Author: Mahmood Rashid Atiyah Publisher: ISBN: Category : Languages : en Pages : 366
Book Description
Carbon nanotubes (CNTs) are widely synthesized at high temperatures via floating catalyst chemical vapor deposition (FC-CVD) method. It is important to reduce the synthesis temperature of CNTs to allow better control of the reactor's conditions, and to eliminate the formation of carbon by-products as well as reduce the overall cost. Therefore, the main objectives of this work were (i) to synthesize carbon nanotubes at low temperatures using some improvements to the CVD technique, (ii) to investigate the effects of temperature on the synthesis of CNTs and (iii) to simulate the temperature and velocity profile of the FC-CVD system in the absence of reaction. The synthesis temperature of CNTs was examined in the range between 500oC and 600oC at 10oC interval. The preheating set temperature was varied between 150oC and 400oC at 50oC interval. All experiments were conducted at 1 atm and exposed sections were insulated with glass wool covered with aluminum foil. Three O-ring heating mantels were used as a preheater and three ceramic boats were used to collect the product. Temperature in-situ monitoring device was used to monitor the temperature profile in the reactor and provide the exact time to heat up the catalyst and, thus, initiate the reaction. A single heat source for both catalyst and reactor was employed to enhance the growth of CNTs. COMSOL Multiphysics was used to simulate the velocity and temperature profiles of the system in the absence of reaction. The morphology and internal structures of the CNTs formed were analyzed via Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and High Resolution Transmission Electron Microscope (HRTEM). The thermal stability and the purity of the products were analyzed by Thermal Gravimetric Analyzer (TGA). The results of the work showed that CNTs were formed at the synthesis temperature ranging from 530oC to 600oC. Both quality and quantity of CNTs synthesized were increased with the increase in synthesis temperature. The highest amount of carbon deposit was obtained when the preheating and the synthesis temperatures were set at 300oC and 600oC, respectively. However, based on the TGA results, the highest purity of CNTs was achieved when the preheating and the synthesis temperatures were set at 200oC and 600oC, respectively. Well aligned CNTs were found when the preheating temperature was set at 400oC for synthesis temperatures of 570oC and 580oC. The use of single heat source for both catalyst and reactor was found to induce the formation of well aligned CNTs at synthesis temperature of 550oC. The simulation results indicated some regions in the reactor have variation in both temperature and velocity profiles. This, indirectly, affects the formation of CNTs. To conclude, this work has successfully achieved the outlined objectives. The amount of product produced and its quality depend both on the preheating values and the synthesis temperature.
Author: Hosam El-Din Saleh Publisher: BoD – Books on Demand ISBN: 1789844010 Category : Technology & Engineering Languages : en Pages : 250
Book Description
Carbon nanotubes belong to new nanomaterials and have been known for almost 20 years, but their history is somewhat lengthier. They have been identified as promising candidates for various applications.High-temperature preparation techniques are conventional techniques for the synthesis of carbon nanotubes using arc discharge or laser ablation, but today these methods are being replaced by low-temperature vapor deposition techniques, since orientation, alignment, nanotube length, diameter, purity, and density of carbon nanotubes can be precisely controlled. The synthesis of carbon nanotubes by chemical vapor deposition on catalyst arrays leads to nanotube models grown from specific sites on surfaces. The controlled synthesis of nanotubes opens up interesting possibilities in nanoscience and nanotechnologies, including electrical, mechanical and electromechanical properties and devices, chemical functionalization, surface chemistry and photochemistry, molecular sensors, and interfacing with moderate biological systems.Carbon nanotubes are used in many applications due to their unique electrical, mechanical, optical, thermal, and other properties. Conductive and high-strength composite materials, energy saving and energy conversion devices, sensors, visualization of field emissions and sources of radiation, means for storing hydrogen, and nanoscale semiconductor devices, probes, and interconnections are some of the many applications of carbon nanotubes.
Author: Christian Peter Deck Publisher: ISBN: Category : Languages : en Pages : 375
Book Description
Carbon nanotubes (CNTs) possess exceptional material properties, making them desirable for use in a variety of applications. In this work, CNTs were grown using two distinct catalytic chemical vapor deposition (CVD) procedures, floating catalyst CVD and thermal CVD, which differed in the method of catalyst introduction. Reaction conditions were optimized to synthesize nanotubes with desired characteristics, and the effects of varying growth parameters were studied. These parameters included gas composition, temperature, reaction duration, and catalyst and substrate material. The CNT products were then examined using several approaches. For each CVD method, nanotube growth rates were determined and the formation and termination mechanisms were investigated. The effects of reaction parameters on nanotube diameters and morphology were also explored to identify means of controlling these important properties. In addition to investigating the effects of different growth parameters, the material properties of nanotubes were also studied. The floating catalyst CVD method produced thick mats of nanotubes, and the mechanical response of these samples was examined using in-situ compression and tension testing. These results indicated that mat structure is composed of discontinuous nanotubes, and a time-dependent response was also observed. In addition, the electrical resistance of bulk CNT samples was found to increase for tubes grown with higher catalyst concentrations and with bamboo morphologies. The properties of nanotubes synthesized using thermal CVD were also examined. Mechanical testing was performed using the same in-situ compression approach developed for floating catalyst CVD samples. A second characterization method was devised, where an optical approach was used to measure the deflection of patterned nanotubes exposed to an applied fluid flow. This response was also simulated, and comparisons with the experimental data were used to determine the flexural rigidity of these CNT arrays. In this work, two potential applications for carbon nanotubes were also considered. Using the experimental method employed for flexural rigidity measurements, a carbon nanotube-based fluid flow sensor that offered fast response and repeatability was demonstrated. There is also great interest in CNTs for high strength applications, and the growth of nanotubes for the spin-processing of CNTs into micron-scale fibers was also investigated.
