used to observe the crack behavior. The beams were tested in two conditions. For the first condition, the beams were tested in original stated without strengthened with carbon fibre sheet (CFS at the bottom of the beam or called as tension part of the beam. For the second condition, the beams were strengthened with CFS at the tension part of the beam. It was found that, beam wrapped with CFS enhanced the strength of the beams in term of maximum ultimate load. Based on the relationship between average frequency (AF and RA value, the cracks of the beams can be classified.

  5. Surface modification of carbon fibers and its effect on the fiber–matrix interaction of UHMWPE based composites

    International Nuclear Information System (INIS)

    Chukov, D.I.; Stepashkin, A.A.; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-01-01

    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

  6. Effect of thermal cycling on flexural properties of carbon-graphite fiber-reinforced polymers.

    Science.gov (United States)

    Segerström, Susanna; Ruyter, I Eystein

    2009-07-01

    To determine flexural strength and modulus after water storage and thermal cycling of carbon-graphite fiber-reinforced (CGFR) polymers based on poly(methyl methacrylate) and a copolymer matrix, and to examine adhesion between fiber and matrix by scanning electron microscopy (SEM). Solvent cleaned carbon-graphite (CG) braided tubes of fibers were treated with a sizing resin. The resin mixture of the matrix was reinforced with 24, 36, 47 and 58wt% (20, 29, 38 and 47vol.%) CG-fibers. After heat polymerization the specimens were kept for 90 days in water and thereafter hydrothermally cycled (12,000 cycles, 5/55 degrees C). Mechanical properties were evaluated by three-point bend testing. After thermal cycling, the adhesion between fibers and matrix was evaluated by SEM. Hydrothermal cycling did not decrease flexural strength of the CGFR polymers with 24 and 36wt% fiber loadings; flexural strength values after thermocycling were 244.8 (+/-32.33)MPa for 24wt% and 441.3 (+/-68.96)MPa for 36wt%. Flexural strength values after thermal cycling were not further increased after increasing the fiber load to 47 (459.2 (+/-45.32)MPa) and 58wt% (310.4 (+/-52.79)MPa). SEM revealed good adhesion between fibers and matrix for all fiber loadings examined. The combination of the fiber treatment and resin matrix described resulted in good adhesion between CG-fibers and matrix. The flexural values for fiber loadings up to 36wt% appear promising for prosthodontic applications such as implant-retained prostheses.

  7. Effects of Mixing the Steel and Carbon Fibers on the Friction and Wear Properties of a PMC Friction Material

    Science.gov (United States)

    Bagheri Kazem Abadi, Sedigheh; Khavandi, Alireza; Kharazi, Yosouf

    2010-04-01

    Friction, fade and wear characteristics of a PMC friction material containing phenolic resin, short carbon fiber, graphite, quartz, barite and steel fiber were investigated through using a small-scale friction testing machine. Four different friction materials with different relative amounts of the carbon fiber and steel fiber were manufactured and tested. Comparing with our previous work which contained only steel fiber as reinforcement, friction characteristics such as fade and recovery and wear resistance were improved significantly by adding a small amount of carbon fiber. For the mixing of carbon and steel fiber, the best frictional and wear behavior was observed with sample containing 4 weight percentage carbon fiber. Worn surface of this specimen was observed by optical microscopy. Results showed that carbon fibers played a significant role in the formation of friction film, which was closely related to the friction performance. The brake pad with Steel fibers in our previous work, showed low friction coefficient and high wear rate. In addition, a friction film was formed on the surface with a relatively poor quality. In contrast, the samples with mixing the steel and carbon fiber generated a stable friction film on the pad surface, which provided excellent friction stability with less wear.

  8. 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.

  9. Capacitor with a composite carbon foam electrode

    Science.gov (United States)

    Mayer, Steven T.; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  10. Roles of acidic functional groups of carbon fiber surfaces in enhancing interfacial adhesion behavior

    International Nuclear Information System (INIS)

    Park, Soo-Jin; Kim, Byung-Joo

    2005-01-01

    The gas phase ozone treatment was used as a method to bind acidic oxygen functional groups on carbon fiber surfaces. The ozone treatment on carbon fibers was varied with the ozone concentration and treatment time. Surface analyses of the carbon fibers before and after treatments were performed by FT-IR, X-ray photoelectron spectrometer (XPS), and dynamic contact angle measurements. Mechanical interfacial properties of the fibers/polymer composites were investigated by using critical stress intensity factor (K IC ) and critical energy release rate (G IC ) measurements. From the results of FT-IR and XPS, it was observed that the oxygen functional groups, such as -OH, O-C=O, C=O, and C-O, were attached on the carbon fiber surfaces after the ozone treatment. The mechanical interfacial properties of the composites also showed higher values than those of untreated composites. Ozone treatment is attributed to the increase of both the acidic functional groups and the degree of adhesion at interfaces between the fibers and polymeric resin in composites

  11. Thin-sheet zinc-coated and carbon steels laser welding

    Directory of Open Access Journals (Sweden)

    Peças, P.

    1998-04-01

    Full Text Available This paper describes the results of a research on CO2 laser welding of thin-sheet carbon steels (zinccoated and uncoated, at several thicknesses combinations. Laser welding has an high potential to be applied on sub-assemblies welding before forming to the automotive industry-tailored blanks. The welding process is studied through the analysis of parameters optimization, metallurgical quality and induced distortions by the welding process. The clamping system and the gas protection system developed are fully described. These systems allow the minimization of common thin-sheet laser welding defects like misalignement, and zinc-coated laser welding defects like porous and zinc volatilization. The laser welding quality is accessed by DIN 8563 standard, and by tensile, microhardness and corrosion tests.

    Este artigo descreve os resultados da investigação da soldadura laser de CO2 de chapa fina de acó carbono (simples e galvanizado, em diferentes combinações de espessura. A soldadura laser é um processo de elevado potencial no fabrico de tailored-blanks (sub-conjuntos para posterior enformação, constituidos por varias partes de diferentes materiais e espessuras para a indústria automóvel. São analisados os aspectos de optimização paramétrica, de qualidade metalúrgica da junta soldada e das deformações resultantes da soldadura. São descritos os mecanismos desenvolvidos de fixação das chapas e protecção gasosa, por forma a minimizar os defeitos típicos na soldadura laser de chapa fina como o desalinhamento e da soldadura laser de chapa galvanizada como os poros e a volatilização do zinco. Por fim apresentam-se resultados da avaliação da qualidade da soldadura do ponto de vista qualitativo através da norma DIN 8563, e do pontos de vista quantitativo através de ensaios de tracção, dureza e corrosão.

  12. A Platform to Optimize the Field Emission Properties of Carbon Nanotube Based Fibers (Postprint)

    Science.gov (United States)

    2016-08-25

    AFRL-RX-WP-JA-2017-0351 A PLATFORM TO OPTIMIZE THE FIELD EMISSION PROPERTIES OF CARBON - NANOTUBE -BASED FIBERS (POSTPRINT) Steven B...28 April 2017 Interim 6 May 2010 – 20 August 2016 4. TITLE AND SUBTITLE A PLATFORM TO OPTIMIZE THE FIELD EMISSION PROPERTIES OF CARBON - NANOTUBE ...Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39-18 A platform to optimize the field emission properties of carbon - nanotube -based

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

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mengjie [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Wang, Shubin, E-mail: shubinwang@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Yu, Yalin; Feng, Qihang; Yang, Jiping; Zhang, Boming [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2017-01-15

    Highlights: • Carboxyl functionalized CF is acquired by simple chemical oxidation method. • These CF have preserved the tensile strength, better electrochemical properties. • The presence of H{sub 3}PO{sub 4} prevented the turbostratic carbon from over-oxidization. • There CF can be used as anodes of multifunctional structural battery. • The preservation and improvement is result from the hindered over-oxidization. - Abstract: Carboxyl functionalized carbon fibers with preserved tensile strength and electrochemical properties were acquired through a simple chemical oxidation method, and the proposed underlying mechanism was verified. The surface of carboxyl functionalizing carbon fibers is necessary in acquiring functional groups on the surface of carbon fibers to further improve the thermal, electrical or mechanical properties of the fibers. Functionalization should preserve the tensile strength and electrochemical properties of carbon fibers, because the anodes of structural batteries need to have high strength and electrochemical properties. Functionalized with mixed H{sub 2}SO{sub 4}/HNO{sub 3} considerably reduced the tensile strength of carbon fibers. By contrast, the appearance of H{sub 3}PO{sub 4} preserved the tensile strength of functionalized carbon fibers, reduced the dispersion level of tensile strength values, and effectively increased the concentration of functional acid groups on the surface of carbon fibers. The presence of phosphoric acid hindered the over-oxidation of turbostratic carbon, and consequently preserved the tensile strength of carbon fibers. The increased proportion of turbostratic carbon on the surface of carbon fibers concurrently enhanced the electrochemical properties of carbon fibers.

  14. Neutron irradiation effects on carbon and graphite cloths and fibers

    International Nuclear Information System (INIS)

    Gray, W.J.

