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膨張黒鉛は,大きな重油収着能を示し,自身重量の80倍程度のA重油あるいは原油を収着した膨張黒鉛から,圧搾法で収着した重油のおよそ80%を,また吸引濾過法でも収着した重油の50-70%を回収することを見いだした。しかしながら,吸引濾過法による回収では,粘性の高いB重油およびC重油では,回収がほぼ不可能であった。この吸引濾過法では,膨張黒鉛特有のかさ高さを壊すことはなく,再収着に使用できた。しかしながら,回収を繰り返すことにより,収着量,回収量は減少していった。一方,回収された重油ともとの原油との間には,炭化水素組成分子量および水分含有量に差は認められず,回収された重油は,そのまま使用可能であることが明らかとなった。

The sorption behaviors of four kinds of heavy oils into exfoliated graphites with different bulk densities were studied. The maximum sorption capacity of an exfoliated graphite with a bulk density of 6 kg/m 3 was found to be suprisingly high, 86 g of A-grade heavy oil and 76 g of crude oil per 1 g of exfoliated graphite, respectively, and also its sorption occured very rapidly, i.e. within 2 min. Sorption capacity was found to depend strongly on the bulk density and pore volume of the exfoliated graphite and the time it took to reach maximum sorption, as well as sorption capacity, as an exfoliated graphite depended strongly on the grade of heavy oil. Heavy oils sorbed into the exfoliated graphite could be recovered either by a simple compression or suction filtration with a recovery ratio of 60–80%. Recovered oils showed no difference in molecular weight and hydrocarbon constituent from the original. No increase of the water content in the recovered oils was detected, suggesting preferential sorption of heavy oil into exfoliated graphite. This result indicates clearly that the oils recovered from the exfoliated graphite can be recycled. From the present work, exfoliated graphite with low bulk density is a promising material for the sorption and recovery of spilled heavy oil.

Monodispersed cerium(IV) oxide (CeO2) particles composed of an agglomeration of primary nanocrystalline particles with a cubic fluorite structure could be synthesized from relatively concentrated cerium(IV) sulfate solutions up to 0.5 mol dm−3 by thermal hydrolysis at 120 to 240 °C. The influences of the presence of urea and its concentration on their crystallite size and morphology were investigated. Upon the addition of urea and increasing its concentration, the morphology gradually changed from monodispersed particles to dispersed ultra-fine particles that had no definite shape and tight agglomeration. The mechanisms for the growth and agglomeration of the particles formed by thermal hydrolysis were discussed. The existence of a dopant such as Gd was effective for suppressing the grain growth of the ceria particles during the calcining and sintering.

In order to estimate the spin densities of hydrogen atom trapped inside the diamond lattice, thermal vibrations around the tetrahedral trapping site were simulated for C 26 H 32 cluster model on the basis of semi-empirical PM3-MO method combined with direct molecular orbital (MO) dynamics calculation. The calculations show that the hydrogen atom behaves as a shallow spin donor in the diamond lattice. Increase of temperature brings about increase in the amplitude of vibration of trapped atom due to the thermal activation, which leads to decrease in the spin densities of the atom from 0.971 at 0 K to 0.958 at 900 K. It is predicted that the effect of temperature on the hyperfine coupling constant of the hydrogen can be detectable experimentally by means of EPR spectroscopy.

Incorporation of iron particles into carbon films was carried out by mixing an iron complex with polyimide in solution and by following carbonization. Iron in the polyimide film promoted the carbonization of matrix polyimide and increased the electrical conductivity of films. The growth of iron particles in carbon films and the change from paramagnetic to ferromagnetic behavior were observed with the increase of carbonization temperature.

The presence of MoOCl 3 with MoCl 5 was found to change the stage structure of resultant graphite intercalation compounds (GICs) with MoCl 5 . Heating MoOCl 3 with MoCl 5 and graphite at 200°C for seven days produced stage-1 MoCl 5 –GIC in a single phase, though no addition of MoOCl 3 resulted in the formation of poorly crystallized stage-3 GIC and a large amount of its addition in no intercalation of MoCl 5 .

