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Volume 2006 (2006)
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- Issue 223 Pages 165-
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Volume 2006, Issue 223
Displaying 1-14 of 14 articles from this issue
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Shunzo Suematsu2006 Volume 2006 Issue 223 Pages 165-168
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSVapor-grown carbon fibers (VGCFs) were successfully dispersed by addition of polyfluorene (PF) in THE solvent without any reduction in length of the VGCFs. Degree of dispersion of the VGCFs in the solvent was enhanced as a ratio of PF to VGCF increases in the ratio ranged from 1/5 to 5/1, probably because of a polymer wrapping effect of the PF onto the surface of the VGCF. The dispersed PF-coated VGCFs (VGCF/PF) led to fabricate uniformly-coated electrodes because of their high dispersibility. Discharge behaviors of the VGCF/PF-based electrodes were also discussed in order to confirm feasibility of the VGCF/PF as an electroactive nano-composite.View full abstractDownload PDF (890K) -
Takahiro Ookubo, Tatsuhiro Takahashi, Hiroshi Awano, Koichiro Yonetake ...2006 Volume 2006 Issue 223 Pages 169-175
Published: June 15, 2006
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSVapor-grown carbon fibers (VGCFs) have outstanding mechanical, thermal, and electric characteristics, and it has strong anisotropy. To take advantage of the enhanced properties, the orientation control of VGCFs should be important. In recent years, the orientational control of VGCFs by magnetic processing has received considerable attention. We have performed the magnetic processing of polymer composite films including VGCFs by using magnetic processing apparatus with permanent magnets (1 T) and superconductive magnet (10 T). We have studied the orientation of VGCFs along the thick-ness direction of the film. It was demonstrated that the oriented VGCFs/polymer composite films were successfully produced even by permanent magnets (1 T). The volume resistivity (Ω·cm) of the film (vertically oriented VGCFs, 1.0 wt %, 10 lim thickness) showed 3.2 × 1012 and 2.1 × 100 Ω·cm along surface and thickness direction, respectively. Vertically oriented VGCFs / polymer composite film could be utilized as an alternative material having anisotropic electric conductive property.View full abstractDownload PDF (1365K) -
Eiji Sato, Michitaka Fujimoto, Tatsuhiro Takahashi, Koichiro Yonetake, ...2006 Volume 2006 Issue 223 Pages 176-182
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIt was unexpectedly observed that the volume electrical resistivity of UV-curable polymer film including a small amount of vapor-grown carbon fiber (VGCF) along thickness direction decreased by three ordered magnitude (from 1010 to 107 Ω· cm) after UV irradiation. The cause of the rapid decrease was investigated by changing various parameters, such as, VGCF concentration, thickness, VGCF structure (linear or branch, dispersion), and volume shrinkage of UV-curable polymer matrix. The decrease occurred reproducibly when the concentration of VGCF was between 0.005 and 0.1 wt % with thickness less than 25 μm. The moving distance of VGCF by UV irradiation through the volume shrinkage of the matrix was confirmed to be around 9.0 micron at the center part of the film. It was suggested from optical microscope observation that the presence of a trace amount of branched VGCF (L, X, Y form) having similar length to the film thickness moved by the volume shrinkage of UV-curable polymer matrix during UV irradiation and made the conductive paths along thickness direction.View full abstractDownload PDF (1616K) -
Tomoyuki Itaya, Katsuyuki Fujiwarat, Kyoichi Oshida, Minoru Moriyama2006 Volume 2006 Issue 223 Pages 183-187
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSWe have found that polysaccharide polymers such as sodium alginate and agar can be convenient dispersion agents for vaper grown carbon fiver (VGCF). VGCF/sodium alginate composite films and VGCF/SiC composite ceramics with good uniformity and dispersion were prepared by utilizing the resulted dispersion solution. The dispersed composition of VGCF into SiC led an increase in flexural strength, fracture toughness and electric conductivity of SiC. In addition to these results, the magnetic properties of metal ions (Fe3+, Gd3+) bound to poly (acrylic) acid-modified multiwalled carbon nanotube (MWCNT) were discussed.View full abstractDownload PDF (1069K) -
