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Hajeeassa, Khdejah S., Mahmoud A. Hussein, Yasir Anwar, Nada Y. Tashkandi, and Zahra M. Al-amshany. "Nanocomposites containing polyvinyl alcohol and reinforced carbon-based nanofiller." Nanobiomedicine 5 (January 1, 2018): 184954351879481. http://dx.doi.org/10.1177/1849543518794818.
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A new class of biologically active polymer nanocomposites based on polyvinyl alcohol and reinforced mixed graphene/carbon nanotube as carbon-based nanofillers with a general abbreviation (polyvinyl alcohol/mixed graphene–carbon nanotubes) has been successfully synthesized by an efficient solution mixing method with the help of ultrasonic radiation. Mixed graphene and carbon nanotubes ratio has been prepared (50%:50%) wt by wt. Different loading of mixed graphene–carbon nanotubes (2, 5, 10, 15, and 20 wt%) were added to the host polyvinyl alcohol polymer. In this study, polyvinyl alcohol/mixed graphene–carbon nanotubesa–e nanocomposites were characterized and analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, and the thermal stability was measured by thermogravimetric analysis and derivative thermal gravimetric. Fourier transform infrared and X-ray diffraction spectra proved the addition of mixed graphene–carbon nanotubes into polyvinyl alcohol matrix. X-ray diffraction patterns for these nanocomposites showed 2 θ = 19.35° and 40° due to the crystal nature of polyvinyl alcohol in addition to 2 θ = 26.5° which attributed to the graphite plane of carbon-based nanofillers. Thermal stability of polyvinyl alcohol/mixed graphene–carbon nanotubes nanocomposites was enhanced comparing with pure polyvinyl alcohol. The main degradation step ranged between 360° and 450°C. Moreover, maximum composite degradation temperature has appeared at range from 285°C to 267°C and final composite degradation temperature (FCDT) displayed at a temperature range of 469–491°C. Antibacterial property of polyvinyl alcohol/mixed graphene–carbon nanotubesa–e nanocomposites were tested against Escherichia coli bacteria using the colony forming units technique. Results showed an improvement of antibacterial property. The rate percentages of polyvinyl alcohol/mixed graphene–carbon nanotubesb, polyvinyl alcohol/mixed graphene–carbon nanotubesc, and polyvinyl alcohol/mixed graphene–carbon nanotubesd nanocomposites after 24 h are 6%, 5%, and 7% respectively. However, polyvinyl alcohol/mixed graphene–carbon nanotubese nanocomposite showed hyperactivity, where its reduction percentage remarkably raised up to 100% which is the highest inhibition rate percentage. In addition, polyvinyl alcohol and polyvinyl alcohol/graphene–carbon nanotubesa–d showed colony forming units values/ml 70 × 106 and 65 ± 2 × 106 after 12 h. After 24 h, the colony forming units values/ml were in the range of 86 × 106–95 × 106.
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Kumar, Ponnusamy Senthil, and G. Janet Joshiba. "Carbon Nanotube Composites." Diffusion Foundations 23 (August 2019): 75–81. http://dx.doi.org/10.4028/www.scientific.net/df.23.75.
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The discovery of carbon nanotubes is one of the remarkable achievement in the field of material science and it is a great advancement of Nanotechnology. A carbon nanotube is an expedient material used in several domains and paves way for the welfare of humans in many ways. Carbon nanotubes are nanosized tubes made from graphitic carbons and it is well known for its exclusive physical and chemical properties. The market demand for the nanotubes has increased progressively due to its size dependent, structure and mechanical properties. The carbon nanotubes possess high tensile strength and it is also found to be the durable fibre ever known. It is also found to possess exceptional electrical properties. The carbon nanotube composites have an excellent young’s modulus and higher tensile strength same as graphite carbon. This review plots the properties of carbon nanotubes and portrays the planning and properties of carbon nanotube composites. The wide application of carbon nanotube composites is also explained.
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Lin, Tong, Vardhan Bajpai, Tao Ji, and Liming Dai. "Chemistry of Carbon Nanotubes." Australian Journal of Chemistry 56, no. 7 (2003): 635. http://dx.doi.org/10.1071/ch02254.
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Judicious application of site-selective reactions to non-aligned and aligned carbon nanotubes has opened a rich field of carbon nanotube chemistry. In order to meet specific requirements demanded by particular applications (e.g. biocompatibility for nanotube biosensors and interfacial strength for blending with polymers), chemical modification of carbon nanotubes is essential. The tips of carbon nanotubes are more reactive than their sidewalls, allowing a variety of chemical reagents to be attached at the nanotube tips. Recently, some interesting reactions have also been devised for chemical modification of both the inner and outer nanotube walls, though the seamless arrangement of hexagon rings renders the sidewalls relatively unreactive. This review provides a brief summary of very recent progress in the research on chemistry of carbon nanotubes.
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Gábor, T., D. Aranyi, Katalin Papp, F. H. Kármán, and Erika Kálmán. "Dispersibility of Carbon Nanotubes." Materials Science Forum 537-538 (February 2007): 161–68. http://dx.doi.org/10.4028/www.scientific.net/msf.537-538.161.
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Availability of a stable carbon nanotube suspension is a prerequisite for production of polymer composites with carbon nanotube as additives. In this work nanotube suspensions, which have been prepared from various nanotubes in different dispersion agents, were compared. Dispersibility of the samples was investigated by scanning electon microscopy and atomic force microscopy. Solution of a non-ionic surfactant was also used successfully as a new dispersion agent. Geometrical parameters of the carbon nanotubes were determined by using atomic force microscopy. Correlation was found between the dispersibility and the parameters of the nanotubes and relative permittivity of the different solvents.
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Marcondes, C. G. N., and M. H. F. Medeiros. "Análisis de la dispersión de soluciones conteniendo nanotubos de carbono para su uso en concretos de Cemento Portland." Revista ALCONPAT 6, no. 2 (May 31, 2016): 84–100. http://dx.doi.org/10.21041/ra.v6i2.131.
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Análisis de la dispersión de soluciones conteniendo nanotubos de carbono para su uso en concretos de Cemento PortlandRESUMENLos nanotubos de carbono (NTC) son estructuras nanométricas de carbono en formas cilíndricas. Para su uso en hormigón, una de las dificultades es su dispersión, enfoque de este trabajo. Se utilizó una herramienta conocida como análisis jerárquico para investigar la eficiencia de dispersión de los NTC en el agua de la mezcla de hormigón. Fueron estudiados 12 maneras de dispersiones en medio acuoso que contiene diferentes productos químicos. Se usaron los nanotubos de carbono de pared múltiple en forma de polvo y los ya procesados, dispersos en agua. El estudio mostró que la herramienta de análisis jerárquico podría constituir una alternativa eficaz para la elección de una mejor dispersión, teniendo en cuenta los factores que influyen en forma sistémica.Palabras clave: Proceso de análisis jerárquico; hormigón; nanotubos de carbón. Analyzing the dispersion of carbon nanotubes solution for use in Portland cement concreteABSTRACTCarbon nanotubes (CNTs) are nanometric carbon structures with cylindrical formats. For use in concretes, one of the difficulties is in its dispersion, focus this work. It used a tool known as hierarchical analysis to investigate the efficiency of the dispersion of carbon nanotubes in concrete kneading water. Were studied 12 forms of dispersions in aqueous medium containing hum Miscellaneous Chemicals. Carbon nanotubes multi-walled in powder form and Processed already dispersed in water were used. The study showed that the hierarchical analysis tool might constitute an alternative to the election of the best choice among the available options, considering the factors of influence in a systemic way.Keywords: Analytical hierarchy process; concrete; carbon nanotubes. Análise da dispersão de soluções contendo nanotubos de carbono para uso em concretos de Cimento PortlandRESUMOOs nanotubos de carbono (NTC) são estruturas nanometricas de carbono com formatos cilindricos. Para uso em concretos, uma das dificuldades está na sua dispersão, foco deste trabalho. Foi usada uma ferramenta conhecida como análise hierárquica. Para investigar a eficiência da dispersão dos nanotubos de carbono na água de amassamento do concreto, foram estudados 12 formas de dispersões em um meio aquoso contendo diversos produtos químicos. Foram utilizados os nanotubos de carbono de paredes múltiplas em forma de pó e os industrializados, já dispersos em água. O trabalho demonstrou que a ferramenta de análise hierárquica poderia se constituir em uma alternativa eficiente para a eleição da melhor dispersão, considerando os fatores de influência de forma sistêmica.Palavras-chave: Análise Hierárquica; concreto; nanotubos de carbono.