The mechanism for the synthesis of MoCl 5 -graphite intercalation compounds (MoCl 5 -GICs) with stage-1 structure, which was successfully done in the presence of either MoOCl 3 or MoO 3 with MoCl 5 , was discussed. The formation of reactive chlorine gas was supposed to be important for the formation of stage-1 structure. Well-ordered stage structures along the c -axis were easily obtained in MoCl 5 -GICs synthesized from natural graphite and also from highly-crystallized graphite films. From detailed observation by STM/AFM on stage-4 GICs, a superstructure in the graphite basal plane (in-plane structure) was found in large intercalated domains with an area of more than 150 μm 2 , having a hexagonal symmetry of which axes rotated by about 30° from graphite axes and having a periodicity of 1.9 nm. The boundaries between large intercalated and non-intercalated domains consisted of linear segments which were parallel to certain crystallographic axes of graphite, but those between small intercalated domains with the area less than 100 nm 2 and non-intercalated domains were irregular. These MoCl 5 -GICs were experimentally shown to have very high stability in various liquids, all of which can dissolve MoCl 5 itself. Even in boiling water, the compounds prepared from graphite hosts with a flake size as large as 400 μm showed only a trace of decomposition of GICs, but those from a flake size as small as 10 μm were decomposed.

Poly(amide acid) was prepared from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) and was then reacted with NaH and various kinds of alkyl iodides to transform it into its alkyl esters. The cast films were imidized as fixed on glass substrates to give polyimide films. The tensile modulus of polyimide films prepared from the methyl ester precursor was lower than that from poly(amide acid), but it increased with increasing size of the alkyl group. The polyimide films were carbonized by heating to 900°C, and then further heated to 2800°C for graphitization. Their degrees of graphitization and orientation of graphite crystallites as a function of weight loss at imidization were studied by measurements of X-ray diffraction at room temperature and magnetoresistance at liquid nitrogen temperature. Both measurements clearly indicate that the graphitized films prepared from poly(amide ester) have high degrees of graphitization. It was also made clear that the orientation of the graphitized films prepared from poly(amide ester) with small alkyl groups is lower than that from poly(amide acid), but the orientation increased with increase in the size of the alkyl group.

Host effect on the intercalation of iron chloride(III) in its nitoromethane (NM) solution was investigated by using host carbons heat-treated at different temperatures, cokes with random orientation and pyrolytic carbons with planar one. Cokes heat-treated below 1900°C were not intercalated even in high concentration solution of FeCl3 (4.8 M). The reactivity of cokes heat-treated above 2100°C was found to be strongly dependent on the concentration of FeCl3 in the solution; the less crystallized coke needed the higher concentration of FeCl3 to be intercalated, and the smaller stage number of resultant intercalation compound from the coke heat-treated at a temperature was obtained in the higher concentration of solution. On the other hand, pyrolytic carbons behaved quite differently; all of them could react even in the 0.6 M solution of FeCl3, where any cokes did not react, to give the same stage-3 structure independent on the crystallinity. These different reactivities of hosts for the intercalation of FeCl3 in NM were discussed by comparing with those for other intercalations as reported previously.

The host effect on the intercalation of MoCl 5 was studied using vapor-grown (VGCFs), mesophase-pitch-based (MPCFs) and PAN-based carbon fibers (PANCFs) heat-treated to different temperatures. MoCl 5 successfully intercalated into VGCFs, but MPCFs and PANCFs showed no intercalation. MoCl 5 intercalated into 2000°C- and 2200°C-treated VGCFs having larger interlayer spacing than 2900°C-treated MPCFs where no intercalation was observed. The use of MoO 3 or MoOCl 3 with MoCl 5 found to affect the stage structure in VGCFs but was not able to perform intercalation in MPCFs and PANCFs. In VGCFs, the intercalation of MoCl 5 depends on the heat treatment temperature. Stage-1 structure in single phase was formed from 3000°C-treated VGCF with MoCl 5 and MoO 3 in the molar ratio of 1:1:0.37. SEM studies of stage-1 VGCF 3000°C-treated fiber showed the peeling of thin layers from the fiber surface and cleavage along the fiber axis of the fiber. Apparent diameter of fibers increased to roughly 3 times after intercalation.