    1977-08-01

    A series of cloth and fiber samples were irradiated to fluences of 3.5, 7.3, and 10 x 10 21 cm -2 at 470 0 C. Dimensional changes of the fibers in the radial direction ranged from -19% to +33% and in the axial direction from -18% to -27%, roughly ten times greater than dimensional changes found for typical nuclear graphites. Despite these large dimensional changes, all but one of the 2-dimensional cloths remained essentially unchanged in overall physical appearance. The 3-dimensional cloths, on the other hand, deteriorated apparently because these types of weaves were less able to accommodate the large axial fiber shrinkages

  15. Development of Circular Disk Model for Polymeric Nanocomposites and Micromechanical Analysis of Residual Stresses in Reinforced Fibers with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    A. R. Ghasemi

    2017-02-01

    Full Text Available In this study, Circular Disk Model (CDM has been developed to determine the residual stresses in twophase and three- phase unit cell. The two-phase unit cell is consisting of carbon fiber and matrix. The three-phase unit cell is consisting of carbon fiber, carbon nanotubes and matrix in which the carbon fiber is reinforced with the carbon nanotube using electrophoresis method. For different volume fractions of carbon nanotubes, thermal properties of the carbon fiber and carbon nanotube in different linear and lateral directions and also different placement conditions of carbon nanotubes have been considered. Also, residual stresses distribution in two and three phases has been studied, separately. Results of micromechanical analysis of residual stresses obtained from Finite Element Method and CDM, confirms the evaluation and development of three dimensional CDM.

  16. PB1-F2 influenza A virus protein adopts a beta-sheet conformation and forms amyloid fibers in membrane environments.

    Science.gov (United States)

    Chevalier, Christophe; Al Bazzal, Ali; Vidic, Jasmina; Février, Vincent; Bourdieu, Christiane; Bouguyon, Edwige; Le Goffic, Ronan; Vautherot, Jean-François; Bernard, Julie; Moudjou, Mohammed; Noinville, Sylvie; Chich, Jean-François; Da Costa, Bruno; Rezaei, Human; Delmas, Bernard

    2010-04-23

    The influenza A virus PB1-F2 protein, encoded by an alternative reading frame in the PB1 polymerase gene, displays a high sequence polymorphism and is reported to contribute to viral pathogenesis in a sequence-specific manner. To gain insights into the functions of PB1-F2, the molecular structure of several PB1-F2 variants produced in Escherichia coli was investigated in different environments. Circular dichroism spectroscopy shows that all variants have a random coil secondary structure in aqueous solution. When incubated in trifluoroethanol polar solvent, all PB1-F2 variants adopt an alpha-helix-rich structure, whereas incubated in acetonitrile, a solvent of medium polarity mimicking the membrane environment, they display beta-sheet secondary structures. Incubated with asolectin liposomes and SDS micelles, PB1-F2 variants also acquire a beta-sheet structure. Dynamic light scattering revealed that the presence of beta-sheets is correlated with an oligomerization/aggregation of PB1-F2. Electron microscopy showed that PB1-F2 forms amorphous aggregates in acetonitrile. In contrast, at low concentrations of SDS, PB1-F2 variants exhibited various abilities to form fibers that were evidenced as amyloid fibers in a thioflavin T assay. Using a recombinant virus and its PB1-F2 knock-out mutant, we show that PB1-F2 also forms amyloid structures in infected cells. Functional membrane permeabilization assays revealed that the PB1-F2 variants can perforate membranes at nanomolar concentrations but with activities found to be sequence-dependent and not obviously correlated with their differential ability to form amyloid fibers. All of these observations suggest that PB1-F2 could be involved in physiological processes through different pathways, permeabilization of cellular membranes, and amyloid fiber formation.

  17. PB1-F2 Influenza A Virus Protein Adopts a β-Sheet Conformation and Forms Amyloid Fibers in Membrane Environments

    Science.gov (United States)

    Chevalier, Christophe; Al Bazzal, Ali; Vidic, Jasmina; Février, Vincent; Bourdieu, Christiane; Bouguyon, Edwige; Le Goffic, Ronan; Vautherot, Jean-François; Bernard, Julie; Moudjou, Mohammed; Noinville, Sylvie; Chich, Jean-François; Da Costa, Bruno; Rezaei, Human; Delmas, Bernard

    2010-01-01

    The influenza A virus PB1-F2 protein, encoded by an alternative reading frame in the PB1 polymerase gene, displays a high sequence polymorphism and is reported to contribute to viral pathogenesis in a sequence-specific manner. To gain insights into the functions of PB1-F2, the molecular structure of several PB1-F2 variants produced in Escherichia coli was investigated in different environments. Circular dichroism spectroscopy shows that all variants have a random coil secondary structure in aqueous solution. When incubated in trifluoroethanol polar solvent, all PB1-F2 variants adopt an α-helix-rich structure, whereas incubated in acetonitrile, a solvent of medium polarity mimicking the membrane environment, they display β-sheet secondary structures. Incubated with asolectin liposomes and SDS micelles, PB1-F2 variants also acquire a β-sheet structure. Dynamic light scattering revealed that the presence of β-sheets is correlated with an oligomerization/aggregation of PB1-F2. Electron microscopy showed that PB1-F2 forms amorphous aggregates in acetonitrile. In contrast, at low concentrations of SDS, PB1-F2 variants exhibited various abilities to form fibers that were evidenced as amyloid fibers in a thioflavin T assay. Using a recombinant virus and its PB1-F2 knock-out mutant, we show that PB1-F2 also forms amyloid structures in infected cells. Functional membrane permeabilization assays revealed that the PB1-F2 variants can perforate membranes at nanomolar concentrations but with activities found to be sequence-dependent and not obviously correlated with their differential ability to form amyloid fibers. All of these observations suggest that PB1-F2 could be involved in physiological processes through different pathways, permeabilization of cellular membranes, and amyloid fiber formation. PMID:20172856

  18. Bootstrap Method for Detecting Damage in Carbon Fiber Reinforced Plastic Using a Macro Fiber Composite Sensor

    OpenAIRE

    DJANSENA, Alradix; 田中, 宏明; 工藤, 亮

    2015-01-01

    CFRP has been used in aircraft structures for decades. Although CFRP is light, its laminationis its main weakness. We have developed a new method to increase the probability of detectingdelamination in carbon fiber reinforced plastic (CFRP) by narrowing the confidence interval ofthe changes in natural frequency. The changes in the natural frequency in delaminated CFRPare tiny compared with measurement errors. We use the bootstrap method, a statisticaltechnique that increases the estimation ac...

  19. 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.

  20. Mechanical and physical properties of carbon-graphite fiber-reinforced polymers intended for implant suprastructures.

    Science.gov (United States)

    Segerström, Susanna; Ruyter, I Eystein

    2007-09-01

    Mechanical properties and quality of fiber/matrix adhesion of poly(methyl methacrylate) (PMMA)-based materials, reinforced with carbon-graphite (CG) fibers that are able to remain in a plastic state until polymerization, were examined. Tubes of cleaned braided CG fibers were treated with a sizing resin. Two resin mixtures, resin A and resin B, stable in the fluid state and containing different cross-linking agents, were reinforced with CG fiber loadings of 24, 36, and 47 wt% (20, 29, and 38 vol.%). In addition, resin B was reinforced with 58 wt% (47 vol.%). After heat-polymerization, flexural strength and modulus were evaluated, both dry and after water storage. Coefficient of thermal expansion, longitudinally and in the transverse direction of the specimens, was determined. Adhesion between fibers and matrix was evaluated with scanning electron microscopy (SEM). Flexural properties and linear coefficient of thermal expansion were similar for both fiber composites. With increased fiber loading, flexural properties increased. For 47 wt% fibers in polymer A the flexural strength was 547.7 (28.12) MPa and for polymer B 563.3 (89.24) MPa when water saturated. Linear coefficient of thermal expansion was for 47 wt% CG fiber-reinforced polymers; -2.5 x 10(-6) degrees C-1 longitudinally and 62.4 x 10(-6) degrees C-1 in the transverse direction of the specimens. SEM revealed good adhesion between fibers and matrix. More porosity was observed with fiber loading of 58 wt%. The fiber treatment and the developed resin matrices resulted in good adhesion between CG fibers and matrix. The properties observed indicate a potential for implant-retained prostheses.

  1. 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.

  2. 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.

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

    International Nuclear Information System (INIS)

    Queiroz, Paulo Cesar Beltrao de; Zouain, Desiree Moraes

    2009-01-01

    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)

  4. Activation and micropore structure determination of activated 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

    1997-09-05

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. These novel monolithic adsorbents can be produced in single pieces to a given size and shape. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The carbon fiber composites are produced at the ORNL and activated at the CAER using different methods, with the aims of producing a uniform degree of activation, and of closely controlling pore structure and adsorptive properties. The main focus of the present work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites and produce controlled pore structures. Several environmental applications have been explored for the activated carbon fiber composites. One of these was to evaluate the activated composites for the separation of CH{sub 4}-CO{sub 2} mixtures, and an apparatus was constructed specifically for this purpose. The composites were further evaluated in the cyclic recovery of volatile organics. The activated carbon fiber composites have also been tested for possible water treatment applications by studying the adsorption of sodium pentachlorophenolate, PCP.

