Sen'i Gakkaishi
Online ISSN : 1884-2259
Print ISSN : 0037-9875
Search
Advanced search
OR
Browse
Search
Volume 64, Issue 1
Displaying 1-40 of 40 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Column
Feature
Commentation
Reports
Warp and weft
Transactions
  • Control over Color of Nanotextured Coatings by Electrospray Deposition
    Haruka Kuwayama, Hidetoshi Matsumoto, Kenji Morota, Mie Minagawa, Akih ...
    2008 Volume 64 Issue 1 Pages 1-4
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.1
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Nanotextured polymer coatings were prepared on aluminum substrates by electrospray deposition (ESD) from poly(ethylene oxide) (PEO) solution. By controlling the size of deposits on the substrate, it is possible to change coloring of coatings — red, orange, yellow, green, and blue, — due to thin-film interference. These results indicate that the ESD method is a useful option for preparing optical coatings.
    View full abstract
    Download PDF (492K)
  • Conducting Nanofiber Yarns Fabricated by Electrospinning
    Hidenori Okuzaki, Takui Takahashi, Hara Yusuke, Hu Yan
    2008 Volume 64 Issue 1 Pages 5-10
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.5
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Unlike conventional electrospun polymer fibers deposited on a target electrode as a randomly oriented mesh, poly(p-xylenetetrahydrothiophenium chloride) (PXTC), a precursor of poly(p-phenylenevinylene) (PPV), was electrospun into centimeters-long yarns vertically on the surface of the electrode but parallelly to the electric field. The formation of the yarn was strongly influenced by the concentration, applied voltage, and relative humidity. The subsequent thermal conversion of thus-electrospun PXTC yarns was carried out at 250°C for 12 h in a vacuum and resulted in the uniaxially aligned PPV nanofibers with an average diameter of 150 nm. The applied voltage increased orientation of PPV nanofibers along the axis of the yarn, while the distribution of fiber diameter was less dependent on the applied voltage. Wide-angle X-ray diffraction analysis indicated that the PPV nanofibers exhibited paractistalline structure with crystallinity and crystallite size of 45% and 75Å, respectively. Furthermore, doping with sulfuric acid changed the color from yellowish brown to black and brought about a significant increase in the electrical conductivity of the PPV nanofiber yarn.
    View full abstract
    Download PDF (1165K)
  • Preoaration and Effect of Carbon Nano-fabric Using Electrospinning Method for Nano-current-collect-layer in DMFC
    Hiroshi Katsura, Toshiki Koyama, Musubu Ichikawa, Yoshio Taniguchi
    2008 Volume 64 Issue 1 Pages 11-14
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.11
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Effects of carbon nano-fabric (CNFbc) as a nano-current-collect-layer on performances of direct methanol fuel cells (DMFCs) were determined. CNFbc was made using the electro-spinning method. CNFbc with an average diameter of 130 nm was placed between a cathode diffusion layer and a cathode catalyst layer. By using CNFbc with thickness of 27±2 μm DMFC, the maximum power density was improved from 46 to 74 mW cm-2 at the cell temperature of 60°C. From SEM images of cross sections of the membrane-electrode-assemblies, it was observed that the CNFbc interlayer has closely contact with both the cathode catalyst layer and the diffusion electrode. By using the CNFbc interlayer the electrical conductivity as well as the cell voltage at 200 mA cm-2 in the DMFC increased to 1.4 times. These results showed that the CNFbc interlayer improved the DMFC performance by decreasing the contact resistance between the cathode catalyst layer and the diffusion electrode. On the other hand, it was also found that too many microbeads in CNFbc reduce the effects of CNFbc interlayer. It was proved that the uniform CNFbc interlayer has useful effects as a nano-current-collect-layer in the DMFC.
    View full abstract
    Download PDF (914K)
  • Infrared Spectroscopy Analysis Using Polyacrylonitrile Nanofiber Assemblies
    Takuma Goto, Masaya Kotaki, Masanori Sato, Sachiko Sukigara
    2008 Volume 64 Issue 1 Pages 15-19
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.15
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Nanofiber assemblies have large surface area to volume ratio and unique porous structure. We demonstrated the concept that nanofiber assemblies can be used as receptor for Infrared Spectroscopy (FT-IR) analysis. Polyacrylonitrile (PAN) nanofiber assemblies were fabricated via electrospinning for the receptor which had high transmittancy in the entire wave number range. Two aqueous solutions, i.e. crystal violet (CV) and p-nitrophenol (p-N) solutions, were used as target samples for the transmission FT-IR analysis. Calibration curves with high correlation coefficient were obtained using PAN nanofiber assemblies. However, it was found that the correlation coefficient was dependent on chemical structure of the target molecules, i.e. lower correlation coefficient was obtained in the case of the p-N solution which had a lower molecular weight and a hydrophilic group.