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Zhang, J. W., Zhen Luo, Y. L. Li, J. D. Zhu, and J. Hao. "A Welding Method for Carbon Nanotubes." Advanced Materials Research 160-162 (November 2010): 737–42. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.737.
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A simple and reliable welding method was developed to weld carbon nanotubes with the power supply here. The carbon nanotubes were synthesized chemical vapor deposition method and Multi-walled carbon nanotubes was uesd here. Firstly, apply less than 5 V voltages between carbon nanotubes when they were in close proximity under direct view of optical microscope. Then, let carbon nanotube contact with each other and increase the external voltage to 7–8V until carbon nanotube was attached to the end of the other, the two carbon nanotube join into a carbon nanotube. Furthermore, some experiments were implemented to analyze the reliability, the images of the weld joint and the weld strength all indicted this method were reliable.
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Shahrukh, Akhtar M., Zhonglie An, Masaya Toda, and Takahito Ono. "140 Mechanical properties of Carbon nanotubes-nickel composite thin films synthesized with high carbon nanotube content." Proceedings of Conference of Tohoku Branch 2016.51 (2016): 77–78. http://dx.doi.org/10.1299/jsmeth.2016.51.77.
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Sun, Bao Min, Yuan Chao Liu, and Zhao Yong Ding. "Carbon Nanotubes Preparation Using Carbon Monoxide from the Pyrolysis Flame." Advanced Materials Research 87-88 (December 2009): 104–9. http://dx.doi.org/10.4028/www.scientific.net/amr.87-88.104.
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Carbon nanotube is a new kind of carbon material. Synthesis of carbon nanotubes from V-type pyrolysis flame is a kind of novel technique. It needs simple laboratory equipments and normal atmosphere pressure. The V-type pyrolysis flame experimental system is introduced. Carbon source is the carbon monoxide which is carried to the middle pipe of V-type pyrolysis flame combustor. Heat source is from acetylene /air premixed flame. Pentacarbonyl iron, served as catalyst, is transported by spray- pyrolysis method into the burner. The carbon nanotubes were characterized by scanning electron microscope and transmission electron microscope. The diameter of carbon nanotubes is approximate 20nm and its length is dozens of microns. The impact of the temperature, reactant composition and catalyst was analyzed to reveal the rule of carbon nanotube growth. Carbon nanotubes with good form and less impurity can be captured when the temperature was from 800°C to 1000°C and carbon monoxide/hydrogen/helium mixed gas flow was supplied. The effective diameter of pentacarbonyl iron nanoparticles is approximate from 5nm to 20nm in the process of carbon nanotube formation. Mechanism of carbon nanotube base on the V-type pyrolysis flame method was proposed. The carbon “dissolved-proliferation-separate out” theory can be used to explain how the pentacarbonyl iron catalyses carbon monoxide to form carbon nanotubes.
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Liu, Yuan Chao, Ya Jie Zhang, Ya Jun Wu, and Bao Min Sun. "Carbon Nanotubes with Special Structure from the Pyrolysis Flame." Advanced Materials Research 261-263 (May 2011): 909–12. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.909.
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Carbon nanotube is the one-dimensional carbon nano-materials. The synthesis of carbon nanotubes from pyrolysis flame is a new method. Variety of carbon nanotubes with special structure can be seen from pyrolysis flame due to the influence of key factors such as the concentration of reactants and catalyst particle size. The morphology and structural of carbon nanotubes were characterized by scanning electron microscope and transmission electron microscopy respectively. Carbon nanotubes with special structure such as bamboo-like, pod-like and coil-like can be seen in the experiment. The bamboo-like carbon nanotube has a bamboo-like structure clearly. The shape of pod-like carbon nanotube is very similar with the peasecod. The coil-like carbon nanotube is similar to carbon nanofiber in structure. It was discussed and analyzed that the formation mechanism of bamboo-like, pod-like and coil-like carbon nanotubes from the V-type pyrolysis flame.
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Dresselhaus, M. S., and H. Dai. "Carbon Nanotubes: Continued Innovations and Challenges." MRS Bulletin 29, no. 4 (April 2004): 237–43. http://dx.doi.org/10.1557/mrs2004.74.
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AbstractThis article outlines the content of the April 2004 issue of MRS Bulletin on Advances in Carbon Nanotubes. Essentially, carbon nanotubes are self-assembling nanostructures constructed of sheets of hexagonal-shaped carbon atoms rolled up into cylinders. Carbon nanotubes have attracted a great deal of attention as model systems for nanoscience and for potential applications. The special interest in carbon nanotubes stems from their unique structure and properties: their very small size (down to ∼0.42 nm in diameter); the possibility for carbon nanotubes to be metallic or semiconducting, depending on their geometrical structure; their exceptional properties of ballistic transport; their extremely high thermal conductivity and high optical polarizability; and the possibilities of high structural perfection. Research in the carbon nanotube field has now advanced to the stage where a good understanding of the structure and many of the basic properties are in place, together with much appreciation of their interrelation. On the other hand, major gaps in basic knowledge remain, with the major obstacles confronting the carbon nanotube field being the lack of a detailed understanding of the nanotube growth mechanism and control of the synthesis process to produce nanotubes with a desired diameter and chirality. The brief review of the carbon nanotube field by leading experts in this issue comes at an opportune time. Many exciting results on the structural, electronic, optical, and transport properties of these tiny well-ordered structures have already been achieved, and the research is well enough developed to assess present progress and identify new research directions waiting to be explored.
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Siregar, Syahril, Sri Oktamuliani, and Yoshifumi Saijo. "A Theoretical Model of Laser Heating Carbon Nanotubes." Nanomaterials 8, no. 8 (July 28, 2018): 580. http://dx.doi.org/10.3390/nano8080580.
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We present a theoretical model of laser heating carbon nanotubes to determine the temperature profile during laser irradiation. Laser heating carbon nanotubes is an essential physics phenomenon in many aspects such as materials science, pharmacy, and medicine. In the present article, we explain the applications of carbon nanotubes for photoacoustic imaging contrast agents and photothermal therapy heating agents by evaluating the heat propagation in the carbon nanotube and its surrounding. Our model is constructed by applying the classical heat conduction equation. To simplify the problem, we assume the carbon nanotube is a solid cylinder with the length of the tube much larger than its diameter. The laser spot is also much larger than the dimension of carbon nanotubes. Consequently, we can neglect the length of tube dependence. Theoretically, we show that the temperature during laser heating is proportional to the diameter of carbon nanotube. Based on the solution of our model, we suggest using the larger diameter of carbon nanotubes to maximize the laser heating process. These results extend our understanding of the laser heating carbon nanotubes and provide the foundation for future technologically applying laser heating carbon nanotubes.