  5. Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing

    Science.gov (United States)

    Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

    2017-11-01

    Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

  6. Histologic pattern of biomechanic properties of the carbon fiber-augmented ligament tendon. A laboratory and clinical study.

    Science.gov (United States)

    Mendes, D G; Iusim, M; Angel, D; Rotem, A; Roffman, M; Grishkan, A; Mordohohovich, D; Boss, J

    1985-06-01

    Implantation of carbon fiber tow (CFT) for ligament and tendon augmentation was investigated in ten dogs and 45 patients. CFT produced a new structure with a remarkably consistent structural pattern. The basic pattern of the CFT-augmented unit consisted of a core of carbon fiber surround by concentric layers of fibroblasts and collagen fibers. This unit structure was developed from continuous irritation of physical structure of the carbon fiber. In dogs, ultimate tensile strength of the augmented tendon one year after surgery averaged 88% of natural tendon. Digestion of the connective tissue component of the CFT unit exposed the original carbon fiber tow. The connective tissue-free CFT maintained its original tensile strength. The continuous production of collagenous tissue surrounding carbon fibers produced a ligamentous structure that was physiologically compatible and biomechanically sufficient.

  7. Solid-state, polymer-based fiber solar cells with carbon nanotube electrodes.

    Science.gov (United States)

    Liu, Dianyi; Zhao, Mingyan; Li, Yan; Bian, Zuqiang; Zhang, Luhui; Shang, Yuanyuan; Xia, Xinyuan; Zhang, Sen; Yun, Daqin; Liu, Zhiwei; Cao, Anyuan; Huang, Chunhui

    2012-12-21

    Most previous fiber-shaped solar cells were based on photoelectrochemical systems involving liquid electrolytes, which had issues such as device encapsulation and stability. Here, we deposited classical semiconducting polymer-based bulk heterojunction layers onto stainless steel wires to form primary electrodes and adopted carbon nanotube thin films or densified yarns to replace conventional metal counter electrodes. The polymer-based fiber cells with nanotube film or yarn electrodes showed power conversion efficiencies in the range 1.4% to 2.3%, with stable performance upon rotation and large-angle bending and during long-time storage without further encapsulation. Our fiber solar cells consisting of a polymeric active layer sandwiched between steel and carbon electrodes have potential in the manufacturing of low-cost, liquid-free, and flexible fiber-based photovoltaics.

  8. 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.

  9. Experimental and numerical study of the electrical anisotropy in unidirectional carbon-fiber-reinforced polymer composites

    Science.gov (United States)

    Park, J. B.; Hwang, T. K.; Kim, H. G.; Doh, Y. D.

    2007-02-01

    In this paper, unidirectional CFRP composites are considered as an electrical percolation system, which consists of electrically conductive carbon fibers and electrically nonconductive epoxy resin. Due to the contact behavior of the carbon fibers, CFRP has electrical conductivity in the width direction. Resistance measurements using the DC four-probe and the DC six-probe methods are conducted for the unidirectional CFRP specimens with different fiber volume fractions, i.e. different contact conditions. On the basis of the electrical anisotropy level obtained, the correlation between the measured anisotropy and the electrical ineffective length δec, over which a broken fiber recovers its current carrying capacity and a key parameter in electromechanical modeling of CFRP, is shown experimentally. The empirical relationship between the electrical anisotropy and δec obtained is also reviewed using a numerical calculation method based on the electric circuit theory of Kirchhoff's rule and the Monte Carlo simulation technique.

  10. Synthesis and Characterization of Carbon Nano fibers Grown on Powdered Activated Carbon

    International Nuclear Information System (INIS)

    Ahmed, Y. M.; Al-Mamun, A.; Jameel, A. T.; AlKhatib, M. F. R.; Amosa, M. K.; AlSaadi, M. A.

    2016-01-01

    Carbon nano fibers (CNFs) were synthesized through nickel ion (Ni 2+ ) impregnation of powdered activated carbon (PAC). Chemical Vapor Deposition (CVD) using acetylene gas, in the presence of hydrogen gas, was employed for the synthesis process. Various percentages (1, 3, 5, and 7 wt. %) of Ni 2+ catalysts were used in the impregnation of Ni 2+ into PAC. Field Emission Scanning Electron Microscope (FESEM), Fourier Transform Infrared (FTIR) Spectroscopy, Energy Dispersive X-Ray Analyzer (EDX), Transmission Electron Microscopy (TEM), Thermal Gravimetric Analysis (TGA), zeta potential, and Brunauer, Emmett, and Teller (BET) were utilized for the characterization of the novel composite, which possessed micro and nano dimensions. FESEM and TEM images revealed that the carbonaceous structure of the nano materials was fibrous instead of tubular with average width varying from 100 to 200 nanometers. The PAC surface area increased from 101 m2/g to 837 m 2 /g after the growth of CNF. TGA combustion temperature range was within 400°C and 570°C, while the average zeta potential of the nano composite materials was −24.9 mV, indicating its moderate dispersive nature in water.

  11. Enhanced CO2 Adsorption on Activated Carbon Fibers Grafted with Nitrogen-Doped Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yu-Chun Chiang

    2017-05-01

    Full Text Available In this paper, multiscale composites formed by grafting N-doped carbon nanotubes (CNs on the surface of polyamide (PAN-based activated carbon fibers (ACFs were investigated and their adsorption performance for CO2 was determined. The spaghetti-like and randomly oriented CNs were homogeneously grown onto ACFs. The pre-immersion of cobalt(II ions for ACFs made the CNs grow above with a large pore size distribution, decreased the oxidation resistance, and exhibited different predominant N-functionalities after chemical vapor deposition processes. Specifically, the CNs grafted on ACFs with or without pre-immersion of cobalt(II ions were characterized by the pyridine-like structures of six-member rings or pyrrolic/amine moieties, respectively. In addition, the loss of microporosity on the specific surface area and pore volume exceeded the gain from the generation of the defects from CNs. The adsorption capacity of CO2 decreased gradually with increasing temperature, implying that CO2 adsorption was exothermic. The adsorption capacities of CO2 at 25 °C and 1 atm were between 1.53 and 1.92 mmol/g and the Freundlich equation fit the adsorption data well. The isosteric enthalpy of adsorption, implying physical adsorption, indicated that the growth of CNTs on the ACFs benefit CO2 adsorption.

  12. 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.

  13. Electroadsorption Desalination with Carbon Nanotube/PAN-Based Carbon Fiber Felt Composites as Electrodes

    Science.gov (United States)

    Liu, Yang; Zhou, Junbo

    2014-01-01

    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. PMID:24963504

  14. Improved interfacial adhesion in carbon fiber/polyether sulfone composites through an organic solvent-free polyamic acid sizing

    International Nuclear Information System (INIS)

    Yuan, Haojie; Zhang, Shouchun; Lu, Chunxiang; He, Shuqing; An, Feng

    2013-01-01

    An organic solvent-free polyamic acid (PAA) nanoemulsion was obtained by direct ionization of the solid PAA in deionized water, with the average particle size of 261 nm and Zeta potential of −55.1 mV, and used as a carbon fiber sizing to improve the interfacial adhesion between the carbon fiber and polyether sulfone (PES). The surface characteristics of PAA coated carbon fibers were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy and dynamic contact angle measurement. The results demonstrated that a continuous and uniform PAA sizing layer was formed on the surface of carbon fibers, and the surface energy of carbon fibers increased from 42.91 to 54.55 mN/m after sizing treatment. The single fiber pull-out testing was also performed, which showed the increased interfacial shear strength (IFSS) of carbon fiber/PES composites from 33.6 to 49.7 MPa by 47.9%. The major reasons for the improved interfacial adhesion were the increased van der Waals forces between the PES matrix and sizing layer as well as the chemical bonding between the sizing layer and carbon fiber surface. Furthermore, the PAA sizing also presented a positive effect on the interfacial adhesion of carbon fiber/PES composites under hydrothermal condition.

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

    OpenAIRE

    Yue Lian-yong; Li Wei; Zu Xu-dong; Huang Zheng-xiang; Gao Zhen-yu

    2016-01-01

    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 pa...

  16. 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.

  17. 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.