重油等の流出事故において従来より使用されているポリプロビレソ製重油吸着マットと膨張黒鉛の吸着能力を比較した場合,膨張黒鉛は,自身重量の80倍程度の大きな重油収着能を示すことを明らかにしてきた.本研究では,かさ密度,全細孔容積の異なる膨張黒鉛試料を用い収着能,収着速度について調べた.その結果,かさ密度0.009/cm3,比表面積49.7m2/g,全細孔容積0.166cm3/gの膨張黒鉛では,A重油を膨張黒鉛重量の83倍を収着したのに対し,かさ密度0.010g/cm3,比表面積44.0m2/g,全細孔容積0.134cm3/gの膨張黒鉛では,A重油を70倍しか吸着しなかつた.粘度の高いC重油では,前者が67倍収着量を示したのに対して,後者は,60倍の収着量を示したのみであつた.原油,B重油でも両者の間には重油収着量で10g程度の差が見られた.これら収着能に差が認められた原因としては,膨張黒鉛形状に差があるためと考察した.事実,用いた膨張黒鉛の形態をSEMにより観察したところ,形状に差が認められた.また,全細孔容積を比較したところ,全細孔容積の小さな試料では,収着量も少ないことが明らかになり,形状,特に細孔が大きく関与していることが明らかになった.

Various carbon fibers with different microstructures were irradiated in the Japan Materials Testing Reactor (JMTR). Tensile tests were conducted and the microstructures were also examined before and after neutron irradiation. Clear correlations between the tensile properties and the microstructures were found before and after irradiation.The data obtained here will be useful for the development of C/C composite materials that have higher resistanceto radiation damage.

It was found that an exfoliated graphite (EG) can sorb a large amount of heavy oilvery quickly. Maximumsorption capacity on EG was shown to be about 80g of heavy oil per 1 g of EG, which is much largr than the packageof absorbents have ever been used. Sorption time of A-grade oil was so quick as to complete within 1 min. On EGsamples compacted to different volumes which had high bulk density, small surface area and total pore volume, lessmaximum sorption capacity was observed; the one having the higher bulk density sorbed the less amount of heavy oil. Time to reach maximum sorption, as well as sorption capacity, for an exfoliated graphite depended on bulk densityand pore.On observation through SEM and porosimeter, differences of morphology on exfoliated graphite were detected. The sorption capacity and time for sorption of heavy oil into exfoliated graphite were supposed to depend strongly onthe size and shape of pores in exfoliated graphite.

Intercalated domains on stage 4 MoCl5–graphite intercalation compounds (MoCl5–GIC’s) were observed by atomic force microscopy (AFM) and scanning tunneling microscopy (STM). On large intercalated domains, a superstructure was found, in relation with a modulation of the electronic properties of the first layer of carbon. From that, the structure of the chloride ions layer was discussed and a model including dimer molecules was proposed. At the boundaries between large intercalated and nonintercalated domains, corrugations were observed along certain crystallographic directions of graphite. Their morphology was studied in detail at atomic scale and formation mechanisms were proposed. Small intercalated domains were also observed. Their shapes were irregular but their boundaries were clear cut.

Degradation of carbon materials after various intercalation reactions was investigated by means of microscope observation of the products and a new aspect to characterize carbon materials was revealed. The degradation of cokes occurred due to the stress to the coke particles accompanied by enlargement of interlayer spacing between carbon layers with intercalation and it depended on the size of intercalates and the stage number of the resultant compounds. For intercalation of alkali metals in ether solutions, the degradation of cokes occurred by the co-intercalation of ether molecules with alkali metal ions. Natural graphite and pyrolytic carbons, on the other hand, were not degraded because of their high degree of planar orientation of crystallites which could relax the stress because of their easy expansion perpendicular to the flake and plate surface. From the comparison between the present observations of degradation and the X-ray diffraction measurements of intercalation compounds, the resistance in the host carbon against the degradation by intercalation and the expansion force to enlarge interlayer spacing in the host by intercalation were closely related to each other, and this resistance was revealed as one of the important factors to govern intercalation.

