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Kouichi Nagata2010 Volume 47 Issue 7 Pages 450-457
Published: July 10, 2010
Released on J-STAGE: July 15, 2010
JOURNAL FREE ACCESSWetting, swelling and redispersion characteristics of green sheets on water and four organic solvents were investigated. Those solvents are different in solubility parameters, index numbers of solvent evaporation rate, viscosities and interfacial tensions. Contact angle correlation with interfacial tension of solvents corresponded with wetting theory in the case of polymer film. In contrast, in the case of green sheet, contact angle and distance travelled by solvent front were not only related with interfacial tension. As the difference of the value of solubility parameter of solvent and that of polymer decreases, an expanse of a solvent to the green sheet surface decreases and a swelling characteristics of green sheet in the solvent increases except experiments with dioctyl phthalate and water. These results are discussed on the base of solvent characteristics and green sheets characteristics.View full abstractDownload PDF (1030K) -
Effect of Diameter Ratio of 2-component Silica Particle on Coagulation State in a Liquid Fluid FieldMikio Yoshida, Makoto Morimoto, Jun Oshitani, Kuniaki Gotoh2010 Volume 47 Issue 7 Pages 458-465
Published: July 10, 2010
Released on J-STAGE: July 15, 2010
JOURNAL FREE ACCESSIn order to obtain knowledge for designing a particle hetero-coagulation in a liquid flow field, effects of the median diameter ratio in 2-component silica particles on particle distribution in various Reynolds number and pH conditions were investigated. The diameter ratio was 0.9-45.8 and the mixing volume ratio was constant at 1 : 1. As evaluation values, (1) amount of coagulation, (2) coagulation diameter and (3) constituting particle diameter of coagulation were calculated. As a result, when the diameter ratio was relatively large, greater or equal 11.2, coagulation was prevented. On the other hand, when the diameter ratio was relatively small, less or equal 1.5, the coagulation diameter and constituting particle diameter can be controlled by Reynolds number. The possible causes of the effects were discussed by focusing on a hetero-coagulation theory and a particle behavior in a flow field.View full abstractDownload PDF (1098K) -
Yoshiyuki Sugai, Hiroshi Idei2010 Volume 47 Issue 7 Pages 466-471
Published: July 10, 2010
Released on J-STAGE: July 15, 2010
JOURNAL FREE ACCESSSynthetic micas were agglomerated by using a spray drying with a disc atomizer (rotary wheel). The agglomerated synthetic micas were shaped like a corolla. The composite materials of these agglomerated synthetic mica particles with flaky titanate compound were successfully prepared without any binders. In order to fix each micas, these agglomerated particles were baked at 900°C for 2 hours. The detailed structures of these particles were examined by a scanning electron microscope. The mechanical and frictional characteristics of the moldings mixed with the baked agglomerated particles were investigated by comparing with the baked synthetic micas. As a result, it was proven that the wear rate decreased with the addition of the baked agglomerated particles.View full abstractDownload PDF (1348K)
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Ken Hirota2010 Volume 47 Issue 7 Pages 472-480
Published: July 10, 2010
Released on J-STAGE: February 04, 2017
JOURNAL RESTRICTED ACCESSAlthough, carbon nanotubes （CNTs） and fibers （CNFs） have attracted remarkable attention as reinforcements of materials because of their exceptional mechanical properties, successful studies of the CNT （CNF）/ceramic composites have been rarely reported. One of the reasons of this is that, their mechanical properties have not been so much improved, due to the lack of good dispersion of nanotubes and fibers and the poor cohesion between the carbon nanomaterials and the matrix. Therefore, the fabrication of nanocarbon-dispersed homogeneous composites remains a technical challenge up to now. In this article, our studies on CNF-dispersed ceramic composites （CNF/Al2O3, CNF/SiC, CNF/SiAlON, and CNF/B4C） have been introduced briefly.
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Motoyuki Iijima2010 Volume 47 Issue 7 Pages 481-484
Published: July 10, 2010
Released on J-STAGE: February 04, 2017
JOURNAL RESTRICTED ACCESSPolymer nanocomposites are attracting the attention of many researchers because they possess unique properties that combine the benefits of polymeric materials and the functional properties of nanoparticles. On preparing nanocomposite materials, maintaining the stability of nanoparticles in polymers is a critical issue to design homogeneous polymer nanocomposites with high properties. In this report, surface modification methods of nanoparticles using silane coupling agents and anionic surfactants toward their dispersion in various organic solvents/polymers will be introduced. Tuning the nanoparticle surface by the combination of hydrophobic and hydrophilic group was effective to maintain their stability in organic solvents and polymers.
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