Author: Suraya Abdul Rashid Publisher: Elsevier ISBN: 0128162597 Category : Technology & Engineering Languages : en Pages : 366
Book Description
Synthesis, Technology and Applications of Carbon Nanomaterials explores the chemical properties of different classes of carbon nanomaterials and their major applications. As carbon nanomaterials are used for a variety of applications due to their versatile properties and characteristics, this book discusses recent advances in synthesis methods, characterization, and applications of 0D -3D dimensional carbon nanomaterials. It is an essential resource for readers focusing on carbon nanomaterials research. Explores the chemical properties of different classes of carbon nanomaterials and their major applications Discusses recent advances in synthesis methods, characterization, and applications of 0D -3D dimensional carbon nanomaterials
Author: Mark Schulz Publisher: William Andrew ISBN: 1455778648 Category : Technology & Engineering Languages : en Pages : 861
Book Description
Nanotube Superfiber Materials refers to different forms of macroscale materials with unique properties constructed from carbon nanotubes. These materials include nanotube arrays, ribbons, scrolls, yarn, braid, and sheets. Nanotube materials are in the early stage of development and this is the first dedicated book on the subject. Transitioning from molecules to materials is a breakthrough that will positively impact almost all industries and areas of society. Key properties of superfiber materials are high flexibility and fatigue resistance, high energy absorption, high strength, good electrical conductivity, high maximum current density, reduced skin and proximity effects, high thermal conductivity, lightweight, good field emission, piezoresistive, magnetoresistive, thermoelectric, and other properties. These properties will open up the door to dozens of applications including replacing copper wire for power conduction, EMI shielding, coax cable, carbon biofiber, bullet-proof vests, impact resistant glass, wearable antennas, biomedical microdevices, biosensors, self-sensing composites, supercapacitors, superinductors, hybrid superconductor, reinforced elastomers, nerve scaffolding, energy storage, and many others. The scope of the book covers three main areas: Part I: Processing; Part II: Properties; and Part III: Applications. Processing involves nanotube synthesis and macro scale material formation methods. Properties covers the mechanical, electrical, chemical and other properties of nanotubes and macroscale materials. Different approaches to growing high quality long nanotubes and spinning the nanotubes into yarn are explained in detail. The best ideas are collected from all around the world including commercial approaches. Applications of nanotube superfiber cover a huge field and provides a broad survey of uses. The book gives a broad overview starting from bioelectronics to carbon industrial machines. First book to explore the production and applications of macro-scale materials made from nano-scale particles Sets out the processes for producing macro-scale materials from carbon nanotubes, and describes the unique properties of these materials Potential applications for CNT fiber/yarn include replacing copper wire for power conduction, EMI shielding, coax cable, carbon biofiber, bullet-proof vests, impact resistant glass, wearable antennas, biomedical microdevices, biosensors, self-sensing composites, supercapacitors, superinductors, hybrid superconductor, reinforced elastomers, nerve scaffolding, energy storage, and many others
Author: Valentin N. Popov Publisher: Springer Science & Business Media ISBN: 9781402045738 Category : Mathematics Languages : en Pages : 284
Book Description
The book comprises reviews on various topics of carbon nanotube research from specialists in the field, together with reports on on-going research. Both are intended to give a detailed picture of the remarkable properties of these one-dimensional nanostructures. Particular attention is paid to the synthesis, characterization, properties, and application of nanotubes. The book will be an indispensable introduction for the newcomers in the field as well as a valuable update for researchers in the field, for it contains the most recent developments.
Author: Yury Gogotsi Publisher: CRC Press ISBN: 1466502428 Category : Science Languages : en Pages : 516
Book Description
This book provides information on synthesis, properties, and applications of carbon nanomaterials. With novel materials, such as graphene (atomically flat carbon) or carbon onions (carbon nanospheres), the family of carbon nanomaterials is rapidly growing. This book provides a state-of-the-art overview and in-depth analysis of the most important ca
Author: Kamel Ahmed Abd-Elsalam Publisher: Micro & Nano Technologies ISBN: 0128197862 Category : Languages : en Pages : 652
Book Description
Carbon Nanomaterials for Agri-food and Environmental Applications discusses the characterization, processing and applications of carbon-based nanostructured materials in the agricultural and environmental sectors. Sections discuss the synthesis and characterization of carbon nanotubes, the technological developments in environmental applications of carbon-based nanomaterials, and agri-food applications. The book also covers the toxic effects of engineered carbon nanoparticles on the environment, and in plants and animals. Finally, quality control and risk management are addressed to assess health and environmental risks. This is an applicable book for graduate students, researchers and those in industrial sectors of science and technology who want to learn more about carbon nanomaterials. Compares a range of carbon-based nanomaterials, showing how they are used for a range of agricultural and environmental applications Discusses the challenges and toxicity of different types of carbon-based nanomaterials for environmental and agricultural applications Explores when different classes of nanomaterial should be used in different environments
Author: Mahmood Rashid Atiyah
Author: Hosam El-Din Saleh
Author: Christian Peter Deck
Author: Suraya Abdul Rashid
Author: Boris S. Bokstein
Author: Mark Schulz
Author: William Murray Whyte
Author: Valentin N. Popov
Author: Yury Gogotsi
Author: Kamel Ahmed Abd-Elsalam