  18. Restructured graphene sheets embedded carbon film by oxygen plasma etching and its tribological properties

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Meiling [Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Diao, Dongfeng, E-mail: dfdiao@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China); Yang, Lei [Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Fan, Xue [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China)

    2015-12-01

    Highlights: • Oxygen plasma etching was developed to improve tribological properties of GSEC film. • Etching restructured 3 nm top layer with smaller crystallite size and higher sp{sup 3} fraction. • The etched film had smoother surface, enhanced mechanical properties, longer wear life. • High electrical conductivity and strong magnetism were retained after etching. - Abstract: An oxygen plasma etching technique was introduced for improving the tribological properties of the graphene sheets embedded carbon (GSEC) film in electron cyclotron resonance plasma processing system. The nanostructural changing in the film caused by oxygen plasma etching was examined by transmission electron microscope, Raman spectroscopy and X-ray photoelectron spectroscopy, showing that the 3 nm thick top surface layer was restructured with smaller graphene nanocrystallite size as well as higher sp{sup 3} bond fraction. The surface roughness, mechanical behavior and tribological properties of the original GSEC and oxygen plasma treated GSEC films were compared. The results indicated that after the oxygen plasma treatment, the average roughness decreased from 20.8 ± 1.1 nm to 1.9 ± 0.1 nm, the hardness increased from 2.3 ± 0.1 GPa to 2.9 ± 0.1 GPa, the nanoscratch depth decreased from 64.5 ± 5.4 nm to 9.9 ± 0.9 nm, and the wear life increased from 930 ± 390 cycles to more than 15,000 frictional cycles. The origin of the improved tribological behavior was ascribed to the 3 nm thick graphene nanocrystallite film. This finding can be expected for wide applications in nanoscale surface engineering.

  19. 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

    2013-04-21

    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.

  20. 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.

  1. Method for imparting improved surface properties to carbon fibers and composite

    International Nuclear Information System (INIS)

    Ueno, S.; Kamata, H.

    1984-01-01

    The invention provides a means for solving the problem of poor affinity between the surface of carbon fibers and a synthetic resin in a resin-based composite material reinforced with the carbon fibers. The method comprises subjecting the surface of the carbon fibers in advance to exposure to low temperature plasma in a low pressure atomosphere of an inorganic gas generated by applying an electric voltage between electrodes. It was unexpectedly discovered that the discharge voltage between the electrodes is very critical and satisfactory results can be obtained when the peak-to-peak value of the discharge voltage between electrodes is 4000 volts or higher. The composition of the atmospheric inorganic gas is also important and the gas is preferably oxygen gas or a gaseous mixture containing at least 10% by volume of oxygen

  2. 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.

  3. Acoustic Research on the Damage Mechanism of Carbon Fiber Composite Materials

    Science.gov (United States)

    Wang, Bing; Liu, Yanlei; Sheng, Shuiping

    This thesis involves the study about different processes including the tensile fracture, inter-layer tear or avulsion, as well as the interlaminar shear or split regarding carbon fiber composite materials with the aid of acoustic emission technique. Also, various acoustic emission signals that are released by composite samples in the process of fracture are analyzed. As is indicated by the test results, different acoustic emissive signals that are released by carbon fiber layers in various stages of damage and fracture bear different characteristics. Acoustic detection can effectively monitor the whole stage of elastic deformation, the damage development, and even the accumulation process while figuring out in an efficient manner about the internal activities of the composites, plus the diverse types of damages. In addition, its fabulous application value lies in its relevant structural evaluation as well as the evaluation of integrity with regard to carbon fiber composite.

  4. Investigation of Carbon-Polymer Structures with Embedded Fiber-Optic Bragg Gratings

    Science.gov (United States)

    Grant, Joseph; Kaul, R.; Taylor, S.; Myers, G.; Sharma, A.

    2003-01-01

    Several Bragg-grating sensors fabricated within the same optical fiber are buried within multiple-ply carbon-epoxy planar and cylindrical structures. Effect of different orientation of fiber-sensors with respect to carbon fibers in the composite structure is investigated. This is done for both fabric and uni-tape material samples. Response of planar structures to axial and transverse strain up to 1 millistrain is investigated with distributed Bragg-grating sensors. Material properties like Young's Modulus and Poisson ratio is measured. A comparison is made between response measured by sensors in different ply-layers and those bonded on the surface. The results from buried fiber- sensors do not completely agree with surface bonded conventional strain gauges. A plausible explanation is given for observed differences. The planar structures are subjected to impacts with energies up to 10 ft-lb. Effect of this impact on the material stiffness is also investigated with buried fiber-optic Bragg sensors. The strain response of such optical sensors is also measured for cylindrical carbon-epoxy composite structures. The sensors are buried within the walls of the cylinder as well as surface bonded in both the axial as well as hoop directions. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 1500 psi. This is done at both room temperature as well as cryogenic temperatures. The recorded response is compared with that from a conventional strain gauge.

  5. Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

    KAUST Repository

    Zhou, Jian

    2018-01-22

    Highly conductive and stretchable fibers are crucial components of wearable electronics systems. Excellent electrical conductivity, stretchability, and wearability are required from such fibers. Existing technologies still display limited performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain high sensitivity (with a gauge factor of 425 at 100% strain), high stretchability, and high linearity. They are also reproducible and durable. Their use as safe sensing components on deformable cable, expandable surfaces, and wearable textiles is demonstrated.

  6. Geckolike high shear strength by carbon nanotube fiber adhesives

    Science.gov (United States)

    Maeno, Y.; Nakayama, Y.

    2009-01-01

    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  7. Thermal management of thermoacoustic sound projectors using a free-standing carbon nanotube aerogel sheet as a heat source.

    Science.gov (United States)

    Aliev, Ali E; Mayo, Nathanael K; Baughman, Ray H; Avirovik, Dragan; Priya, Shashank; Zarnetske, Michael R; Blottman, John B

    2014-10-10

    Carbon nanotube (CNT) aerogel sheets produce smooth-spectra sound over a wide frequency range (1-10(5) Hz) by means of thermoacoustic (TA) sound generation. Protective encapsulation of CNT sheets in inert gases between rigid vibrating plates provides resonant features for the TA sound projector and attractive performance at needed low frequencies. Energy conversion efficiencies in air of 2% and 10% underwater, which can be enhanced by further increasing the modulation temperature. Using a developed method for accurate temperature measurements for the thin aerogel CNT sheets, heat dissipation processes, failure mechanisms, and associated power densities are investigated for encapsulated multilayered CNT TA heaters and related to the thermal diffusivity distance when sheet layers are separated. Resulting thermal management methods for high applied power are discussed and deployed to construct efficient and tunable underwater sound projector for operation at relatively low frequencies, 10 Hz-10 kHz. The optimal design of these TA projectors for high-power SONAR arrays is discussed.

  8. Polymer-derived ceramic composite fibers with aligned pristine multiwalled carbon nanotubes.

    Science.gov (United States)

    Sarkar, Sourangsu; Zou, Jianhua; Liu, Jianhua; Xu, Chengying; An, Linan; Zhai, Lei

    2010-04-01

    Polymer-derived ceramic fibers with aligned multiwalled carbon nanotubes (MWCNTs) are fabricated through the electrospinning of polyaluminasilazane solutions with well-dispersed MWCNTs followed by pyrolysis. Poly(3-hexylthiophene)-b-poly (poly (ethylene glycol) methyl ether acrylate) (P3HT-b-PPEGA), a conjugated block copolymer compatible with polyaluminasilazane, is used to functionalize MWCNT surfaces with PPEGA, providing a noninvasive approach to disperse carbon nanotubes in polyaluminasilazane chloroform solutions. The electrospinning of the MWCNT/polyaluminasilazane solutions generates polymer fibers with aligned MWCNTs where MWCNTs are oriented along the electrospun jet by a sink flow. The subsequent pyrolysis of the obtained composite fibers produces ceramic fibers with aligned MWCNTs. The study of the effect of polymer and CNT concentration on the fiber structures shows that the fiber size increases with the increment of polymer concentration, whereas higher CNT content in the polymer solutions leads to thinner fibers attributable to the increased conductivity. Both the SEM and TEM characterization of the polymer and ceramic fibers demonstrates the uniform orientation of CNTs along the fibers, suggesting excellent dispersion of CNTs and efficient CNT alignment via the electrospinning. The electrical conductivity of a ceramic fibers with 1.2% aligned MWCNTs is measured to be 1.58 x 10(-6) S/cm, which is more than 500 times higher than that of bulk ceramic (3.43 x 10(-9) S/cm). Such an approach provides a versatile method to disperse CNTs in preceramic polymer solutions and offers a new approach to integrate aligned CNTs in ceramics.

  9. 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.

    2008-06-01

    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.

  10. Formation of a supersaturated carbon solution in a metal under the process of carbon nano fibers obtaining by PECVD

    International Nuclear Information System (INIS)

    Takopulo, D. A.; Fisenko, S. P.

    2012-01-01

    Heat and mass transfer processes in a highly porous carbon layer appeared on a catalytic surface of a plasma chemical reactor during carbon nano fibers obtaining by PECVD (plasma enhanced CVD) are considered. Nano fibers formation in such a process is carried out as a result of the catalytic decomposition of the carbon contained plasma pyrolysis yields followed by carbon atoms diffusion into the catalyst bulk with a subsequent formation of carbon in a metal solid solution. The results of the numerical investigation of the transfer processes in the porous layer have shown that the layer thickness growth significantly reduces the catalytic surface temperature. This effect causes the carbon solid solution supersaturation, which is an obligatory condition of the carbon clusters nucleation. The transfer problems initial data have been obtained in a result of experimental investigations of thin porous carbon layers gathered from the catalytic surface of the plasma chemical reactor. It have been determined that the layer porosity has an average value of about 70%, and it's effective heat conductivity in the temperature range of 600-1000 C is about 10 -1 W/(m*K) and slightly depends on the temperature. A numerical modeling has been made for a steady state approximation. The correctness of this approximation is based on the comparison of the steady stale stabilization characteristic time with the porous layer growth characteristic time. The latter appeared to be much longer than the former one. (authors).

