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Ultrathin sections prepared from both transverse and longitudinal PAN precursor fibers were examined by high-resolution transmission electron microscopy. Ordered and amorphous phases coexist in these sections, providing verification for the two-phase structure of PAN fibers, however, onion-like spheres and crystallites predominate in the transverse sections, and highly oriented structures are dominant...
The superlative mechanical properties of carbon nanotubes make them the filler material of choice for composite reinforcement. In this paper we review the progress to date in the field of mechanical reinforcement of polymers using nanotubes. Initially, the basics of fibre reinforced composites are introduced and the prerequisites for successful reinforcement discussed. The effectiveness of different...
We investigated sp 2 carbon microrods resulting from the reaction of lithium with hexachlorobenzene. The material exhibits high surface area (200–340m 2 /g, depending on heat treatment) and a reversible lithium storage capacity in excess of 500mAh/g. The discharge/charge behavior of the material resembles that of high specific capacity non-graphitic carbon. Without distinguishable...
Platinum nanoparticles were prepared as catalysts supported on microporous amorphous carbon with and without a graphitic carbon shell. The electro-oxidation of methanol in acidic solutions at room temperature was used as a probe reaction to explore the effect of the carbon structure on catalysis. CO anodic stripping voltammetry and cyclic voltammetry both recorded enhanced performance for the catalyst...
Vapor-grown carbon fibers (VGCFs) with high-purity have been successfully prepared from the thermal cracking of deoiled asphalt (DOA) with ferrocene as catalyst by chemical vapor deposition (CVD) in argon atmosphere and characterized systematically by field-emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques...
The methane conversion and carbon yield of the chemical vapor deposition (CVD) reaction suggests that the optimum reaction conditions of the formation of multi-wall carbon nanotubes (MWCNTs) can be obtained by using a 50mg of nano-MgNi alloy under pyrolysis of the pure CH 4 gas with the flow rate about 100–120cm 3 /min at 650°C for 30min. Raman results indicate the CNTs are in multi-wall...
The present study aimed at development of a method for synthesizing multi-walled carbon nanotubes (CNTs) on carbon paper substrates (CP) at densities as high as those so far reported for CNTs formed on quartz substrates. Applying conditions optimized for CNTs synthesis on quartz substrates, in which CP was heated at 1073K, being placed parallel to the flow of m-xylene/ferrocene vapor, resulted in...
The effects of laser radiation on soot in a vacuum were studied by Raman spectroscopy and transmission electron microscopy. It was found that defective carbon onions could be formed simply by irradiation of focused common diode lasers with intensity much lower (10 3 –10 6 W/cm 2 ) than those used in the previous work. A modified Melton model was introduced to analyze the formation...
The thermal decomposition of ferrocene combined with a catalyst-assisted structuring of a Si-substrate surface is a favourable way to produce Fe-filled carbon nanotubes in good quality and in high yields. In this work we have studied the growth of such aligned filled nanotubes on iron and cobalt pre-coated Si-substrates and their dependence on the deposition time. The nanotube diameter depends on...
A method has been developed to synthesize composites with cross-linked natural rubber (NR) and dispersed single-wall carbon nanotubes (SWNT). The mechanical response of the NR samples was observed to change as a function of the amount of sulfur used for cross-linking, based on the number density of cross-links resulting from the vulcanization process. The relationship between SWNTs D ∗ wavenumber...
Product distributions in the pyrolysis of ethylene, acetylene, and propylene are studied to obtain an experimental database for a detailed kinetic modeling of gas phase reactions in chemical vapor deposition of carbon from these light hydrocarbons. Experiments were performed with a vertical flow reactor at 900°C and pressures from 2 to 15kPa. Gas phase components were analyzed by both on-line and...
Mechanical properties of long multi-walled CNT ropes prepared using the floating catalyst chemical vapour deposition method were tested, obtaining an average tensile strength and Young’s modulus of 210MPa and 2.2GPa, respectively. Furthermore, the ropes showed excellent NH 3 detecting sensitivity at both high and low NH 3 concentrations. Increasing the temperature, NH 3 desorbed...
Mesocarbon microbeads have proved to be an excellent precursor for high-density carbon materials. In this article, the impact of oxidation on carbonization behavior and mechanical property of the graphitized pellets are studied. Thermal analysis shows that the oxidation is the competition between weight gain, due to the incorporation of oxygen into the structure and weight loss caused by the consumed...
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