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ALDAJAH, S., J. CHATTERJEE, M. ALRAWADEH, A. KOSURI, and Y. HAIK. "ALIGNMENT OF CARBON NANOTUBES USING MAGNETIC NANOPARTICLES." International Journal of Nanoscience 08, no. 03 (June 2009): 251–59. http://dx.doi.org/10.1142/s0219581x09006067.
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Carbon nanotubes are driving scientific research nowadays. This field has several important directions in basic research, including chemistry, electronic transport, mechanical, and field emission properties. The most eye-catching features of carbon nanotubes are their electronic, mechanical, optical, and chemical characteristics, which open a way to future applications. One of the most important applications of nanotubes based on their properties will be as reinforcements in composite materials. One of the biggest concerns to nanotube industry is the alignment problem which has limited the usage and utilizations of carbon nanotubes in composites. The ability to impose a preferred alignment of carbon nanotubes in a composite will increase the effectiveness of utilizing nanotubes in composite applications. The alignment of nanotubes will maximize the interfacial bonding across the nanotube matrix interface. In this research, we developed a methodology and a process to align nanotubes in polymer nanocomposites by means of a magnetic field. By doing so, we will get a very strong nanocomposite that can be used in the composites industry. The proposed mechanism aims at aligning the carbon nanotubes by means of nanomagnetic particles that are adsorbed on the nanotube surfaces and by applying an external magnetic field. SEM analysis have shown that nanomagnetic particles with the assistance of the magnetic field were able to align the carbon nanotubes in the desired direction.
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Kim, Jeong-Hyeon, Jong-Min Kim, Sungkyun Park, Kang Hyun Park, and Jae-Myung Lee. "Synthesis and cryogenic mechanical properties of CO2-blown carbon-reinforced polyurethane foam." Journal of Cellular Plastics 54, no. 4 (December 29, 2017): 743–63. http://dx.doi.org/10.1177/0021955x17750389.
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In the present study, carbon-nanotube-polyurethane foams were synthesized by adding (0.02, 0.1, and 0.3 wt%) carbon nanotubes during the polymerization reaction between polyol and isocyanate liquids. After the synthesis process, the microstructural cell morphology of the carbon-nanotube-polyurethane foams, based on the amount of carbon nanotubes, was observed using field emission scanning electron microscopy. To evaluate the mechanical characteristics of the carbon-nanotube-polyurethane foams, temperature-dependent (20°C, −90°C, and −163°C) compressive tests were performed, and the results were compared to those of the pure polyurethane foam to verify the effectiveness of the developed carbon-nanotube-polyurethane foams. Specifically, the effects of the weight percent of carbon nanotubes, density, and temperature on the overall behavior of the carbon-nanotube-polyurethane foams were considered. Finally, the permanent deformation ratio and material failure characteristics were investigated. The results showed that the cell morphology and compressive strength of the carbon-nanotube-polyurethane foam with 0.02 wt% carbon nanotubes were superior to those of pure polyurethane foam, and these properties showed a significant dependence on the weight percent of carbon nanotubes, test temperatures, and the density.
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Huseynov, Asgar, Aydin Israfilov, Samira Mammadova, Sevda Abdullayeva, Sergey Sokolov, Alexey Goryunkov, and Akif Guliyev. "Fabrication and characterization of MWCNT/natural Azerbaijani bentonite electroconductive ceramic composites." Journal of Composite Materials 53, no. 26-27 (May 13, 2019): 3909–23. http://dx.doi.org/10.1177/0021998319848798.
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Multi-walled carbon nanotubes have been synthesized by Aerosol-Chemical Vapor Deposition method. Carbon nanotubes firstly have been used as filler in affordable and prevalent natural Azerbaijani bentonite clays for fabrication electroconductive ceramic composites. In this paper, multi-walled carbon nanotubes/natural Azerbaijani bentonite ceramic composites were prepared by two-factor mechanical method and followed by calcination at 1050℃ in an inert atmosphere. The ceramic composites were characterized by scanning electron microscope, atomic force microscope, X-ray diffraction and thermogravimetric-differential-thermal analysis. X-ray diffraction analysis confirmed the presence of two principal components – multi-walled carbon nanotube and bentonite in composites. From the thermogravimetric-differential-thermal data, it was revealed that multi-walled carbon nanotube/ bentonite ceramic composites demonstrate thermo-oxidative stability up to 580–640℃. Scanning electron microscope images demonstrated a sufficiently high dispersibility of carbon nanotubes and satisfactory homogeneity in the composites. Experimental results demonstrated that by increasing the mass fraction of multi-walled carbon nanotubes from 1% to 8% in multi-walled carbon nanotube/bentonite ceramic composites, the electrical conductivity enhances substantially. The enhancement of electrical conductivity of the composites explained the mass fraction of multi-walled carbon nanotubes, as well as the uniform dispersion of multi-walled carbon nanotubes in the bentonite clays. Compared with other 8% multi-walled carbon nanotubes/bentonite ceramic composites, the electrical conductivity of heptane-multi-walled carbon nanotube/Gobu bentonite (σ = 397 S·m−1) and heptane-multi-walled carbon nanotubes/Atyali (σ = 305 S·m−1) composites is 2–5 times higher than the conductivity of composites obtained with cyclohexane carbon nanotubes- cyclohexane-multi-walled carbon nanotube/Atyali (σ = 78 S·m−1), cyclohexane-multi-walled carbon nanotube/Gobu (σ = 111,5 S·m−1). These results can be explained with the structure, the number of layers, purity and diameter distribution, as well as the type and amount of defects in internal and external layers of Hep-multi-walled carbon nanotubes which cause better dispersion in bentonite clays. Due to the high conductivity and high temperature stability, these composites can be used as promising material for fabrication heating elements, electrodes, substrates for microelectronic devices, etc.
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Marquis, Fernand D. S. "Carbon Nanotube Nano Composites for Multifunctional Applications." Materials Science Forum 561-565 (October 2007): 1397–402. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1397.
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Owing to their exceptional stiffness, strength, thermal and electrical conductivity, carbon nanotubes have the potential for the development of nano composites materials for a wide variety of applications. In order to achieve the full potential of carbon nanotubes for structural, thermal and electrical multifunctional applications, both single wall carbon nanotubes (SWNTs), double wall nanotubes (DWNTs) and multi wall nanotubes (MWNTs) need to be developed into fully integrated carbon nanotube composites. Full integration of nanotubes requires their development beyond conventional composites so that the level of the non-nanotube material is designed to integrate fully with the amount of nanotubes and where the nanotubes are part of the matrix rather than a differing component, as in the case of conventional composites. In order to advance the development of multifunctional materials from nanotubes, this research is focused on the simultaneous control of structural properties, thermal and electrical conductivity of fully integrated carbon nanotube composites. These are hybrid material systems designed to surpass the limits of rule of mixtures engineering and composite design. The goals are to implement designs to fully mimic the properties of carbon nanotubes on larger scales for enhanced thermal and electrical management in addition to controlled strength and toughness. These new approaches involve, functionalization, dispersion, stabilization, alignment, polymerization and reaction bonding, in order to achieve full integration. Typical examples of polymeric and ceramic matrices, as well as other material systems are presented and discussed.
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Mei, Hui, Qianglai Bai, Konstantinos Dassios, Haiqing Li, Laifei Cheng, and Costas Galiotis. "Morphological and Microstructural Property Comparison of Bulk and Aligned Cvd-Grown Carbon Nanotubes." Advanced Composites Letters 23, no. 1 (January 2014): 096369351402300. http://dx.doi.org/10.1177/096369351402300101.