  11. Characterization of adhesion at carbon fiber-fluorinated epoxy interface and effect of environmental degradation

    Science.gov (United States)

    Dasgupta, Suman

    2011-12-01

    Carbon fiber reinforced polymers are excellent candidates for aerospace, automobile and other mobile applications due to their high specific strength and modulus. The most prominent aerospace application of carbon fiber composites in recent times is the Boeing 787 Dreamliner, which is the world's first major commercial airliner to extensively use composite materials. The critical issue, which needs to be addressed hereby, is long-term safety. Hence, long-term durability of composite materials in such applications becomes a point of concern. Conventional polymer matrices, such as thermosetting resins, which are used as matrix material in carbon fiber composites, are susceptible to degradation in the form of chemical corrosion, UV degradation and moisture, in severe environmental conditions. Fluorinated polymers offer a viable alternative as matrix material, due to their reduced susceptibility to environmental degradation. The epoxy system used in this study is fluorinated Tetra-glycidyl methylene di-aniline (6F-TGMDA), which was developed by polymer scientists at NASA Langley Research Center. The hydrophobic nature of this epoxy makes it a potential matrix material in aerospace applications. However, its compatibility in carbon fiber-reinforced composites remains to be investigated. This study aims to characterize the interfacial properties in carbon fiber reinforced fluorinated epoxy composites. Typical interfacial characterization parameters, like interfacial shear strength, estimated from the microbond test, proved to be inadequate in accurately estimating adhesion since it assumes a uniform distribution of stresses along the embedded fiber length. Also, it does not account for any residual stresses present at the interface, which might arise due to thermal expansion differences and Poisson's ratio differences of the fiber and matrix. Hence, an analytical approach, which calculates adhesion pressure at the interface, was adopted. This required determination of

  12. Effect of Surface Treatment on Performance of Electrode Material Based on Carbon Fiber Cloth

    Directory of Open Access Journals (Sweden)

    XU Jian

    2018-01-01

    Full Text Available The carbon fiber cloth was treated by surface treatment, and then it was used as the electrode substrate. The electrode material based on carbon fibers was synthesized by a galvanostatic electrodeposition method. The interface resistivity, electrochemical property and corrosion resistance of the CF/β-PbO2 electrode were characterized by four-probe method and electrochemical workstation, respectively. The results show that the surface roughness and chemical activity of the carbon fibers can be significantly improved through surface treatment. The carbon fibers possess the best chemical activity on the surface at the hot-air oxidation temperature of 400℃. Joint hot-air and liquid-phase oxidations show that the chemical activity of the carbon fibers on the surface is further improved, the grooves and pits on the surface of the carbon fibers are more obvious, after this treatment, the interface resistivity of the CF/β-PbO2 electrode reaches the minimum value of 6.19×10-5Ω·m, meanwhile, the conductivity and the electrochemical property of the CF/β-PbO2 electrode reaches the best, and with the best corrosion resistance, the corrosion rate is only 1.44×10-3g·cm-2·h-1.Thus, the interface resistivity, electrochemical property and corrosion resistance of the CF/β-PbO2 electrode depend on the the interface structure of the CF/β-PbO2 electrode obtained under different surface treatments.

  13. Carbon Footprint Estimation in Fiber Optics Industry: A Case Study of OFS Fitel, LLC

    Directory of Open Access Journals (Sweden)

    Suresh Inakollu

    2017-05-01

    Full Text Available Detailed carbon footprinting assignments have been on the rise in more and more major manufacturing industries. The main strength of carbon footprinting is to make product manufacturers aware of carbon emissions and understand its meaning due to perceived global warming effects. Carbon foot-printing through life-cycle assessment in conjunction with greenhouse gas (GHG accounting is essential for identifying opportunities for environmental efficiencies. Case studies of goods that require more complex production elements have also been increasing, like optical fiber manufacturing. From making ultra-pure glass rods to elongating hot fibers, the whole process involves using a high volume of chemicals and extensive energy. Hence, standard numbers addressing carbon footprinting specifically for fiber optics is helpful for the quantification of greenhouse gas intensity, mitigation of global warming, and adaptation against future climate change scenarios. This paper calculates and helps standardize the emission factor for the production of optical fiber from the scope of gate-to-gate: 4.81 tonnes CO2eq per million meters of produced fiber (which is 72.92 kg CO2eq per kg of produced fiber in order to allow other industries to use this information in their own carbon footprint calculations. Since governmental regulatory agencies have largely failed to confront the risks associated with climate change borne by industries, it is essential for all industries to disclose their emissions in a standardized and comparable form in order to develop standard guidelines for all. This paper provides a practical life-cycle approach, concludes with requirements for further research and evaluation.

  14. Carbon nanotube-based structural health monitoring for fiber reinforced composite materials

    Science.gov (United States)

    Liu, Hao; Liu, Kan; Mardirossian, Aris; Heider, Dirk; Thostenson, Erik

    2017-04-01

    In fiber reinforced composite materials, the modes of damage accumulation, ranging from microlevel to macro-level (matrix cracks development, fiber breakage, fiber-matrix de-bonding, delamination, etc.), are complex and hard to be detected through conventional non-destructive evaluation methods. Therefore, in order to assure the outstanding structural performance and high durability of the composites, there has been an urgent need for the design and fabrication smart composites with self-damage sensing capabilities. In recent years, the macroscopic forms of carbon nanotube materials have been maturely investigated, which provides the opportunity for structural health monitoring based on the carbon nanotubes that are integrated in the inter-laminar areas of advanced fiber composites. Here in this research, advanced fiber composites embedded with laminated carbon nanotube layers are manufactured for damage detection due to the relevant spatial electrical property changes once damage occurs. The mechanical-electrical coupling response is recorded and analyzed during impact test. The design and manufacturing of integrating the carbon nanotubes intensely affect the detecting sensitivity and repeatability of the integrated multifunctional sensors. The ultimate goal of the reported work is to develop a novel structural health monitoring method with the capability of reporting information on the damage state in a real-time way.

  15. 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.

  16. Controlling the set of carbon-fiber embedded cement with electric current

    Science.gov (United States)

    Mattus, Alfred J.

    2004-06-15

    A method for promoting cement or concrete set on demand for concrete that has been chemically retarded by adding carbon fiber to the concrete, which enables it to become electrically conductive, sodium tartrate retardant, and copper sulfate which forms a copper tartrate complex in alkaline concrete mixes. Using electricity, the concrete mix anodically converts the retarding tartrate to an insoluble polyester polymer. The carbon fibers act as a continuous anode surface with a counter electrode wire embedded in the mix. Upon energizing, the retarding effect of tartrate is defeated by formation of the polyester polymer through condensation esterification thereby allowing the normal set to proceed unimpeded.

  17. Double resonance calibration of g factor standards: Carbon fibers as a high precision standard

    Science.gov (United States)

    Herb, Konstantin; Tschaggelar, Rene; Denninger, Gert; Jeschke, Gunnar

    2018-04-01

    The g factor of paramagnetic defects in commercial high performance carbon fibers was determined by a double resonance experiment based on the Overhauser shift due to hyperfine coupled protons. Our carbon fibers exhibit a single, narrow and perfectly Lorentzian shaped ESR line and a g factor slightly higher than gfree with g = 2.002644 =gfree · (1 + 162ppm) with a relative uncertainty of 15ppm . This precisely known g factor and their inertness qualify them as a high precision g factor standard for general purposes. The double resonance experiment for calibration is applicable to other potential standards with a hyperfine interaction averaged by a process with very short correlation time.

  18. Possibilities to improve electromagnetic shielding of plaster composites adding carbon fibers

    Science.gov (United States)

    Samková, A.; Kulhavý, P.; Pechočiaková, M.

    2017-10-01

    This paper studies size of electromagnetic shielding in plaster composites, using different volume fractions of carbon fibers. Conventional types of plaster, which are normally used in construction (i.e. cement, lime, gypsum and lime cement) were the main parts of the created composites The carbon microfibers with a length of 8 mm were added as reinforcing and simultaneously shielding element into plaster samples. The tested samples were created at three different volume fractions of the fibres and also into the base plaster for possibilities of their comparison. The results of carried measurement show that the electromagnetic shielding in the plaster composite grows with increasing fiber content in the tested ratio almost linearly.

  19. Curing agent for polyepoxides and epoxy resins and composites cured therewith. [preventing carbon fiber release

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D. (Inventor)

    1981-01-01

    A curing for a polyepoxide is described which contains a divalent aryl radical such as phenylene a tetravalent aryl radical such as a tetravalent benzene radical. An epoxide is cured by admixture with the curing agent. The cured epoxy product retains the usual properties of cured epoxides and, in addition, has a higher char residue after burning, on the order of 45% by weight. The higher char residue is of value in preventing release to the atmosphere of carbon fibers from carbon fiber-epoxy resin composites in the event of burning of the composite.