Two types of boron containing polyimide (Kapton type) film were prepared either by adding dihydroxyphenylborane (DPB) to polyamic acid [mixing method] or by using diaminodiphenyl ether having a boron containing functional group (DDE–B) to prepare polyamic acid [substitution method]. Formed polyimide films containing boron were carbonized at 600–1200°C. By doping boron into the precursor polyimide, preferential formation of B–N bonds in carbonized films was observed and appreciable amounts of nitrogen were chemically trapped in the carbon film even after carbonization at 1200°C. The polyimide prepared by the substitution method gave uniform carbon films in composition and structure, though DDE–B is not simply synthesized and didn't polymerize to high degree. The polyimide prepared by the mixing method gave non-uniform carbon films, but the process was very simple and possible to increase boron content by using different boron compounds.

The mechanism of formation of MoCl 5 –graphite intercalation compounds (MoCl 5 –GICs) was proposed on the basis of the experimental results obtained in the present and previous works. The amount of reactive chlorine formed in the reaction system was concluded to be the determining factor for the stage structure in resulting MoCl 5 –GICs. Reactive atomic chlorine produced during the decomposition of only 2% MoCl 6 , which was formed from MoCl 5 at high temperature, seemed not enough for the formation of pure stage 1 MoCl 5 –GIC and therefore only stage 2 structure was obtained. Heating the MoCl 5 in presence of either MoOCl 3 or MoO 3 formed MoOCl 4 , which evolved high amount of reactive chlorine which formed the stage 1 MoCl 5 –GIC in single phase.

The creation of structural defects on natural graphite surfaces by slight treatment of oxygen plasma was studied by scanning tunneling microscopy (STM) at nanoscopic scale. Most of the defects were vacancies with the depth of one or two layers, while the mean number of defects per μm 2 of graphite surface and the mean area of defects increased with the increase in input power, time and temperature of the irradiation. After very slight treatment at room temperature, single carbon atom vacancies were obtained on graphite surfaces with a percentage more than 50%, though some large vacancies were formed. After slight irradiation at a high temperature (400°C), an agglomeration of defects occurred (the mean area increases whereas the defect density decreases), while the defects once formed were difficult to be annealed by heating at high temperatures up to 400°C in vacuum. The present work showed the possibility to control the modification of natural graphite surfaces for further applications by changing the condition of oxygen plasma treatment.

Chemical state of nitrogen atoms in the carbon films prepared from different organic precursors (different polyimides, POD and PAN) was studied by XPS and chemical analysis. In the carbon films prepared from all these precursors by the heat-treatment up to 1200°C, nitrogen atoms give a single XPS peak at 401 eV, suggesting that nitrogen atoms substitute carbon atoms in hexagonal carbon layers.

Carbonization of stabilized PAN fibers was studied by focusing nitrogen using elemental analysis and XPS, in relation to mechanical properties. A difference in denitrogenation on the surface and in the bulk of the fibers was observed in a range of carbonization temperatures between 600 and 1000°C, with denitrogenation on the surface occurring much earlier (600–800°C) than in the bulk (>800°C). The chemical state of nitrogen seemed to be different between the surface and the core; more tertiary nitrogen (– N | –) was present at the surface than in the core in a temperature range between 600 and 1000°C. This difference might be responsible for the retardation in the tensile strength development of the fibers while increasing the HTT from 700 to 800°C.

Sodium intercalation in three unidentate and three bidentate ether solutions having different molecular sizes was investigated using poly(vinyl chloride) cokes heat-treated at different temperatures. Co-intercalation of ether molecules with sodium cations was found to be governed strongly by the graphitization degree of hosts in contrast with other alkali metals. This tendency is dependent on the strength of bond between sodium and ether molecule, and also the bulk of coordinated molecules; the limit of graphitization degree for co-intercalation of solvent molecules was lower in bidentate solution than in unidentate ones, and the large solvents were prevented from co-intercalation more strongly than small ones.