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Carbon nanotubes are one-dimensional materials found in various forms, the most important of which are bulk unordered carbon nanotubes of lengths of few microns and aligned tubes regularly a few millimeters long. Differences in length, orientation, alignment, nanotube graphitization and purity will influence the eventual performance of the material. Herein four characterization methods are used to characterize and compare bulk and aligned carbon nanotubes. Results show that the diameters of the millimeter-long aligned carbon nanotubes are approximately 60 ∼ 80 nm with thick nanotube walls of about 25–30 nm, while the diameters of the bulk carbon nanotubes are about 15–20 nm with much thinner walls. The aligned carbon nanotubes have significantly larger graphitization degrees, higher purity and greater orientation than the bulk carbon nanotubes that tend to self-agglomerate under no external stimulus. Silicon carbide matrix nanocomposites reinforced by the aligned carbon nanotubes were found to be denser that those reinforced by the bulk carbon nanotubes and also exhibit extensive, uniform, and long pullout of carbon nanotubes.
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Mylvaganam, Kausala, and Liang Chi Zhang. "Possible Chemical Bond Formation between a Carbon Nanotube and Alumina Matrix - A Quantum Mechanics Investigation." Key Engineering Materials 443 (June 2010): 723–28. http://dx.doi.org/10.4028/www.scientific.net/kem.443.723.
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To improve the structural properties of engineering ceramics, carbon nanotubes have been used as a reinforcement phase to produce stronger ceramic matrix composites. This paper investigates the possible chemical bond formation between a carbon nanotube and alumina with the aid of quantum mechanics analysis. The cases with and without functionalizing the nanotubes were examined. The nanotubes were modeled by nanotube segments with hydrogen atoms added to the dangling bonds of the perimeter carbons. The cleaved ceramic (0001) surface was represented by an alumina molecule with the oxygen atoms on either end terminated with hydrogen. Methoxy radicals were used to functionalize the CNTs. The study predicts that covalent bonding between Al atoms on a cleaved single crystal alumina surface and C atoms on a nanotube are energetically favorable.
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Obitayo, Waris, and Tao Liu. "A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors." Journal of Sensors 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/652438.
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The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.
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Wang, Can, Yan-li Wang, Liang Zhan, Zheng-Hong Huang, Wen-ming Qiao, Xiao-yi Liang, and Li-cheng Ling. "Growth of carbon nanotubes and nitrogen-doped carbon nanotubes on “carbon nanotube seeds”." Carbon 49, no. 11 (September 2011): 3705. http://dx.doi.org/10.1016/j.carbon.2011.04.024.
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Hou, Wenyi, and Shaoping Xiao. "Mechanical Behaviors of Carbon Nanotubes with Randomly Located Vacancy Defects." Journal of Nanoscience and Nanotechnology 7, no. 12 (December 1, 2007): 4478–85. http://dx.doi.org/10.1166/jnn.2007.862.
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In this paper, 10 0 zigzag nanotubes and (6, 6) armchair nanotubes are considered to investigate the effects of randomly distributed vacancy defects on mechanical behaviors of single-walled carbon nanotubes. A spatial Poisson point process is employed to randomly locate vacancy defects on nanotubes. Atomistic simulations indicate that the presence of vacancy defects result in reducing nanotube strength but improving nanotube bending stiffness. In addition, the studies of nanotube torsion indicate that vacancy defects prevent nanotubes from being utilized as torsion springs.
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Han, Ki Bong, and Yong Ho Choi. "Characterization of Contact Resistance between Carbon Nanotubes Film and Metal Electrodes." Advanced Materials Research 683 (April 2013): 238–41. http://dx.doi.org/10.4028/www.scientific.net/amr.683.238.
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Carbon nanotube has attracted great research attentions due to its outstanding electrical, physical, mechanical, chemical properties. Based on its excellent properties, the carbon nanotube is promising nanoscale material for novel electrical, mechanical, chemical, and biological devices and sensors. However, it is very difficult to control the structure of carbon nanotube during synthesis. A carbon nanotubes film has 3 dimensional structures of interwoven carbon nanotubes as well as unique properties such as transparency, flexibility and good electrical conductivity. More importantly, the properties of carbon nanotubes are ensemble averaged in this formation. In this research, we study the contact resistance between carbon nanotubes film and metal electrode. For most of electrical devices using carbon nanotubes film, it is necessary to have metal electrodes on the film for current path. A resistance at the contact lowers the electrical efficiencies of the devices. Therefore, it is important to measure and characterize the contact resistance and lower it for better efficiencies. The device demonstrated in this study using classical technique for metal contacts provides relatively reliable contact resistance measurements for carbon nanotubes film applications.
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Kohno, Hideo, and Takafumi Nogami. "Formation of Nanotubes of Carbon by Joule Heating of Carbon-Contaminated Si Nanochains." Key Engineering Materials 470 (February 2011): 171–74. http://dx.doi.org/10.4028/www.scientific.net/kem.470.171.
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We report a new route to fabricating carbon nanotubes and nanotube interconnects. Insulating Si nanochains covered with hydrocarbon, which are a kind of Si nanowire, can be transformed into distorted nanotubes of carbon by Joule heating. Transmission electron microscopy observations of the transformation reveal that first a surface carbon shell is formed, and then oxide evaporates by Joule heating forming a nanotube.
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Johnson, H. T., B. Liu, and Y. Y. Huang. "Electron Transport in Deformed Carbon Nanotubes." Journal of Engineering Materials and Technology 126, no. 3 (June 29, 2004): 222–29. http://dx.doi.org/10.1115/1.1743426.
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Carbon nanotubes are a material system of increasing technological importance with superb mechanical and electrical properties. It is well known that depending on details of atomic structure, nanotubes may be electrically conducting, semiconducting, or insulating, so deformation is believed to have strong effects on nanotube electrical properties. In this paper, a combination of continuum, empirical atomistic, and quantum atomistic modeling methods are used to demonstrate the effect of homogeneous deformation—tension, compression, and torsion—on the electrical conductance and current versus voltage (I(V)) characteristics of a variety of single wall carbon nanotubes. The modeling methods are used in a coupled and efficient multiscale formulation that allows for computationally inexpensive analysis of a wide range of deformed nanotube configurations. Several important observations on the connection between mechanical and electrical behavior are made based on the transport calculations. First, based on the I(V) characteristics, electron transport in the nanotubes is evidently fairly insensitive to homogeneous deformation, though in some cases there is a moderate strain effect at either relatively low or high applied voltages. In particular, the conductance, or dI/dV behavior, shows interesting features for nanotubes deformed in torsion over small ranges of applied bias. Second, based on a survey of a range of nanotube geometries, the primary determining feature of the I(V) characteristics is simply the number of conduction electrons available per unit length of nanotube. In other words, when the current is normalized by the number of free electrons on the tube cross section per unit length, which itself is affected by extensional (but not torsional) strain, the I(V) curves of all single walled carbon nanotubes are nearly co-linear.
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Alanka, Sandeep, Chanamala Ratnam, and Balla Srinivasa Prasad. "Characterization of cubic tumbler rod milled dispersed carbon nanotubes–Aluminum composites." Journal of Composite Materials 52, no. 28 (May 1, 2018): 3973–85. http://dx.doi.org/10.1177/0021998318773437.
