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Volume 1995 (1995)
- Issue 170 Pages 247-
- Issue 169 Pages 201-
- Issue 168 Pages 149-
- Issue 167 Pages 89-
- Issue 166 Pages 2-
Volume 1995, Issue 168
Displaying 1-10 of 10 articles from this issue
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Seiji Maeda, Toshimasa Hashimoto, Akira Takaku, Atsushi Hagiwara, Kazu ...1995 Volume 1995 Issue 168 Pages 149-156
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSWe have developed a new starting 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/cm3. These values are much higher than the ordinary starting resins, such asphenolic resin, cellulose and PVC. The carbonized PCDI also has higher mechanical strength and gas permeability. These properties can be explained by the high density of the crystalline and the inter-crystalline structures.
The IR spectrum shows that two kinds of crosslinkage, dimer and trimer, are formed densely below 230°C in air. These crosslinkages come from reactive carbodiimide groupsin the molecular main chain of PCDI. Partial oxidation of the sample promote the formation of the trimer from the dimer and the carbodiimide groups, so that the sample becomes more heat stable.View full abstractDownload PDF (992K) -
Kazuo Kobayashi, Takahiro Inoue, Hideaki Sano, Yasuo Uchiyama1995 Volume 1995 Issue 168 Pages 157-163
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSPacking behaviour and electrical resistivity of the 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 with applied pressure. Shape of the particles was observed by SEM. Value of n of the formula ρ =αP-n+b, (where ρ is electrical resistivity, P is an applied pressure, α and b are constant) was also estimated.
CMB particles with spherical shape had almost closed packing state at the beginning stage of packing and electrical resistivity changed mainly with change of the area of the contact points between CMB particles with elastic deformation under applied pressure. While, EG particleswith irregular shape were rearranged and gradually exhibited the preferred orientation by repetition of applying a pressure showing a big elastic deformation. This caused an increase of electrical resistivity along a direction of applied pressure by repetition of loading and unloading. In the case of EG particles change of number of contact points under pressure was thought to cause a change of the electrical resistivity of the powders.View full abstractDownload PDF (1684K) -
Shinsuke Hoshii, Akira Kojima, Hiroshi Ooi, Hiroshi Suwa, Sugio Otani1995 Volume 1995 Issue 168 Pages 164-168
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCF/ceramic composite was prepared using 2.5-dimensionally wove CF cloth as a reinforcement of combination weave, and borosiloxane (PBS) as a matrix precursor material of organometallic compound. 2.5-dimensionally wove CF cloth was impregnated with acetone solution of PBS. After air-drying, it was heat-treated primarily up to 500°C and secondarily up to 1000°C to prepare CF/ceramic composite. The primary and secondary heat-treatments were carried out under pressure in a hot-press to give the composite high strength and high density. As a standard for comparison, another CF/ceramic composite was prepared using satin wove CF cloth equally heat-treated under the pressure. CF/ceramic composite thus prepared underwent measurement of mechanical properties (bending strength and Young's modulus), investigation of breaking configuration, observation of cross-section by SEM, and X-ray diffraction analysis of the matrix. Composite prepared with 2.5-dimensionally wove CF cloth was recognized to have higher density and higher strength by the pressurization in a hot-press (0-0.3MPa), showing values of 1.62g/cm3 in bulk density and 83MPa in bending strength. As to the breaking configuration of CF/ceramic composites, those from 2.5-dimensionally wove CF cloth showed more toughness and high breaking energy, while those from satin wove CF cloth was more brittle. These results made it clear that 2.5-dimensionally wove CF cloth has a high strengthening effect as a reinforcement for composite materials.View full abstractDownload PDF (892K) -
Akira Yoshida, Yoshihiro Hishiyama, Munehiro Ishioka, Michio Inagaki1995 Volume 1995 Issue 168 Pages 169-175
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSVapor-grown carbon fiber (VGCF) is known to have an annual ring texture, and to be one of the most graphitizable carbons. A structural characteristic of VGCSs heat-treated at high temperatures is polygonal appearance. The present paper concetns a study of the polygonization process using a field emission gun type scanning electon microscope. VGCFs examind were prepared from a mixture of benzene and Linz-Donawitz converter gas floating catalytic seeds derived from ferrocene, cobalt acetylacetonate and thiophene. Heat treatments of VGCFs were made at the temperatures between 1900 and 3000°C for 30min. Effects of the heating time on polygonization were investigated at 2300, 2400 and 2500°C by changing it steparese as 5, 30 and 60 min. Surfaces and cross sections of these samples were observed with high fidelity modes. Polygonization of VGCF was found to initiate around 2400°C; the thinner the diameter the lower the heat treatment temperature at which polygonal from appears, It is inferred that the polygonization takes place first at the inside relatively close to hollow tube, and advances outward vertically to the tube axis.View full abstractDownload PDF (13486K) -
Toshiaki Sogabe, Masaki Okada1995 Volume 1995 Issue 168 Pages 176-178
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSGas permeability (K) of a large cylindrical isotropic graphite with a size of φ95×φ75×40cm was determined by measuring the flow of nitrogen gas to keep the inside pressure of 140 kPa. The gas permeability of 4×10-1cm2/s measured on a large specimen agreed with those on small cylindrical specimens by a conventional method.View full abstractDownload PDF (374K) -
Hiroyuki Fujimoto1995 Volume 1995 Issue 168 Pages 179-182
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe probability functions for the 1st and 2nd nearest neighbor layers were calculated for the carbon black, the Fourier coefficients An (hk) of which were obtained by Houska & Warren. As a result, the probability function indicating the AB stacking was obtained and it was in good agreement with the positions of carbon atoms in an unit cell of hexagonal system. Twist angle between the adjacent layers due to the turbostratic structure was estimated to be 1.14° from the probability function of the 1st nearest neighbor layer. The simulation of turbostratic structure based on the result shows the moire patterns indicating the existence of the island structure of AA stacking with the equi-distance of ca.11nm.View full abstractDownload PDF (614K) -
Seiichi Tanuma, Andrei Palnickenko1995 Volume 1995 Issue 168 Pages 183-191
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1525K) -
[in Japanese]1995 Volume 1995 Issue 168 Pages 193
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (183K) -
[in Japanese]1995 Volume 1995 Issue 168 Pages 194
Published: September 10, 1995
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (168K) -
1995 Volume 1995 Issue 168 Pages 200
Published: 1995
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (70K)
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