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Unidirectional, pitch-based-matrix composites fabricated from PAN-based Courtaulds fibres were oxidised in air at temperatures of 420 and 730°C to low extents of burn-off (less than 3.5%). Material loss occurred primarily at fibre-matrix interfaces at the edge regions of the composites and, in the case of the lower temperature heat-treated materials, in the areas close to internal pores and cracks...
The probability functions for the 1st and 2nd nearest neighbor layers were calculated for carbon black, the Fouier coefficients A n (hk) of which were obtained by Houska & Warren. As a result, the probability function indicating the AB stacking was obtained and was in good agreement with the positions of carbon atoms in a unit cell of the hexagonal system. The twist angle between the...
We have synthesized K-GICs (potassium-graphite intercalation compounds) by the modified two-bulb method. The compounds were kept under a stabilization agent (liquid paraffin). The stage transition of K-GDICs (graphite deintercalation compounds), owing to the slow diffusion of water, was observed by X-ray diffraction measurements. The effect of the formation of higher-stage K-GDICs by oxidation...
Gas permeability (K) of a large cylindrical isotropic graphite with a size of φ95 φ75 40 cm was determined by measuring the flow of nitrogen gas to keep the inside pressure of 140 kPa. The gas permeability of 4 10 -1 cm 2 /s measured on a large specimen agreed with those obtained on small cylindrical specimens by a conventional method.
We have developed a new precursor polymer for glass-like carbon film; poly-carbodiimide (PCDI). The purposes of this paper are to determine the structure of the carbonized PCDI and to reveal the mechanism for the carbonization.After heat treatment at 1000°C, the total yield was ca. 75% and the density reached 1.78g/cm 3 . These values are much higher than the ordinary precursor resins, such...
The structural parameters of mesophase pitch with optical anisotropy have been successfully obtained by using high-temperature 13 C-NMR spectroscopy. Well-resolved spectra were obtained from the mesophase pitch with the addition of pyrene, which played the role of solvent for a quinoline-insoluble rich mesophase pitch during NMR measurement at 573 K. The resolution of NMR spectra was...
Pyrolysis mechanism of Kapton-type polyimide was investigated with special attention to the early stage. Two approaches were employed to reveal the pyrolysis reactions: one is an analysis of evolved compounds, the other is a hydrolysis method that selectively converts polyimide char into low-molecular-weight compounds. In the initial step of pyrolysis, bond cleavage around imide ring and following...
The purpose of the work reported here is to give carbon black with a high functional surface, especially for use in battery electrodes. The authors have investigated the surface properties, such as wettability, electric conductivity, and rate constant of H 2 O 2 decomposition of surface modified carbon black (CB) by anodic oxidation processing. This work also describes the relationships...
A number of different products are formed in the synthesis of fullerenes using the DC carbon arc evaporation of graphite. Fullerenes are found in the soot that condenses from the vapour phase, while nanotubes are located in the material that deposits on the cathode. This paper reports the discovery of a deposit on the anode, which is similar in appearance and composition to that formed on the cathode;...
We describe the preparation of hard carbon samples from epoxy resins. These materials are shown by wide angle X-ray diffraction to be constructed of graphene sheets of small lateral extent (about 25 in diameter). By controlling the synthesis conditions, it is possible to prepare materials wherein the fraction of graphene sheets present as single layers can be adjusted. Using small angle X-ray...
A quantitative model describing the changes undergone by a carbon fibre during gasification (porosity, surface area, pore volume, fibre diameter, reactivity, losses of carbon by percolation, etc.) is presented. In the approach adopted, the porous network of a carbonized fibre is described by a random pore model, which takes into account different reaction regimes (chemical and diffusional control)...
The rheology of mesophase-pitches, having different percentage mesophase content, has been investigated by means of controlled stress, oscillatory rheometry. Three thermally transformed mesophase-pitches (prepared from Ashland A240), with mesophase contents in the range 60-95%, together with a 100% optically anisotropic synthetic mesophase-pitch from Mitsubishi Gas-Chemical Company were studied....
CF/ceramic composite was prepared using 2.5-dimensionally woven CF cloth as a reinforcement of combination weave, and borosiloxane (PBS) as a matrix precursor material of an organometallic compound. 2-5-dimensionally woven CF cloth was impregnated with an acetone solution of PBS. After air-drying, it was heat-treated first to 500°C and then to 1000°C to prepare the CF/ceramic composite. The primary...
Packing behaviour and electrical resistivity of a powder under compression were investigated on carbon microspheres (CMB) with 1 to 15 μm size made from phenol-formaldehyde resin and porous graphite particles (EG) with 15 to 150 μm size. Packing density, height of packed particles and electrical resistivity were measured in relation to applied pressure. Shape of the particles was observed by SEM...
Semiconducting carbon tubules (n- and p-type) of band gap 1.96-1.98 eV have been synthesised from the soot of naturally occurring camphor for the first time. The mechanism of the formation of multichannel-multilayered camphoric tubules is discussed. Tubules are characterised by SEM, AFM, TEM, XRD, ESR, FTIR and electrical conductivity studies.
Fractal analysis of adsorption isotherms is used to study the surface roughness of carbon blacks graphitized at 3000 K. Gases of various molecular sizes (nitrogen, argon, ethane, propane, and butane) are adsorbed on different grades of carbon black. Using the molecular yardstick method, it is found that the surface fractal dimension of graphitized carbon black is 2.0±0.1 and is independent of carbon...
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