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In this work, cubic tumbler rod milling was used to disperse X wt% multiwalled carbon nanotubes (X = 0.5, 0.75, 1.0) in an aluminum matrix. Dispersed precursor of aluminum–multiwalled carbon nanotube composite was subsequently consolidated by cold compaction followed by sinter-forged process. Microstructural and mechanical behaviors of as-produced aluminum–multiwalled carbon nanotube composites with different concentration were investigated. Findings revealed that the as-produced Al–0.75 wt% carbon nanotube sinter-forged composite exhibits homogenous distribution and embedded nanotubes confirmed by the scanning electron microscope and the properties were observed to be increased significantly up to addition of 0.75 wt% of carbon nanotubes concentration than the pure aluminum as well as extruded composite and decrease to 1.0 wt% carbon nanotube due to the agglomeration of multiwalled carbon nanotube. However, enhancement of hardness, tensile strength, and Young’s modulus of the nanocomposites, compared with pure aluminum are 48.5, 83.8, and 30%, respectively. The tensile fractography of sinter-forged composite shows carbon nanotubes act like a bridge and barring the crack growth of aluminum matrix, remaining are pullout. Hence, it can be concluded that aluminum carbide phase starting from 0.75 wt% carbon nanotube and a strong interfacial bonding in as-produced aluminum–carbon nanotube composite has been observed which gives effective load transfer between aluminum matrix and carbon nanotubes.
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Levchenko, I., K. Ostrikov, and M. Keidar. "Plasma-Assembled Carbon Nanotubes: Electric Field–Related Effects." Journal of Nanoscience and Nanotechnology 8, no. 11 (November 1, 2008): 6112–22. http://dx.doi.org/10.1166/jnn.2008.sw10.
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The paper presents results of comparative investigation of carbon nanotubes growth processes in dense low-temperature plasma and on substrate surface. Hybrid/Monte-Carlo numerical simulations were used to demonstrate the differences in the ion fluxes, growth rates and kinetics of adsorbed atoms re-distribution on substrate and nanotubes surfaces. We show that the plasma parameters significantly affect the nanotubes growth kinetics. We demonstrate that the growth rates of the nanotubes in plasma and on surface can differ by three orders, and the specific fluxes to the nanotube in the plasma can exceed the flux to surface-grown nanotube by six orders. We also show that the metal catalyst used for the nanotubes production on surface and in arc is a subject to very different conditions and this may be a key factor for the nanotube growth mode. The obtained dependencies for the ion fluxes to the nanotubes and nanotubes growth rates on the plasma parameters may be useful for selection of the production methods.
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Iijima, Sumio. "Carbon Nanotubes." MRS Bulletin 19, no. 11 (November 1994): 43–49. http://dx.doi.org/10.1557/s0883769400048405.
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Nanostructured materials have recently attracted the attention of some materials scientists. Because of their unique properties occurring in low-dimensional structures, nanostructured materials are sought for their possible industrial applications. This article introduces a specific nanostructured material, the carbon nanorube—an extremely thin filaments of graphite considered to be a quasi one-dimensional structure, with a simple well-understood atomic structure. Because of these qualities, the carbon nanorube has elicited great interest from diverse fields of basic and technological research. My discovery of carbon nanotubes was inspired by the discovery of C60 and its family and their mass production. The carbon nanotubes were serendipitously found during the examination of fullerene materials by a high-resolution transmission electron microscope (HRTEM). Since introducing this technique in 1971, I have been employing HRTEM to characterize the microscopic structural details of a variety of materials, including carbonaceous materials. So far, only nanotubes have been revealed with HRTEM.Interest in the carbon nanorube is multifold. Academically the nanotube is an ideal model structure for a quasi one-dimensional structure since its known atomic structure makes computer simulations more reliable. It is worthwhile to study both rare structures of graphite—cylindrical forms with a helical arrangement of carbon atom hexagons and flexible graphitic sheets containing topological surface defects. These materials may find practical uses as tough graphite fibers, molecular wires, catalyst supports, molecular adsorbers, and so on.
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Cox, Barry J., Ngamta Thamwattana, and James M. Hill. "Mechanics of nanotubes oscillating in carbon nanotube bundles." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 464, no. 2091 (January 8, 2008): 691–710. http://dx.doi.org/10.1098/rspa.2007.0247.
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Carbon nanotubes are nanostructures that promise much in the area of constructing nanoscale devices due to their enhanced mechanical, electrical and thermal properties. In this paper, we examine a gigahertz oscillator that comprises a carbon nanotube oscillating in a uniform concentric ring or bundle of carbon nanotubes. A number of existing results for nanotube oscillators are employed to analyse the design considerations of optimizing such a device, and significant new results are also derived. These include a new analytical expression for the interaction per unit length of two parallel carbon nanotubes involving the Appell hypergeometric functions. This expression is employed to precisely determine the relationship between the bundle radius and the radii of the nanotubes forming the bundle. Furthermore, several pragmatic approximations are also given, including the relationships between the bundle radius and the constituent nanotube radius and the oscillating tube radius and the bundle nanotube radius. We also present a simplified analysis of the force and energy for a nanotube oscillating in a nanotube bundle leading to an expression for the oscillating frequency and the maximum oscillating frequency, including constraints on configurations under which this maximum is possible.
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Majidi, Roya, Hamid Reza Taghiyari, and Mahsa Ekhlasi. "Adsorption Patterns of Helium on Carbon and Cellulose Nanotubes: Molecular Dynamics Simulations." Nano 12, no. 03 (March 2017): 1750036. http://dx.doi.org/10.1142/s1793292017500369.
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Molecular dynamics simulations were performed to study helium adsorption on carbon and cellulose nanotubes. Adsorption isotherms were analyzed at different temperatures and pressures. All adsorption isotherms for carbon and cellulose nanotubes were predicted to be of Langmuir shape type I. Helium adsorption was observed both inside and outside of open-ended tubes. Increasing temperatures caused lower helium adsorption on carbon and cellulose nanotubes. The calculated quantities confirmed that the adsorption capacity of the cellulose nanotube was greater than that of the carbon nanotube. The adsorption capacity, isosteric heat of adsorption and binding energy indicated that cellulose nanotubes as well as carbon nanotubes are proper materials for gas storage.
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Abaszade, R. G., O. A. Kapush, S. A. Mamedova, A. M. Nabiyev, S. Z. Melikova, and S. I. Budzulyak. "Gadolinium doping influence on the properties of carbon nanotubes." Physics and Chemistry of Solid State 21, no. 3 (September 29, 2020): 404–8. http://dx.doi.org/10.15330/pcss.21.3.404-408.
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This article is devoted to the analysis of a carbon nanotube, a functionalized b-carboxyl group of a carbon nanotube and a gadolinium-doped carbon nanotube. Were analyzed the structure, purity, quality, and surface morphology, as well as the homogeneity (heterogeneity) of nanotubes. The analysis of a carbon nanotube were performed using a scanning electron microscope (SEM), energy dispersive analysis (EXD), X-ray diffraction analysis, Raman scattering, and IR luminescence. It was found that 10% doping with gadolinium strongly affects the physical properties of carbon nanotubes functionalized by a carboxyl group.
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Liu, Jie, and Mark C. Hersam. "Recent Developments in Carbon Nanotube Sorting and Selective Growth." MRS Bulletin 35, no. 4 (April 2010): 315–21. http://dx.doi.org/10.1557/mrs2010.554.
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AbstractDue to their high carrier mobilities, electromigration resistance, and tailorable optical properties, carbon nanotubes are promising candidates for high-performance electronic and optoelectronic applications. However, traditional synthetic methods have lacked control over the structure and properties of carbon nanotubes. This polydispersity problem has confounded efforts to take carbon nanotubes from the research laboratory to the marketplace, especially for electronic and optoelectronic applications, where reliable and reproducible performance is paramount. In recent years, the research community has devoted significant effort to this issue, leading to substantial advances in the preparation of monodisperse carbon nanotube materials. This article highlights the most recent and promising developments from two perspectives: post-synthetic sorting and selective growth of carbon nanotubes of predetermined physical and electronic structure. These complementary approaches have yielded improved uniformity in carbon nanotube materials, resulting in impressive advances in carbon nanotube electronic and optoelectronic technology.