A new and simple method was developed to synthesize graphite intercalation compounds (GICs) with Cr VI compounds from natural graphite host with different sizes from 10 to 400 μm at room temperature under atmospheric conditions. The stage structure of the GICs was controlled by changing the reaction time and relative amounts of graphite, CrO 3 and HCl; stage-2 GIC was produced after keeping graphite, CrO 3 and 12 M HCl in a molar ratio of 1:2:1 for 15 days. The stage number increased with increase in the relative amount of HCl and no intercalation was observed using more than 5 mol. A lower concentration of HCl (3 M) also performed the intercalation. The presence of Cr VI in GICs synthesized was proved by X-ray photoelectron spectroscopy.

Polyamide acid was prepared from pyromellitic dianhydride and p-phenylenediamine and was then reacted with NaH and various kinds of alkyl halides to transform into alkyl esters. The cast films were imidized as fixed on glass substrate to give polyimide films and were then carbonized by heating to 900°C. The electrical conductivity of the carbonized films decreased with the increase of the size of the leaving group at the imidization step. The carbonized films were further heated to 2800°C for graphitization. Their degrees of graphitization and orientation of the graphite crystallite as a function of weight loss at imidization were studied by X-ray diffraction measurement at room temperature and magnetoresistance measurement at liquid nitrogen temperature. Both measurements clearly indicate that the graphitized films prepared from polyamide acid alkyl ester have high degrees of graphitization. It was also made clear that the orientation of the graphitized films increased with the increase of the size of the leaving group at the imidization step. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci John Wiley & Sons, Inc.J Appl Polym Sci 68: 1613–1620, 1998

Stage-1 MoCl 5 —graphite intercalation compound (GIC) was successfully prepared in a single phase by heating the mixture of MoCl 5 and MoO 3 with natural graphite of different sizes ranging from 10 to 400 μm. The stage structure of resultant MoCl 5 GICs was found to be dependent on the amount of MoO 3 . Use of MoO 3 was also found to accelerate the intercalation reaction, similar to MoOCl 3 in our earlier studies. However, MoO 3 was much better than MoOCl 3 because of its stability, availability and non-hygroscopic nature. A comparative study of the use of MoOCl 3 with MoCl 5 to form the pure stage-1 MoCl 5 GIC was also carried out.

Stability of graphite intercalation compounds of MoCl5 (MoCl5GICs) with stage-2 and -4 structure was studied in various solutions. The change in the X-ray powder pattern of these GICs could be hardly observed, so they were proved to be stable not only in water at room temperature but also in boiling water, acetone, KCl-saturated aqueous solution and CCl4, all of which can dissolve MoCl5 itself. In boiling water, however, the stability of GICs was found to depend strongly on the flake size of the host graphite of the starting GICs: decomposition was observed on those with flake size of 10 μm, but those of size 400 μm were perfectly stable.

A soft process for the intercalation of different ammonium cations into vanadium pentoxide was developed. By refluxing an aqueous solution containing ammonium, tetramethylammonium (CH3)4N+, and tetraethylammonium (C2H5)4N+with V2O5powders, intercalation compounds containing corresponding ammonium cations were obtained. The compound with aniline C6H5NH2was also synthesized by the same process. The compounds with (CH3)4N+, (C2H5)4N+, and also C6H5NH2had diffraction patterns consisting of very sharp00llines. The spacing for sandwiching the intercalates (the identity period), (CH3)4N+, (C2H5)4N+, and C6H5NH2, was 1.29, 1.31, and 1.39 nm, respectively.

Boronated natural graphite compacts were prepared at a temperature of 1750°C under pressures between 0.1 and 0.5 GPa with a nominal B4C content of 2 wt.% and at 2200°C under a pressure of 19.8 MPa with nominal B4C contents of 1, 2.5 and 50 wt.%. Their interlayer spacing d002 and lattice constant a0 were determined. The measurements of the electrical resistivity, magnetoresistance and Hall coefficient for the compacts were carried out mainly at liquid nitrogen temperature. With the increased substitution of boron atoms, the interlayer spacing d002 decreases from the values of the reference natural graphite compacts, showing a trend of the lattice constant a0 to increase slightly. At liquid nitrogen temperature, all of the boronated compacts show the positive Hall coefficient decreasing with the increase in substituted and ionized boron atoms. Below liquid nitrogen temperature, the boronated compacts except the slightly boronated ones exhibit the negative magnetoresistance and almost temperature in...

