Papers by Keyword: Carbon Nanomaterials

Abstract: The purpose of the work is to develop new polymer composite nanomodified materials for the restoration of hull parts of agricultural machinery.As a result of research, a comparative analysis of the properties of composites based on epoxy resin ED-20 with the addition of 0.1-1.5 mass parts of carbon nanotubes “Taunit-M” obtained by free casting and direct pressing was carried out. The effectiveness of the developed compositions is proved when using them as binders in the production of fiber-reinforced composites.It was found that the introduction of 0.5 to 1 mass. parts CNT "Taunit" allows you to increase the strength characteristics of the resin ED-20 1.5-4 times with uniaxial tension, 2-2.5 times with three-point bending and reduce weight wear by 5-10 times.

Abstract: The article presents the most significant advantages and disadvantages inherent in methods for producing carbon nanomaterials. The most optimal method for obtaining nanofiber material has been determined, and today it is the method of low-temperature destruction (pyrolysis). The analysis of the catalysts with the identification of the most effective for the process of pyrolysis of associated gas. The operating characteristics of the experiment are described: temperature 600±50 °C; gas consumption per gram of catalyst 100 l/h; working medium: liquefied hydrogen. The results of research on the production of carbon nanofibers based on Nickel catalysts are presented. Photos of nanofibers of various sizes are presented.

Abstract: Incorporation of carbon nanomaterials (CNMs) into polymer such as Polyacrylonitrile (PAN) fibres allow electric current to pass through easily. Therefore in this study, bulk quantities of CNMs are synthesised using Chemical Vapor Deposition (CVD) method by manipulating the reaction time and catalyst ratio. Polypropylene wastes are used as the carbon precursor and ferrocene as metal catalyst in the CVD experiment. Addition of 1 wt% synthesised-CNMs into electrospun PAN fibres successfully increased the electrical conductivity by 50%. Addition of CNMs improved the crystallinity of electrospun-PAN/CNMs fibres as proven by XRD analysis. Electrospun PAN/CNMs-A fibres show larger diameter than the diameter of electrospun PAN/CNMs-B. Large bead formations contained densely-packed CNMs-A within the structure of electrospun PAN/CNMs-A fibres hindered their effectiveness to conduct the electricity. On the contrary, PAN/CNMs-B shows remarkable improvement in electrical conductivity when loosely-packed CNMs-B are added to the PAN fibres.

Abstract: Dense [boron carbide (B₄C)]/[carbon nanomaterials] composites were synthesized and sintered simultaneously using pulsed electric-current pressure sintering (PECPS) at 2173 K for 6.0×10² s (10 min) under 50 MPa in a vacuum. The starting powders were amorphous B and C nanopowders and nanocarbons. The latter were acid-treated carbon nanofiber CNF and carbon nanotube CNT. The sintered composites were evaluated from the viewpoints of mechanical properties at high temperatures up to ~ 2023 K in inert atmosphere. Thus fabricated composites with 10vol%CNF maintained high bending strength σ_b around 750 MPa even at 1973 K; this temperature is 100 K higher than that of conventional B₄C/CNF composites, and furthermore 600 MPa at 2023 K. These high σ_b at elevated temperatures might be explained by both the low content of catalytic Fe particles and the rough surface of CNF after the acid-treatment. On the other hand, B₄C/CNT composites displayed 770 MPa at 1723 K. The stress-strain curves demonstrate that B₄C/CNF composite deformed elastically until 1273 K and plastically up to 1973 K, however, the B₄C/CNT composites displayed elastic deformation up to around 1873 K.

Abstract: This article presents elemental and phase analysis results of carbon soot samples obtained by electric arc method in a environment of helium, argon and the initial sample. Also analysis results of samples after extraction of carbon nanomaterials are presented (CNM)

Abstract: The use of proppants in hydraulic fracturing has significantly grown worldwide in recent years. Discoveries of large unconventional reservoirs in the north of Brazil have collaborated to give it the 10^th position among countries with the world's largest shale reserves. Nowadays, studies on nanomaterials that are used as additives in proppants are the focus of North America's companies and universities in order to develop either proppants that can suffer mechanical and chemical changes inside the reservoir or that enable their traceability and direction. This paper presents a study on synthesis and characterization of metakaolin’s based ceramic proppants incorporating different types of nanocarbon materials. The method adopted was based on use of high intensive mixing of raw material (metakaolin) granulated with alkaline water solution of dispersed carbon nanomaterials. The SEM analysis testify the carbon nanomaterials dispersion on proppant bulk structure. Mechanical tests (crush resistance or K-value) indicated that metakaolin based proppants reached similar characteristics of white sand natural proppants.

Abstract: Metals are increasingly used in engineering due to their high specific strength. However, some of pure metals do not posses good corrosion resistance. Therefore carbon nanomaterials (CNMs) has been studied to overwhelm the corrosion existed on the metal’s surface. CNMs are synthesized directly on various metal substrates by Chemical Vapor Deposition (CVD) technique without addition of any external catalyst, in reactor at temperature of 800°C. Argon with a flow rate of 200ml/min was used as a carrier gas and acetone as a carbon source. In this study, two different metals were used as metal substrate: mild steel and stainless steel 316. The morphology, existence of CNTs and elemental analysis of the CNMs on metal substrate are evaluated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX), respectively. It was proven that the different element composition of metal substrate influenced the size and morphology of CNMs. The most suitable metal to grow CNTs was found to be stainless steel.

Abstract: Some carbon nanomaterials have been proved to be able to improve the PCR amplification efficiency. If used in quantitative real-time PCR (qPCR), these nanomaterials must be tested whether fluorescence processing is interfered after they are added in the PCR system. In this study, 76 different carbon nanomaterials were tested in SYBR Green I-based qPCR, and the results demonstrated that about half carbon nanomaterials tested in this study could alter the PCR amplification profile probably due to the fluorescence quenching. Surprisingly, lower concentrations of nanomaterials led to more slight interference with the melting temperature.

Abstract: Carbon nanotubes were produced from the aerosol-assisted catalytic CVD method using palm oil as the precursor and ferrocene as the catalyst. The CNTs were yielded at optimized temperature of 700oC and the Field Emission Scanning Electron Microscope showed the image of CNTs produced. Raman Spectroscopy, energy dispersive X-ray and Thermogravimetric Analysis were then used to further study the Raman Spectra, purity and identification of samples.

Abstract: Raman analysis is one of the main methods use to investigate type of graphitized carbon nanomaterials. It provides information on the vibration of crystal lattice, electron structure and regularity of crystal structure of the graphitized carbon materials. In this work the single step chemical vapour deposition (CVD) method was introduced for the direct growth of all as-synthesized carbon nanomaterials; carbon nanotubes (CNTs), carbon nanofiber (CNF), carbon nanosphere chain (CNSC) and CNT heterojunctions (HJCNTs). Series of metal catalysts were formulated from Ni, Fe, Cr and Cu, and were used in the synthesis of the respected carbon nanomaterials (CNMs). By introducing the right combination of the reaction conditions consisting of the formulated catalyst, reaction temperature and flow rate as well as type of carbon source resulted in the formation of different types of carbon nanomaterials. Raman spectra analysis revealed that the used of acetylene and ethanol as the carbon precursors are proficient to produce different form of carbon nanomaterials as depicted by the evolution of the G-band and D-band intensities. The FESEM micrographs obtained confirmed the morphology and types of the respected carbon nanomaterials synthesized in this study.