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Mierczynska, A., J. Friedrich, H. Maneck, G. Boiteux, and J. Jeszka. "Segregated network polymer/carbon nanotubes composites." Open Chemistry 2, no. 2 (June 1, 2004): 363–70. http://dx.doi.org/10.2478/bf02475579.
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AbstractIn this work we present the preparation of conductive polyethylene/carbon nanotube composites based on the segregated network concept. Attention has been focused on the effect of decreasing the amount of filler necessary to achieve low resistivity. Using high- and low-grade single-walled carbon nanotube materials we obtained conductive composites with a low percolation threshold of 0.5 wt.% for high-grade nanotubes, about 1 wt% for commercial nanotubes and 1.5 wt% for low-grade material. The higher percolation threshold for low-grade material is related to low effectiveness of other carbon fractions in the network formation. The electrical conductivity was measured as a function of the single-walled carbon nanotubes content in the polymer matrix and as a function of temperature. It was also found that processing parameters significantly influenced the electrical conductivity of the composites. Raman spectroscopy was applied to study single wall nanotubes in the conductive composites.
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Kavecký, Štefan, and Pavol Šajgalík. "Carbon Nanotubes Prepared by CVD." Key Engineering Materials 290 (July 2005): 230–33. http://dx.doi.org/10.4028/www.scientific.net/kem.290.230.
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Carbon nanotubes have been prepared by CVD from acetylene-argon gaseous system in tubular flow reactor. Acetylene gas was used as the carbon source needed for carbon nanotube growth. Several types of high porosity foam-like Ni substrate were used as catalyst material at pyrolysis temperatures from 673 to 973 K. Influence of the surface morphology of the foam-like Ni substrates on the carbon nanotubes morphology and growth have been studied.
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Kulnitskiy, B. A., and V. D. Blank. "Iron Carbide Formation inside Carbon Nanotubes." Advanced Materials & Technologies, no. 3 (2017): 034–39. http://dx.doi.org/10.17277/amt.2017.03.pp.034-039.
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Komane, Patrick P., Yahya E. Choonara, Lisa C. du Toit, Pradeep Kumar, Pierre P. D. Kondiah, Girish Modi, and Viness Pillay. "Diagnosis and Treatment of Neurological and Ischemic Disorders Employing Carbon Nanotube Technology." Journal of Nanomaterials 2016 (2016): 1–19. http://dx.doi.org/10.1155/2016/9417874.
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Extensive research on carbon nanotubes has been conducted due to their excellent physicochemical properties. Based on their outstanding physicochemical properties, carbon nanotubes have the potential to be employed as theranostic tools for neurological pathologies such as Alzheimer’s disease and Parkinson’s disease including ischemic stroke diagnosis and treatment. Stroke is currently regarded as the third root cause of death and the leading source of immobility around the globe. The development and improvement of efficient and effective procedures for central nervous system disease diagnosis and treatment is necessitated. The main aim of this review is to discuss the application of nanotechnology, specifically carbon nanotubes, to the diagnosis and treatment of neurological disorders with an emphasis on ischemic stroke. Areas covered include the conventional current diagnosis and treatment of neurological disorders, as well as a critical review of the application of carbon nanotubes in the diagnosis and treatment of ischemic stroke, covering areas such as functionalization of carbon nanotubes and carbon nanotube-based biosensors. A broad perspective on carbon nanotube stimuli-responsiveness, carbon nanotube toxicity, and commercially available carbon nanotubes is provided. Potential future studies employing carbon nanotubes have been discussed, evaluating their extent of advancement in the diagnosis and treatment of neurological and ischemic disorders.
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Wang, C. Y., Y. Y. Zhang, C. M. Wang, and V. B. C. Tan. "Buckling of Carbon Nanotubes: A Literature Survey." Journal of Nanoscience and Nanotechnology 7, no. 12 (December 1, 2007): 4221–47. http://dx.doi.org/10.1166/jnn.2007.924.
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This survey paper comprises 5 sections. In Section 1, the reader is introduced to the world of carbon nanotubes where their structural form and properties are highlighted. Section 2 presents the various buckling behaviors exhibited by carbon nanotubes that are discovered by carbon nanotube researchers. The main factors, such as dimensions, boundary conditions, temperature, strain rate and chirality, influencing the buckling behaviors are discussed in Section 3. Section 4 presents the continuum models, atomistic simulations and experimental techniques in studying the buckling phenomena of carbon nanotubes. A summary as well as recommendations for future research are given in Section 5. Finally a large body of papers, over 200, is given in the reference section. It is hoped that this survey paper will provide the foundation knowledge on carbon nanotube buckling and inspire researchers to advance the modeling, simulation and design of carbon nanotubes for practical applications.
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Treacy, M. M. J., and T. W. Ebbesen. "Mechanical Properties of Carbon Nanotubes Inferred from TEM." Microscopy and Microanalysis 3, S2 (August 1997): 393–94. http://dx.doi.org/10.1017/s1431927600008850.
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The discovery of carbon nanotubes by Iijima has stimulated considerable research into their structural, chemical, electrical and mechanical properties. Apart from their intrinsic beauty as macromolecules, and their possibilities as one-dimensional conductors, researchers are stimulated by the notion that a structurally perfect nanotube may be one of the strongest known materials.It is known that when nanotubes are bent through large angles, regions of high curvature buckle to develop crimps, similar to those observed when metal pipes are bent too much. Figure la shows a multi-walled nanotube that has one end embedded in a ceramic matrix. The other end is snagged so that the tube is bent. Several crimps are visible on the nanotube. Figure lb shows the same nanotube imaged a few moments later. Remarkably, the nanotube has sprung straight and the crimps have disappeared. This demonstrates that buckling in nanotubes does not involve plastic deformation, and that nanotubes can maintain their structural integrity even after severe deformation.
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Tadi Beni, Yaghoub, Fahimeh Mehralian, and Mehran Karimi Zeverdejani. "Free vibration of anisotropic single-walled carbon nanotube based on couple stress theory for different chirality." Journal of Low Frequency Noise, Vibration and Active Control 36, no. 3 (March 29, 2017): 277–93. http://dx.doi.org/10.1177/0263092317700153.
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In the present work, using the couple stress theory, a new model is provided for vibrating behavior of anisotropic carbon nanotubes. Carbon nanotubes have many applications, and careful analysis of their behavior is important. So far, using the isotropic models, several studies have been conducted on carbon nanotube vibration. According to the arrangement of carbon atoms on the nanotube walls, their properties will be different in various directions. Therefore, the behavior of carbon nanotubes must be considered as anisotropic materials. In this article, initially, using the Hamilton's principle, motion equations, and boundary conditions of carbon nanotubes are extracted based on couple stress theory. Afterwards, the equations are solved using the analytical solution method. In the results section, the effect of different parameters, particularly the anisotropic effect, on the carbon nanotube natural frequency is investigated.
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Shahbaz, Shah R., and Ömer B. Berkalp. "Effect of MWCNTs addition, on the mechanical behaviour of FRP composites, by reinforcement grafting and matrix modification." Journal of Industrial Textiles 50, no. 2 (January 13, 2019): 205–23. http://dx.doi.org/10.1177/1528083718825317.