The post spinning treatment of Polyacrylonitrile (PAN) fibers using succinic acid has been studied. Succinic acid itself did not react with the PAN fibers, but converted into succinic anhydride during heating in thermal stabilization, which could act as plasticizer, and resulted in more than three times larger elongation in the treated fibers as compared to untreated fibers by stretching. The resulting carbon fibers had a small diameter of 1 μm against 6.1 μm and high mechanical properties after heat treatment to 1500 °C and 2500 °C.

Carbon thin films on the surface of quartz substrates were prepared by the thermal decomposition of organiccompounds with low molecular weight, such as benzene, cyclohexane, tetrahydrofuran and pyridine. The structure andelectrical properties of the films obtained were studied. From SEM observations, it was found that the thickness of thecarbon films increased with the increase of the deposition time. The homogeneous films without any cracks and withoutany peeling off from the substrates were obtained with a thickness less than 1 μm. By the XRD measurements of the filmson the substrate, it was clarified that the graphitization degree of these films had very low. In order to examine thechemical bonding state in the carbon films, X-ray photoelectron spectroscopy was carried out in all films obtained. Inthe case of the film prepared from pridine, the nitrogen existed as a tertiary bonding state, replacing carbon atoms inhexagonal layers. The electrical conductivity of the film obtained from cyclohexane showed the high value of 2.5 × 105S/m, but that of the film prepared from benzene gave a small value of 0.3 × 105 S/m. Hall coefficient was found to showextremely small values at room temperature in all films obtained, ranging from 2.3 × 10-9 to-2.4 × 10-9 m3/C.

A zirconium carbide (ZrC) single crytal was oxidized isothermally at temperatures of 600–1500 °C in a mixed atmosphere of oxygen and argon with an oxygen partial pressure ( P O 2 ) of 0.02–2kPa for 1–20 hours. Preferred orientation of tetragonal or monoclincal ZrO2 (t- and m-ZrO2) was occasionally observed on the surface of the oxidized crystal. The oxidized crystal possessed two subscales, outer (white) and inner (black) scales, which could be separated as oxide plates and carbon films, respectively, from the oxidized ZrC by treatment with a concentrated HF solution. The structure and morphology of the carbon films was examined by Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The films obtained at low temperatures (700 to 110 °C) were amorphous, as evidenced by TEM observation and Raman spectra. The hexagonal planes of carbon in the films tended to grow; on the electron diffraction pattern, halos changed to arcs or rings at 1500 °C. The t-ZrO2 particles, several to tens of nanometers in size, were dispersed in the carbon films.

The chemical bonding state of the nitrogen which remains in the carbon films derived from a polyimide Kapton film was studied by X-ray photoelectron spectroscope and related to the changes in structure and transport properties. The nitrogen remaining after heat treatment up to 2200 °C was in a tertiary bonding state, replacing carbon atoms in hexagonal layers, which was supported by theoretical calculation based on ab-initio molecular orbital theory. The departure of substituted nitrogen atoms from hexagonal layers showed a good correspondence with structure development and changes in transport properties, the presence of nitrogen depressing the developments in structure and transport properties. After the departure of nitrogen above 2300 °C graphitization of the films was very remarkable.

Polyamide acid was prepared from pyromellitic dianhydride (PMDA) and oxydianiline (ODA), and was then reacted with NaH and various kinds of alkyl halides for transformation into alkyl ester. The cast films were imidized as fixed on glass substrate to give Kapton-type polyimide films, and were then carbonized by heating to 900 °C. It was shown that the electrical conductivity of the carbonized films decreased with the increase of the size of the leaving group at the imidization. The carbonized films were further heated to 2800 °C for graphitization. Their degrees of graphitization and orientation of the graphite crystallites as a function of weight loss at imidization were studied by X-ray diffraction measurements at room temperature and magnetoresistance measurements at liquid nitrogen temperature. Both measurements clearly indicate that the graphitized films prepared from polyamide acid alkyl ester starting from PMDA and ODA have high degrees of graphitization. It was also made clear that, in the case of polyimide having flexible ether linkage, the orientation of the graphitized films did not depend on the size of the leaving group at imidization.