Jacob Samuel, Hiroshi Awano, Tatsuhiro Takahashi, Koichiro Yonetake, K ...2006 Volume 2006 Issue 223 Pages 188-190
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSFundamental dispersion study of vapor-grown carbon fibers (VGCFs), which, as received, had an aggregated lump form, was performed using a series of ionic liquid, which is N-metyl-N'-alkyllimidazoliumtetrafluoroborate having different alkyl (CnH2n+1) chain length (n=2, 4, 6, 8). In situ optical microscope observation was carried out for the dispersion of a trace amount of VGCF in each ionic liquid, prepared by ultrasonic treatment and magnetic stirring. The degree of VGCF dispersion was improved when the alkyl chain length of ionic liquid became longer. The initial aggregated lump of VGCF still remained in the ionic liquid having the shortest alkyl chain (n=2), but completely disappeared in the ionic liquid having the longest alkyl chain (n=8).View full abstractDownload PDF (672K) -
Akihiko Nagasaka, Tatsuo Nakazawa, Kyoichi Oshida, Hiroshi Kuriyama, K ...2006 Volume 2006 Issue 223 Pages 191-193
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn the present work, mechanical properties of the carbonnano-fibereinforced plastic were investigated. Two kinds of carbonnano-fibers are employed for the filler of the composites, which are vapor grown carbon fiber (VGCF) and cups-stacked type carbon nanofiber (CS). For the matrix of the composites, two kinds of thermoplastic resins are used which are Acrylonitrile Butadiene Styrene (ABS) having different tensile strength. For the 5 wt % of VGCF in ABS resins, the tensile strength of the wire specimen of 0.5 mm in diameter by the extrusion molding shows doubled compared with that of the sheet specimen of 0.5 mm in thickness.View full abstractDownload PDF (635K) -
Tatsuhiro Takahashi, Takeshi Yasuda, Takahiro Ookubo, Hiroshi Awano, K ...2006 Volume 2006 Issue 223 Pages 194-205
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCarbon nanotube (CNT) /polymer composites have been expected for a promising application of CNT and have received considerable attention in fundamental studies. Recent progress of Carbon nanotube/polymer composites is reviewed from polymer material point of view for utilizing CNTs into polymer matrix.View full abstractDownload PDF (2739K) -
Fujio Okino, Michiya Ota2006 Volume 2006 Issue 223 Pages 206-214
Published: June 15, 2006
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSCarbon fiber reinforced carbon (C/C) composite materials with low density, high specific strength and elastic modulus, high ablation property, high frictional and wear properties have been used in the field of aerospace engineering and vehicle industry. Further improvement in their manufacturing processes and brittle properties are requested as one of the most promising advanced composite materials. Mechanical and other properties should be improved by controlling the microstructures in carbon fiber and matrix carbon and their interfacial properties. In the meantime, a series of nanocarbon materials represented by fullerenes and carbon nanotubes began to be regarded as future advanced high performance materials since their discovery before and after 1990. Nanocarbon reinforced plastic composites are also reported as new nanoscaled composite materials with controlled microstructures and interfacial properties. Carbonized composite materials with nanocarbons are, therefore, expected to possess improved mechanical strength, fracture behavior, frictional and wear properties, electrical conductivity, and thermal properties. Here we review the preparation and properties of nanocarbon reinforced carbon composite materials with our recent proposals concerning the nano-C/C composite materials.View full abstractDownload PDF (2184K) -
Yuichi Kato, Motoi Machida, Qingrong Qian, Hideki Tatsumoto2006 Volume 2006 Issue 223 Pages 215-219