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Carbon nanotubes have extraordinary potential for the modification of reinforcements and matrices in fiber-reinforced polymer composites for enhanced mechanical properties. In this study, 12 fiber-reinforced polymer composites were produced with and without the addition of functionalized multi-wall carbon nanotubes using different stacking sequences of E-glass and carbon fabric reinforcements in simple and hybrid configurations. Carbon nanotubes were incorporated into the fiber-reinforced polymer components prior to composite fabrication by: (i) grafting on reinforcements, and (ii) matrix modification by carbon nanotubes. The grafting of carbon nanotubes exhibited a pronounced tensile behaviour with carbon-rich fiber-reinforced polymers, whereas carbon nanotube-modified matrix showed more enhanced flexural behaviour overall. Around 12% increase in tensile strength was observed when the carbon nanotubes were grafted on to the reinforcements compared to respective pristine composites, while around 70% increase in the flexural strength was noticed as compared to the respective pristine composties when carbon nanotube-modified matrix was used.
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Kumar, Lailesh, Syed Nasimul Alam, and Santosh Kumar Sahoo. "Mechanical properties, wear behavior and crystallographic texture of Al–multiwalled carbon nanotube composites developed by powder metallurgy route." Journal of Composite Materials 51, no. 8 (July 28, 2016): 1099–117. http://dx.doi.org/10.1177/0021998316658946.
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Aluminum (Al)-based metal matrix composites reinforced with multiwalled carbon nanotubes were developed by powder metallurgy route. The Al and multiwalled carbon nanotubes powder mixtures were consolidated under a load of 565 MPa followed by sintering at 550℃ for 2 h in inert atmosphere. Al–1, 2, and 3 wt.% multiwalled carbon nanotube composites were developed. In the present study, the microstructure, mechanical properties, sliding wear behavior, and crystallographic texture of various Al–multiwalled carbon nanotube composites were investigated. The multiwalled carbon nanotubes produced by low-pressure chemical vapor deposition technique and the various sintered composites were characterized using scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis, Raman spectroscopy, and Fourier transform infrared spectroscopy. A significant improvement in relative density, Vickers microhardness, and wear resistance of the composites up to addition of 2 wt.% of multiwalled carbon nanotubes was observed. The deterioration in these properties beyond 2 wt.% of multiwalled carbon nanotubes was possibly due to the agglomeration of multiwalled carbon nanotubes in the Al matrix. The tensile strength of Al–multiwalled carbon nanotube composites continuously decreases with the addition of multiwalled carbon nanotubes. The decrease in tensile strength can be attributed to the detrimental effect of Al4C3 formed at the interface of the Al matrix and the multiwalled carbon nanotubes which will cause premature failure of the composite. The addition of multiwalled carbon nanotubes altered the crystallographic texture of the composites. The residual stresses in the various composites were found to be compressive in nature and also show improvement up to addition of 2 wt.% multiwalled carbon nanotubes in the Al matrix.
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McCrary-Dennis, Micah CL, Eduardo Fernandez, and Okenwa I. Okoli. "A study on the fabrication of plasticized polystyrene-carbon nanotube nanocomposites for foaming." Journal of Cellular Plastics 54, no. 3 (November 30, 2016): 445–62. http://dx.doi.org/10.1177/0021955x16681501.
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The impregnation of carbon nanotubes within fiber-reinforced polymers (FRPs) is a sought after capability for the advancement of composite systems. This study evaluates the novel processing of a carbon nanotube nanocomposite that has been developed to incorporate varying carbon nanotube loadings within final composite foams. This material is manufactured through a melt mix process of carbon nanotubes and polystyrene at ∼2.0–13.0 wt.% that further underwent a plasticization process in an acetone solvent. The chemical foaming agent 2.2′-Azobi(isobutyronitrile) is used to facilitate foaming at a constant 3.0 wt.% concentration. The foamed nanocomposite results in a carbon nanotube-loaded micro-porous structure showing capabilities of delivering localized carbon nanotube placement within fiber composite laminate systems. This report’s aim is to illustrate the effects of plasticizing polystyrene-carbon nanotube nanocomposite and calendaring the softened material to form foams imbedded with carbon nanotubes (carbon nanotubes). Scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy were the tools that are used to characterize the materials at the various morphologies with their findings inclusive.
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Srivastava and, Deepak, Chenyu Wei, and Kyeongjae Cho. "Nanomechanics of carbon nanotubes and composites." Applied Mechanics Reviews 56, no. 2 (March 1, 2003): 215–30. http://dx.doi.org/10.1115/1.1538625.
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Computer simulation and modeling results for the nanomechanics of carbon nanotubes and carbon nanotube-polyethylene composite materials are described and compared with experimental observations. Young’s modulus of individual single-wall nanotubes is found to be in the range of 1 TPa within the elastic limit. At room temperature and experimentally realizable strain rates, the tubes typically yield at about 5–10% axial strain; bending and torsional stiffness and different mechanisms of plastic yielding of individual single-wall nanotubes are discussed in detail. For nanotube-polyethylene composites, we find that thermal expansion and diffusion coefficients increase significantly, over their bulk polyethylene values, above glass transition temperature, and Young’s modulus of the composite is found to increase through van der Waals interaction. This review article cites 54 references.
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Cui, Shuwen, Weiwei Liu, and Xiaosong Wang. "Theoretical Study of Atoms Filled in Carbon Nanotubes." Journal of Computational and Theoretical Nanoscience 13, no. 10 (October 1, 2016): 6974–77. http://dx.doi.org/10.1166/jctn.2016.5655.
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The nano-sized quasi-one dimensional hollow cores of carbon nanotubes make it possible for them to be filled with and wetted by foreign materials. With C, S and Se atoms as example, we have studied the filling and wetting of these atoms into carbon nanotubes from local density functional theory in first principles calculations. The results suggest that the effect of nanotube length is negligible when it exceeds 3.6 Å, there is a relation between nanotube diameter and filling and wetting. Our studies would be important implications for the further use of carbon nanotubes.
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Kharlamova, Marianna V. "Investigation of growth dynamics of carbon nanotubes." Beilstein Journal of Nanotechnology 8 (April 11, 2017): 826–56. http://dx.doi.org/10.3762/bjnano.8.85.
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The synthesis of single-walled carbon nanotubes (SWCNTs) with defined properties is required for both fundamental investigations and practical applications. The revealing and thorough understanding of the growth mechanism of SWCNTs is the key to the synthesis of nanotubes with required properties. This paper reviews the current status of the research on the investigation of growth dynamics of carbon nanotubes. The review starts with the consideration of the peculiarities of the growth mechanism of carbon nanotubes. The physical and chemical states of the catalyst during the nanotube growth are discussed. The chirality selective growth of nanotubes is described. The main part of the review is dedicated to the analysis and systematization of the reported results on the investigation of growth dynamics of nanotubes. The studies on the revealing of the dependence of the growth rate of nanotubes on the synthesis parameters are reviewed. The correlation between the lifetime of catalyst and growth rate of nanotubes is discussed. The reports on the calculation of the activation energy of the nanotube growth are summarized. Finally, the growth properties of inner tubes inside SWCNTs are considered.
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Tayfun, Umit, Yasin Kanbur, Ufuk Abacı, Hasan Yüksel Güney, and Erdal Bayramlı. "Mechanical, electrical, and melt flow properties of polyurethane elastomer/surface-modified carbon nanotube composites." Journal of Composite Materials 51, no. 14 (September 14, 2016): 1987–96. http://dx.doi.org/10.1177/0021998316666158.