Prerequisite for readers: Chapter 3.4 (Fibrous carbons) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Prerequisite for readers: Chapter 3.3 (Non-graphitizing and glass-like carbons) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Prerequisite for readers: Chapter 3.2 (Highly oriented graphite) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Prerequisite for readers: Chapters 2.3 (Nanotexture development in carbon materials (carbonization)) and 2.4 (Novel techniques for carbonization) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Preparation processes for carbon foam are reviewed by focusing how cell structure is controlled, and some of applications are discussed. Carbon foams are prepared via three routes, exfoliation and compaction of graphite, blowing of carbon precursors (mostly pitches) with subsequent carbonization, and template carbonization of carbon precursors. Their applications to different fields are discussed; thermal energy storage (latent heat thermal storage) as a container having high thermal conductivity for phase change materials (such as paraffin), various electrochemical measurements as electrodes, adsorption/desorption of gaseous species as molecular sieves, and absorption of electromagnetic waves.

Carbonization under pressure is classified into three, (1) carbonization under pressure built-up by the decomposition gases of the precursor, (2) carbonization under hydrothermal conditions and (3) reduction of CO2 under pressure. The experimental works on carbonization under pressure are reviewed mainly focusing on the yield and morphology of resultant carbons in relation to the carbonization conditions. The conditions to obtain spherical carbon materials are discussed from the temperature-pressure conditions during carbonization and also from the chemical composition of precursors. Carbonization under built-up pressure, including hydrothermal and supercritical conditions, is reviewed by focusing on the formation of spherical carbons.

Prerequisite for readers: Chapters 3.5 (Porous carbons) and 3.8 (Carbon materials for energy storage) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Prerequisite for readers: Chapter 3.1 (Polycrystalline graphite blocks) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Graphitization of various carbon materials under pressures and the acceleration of graphitization with the combination of pressure and coexistence of some minerals are reviewed. Under the pressure above 0.3 GPa, non-graphitizing carbons, as well as graphitizing carbons, can be converted to graphite at a temperature above 1600 oC. Under 0.3 GPa in the coexistence of minerals, graphitization of carbon is much accelerated, partial graphitization being observed even at 800 oC in the coexistence of Ca(OH)2. On the basis of these experimental results, the occurrence of graphite in nature is discussed. The structural change due to stress in carbon/carbon composites is also reviewed.

Wide variety of carbon materials is classified into four families, diamond, graphite, fullerene and carbyne, on the basis of carbon-carbon bonds, sp3-sp3, flat sp2-sp2, curved sp2-sp2 and sp-sp. Crystalline structures of the compounds of other atoms neighboring to carbon in The Periodic Table, i.e., B4C, C3N4, SiC, BN, are discussed in the relation with the structural modifications in carbon.

Prerequisite for readers: Chapter 3.5 (Porous carbons) in Carbon Materials Science and Engineering: From Fundamentals to Applications , Tsinghua University Press.

Production process and properties of polycrystalline graphite is explained together with the starting materials, cokes and binder pitches. Forming process of blended mixture of filler coke and binder pitch, extrusion, molding and isostatic pressing, governs the texture due to the preferred orientation of anisotropic particles of coke. High-density isotropic graphite is described in detail, including three production processes. Applications of polycrystalline graphite are briefly shown with some requirements for graphite blocks. Structure, nanotexture and fundamental properties of filler cokes are described, with their changes with heat treatment at high temperatures. Basic properties of binder pitches are explained through their viscoelastic behavior coupled with their fractionation.

Carbon materials used for electrochemical capacitors are reviewed by dividing the electrode construction into symmetric and asymmetric ones. Carbon materials used as electrodes of symmetric super-capacitors are reviewed by referring activated carbons, templated carbons, carbide-derived carbons, exfoliated carbon fibers, carbons containing foreign atoms, carbon nanotubes and nanofibers. Capacitive performance of asymmetric super-capacitors and asymmetric capacitors consisting of electric double-layer formation in nanoporous carbon electrode and faradaic charge transfer reaction with Li+ in MnO2 and Li4Ti5O12 are also reviewed. Effect of carbon coating on electrode materials, WC and Mo2C, is also discussed.