  20. Current Status of the Carbon Fiber Industry in Japan

    Science.gov (United States)

    1989-04-01

    has been improving steadily since then. Several large Japanese manu- facturing corporations, such as Toray, Toho, Mitsubishi Rayon, and Kureha , are...remaining 15 percent or less is mostly general-purpose pitch-based fibers produced by Kureha Co., Mitsubishi Chemical Co., and Osaka Gas Co. Some high...2 5.9 315 LM-5 5.9 345 HM-2 4.7 420 SM-1 3.9 485 Producers of Pitch-Based Fibers Kureha Chemical Industry Co., Ud. This company produces

  1. 3D-Printing of Meso-structurally Ordered Carbon Fiber/Polymer Composites with Unprecedented Orthotropic Physical Properties

    Science.gov (United States)

    Lewicki, James P.; Rodriguez, Jennifer N.; Zhu, Cheng; Worsley, Marcus A.; Wu, Amanda S.; Kanarska, Yuliya; Horn, John D.; Duoss, Eric B.; Ortega, Jason M.; Elmer, William; Hensleigh, Ryan; Fellini, Ryan A.; King, Michael J.

    2017-03-01

    Here we report the first example of a class of additively manufactured carbon fiber reinforced composite (AMCFRC) materials which have been achieved through the use of a latent thermal cured aromatic thermoset resin system, through an adaptation of direct ink writing (DIW) 3D-printing technology. We have developed a means of printing high performance thermoset carbon fiber composites, which allow the fiber component of a resin and carbon fiber fluid to be aligned in three dimensions via controlled micro-extrusion and subsequently cured into complex geometries. Characterization of our composite systems clearly show that we achieved a high order of fiber alignment within the composite microstructure, which in turn allows these materials to outperform equivalently filled randomly oriented carbon fiber and polymer composites. Furthermore, our AM carbon fiber composite systems exhibit highly orthotropic mechanical and electrical responses as a direct result of the alignment of carbon fiber bundles in the microscale which we predict will ultimately lead to the design of truly tailorable carbon fiber/polymer hybrid materials having locally programmable complex electrical, thermal and mechanical response.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (paper)

  3. Green synthesis of nitrogen-doped graphitic carbon sheets with use of Prunus persica for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Atchudan, Raji, E-mail: atchudanr@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of); Edison, Thomas Nesakumar Jebakumar Immanuel [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of); Perumal, Suguna [Department of Applied Chemistry, Kyungpook National University, Daegu 41566 (Korea, Republic of); Lee, Yong Rok, E-mail: yrlee@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of)

    2017-01-30

    Highlights: • N-GCSs was synthesized from the unripe Prunus persica by direct hydrothermal method. • The resulting N-GCSs-2 exhibit an excellent graphitization with 9.33% of nitrogen. • N-GCSs-2 provide high C{sub s} of 176 F g{sup −1} at current density of 0.1 A g{sup −1} in 1 M H{sub 2}SO{sub 4}. • N-GCSs-2 have high capacitance retention and 20% capacity growth after 2000 cycles. • First time, N-GCSs resulted from peach via green route for flexible supercapacitors. - Abstract: Nitrogen-doped graphitic carbon sheets (N-GCSs) were prepared from the extract of unripe Prunus persica fruit by a direct hydrothermal method. The synthesized N-GCSs were examined by high resolution transmission electron microscopy (HRTEM), nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy. HRTEM showed that the synthesized carbon sheets were graphitic with lattice fringes and an inter-layer distance of 0.36 nm. Doping with the nitrogen moiety present over the synthesized GCSs was confirmed by XPS, FT-IR spectroscopy, and energy dispersive X-ray spectroscopy elemental mapping. The fruit extract associated with hydrothermal-carbonization method is economical and eco-friendly with a single step process. The resulting carbon sheets could be modified and are promising candidates for nano-electronic applications, including supercapacitors. The synthesized N-GCSs-2 provided a high specific capacitance of 176 F g{sup −1} at a current density of 0.1 A g{sup −1}. This electrode material has excellent cyclic stability, even after 2000 cycles of charge-discharge at a current density of 0.5 A g{sup −1}.

  4. Fibers comprised of epitaxially grown single-wall carbon nanotubes, and a method for added catalyst and continuous growth at the tip

    Science.gov (United States)

    Kittrell, W. Carter; Wang, Yuhuang; Kim, Myung Jong; Hauge, Robert H.; Smalley, Richard E.; Marek leg, Irene Morin

    2010-06-01

    The present invention is directed to fibers of epitaxially grown single-wall carbon nanotubes (SWNTs) and methods of making same. Such methods generally comprise the steps of: (a) providing a spun SWNT fiber; (b) cutting the fiber substantially perpendicular to the fiber axis to yield a cut fiber; (c) etching the cut fiber at its end with a plasma to yield an etched cut fiber; (d) depositing metal catalyst on the etched cut fiber end to form a continuous SWNT fiber precursor; and (e) introducing feedstock gases under SWNT growth conditions to grow the continuous SWNT fiber precursor into a continuous SWNT fiber.

  5. 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.

  6. Atomistics of carbon nanotube-polyacrylonitrile interfaces for next-generation carbon fibers: A multiscale computational study

    Science.gov (United States)

    Lee, Juho; Choi, Ji Il; Jang, Seung Soon; Kumar, Satish; Cho, Art E.; Kim, Yong-Hoon

    Atomic-scale understanding of the carbon nanotube (CNT) - polyacrylonitrile (PAN) interfaces is a critical missing element for the development of next-generation carbon fibers. In this presentation, we provide the systematic atomistic analyses of the CNT-PAN interfaces based on a multiscale computational approach combining density-functional theory (DFT) and force-fields molecular dynamics (FFMD) simulations. Based on DFT calculations, we identify the preferable CNT-PAN configurations and furthermore elucidate the electronic origin of the CNT-PAN binding. Next, via FFMD simulations, we extract more realistic large-scale interfacial CNT-PAN atomic configurations and confirm that they faithfully reflect the geometric motives identified in DFT calculations. Implications of our findings in the context of development of advanced carbon fibers will be discussed. corresponding author.

  7. Hybrid Carbon-Glass Fiber/Toughened Epoxy Thick Composite Joints Subject to Drop-Weight and Ballistic Impacts

    National Research Council Canada - National Science Library

    Liaw, Benjamin; Delale, Feridun

    2007-01-01

    .... The main objectives of this project are (1) to conduct tensile, drop-weight impact and ballistic impact tests of monolithic S2 glass fiber/toughened epoxy composites and hybrid carbon-S2 glass fiber/toughened epoxy composites, (2...

  8. Synergistic Effect between Metal-Nitrogen-Carbon Sheets and NiO Nanoparticles for Enhanced Electrochemical Water-Oxidation Performance.

    Science.gov (United States)

    Wang, Jun; Li, Kai; Zhong, Hai-xia; Xu, Dan; Wang, Zhong-li; Jiang, Zheng; Wu, Zhi-jian; Zhang, Xin-bo

    2015-09-01

    Identifying effective means to improve the electrochemical performance of oxygen-evolution catalysts represents a significant challenge in several emerging renewable energy technologies. Herein, we consider metal-nitrogen-carbon sheets which are commonly used for catalyzing the oxygen-reduction reaction (ORR), as the support to load NiO nanoparticles for the oxygen-evolution reaction (OER). FeNC sheets, as the advanced supports, synergistically promote the NiO nanocatalysts to exhibit superior performance in alkaline media, which is confirmed by experimental observations and density functional theory (DFT) calculations. Our findings show the advantages in considering the support effect for designing highly active, durable, and cost-effective OER electrocatalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Fatigue Damage Evaluation of Short Carbon Fiber Reinforced Plastics Based on Phase Information of Thermoelastic Temperature Change

    OpenAIRE

    Shiozawa, Daiki; Sakagami, Takahide; Nakamura, Yu; Nonaka, Shinichi; Hamada, Kenichi

    2017-01-01

    Carbon fiber-reinforced plastic (CFRP) is widely used for structural members of transportation vehicles such as automobile, aircraft, or spacecraft, utilizing its excellent specific strength and specific rigidity in contrast with the metal. Short carbon fiber composite materials are receiving a lot of attentions because of their excellent moldability and productivity, however they show complicated behaviors in fatigue fracture due to the random fibers orientation. In this study, thermoelastic...

  10. 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.