    View full abstract
    Download PDF (1328K)
  • Analysis of Pore Structure in Electrospun Fiber Webs Using a Multi-layer Stochastic Model
    Jooyong Kim, Sumin Lee, Jong Chul Park, Yoshimi Watanabe, Ick-soo Kim
    2008 Volume 64 Issue 1 Pages 20-23
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.20
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Nano web has various types of pore and pore size according to manufacturing condition. So, it is necessary to investigate the structure and mechanism of the web using mathematical method. First of all, nano web images were taken form SEM in order to make algorithm. Then we used a multi-layer stochastic model that includes the correlation between random arbitrary measurement lengths. Correlation functions of arbitrary measurement lengths are derived directly from the variance-length curve given without requiring any further information. Use of the correlation functions has more advantages over the traditional variance-length curves. First, they represent a yarn diameter (or mass) profile both in scale (resolution) and frequency (periodicity) rather than in scale only which is in the case for variance-length curves. Second, periodicities hidden in seemingly irregular signals are easily detected and revealed by the correlation functions. It is also beneficial that the functions are readily available from a variance-length curve without further efforts for measurement and analysis.
    View full abstract
    Download PDF (875K)
  • Establishment of Nanofiber Preparation Technique by Electrospinning
    Yoshihiro Yamashita, Frank Ko, Hajime Miyake, Akio Higashiyama
    2008 Volume 64 Issue 1 Pages 24-28
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.24
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    We examined the applicable developments of the electrospinning device and the conditions for producing nanofiber on some polymers within the range of lab-scale to manufacturing. It is understood that the use of multi-nozzle heads is more effective than increasing the flow rate. The solution concentration is an important factor for the control of the fiber diameter of the nanofiber. Moreover, it has been understood the nanofiber that uses the electrospinning process is to apply it to medical, cosmetics, and sanitary goods.
    View full abstract
    Download PDF (503K)
Notes
  • Ultra-Fine Fibers Produced by Laser-Electrospinning
    Midori Takasaki, Hao Fu, Kazuhiro Nakata, Yutaka Ohkoshi, Toshihiro Hi ...
    2008 Volume 64 Issue 1 Pages 29-31
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.29
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    We used a CO2 laser as a heat source to avoid thermodegradation in the melt-electrospinning process (termed “laser electrospinning” (LES)). Nylon 6, polypropylene, poly (ethylene terephthalate) and poly (L-lactide-co-ε-caprolactone) fiber webs were prepared by the LES. For Nylon 6 and poly (L-lactide-co-ε-caprolactone), fibers having average diameters of approximately 1 μm and a coefficient of variation (CV) of no more than 20% were obtained. The effects of the applied voltage and laser power on the diameter of the PET fibers were investigated. The average diameter of the electrospun PET fibers decreased with a decrease in the applied voltage; however, using an applied voltage that was too low caused thermodegradation. The average diameter decreased with an increase in laser power. Above a certain laser power, however, shot particles and large deviations in the fiber diameter were observed.
    View full abstract
    Download PDF (279K)
  • Morphological Study on Electrospun Nanofibers of Aromatic Polyesters
    Atsushi Nakayama, Ryosuke Takahashi, Tsubasa Hamano, Taiyo Yoshioka, M ...
    2008 Volume 64 Issue 1 Pages 32-35
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.32
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Nanofibers of poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT) and poly(ethylene 2,6-naphtalene dicarboxylate) (PEN) were prepared by electrospinning, and the resulting morphologies were investigated by polarizing optical microscopy, scanning electron microscopy and transmission electron microscopy. The major technological parameters (the concentration of polymer solution and the electrical field strength) which influence morphology of the obtained fibers were examined. PET, PBT and PEN nanofibers without beads were prepared by appropriately setting these parameters. In order to align and collect nanofibers parallel to each other, we used the homemade collector with parallel electrodes. The selected-area electron diffraction of nanofibers, which were drawn and/or heat-treated with being as-deposited on the collector, showed a well-developed fiber pattern.
    View full abstract
    Download PDF (709K)
Comprehensive Paper
  • Electrospinning of Natural and Bio-Related Polymeric Materials
    Kousaku Ohkawa
    2008 Volume 64 Issue 1 Pages 36-44
    Published: 2008
    Released on J-STAGE: March 08, 2008
    DOIhttps://doi.org/10.2115/fiber.64.36
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The present article describes our recent research works on the electrospinning of natural and bio-related polymeric materials. A synthetic poly(amino acids), poly(γ-benzyl-L-glutamate) (PBLG) and two natural polysaccharides, chitosan and cellulose, have been successfully spun into submicro- or nano-scaled fibers, which can be obtained as “electrospun non-woven fabrics (ESNWs)”. The major topics are (i) relationship between the chain conformation of PBLG in the pre-spun solution and the resulting post-spun morphology and mechanical property of PBLG-ESNWs, (ii) direct electrospinning of chitosan solution, preparation of the nanofibers, and post-spun treatment of the chitosan-ESNWs, with respect to the polymer chemical properties, and (iii) preparation of cellulose-ESNWs composed of the nano-scaled fibrous network and biomedical application as drug-carrier and releasing materials. Finally, technological aspects of the industrial application of these ESNWs were discussed, enclosing with perspectives for the future research subjects and possible applications.
    View full abstract
    Download PDF (1658K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top