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSInfluence of surface functional groups and solution pH on the adsorption of dissolved organic substances (aniline andnitrobenzene) and a heavy metal (Cd (II)) on activated carbon has been studied. Commercially available activated carbon (AC) and oxidized one with nitric acid (Ox-AC) were employed as adsorbents for the experiments. Adsorption ability of the adsorbents was evaluated by Langmuir- and Freundlich-type adsorption isotherms. Point of zero charge (pHpzc) of the activated carbon was dropped from 9.2 to 3.2 by the oxidation. Decrease in organic matter uptake was also observed for Ox-AC due to decrease in π electron density and formation of water molecular clusters on the carboxyl groups located on the pore mouth at higher pH region. When aniline was used as adsorbate, decline of adsorption probably owing to repulsive force between anilinium ion and graphene layer occurred at lower pH value. On the other hand, Cd (II) uptake by Ox-AC was rapidly increased as the equilibrium solution pH rose, whereas it was not for AC. Since Cd (II) adsorption sites were considered to be carboxyl groups at the edge of the graphene layers, the Cd (II) adsorption capability was greatly influenced by the charge of them on the Ox-AC.View full abstractDownload PDF (1022K) -
Takahiro Morishita, Rieko Suzuki, Tomoki Tsumura, Hiroki Habazaki, Mic ...2006 Volume 2006 Issue 223 Pages 220-226
Published: June 15, 2006
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSPorous carbons with high surface area were successfully prepared from thermoplastic precursors, such as poly (vinyl alcohol) (PVA), by the carbonization of mixtures with MgO precursor at 900°C in inert atmosphere. MgO in the carbonization products was dissolved out by using a diluted acid, either sulfuric or acetic acid. The carbon precursors with MgO precursors (reagent grade magnesium acetate and citrate) were mixed either in powder (powder mixing) or in aqueous solution (solution mixing). Pore structure of the resultant carbons depended strongly on the mixing method. The BET surface area of the carbons obtained through solution mixing could reach to very high value, such as 2000 m2/g, even though any activation process was not applied. The carbons prepared through solution mixing method were rich in mesopores. By changing the size of MgO particles formed by pyrolysis of MgO precursor, the size of mosopores could be controlled. It was experimentally shown that substrate MgO was easily recycled.View full abstractDownload PDF (1525K) -
Katsuya Konno, Kousuke Kurakane, Kikuo Harigaya, Kaoru Onoe, Tatsuaki ...2006 Volume 2006 Issue 223 Pages 227-231
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSAs carbon nanotubes (CNTs) have properties superior to other carbon materials, a variety of applications, such as display devices, hydrogen storage materials and electrodes for electric double-layer capacitors, are anticipated. In order to compare the characteristics of CNTs synthesized by microwave plasma and pyrolysis techniques, CNTs were prepared using similar experimental conditions such as catalyst, temperature and pressure, and characterized using techniques such as SEM, TEM, and Raman spectroscopy. By comparing the results of carbon yield and SEM imaging of CNTs, it was noted that the carbon yield was same and CNTs yield was similar by the both method. CNTs obtained by microwave plasma were straight and helical, whereas CNTs obtained by pyrolysis were only straight. Also, TEM imaging revealed that the structures of CNTs formed by microwave plasma were multi-walled nanotubes and their outermost diameters (11 nm) were constantly independent of reaction time. Raman spectroscopy was used to determine that the ID/IG of CNTs formed by microwave plasma, using methane as the carbon source, was 0.68. In comparison, the ID/IG of CNTs synthesized by pyrolysis, using acetylene/hydrogen as the carbon source, was higher with a value of 0.81. It was suggested that the microwave plasma afforded higher quality CNTs due to the reactive effect of active species from methane formed by microwave plasma.View full abstractDownload PDF (1603K) -
Hironori Arai2006 Volume 2006 Issue 223 Pages 232-243
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (2381K) -
Takeshi Abe2006 Volume 2006 Issue 223 Pages 244-248
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1039K) -
[in Japanese]2006 Volume 2006 Issue 223 Pages 253-255
Published: June 15, 2006
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (651K)
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