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Carbon nanotube-reinforced polyurethane elastomer composites were prepared by melt-mixing. Nitric acid oxidation and silanization were applied to carbon nanotube surfaces to achieve better interfacial interactions with polyurethane elastomer. Tensile and hardness tests, differential scanning calorimetry, melt flow index test, dielectric measurements, and morphological studies of composites were reported. The best results were obtained for surface-modified carbon nanotubes containing composites with lower loading levels. Addition of carbon nanotubes leads to almost two-fold increase in strain and modulus compared to pristine polyurethane elastomer. Tensile strength of composites was also improved by inclusion of carbon nanotubes. However, strength values drop down with increasing carbon nanotube content. Shore hardness increased with the inclusion of modified carbon nanotube to polyurethane elastomer while pristine carbon nanotube caused remarkable decrease in hardness of polyurethane elastomer. Relatively higher melting points and slightly lower glass transition temperatures were observed for carbon nanotube-loaded composites compared to polyurethane elastomer because of plasticizing effect of carbon nanotube. Incorparation of carbon nanotube to polyurethane elastomer matrix caused reduction in melt flow index values due to formation of agglomarates, and n the contrary, surface modifications of carbon nanotube exhibited increase in melt flow index thanks to enhanced interfacial interactions between carbon nanotube and polyurethane elastomer. Significant increase in dielectric constant of composites was observed. Better dispersion of surface modified carbon nanotubes into polyurethane elastomer was also concluded from SEM micrographs of composites.
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Bandow, S., K. Hirahara, T. Hiraoka, G. Chen, P. C. Eklund, and S. Iijima. "Turning Peapods into Double-Walled Carbon Nanotubes." MRS Bulletin 29, no. 4 (April 2004): 260–64. http://dx.doi.org/10.1557/mrs2004.77.
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AbstractThe formation pathway to double-walled carbon nanotubes (DWNTs) from C60 encased within single-walled carbon nanotubes (peapods) is introduced in this article. Onedimensionally arranged C60 molecules coalesce gradually within the nanotube and change the structure to C60 dimers, trimers, tetramers, and so on as intermediates. In addition to these interesting structural transformations visualized in the nanotube space, the nanotube itself is very stable, and this structural stability is very important when using the interior of the nanotube as the reaction field or the space for molecular storage. In terms of optical absorption, the lowest energy absorption band for DWNTs, ∼0.65 eV, shows broadened and downshifted features as compared with that of SWNTs.We expect that this opticalabsorption feature will lead to the use of DWNTs in absorbing devices for optical-fiber communications. The Raman experiments give new information about the frequency of the C-C stretching-mode vibration for nanotubes with diameters of less than ∼1 nm, which shows a decrease in vibration frequency with decreasing tube diameter. This diameter dependence can be explained by an admixture of sp3 character in the C-C interaction. Therefore, the electronic and mechanical properties of nanotubes with diameters of <1 nm are expected to be different from nanotubes of the ∼1-nm-diameter class, and we anticipate that new phenomena will occur in small-diameter tubes.
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Camilli, Luca, and Maurizio Passacantando. "Advances on Sensors Based on Carbon Nanotubes." Chemosensors 6, no. 4 (December 6, 2018): 62. http://dx.doi.org/10.3390/chemosensors6040062.
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Carbon nanotubes have been attracting considerable interest among material scientists, physicists, chemists, and engineers for almost 30 years. Owing to their high aspect ratio, coupled with remarkable mechanical, electronic, and thermal properties, carbon nanotubes have found application in diverse fields. In this review, we will cover the work on carbon nanotubes used for sensing applications. In particular, we will see examples where carbon nanotubes act as main players in devices sensing biomolecules, gas, light or pressure changes. Furthermore, we will discuss how to improve the performance of carbon nanotube-based sensors after proper modification.
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ROLAND, C., M. BUONGIORNO NARDELLI, H. GUO, H. MEHREZ, J. TAYLOR, J. WANG, and Y. WEI. "THEORETICAL INVESTIGATIONS OF QUANTUM TRANSPORT THROUGH CARBON NANOTUBE DEVICES." Surface Review and Letters 07, no. 05n06 (October 2000): 637–42. http://dx.doi.org/10.1142/s0218625x00000774.
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By combining a nonequilibrium Green's function analysis with a standard tight-binding model, we have investigated quantum transport through carbon nanotube devices. For finite-sized nanotubes, transport is dominated by resonant tunneling, with the conductance being strongly dependent on the length of the nanotubes. Turning to nanotube devices, we have investigated spin-coherent transport in ferromagnetic–nanotube–ferromagnetic devices and nanotube-superconducting devices. The former shows a significant spin valve effect, while the latter is dominated by resonant Andreev reflections. In addition, we discuss AC transport through carbon nanotubes and the role of photon-assisted tunneling.
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Zhang, Qian, Xin Bao Gao, and Tian Peng Li. "Effect of Expanded Temperature on Microstructure of Carbon Nanotubes/Expanded Graphite Composites." Advanced Materials Research 716 (July 2013): 373–78. http://dx.doi.org/10.4028/www.scientific.net/amr.716.373.
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Carbon nanotube/expanded graphite composite material was prepared by expanding the mixture of multi-walled carbon nanotubes and expansible graphite under the condition of high temperature. The microstructure and composition was studied by using SEM and XRD. The study shows that the tubular structure of carbon nanotubes in the composite material is changed by high temperature expanding process, and the microstructure is different with different expanding temperature. When the expanding temperature was 900°C, carbon nanotubes transformed, then attached to the surface of expanded graphite flake, so carbon nanotubes and expanding graphite combined strongly; globular carbon nanotubes attached to the surface of expanded graphite flake at the temperature of 700°C, both were combined much more strongly; carbon nanotubes retained the tube structure at the temperature of 500°C, combination was looser due to the simple physical adsorption. The result shows that the choice of expanding temperature has an important effect on microstructure of carbon nanotube/expanded graphite composite material.
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Chin, Kok Chung, Amarsinh Gohel, Hendry Izaac Elim, Weizhe Chen, Wei Ji, Ghee Lee Chong, Chorng Haur Sow, and Andrew T. S. Wee. "Modified carbon nanotubes as broadband optical limiting nanomaterials." Journal of Materials Research 21, no. 11 (November 2006): 2758–66. http://dx.doi.org/10.1557/jmr.2006.0338.
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Carbon nanotubes have been shown to be effective broadband optical limiters for nanosecond laser pulses. In this paper, we review the recent developments of carbon nanotube-based optical limiters, in particular the effects of modifying carbon nanotubes for device applications. The techniques used to modify carbon nanotubes mainly include thin film coating, doping, and blending with optical absorbing dye. These modifications can greatly enhance the optical limiting performance of carbon nanotubes, with the goal of fabricating an optimal optical limiter system.
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Mananghaya, Michael, Emmanuel Rodulfo, Gil Nonato Santos, and Al Rey Villagracia. "Theoretical Investigation on the Solubilization in Water of Functionalized Single-Wall Carbon Nanotubes." Journal of Nanotechnology 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/780815.
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An important technique to increase the solubility and reactivity of carbon nanotube is through functionalization. In this study, the effects of functionalization of some single-walled carbon nanotubes (SWCNTs) were investigated with the aid of density functional theory. The SWCNT model used in the study consists of a finite, (5, 0) zigzag nanotube segment containing 60 C atoms with hydrogen atoms added to the dangling bonds of the perimeter carbons. There are three water-dispersible SWCNTs used in this study that were functionalized with (a) formic acid, as a model of carboxylic acid, (b) isophthalic acid, as a model aromatic dicarboxylic acid, and (c) benzenesulfonic acid, as a model aromatic sulfonic acid. Binding energies of the organic radicals to the nanotubes are calculated, as well as the HOMO-LUMO gaps and dipole moments of both nanotubes and functionalized nanotubes. Binding was found out to be thermodynamically favorable. The functionalization increases the electrical dipole moments and results in an enhancement in the solubility of the nanotubes in water manifested through favorable changes in the free energies of solvation. This should lower the toxicity of nanotubes and improve their biocompatibility.