  11. Static and dynamic behavior of carbon fiber reinforced aluminum (CARALL) laminates

    Science.gov (United States)

    Dhaliwal, Gurpinder Singh

    The main aim of this research work was to investigate the static and dynamic properties of carbon fiber reinforced aluminum laminates cured without using any external adhesive and acid treatment of aluminum layers. A comprehensive study was undertaken to study the effect of adding epoxy resin rich polyester synthetic surface veil cloth layers on the failure modes and flexural and tensile response of these fiber metal laminates (FMLs). The main purpose of adding veil cloth layers was to prevent the occurrence of galvanic corrosion by avoiding direct contact between aluminum and carbon fiber layers. The addition of veil cloth layers leads to the combined failure of all layers in carbon fiber reinforced aluminum laminates at the same time, whereas the carbon fiber/ epoxy layers break before the failure of aluminum layers in samples cured without using veil cloth layers under tensile loading. The delamination was found to be reduced to a great extent in these laminate configurations due to the addition of veil cloth layers. Thermal residual stress developed during the curing of fiber metal laminates were predicted by utilizing analytical equations and finite element modeling. It was found out that the veil cloth layer does not affect much in reducing the thermal residual stress. Low-velocity impact tests were carried out using a drop-weight impact tower by impacting these fiber metal laminates at the center with three different energy levels to address energy absorption characteristics of these composites. Results showed that these laminates give higher forces and smaller displacement with the addition of polyester veil cloth layers due to reduced delaminated area across all interfaces of aluminum and carbon fiber layers, thus increasing slightly the energy absorption capabilities of these laminates. Primary failure modes observed during impact tests in these FMLs were cracks in the non-impacted aluminum layer, carbon fiber (CFRP) layer breakage and delamination b

  12. Influence of double hydrogen bonds and alkyl chains on the gelation of nonchiral polyurethane model compounds: sheets, eaves trough, tubes and oriented fibers.

    Science.gov (United States)

    Khanna, Shalini; Khan, Mostofa Kamal; Sundararajan, Pudupadi

    2009-11-17

    We describe the gelation, upon self-assembly of a series of nonchiral molecules, resulting in tubular morphology of the fibers. These are biscarbamates, which are model compounds for polyurethanes with two hydrogen bonding groups separated by a (CH(2))(6) spacer and symmetrically substituted with alkyl chains on either side varying in length from C(6) to C(18). Upon gelation, these molecules form a sheet initially. The sheets then tend to wrap, leading to tubules. Those with partial wrapping resemble eaves troughs. With the predominant growth along the hydrogen bonding direction, the energy of interaction between the molecules along this direction would be more dominant than just the van der Waals interaction in the other two, leading to asymmetry of interaction in the sheet. We rationalize such tube formation in this case on the basis of the theories [Schnur, J. M.; Ratna, B. R.; Selinger, J. V.; Singh, A.; Jyothi, G.; Easwaran, K. R. K. Science, 1994, 264, 945. Schnur, J. M. Science, 1993, 262, 166. McKierman, R. L.; Heintz, A. M.; Hsu, S. L.; Gido, S. P.; Penelle, J. Polym. Mater. Sci. Eng. 2001, 84, 416.] which were developed for amphiphilic mono and bilayers, which state that these bilayers are not at their minimal energy when they are flat, and prefer a bent state. The gelation behavior of this series with double hydrogen bond is compared with the monocarbamates with a single hydrogen bonding motif [Moniruzzaman, M.; Sundararajan, P. R. Langmuir 2005, 21, 3802.]. We attribute the tendency toward both gelation and crystallization in some cases to the competing contributions of the hydrogen bond and van der Waals interactions between the long alkyl side chains. Oriented fibers for X-ray diffraction were obtained by simply using a magnetic stir bar during gelation. It is also found that the solvents that gel with diureas [van Esch, J.; Kellogg, R. M.; Feringa, B. L. Tetrahedron Lett. 1997, 38, 281] also form gels with biscarbamates. While the biscarbamates with

  13. Smart carbon nanotube/fiber and PVA fiber-reinforced composites for stress sensing and chloride ion detection

    Science.gov (United States)

    Hoheneder, Joshua

    Fiber reinforced composites (FRC) with polyvinyl alcohol (PVA) fibers and carbon nanofibers (CNF) had an excellent flexural strength in excess of 18.5 MPa compared to reference samples of 15.8 MPa. It was found that the developed, depending on applied stress and exposure to chloride solutions, composites exhibit some electrical conductivity, from 4.20×10 -4 (Ω-1m-1 to 4.13×10 -4 Ω-1m-1. These dependences can be characterized by piezioresistive and chemoresistive coefficients demonstrating that the material possesses self-sensing capabilities. The sensitivity to stain and chloride solutions can be enhanced by incorporating small amounts of carbon nanofibers (CNF) or carbon nanotube (CNT) into composite structure. Conducted research has demonstrated a strong dependency of electrical properties of composite on crack formation in moist environments. The developed procedure is scalable for industrial application in concrete structures that require nondestructive stress monitoring, integrity under high service loads and stability in harsh environments.

  14. Synthesis and characterization of vertically aligned carbon nanotube forest for solid state fiber spinning.

    Science.gov (United States)

    Ryu, Seong Woo; Hwang, Jae Won; Hong, Soon Hyung

    2012-07-01

    Continuous carbon nanotubes (CNT) fibers were directly spun from a vertically aligned CNT forest grown by a plasma-enhanced chemical vapor deposition (PECVD) process. The correlation of the CNT structure with Fe catalyst coarsening, reaction time, and the CNTs bundling phenomenon was investigated. We controlled the diameters and walls of the CNTs and minimized the amorphous carbon deposition on the CNTs for favorable bundling and spinning of the CNT fibers. The CNT fibers were fabricated with an as-grown vertically aligned CNT forest by a PECVD process using nanocatalyst an Al2O3 buffer layer, followed by a dry spinning process. Well-aligned CNT fibers were successfully manufactured using a dry spinning process and a surface tension-based densification process by ethanol. The mechanical properties were characterized for the CNT fibers spun from different lengths of a vertically aligned CNT forest. Highly oriented CNT fibers from the dry spinning process were characterized with high strength, high modulus, and high electrical as well as thermal conductivities for possible application as ultralight, highly strong structural materials. Examples of structural materials include space elevator cables, artificial muscle, and armor material, while multifunctional materials include E-textile, touch panels, biosensors, and super capacitors.

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

    Directory of Open Access Journals (Sweden)

    Haitao Wang

    2014-02-01

    Full Text Available 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.

  16. A technique to evaluate the good operation of FBG sensors embedded in a carbon fiber beam

    Science.gov (United States)

    Cazzulani, Gabriele; Cinquemani, Simone; Comolli, Lorenzo

    2013-05-01

    Embedding FBG sensors in carbon fiber structures is a very attractive solution, due to the small fiber diameter, and the possibility to manufacture arrays of many gratings into a single optical fiber. These embedding is particularly useful for the manufacturing of smart structures, able to improve their characteristics thanks to embedded sensors and actuators. In this work a carbon fiber beam of 3 m length, with an array of 30 FBG sensors and 3 piezoelectric actuators, is described. The focus of the work is on the evaluation of the good operation of embedded FBG sensors, that is not easy due to the microstructure of woven carbon fiber layers, producing non-homogeneous strain field, a well known problem for the reliability of FBG strain measurements. The proposed technique looks at the standard deviation of the full width at -6 dB of the spectra of each FBG sensors, during a quasi-static motion producing quasi-static strains. 37% of the 30 FBG sensors have been found to produce measurements corrupted by a small error. At the end, vibration control of the described structure is shown.

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

    Directory of Open Access Journals (Sweden)

    M. M. VIEIRA

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

  18. Nitrogen-doped two-dimensional porous carbon sheets derived from clover biomass for high performance supercapacitors

    Science.gov (United States)

    Wang, Cunjing; Wu, Dapeng; Wang, Hongju; Gao, Zhiyong; Xu, Fang; Jiang, Kai

    2017-09-01

    Highly porous carbon sheets were prepared from fresh clover stems under air atmosphere via a facile potassium chloride salt-sealing technique, which not only avoids using the high cost inert gas protection but also spontaneously introduce multi-level porosity into the carbon structure taking advantage of the trace of oxygen in the molten salt system. The as-obtained porous carbon sheets possess high specific surface area of 2244 m2 g-1 and interconnected hierarchical pore structures from micro-to macro-scale, which provide abundant storage active sites and fast ion diffusion channels. In addition, the spontaneously formed N (2.55 at%) and O (6.94 at%) doping sites not only improve the electron conductivity of the electrode but also enhance the specific capacitance by introducing pseudocapacitance. When employed as supercapacitor electrodes, a high specific capacitance of 436 F g-1 at 1 A g-1 and an excellent rate capacity with capacitance remaining 290 F g-1 at 50 A g-1 are demonstrated. Furthermore, the assembled symmetric supercapacitor delivers a high specific capacitance of 420 F g-1 at 0.5 A g-1, excellent energy density of 58.4 Wh kg-1 and good cycling stability which retains 99.4% of the initial capacitance at 5 A g-1 after 30,000 cycles.

  19. Synergistic increase of oxygen reduction favourable Fe-N coordination structures in a ternary hybrid of carbon nanospheres/carbon nanotubes/graphene sheets.

