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Iron oxide (Fe 2 O 3 ) was examined as an additive to improve the yield of the insoluble fraction in the synthetic mesophase pitch and to inhibit the expansion of the pitch during the heat-treatment and the successive carbonization of the insoluble fraction. The pitch was heat-treated at 350 o C for 4 h under 500 rev./min stirring by adding 0, 6, 17, and 25 wt.% Fe 2 ...
Anodic performances and structures of hard carbons prepared from synthetic isotropic pitches through solid phase oxidation were investigated to discuss their insertion sites for lithium ion and correlation between the capacity and structure. The derived hard carbons showed complicated voltage profiles of charge and discharge, indicating five kinds of insertion sites; partially charge transferring...
The recent development of de-SO x and de-NO x using activated carbon fibers (ACF) in Japan is introduced in this review comparing it with the conventional commercialized system. Pitch-based ACFs showed higher de-SO x activity than other ACFs from different precursors. De-SO x activity can be further modified by the heat-treatment, continuous and complete removal of...
The development of mesoscopic texture, which describes the structural units 10–100 nm in size, at the transverse skin area in mesophase pitch-based carbon fibers as a result of heat-treatment were examined using a high resolution scanning electron microscope (HR-SEM). The graphitized carbon fiber was found to be composed of plate-like mesoscopic structural units defined as rectangular microdomains...
Mesophase pitch-based short carbon fibers prepared by the melt blown method exhibited diameters 6 to 16 μm distributed along the filament. The transverse surfaces of the thicker and thinner parts of the filament were very different. The thicker part showed a skin/core texture where very thick and long domains run parallel to the core while the thinner one had a PAN-AM texture where sets of straight...
Mesophase pitch has been synthesized from pure aromatic hydrocarbons (naphthalene, methylnaphthalene) aided by an HF–BF 3 catalyst. These synthesized pitches have better performance for many applications — carbon fibers, binders, and anode materials for lithium ion batteries etc. — because the purity and high aromaticity leads to high orientation. This paper discusses the kinds of pitch, the...
Soot produced from graphite through arc discharge was separated into four fractions which were structurally analyzed. The toluene-soluble fraction carried C 60 , C 70 , and C 76 -C 120 fullerenes while the toluene-insoluble quinoline-soluble fraction (ca. 1 wt%) consisted of larger clusters of C 70 to C 400 which...
The puffing inhibiting ability of iron(II) sulfate impregnated into coal-tar-based needle coke was examined in comparison with that of boric acid. Both inhibitors exhibited similar ability to suppress the puffing of coal-tar-based needle coke by impregnating from their aqueous solutions, drying and heat-treating at 1223 K before kneading with the binder pitch. Addition of iron(III) oxide at the kneading...
Puffing of pitch needle coke was successfully suppressed by both impregnating boric acid and adding ferric oxide. The boric acid was impregnated into calcined coke and preheated above 870 K to convert boric acid to boron trioxide which melts above 850 K to get into the pore. Filled boron trioxide inhibits the binder pitch getting into the pore at the kneading and sublimes to open the pore above 1800...
Development of mesoscopic texture in the longitudinal surface of mesophase pitch-based carbon fibers through heat treatment was characterized in as-spun, stabilized, carbonized and graphitized fibers using a high resolution scanning electron microscope (HR-SEM). The basic structural units on the longitudinal surface of the mesophase pitch-based graphitized fibers defined as the pleat and fibril were...
Naphthalene-derived mesophase pitch (NMP) and phenolic resins of novolac type and resol type were applied for the binder of MgO-C brick. NMP provided a brick of high strength at over 1000 o C and high oxidative resistivity, however, the apparent porosity of the brick was high because of NMP's expansion at the carbonization. Both types of resins provided bricks of high strength and low apparent...
The anodic performances of anisotropic carbon derived from quinoline pitch (CQP) to be used in the lithium ion battery were studied to clarify the influence of nitrogen in the carbon hexagonal sheet. The quinoline pitch was synthesized by using HF/BF 3 as a catalyst. Nitrogen in the carbon existed as pyridinic, pyrrolic and quaternary types to be converted in this sequence, depending upon...
Mesocarbon microbeads (MCMB) prepared from a synthetic naphthalene isotropic pitch with or without carbon black were compared in their microstructure observed under high resolution scanning electron microscopy and transmission electron microscopy (TEM). The spheres prepared without carbon black exhibited an assemble of microdomain units with a number of voids among the units after isolation by pyridine...
Development of the transversal texture in the mesophase pitch-based as-spun at 310°C, stabilized, carbonized, calcined and graphitized fibers was examined using a high resolution scanning electron microscope (HR–SEM). The cross-sectional surface of the as-spun fiber showed randomly oriented microdomains of spherical or ellipsoidal shape, ca. 50 nm long in their longer axis. Such shape and orientation...
Moulding and successive carbonization of the toluene-insoluble fraction in fullerene soot were studied to prepare carbon disks with unique properties. Separation of the graphitic component by precipitation in acetone allows the fraction to be moulded and carbonized into a carbon disk of significant strength. The disk was found to consist of large grains and fine particles which were densely packed...
Two pitches containing mesophase spheres were prepared from a synthetic isotropic naphthalene pitch at 360°C and 375°C so as to contain spheres of different diameters. Both pitches were smoothly spun into thin fibers, which were converted into carbon fibers through stabilization, carbonization and graphitization. The fiber from the pitch with finer spheres exhibited a higher compressive strength,...
Puffing inhibition of coal tar based needle coke was effectively achieved regardless of the repeated impregnating and heating rate at the graphitization by impregnation with disodium hydrogen phosphate (DHP) and boric acid into the needle coke. Inhibitors were found dispersed into pores of the coke by impregnating and heat-treating the inhibitors on the coke. Such inhibitors in the pore prohibited...
Carbonization properties and stabilization reactivity of MCMB prepared at a high yield from a particular synthetic naphthalene isotropic pitch with and without carbon black (CB) were evaluated in terms of their fusibility, adhesion ability and graphitizability. MCMB prepared without CB carried much higher hydrogen content which is attributed to aliphatic or naphthenic hydrogens, showing high fusibility...
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