    Science.gov (United States)

    Zhang, Shiming; Liu, Bin; Chen, Shengli

    2013-11-14

    A Fe/N co-doped ternary nanocarbon hybrid, with uniform bamboo-like carbon nanotubes (CNTs) in situ grown on/between the single/few-layer graphene sheets interspaced by carbon nanosphere aggregates, was prepared through a one-pot heat treatment of a precursor mixture containing graphene oxide, Vulcan XC-72 carbon nanospheres, nitrogen rich melamine and small amounts of Fe ions. Physical characterization including electron microscopic images, N2 adsorption-desorption isotherms, pore size distribution, XPS, XRD, Mössbauer spectra, and EDX revealed that the 0-D/1-D/2-D ternary hybrid architecture not only offered an optimized morphology for high dispersion of each nanocarbon moiety, while the carbon nanosphere interspaced graphene sheets have provided a platform for efficient reaction between Fe ions and melamine molecules, resulting in uniform nucleation and growth of CNTs and formation of high density Fe-N coordination assemblies that have been believed to be the active centers for the oxygen reduction reaction (ORR) in carbon-based nonprecious metal electrocatalysts. In the absence of graphene oxides or carbon nanospheres, a similar heat treatment was found to result in large amounts of elemental Fe and Fe carbides and entangled CNTs with wide diameter distributions. As a result, the ternary Fe/N-doped nanocarbon hybrid exhibits ORR activity much higher than the Fe-N doped single or binary nanocarbon materials prepared under similar heat treatment conditions, and approaching that of the state-of-the-art carbon-supported platinum catalyst (Pt/C) in acidic media, as well as superior stability and methanol tolerance to Pt/C.

  20. Specific-heat measurement of single metallic, carbon, and ceramic fibers at very high temperature

    International Nuclear Information System (INIS)

    Pradere, C.; Goyheneche, J.M.; Batsale, J.C.; Dilhaire, S.; Pailler, R.

    2005-01-01

    The main objective of this work is to present a method for measuring the specific heat of single metallic, carbon, and ceramic fibers at very high temperature. The difficulty of the measurement is due to the microscale of the fiber (≅10 μm) and the important range of temperature (700-2700 K). An experimental device, a modelization of the thermal behavior, and an analytic model have been developed. A discussion on the measurement accuracy yields a global uncertainty lower than 10%. The characterization of a tungsten filament with thermal properties identical to those of the bulk allows the validation of the device and the thermal estimation method. Finally, measurements on carbon and ceramic fibers have been done at very high temperature

  1. AN INITIAL EVALUATION OF POLY(VINYLACETYLENE) AS A CARBON-FIBER PRECURSOR

    NARCIS (Netherlands)

    MAVINKURVE, A; VISSER, S; PENNINGS, AJ

    1995-01-01

    Poly(vinylacetylene) obtained by the selective polymerization of monovinylacetylene through the vinyl group has been investigated for its use as an alternative precursor for carbon fibers. The low yield of char obtained on pyrolysis of the polymer in an inert atmosphere was improved dramatically by

  2. Laser surface treatment for enhanced titanium to carbon fiber-reinforced polymer adhesion

    NARCIS (Netherlands)

    Palavra, Armin; Coelho, Bruno N.; de Hosson, Jeff Th. M.; Lima, Milton S. F.; Carvalho, Sheila M.; Costa, Adilson R.

    The adhesion between carbon fiber-reinforced polymer (CFRP) and titanium parts can be improved by laser surface texturing before gluing them together. Here, a pulsed Nd:YAG laser was employed before bonding of the textured surfaces using an epoxy paste adhesive. To investigate the influence of the

  3. 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

  4. Microstructure and mechanical properties of CVI carbon fiber/SiC composites

    International Nuclear Information System (INIS)

    Noda, T.; Araki, H.; Abe, F.; Okada, M.

    1992-01-01

    Microstructures and mechanical properties of carbon fiber/SiC composites prepared with chemical vapor infiltration (CVI) were examined to optimize the process conditions such as reactant and infiltration temperature. Ethyl-trichloro-silane (ETS) and methyl-trichloro-silane (MTS) were used as a source of SiC. CVI was conducted for 108 ks at maximum under a pressure of 13.3 kPa at 1273-1573 K. The composite with a density higher than 80% was obtained at 1373-1423 K and 1423-1374 K from ETS and MTS, respectively. The main matrix formed was β SiC for both reactants. However, silicon also deposited in SiC matrix for MTS. Preferential wettability of SiC to the carbon fiber was observed, and graphite was detected in the interface between the matrix and the carbon fiber by TEM. Mechanical properties were evaluated by bend tests at room temperature. High strength of around 800 MPa was obtained for the composites if the thickness of the surface coated layer was less than 50 μm. Apparent fracture thoughness of the present carbon fiber/SiC composite was 6-10 MPa m 1/2 at room temperature. (orig.)

  5. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant.

    Science.gov (United States)

    Petersen, Richard C

    2011-05-03

    Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P < 10 -4 , and 19.3% to 77.7% at 0.1 mm, P < 10 -8 . Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  6. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2011-01-01

    Full Text Available Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P<10−4, and 19.3% to 77.7% at 0.1 mm, P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  7. 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

  8. Calculation of the bending of electromechanical aircraft element made of the carbon fiber

    Science.gov (United States)

    Danilova-Volkovskaya, Galina; Chepurnenko, Anton; Begak, Aleksandr; Savchenko, Andrey

    2017-10-01

    We consider a method of calculation of an orthotropic plate with variable thickness. The solution is performed numerically by the finite element method. The calculation is made for the springs of a hang glider made of carbon fiber. The comparison of the results with Sofistik software complex is given.

  9. 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...

  10. The synthesis of a new kind of magnetic coating on carbon fibers by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Wang Rui; Wan Yizao; He Fang; Qi Yu; You Wei [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Luo Honglin, E-mail: hlluo64@yahoo.com [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2012-01-15

    Nickel/Fe{sub 3}O{sub 4} nanoparticle (Ni/Fe{sub 3}O{sub 4}-NPs) composite coatings on the surface of carbon fiber were prepared by electrodeposition in a nickel-plating bath containing Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}-NPs). The composite of carbon fiber with nanocomposite coatings were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) analysis, thermogravimetric (TG) analysis and vibrating sample magnetometer (VSM). The microstructure observation reveals that the Fe{sub 3}O{sub 4}-NPs distribute uniformly in the coatings. TG and VSM analysis show that the carbon fibers with Ni/Fe{sub 3}O{sub 4}-NPs composite coatings exhibit higher thermal stability and saturation magnetization than carbon fiber with Ni coatings. The result is attributed to the homogeneous distribution of magnetic Fe{sub 3}O{sub 4} in the composite coatings.

  11. Sterilization Decomposition Evaluation of Composite Materials based on Carbon Fibers for use in Medicine

    Czech Academy of Sciences Publication Activity Database

    Sedláček, R.; Suchý, Tomáš; Balík, Karel; Sochor, M.; Sucharda, Zbyněk

    2011-01-01

    Roč. 14, 109-111 (2011), s. 9-11 ISSN 1429-7248 R&D Projects: GA ČR(CZ) GAP108/10/1457 Institutional research plan: CEZ:AV0Z30460519 Keywords : composite material * sterilization decomposition * carbon fibers Subject RIV: BO - Biophysics http://www.biomat.krakow.pl/english/journal/editorial.html

  12. Mechanical and Electrical Characterization of Novel Carbon Nano Fiber Ultralow Density Foam

    Science.gov (United States)

    2013-12-01

    Measure changes in the sample conductivity as pressure is applied or as space between fibers is reduced and more physical contacts among nanomaterials ...film piezoresistive sensors,” Carbon, vol. 59, pp. 315–324, Aug 2013. [15] C. Rao et al., “Large aligned-nanotube bundles from ferrocene pyrolysis

  13. Electromagnetic shielding of epoxy resin composites containing carbon fibers coated with polyaniline base

    Czech Academy of Sciences Publication Activity Database

    Paligová, M.; Vilčáková, J.; Sáha, P.; Křesálek, V.; Stejskal, Jaroslav; Quadrat, Otakar

    2004-01-01

    Roč. 335, 3-4 (2004), s. 421-429 ISSN 0378-4371 R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : polymer composites * short carbon fibers * polyaniline base Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.369, year: 2004

  14. Fiber

    Science.gov (United States)

    ... for the treatment of diverticulosis , diabetes , and heart disease . ... fiber is found in oat bran, barley, nuts, seeds, beans, lentils, peas, ... heart disease. Insoluble fiber is found in foods such as ...

  15. Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel.

    Science.gov (United States)

    Park, Jaeyeong; Kim, Jung-Su; Kang, Minju; Sohn, Seok Su; Cho, Won Tae; Kim, Hyoung Seop; Lee, Sunghak

    2017-01-09

    TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties.

  16. Durability-Based Design Properties of Reference Crossply Carbon-Fiber Composite

    Energy Technology Data Exchange (ETDEWEB)

    Corum, J.M.

    2001-04-16

    This report provides recommended durability-based design properties and criteria for a crossply carbon-fiber composite for possible automotive structural applications. Although the composite utilized aerospace-grade carbon-fiber reinforcement, it was made by a rapid-molding process suitable for high-volume automotive use. The material is the first in a planned progression of candidate composites to be characterized as part of an Oak Ridge National Laboratory project entitled Durability of Carbon-Fiber Composites. The overall goal of the project, which is sponsored by the U.S. Department of Energy's Office of Advanced Automotive Technologies and is closely coordinated with the Advanced Composites Consortium, is to develop durability-drive