Sen'i Gakkaishi
Online ISSN : 1884-2259
Print ISSN : 0037-9875
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Volume 66, Issue 2
Displaying 1-9 of 9 articles from this issue
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  • Effect of Polymer Molecular Weight on the Electrospinning of Polylactides in Entangled and Aligned Fiber Forms
    Amalina M. Afifi, Hideki Yamane, Yoshiharu Kimura
    2010 Volume 66 Issue 2 Pages 35-42
    Published: 2010
    Released on J-STAGE: April 10, 2010
    DOIhttps://doi.org/10.2115/fiber.66.35
    JOURNAL FREE ACCESS
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    Thin fibers having diameters ranging from 25 nm to 2 micro-m were successfully electrospun from solutions of polylactides (PLA) having different molecular weights both in entangled and aligned fiber forms. The latter aligned fibers were collected with a new target comprising a rotor around which several fins were attached. Low viscosity of the solutions resulted in formation of beads or beads-on-strings, while high viscosity gave homogeneous fibers at optimum conditions. The resultant aligned fibers were drawn to 2 - 3 times at various optimum temperatures. WAXD of the drawn fibers revealed smectic nature of the PLA chain arrangement in spite of crystal orientation supported. The mechanical properties of the PLA fibers were also improved after drawing.
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  • Estimating Wastepaper Pulp Content in Recycled Paper by Visual Observation using a Fluorescence Microscope
    Susumu Kawanobe, Takayuki Okayama
    2010 Volume 66 Issue 2 Pages 43-50
    Published: 2010
    Released on J-STAGE: April 10, 2010
    DOIhttps://doi.org/10.2115/fiber.66.43
    JOURNAL FREE ACCESS
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    The utilization of recovered paper for high-grade paper such as printing, communication, and tissue papers has been limited because using recovered paper tends to reduce the quality of these papers. Therefore, despite an increasing recovery rate, the wastepaper utilization rate in Japan was still only 61.8% in 2008. In Japan, the regulations of the "Law Concerning the Promotion of Procurement of Eco-Friendly Goods and Services by the State and Other Entities" were strengthened in 2009 to counteract the practice exposed in the so-called "Wastepaper Camouflage Scandal". In order to assess the wastepaper pulp content in recycled paper, a new method using a fluorescence microscope is developed. As fluorescent whitening agents are commonly used to enhance the whiteness and brightness of paper, most recovered printing paper contains fluorescent whitening agents. Both visual observation and image analysis techniques were investigated to differentiate between virgin and wastepaper pulp fibers. Recycled handsheets were prepared to establish the fluorescence observation technique for evaluating the wastepaper content. More than 1,200 fibers should be counted to accurately determine the wastepaper content by this technique. The results obtained by the visual observation technique agree with image analysis of the recycled handsheets. The actual precision of the quantitative wastepaper pulp fiber analysis by the fluorescence observation technique depends on the wastepaper pulp content and the amount of fluorescent whitening agent in the recycled-content paper.
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  • Effects of Urea on Hydrogen Peroxide Bleaching of Cotton Fabrics
    Sunmi Yang, Mitsuru Tahara, Masako Maekawa
    2010 Volume 66 Issue 2 Pages 51-55
    Published: 2010
    Released on J-STAGE: April 10, 2010
    DOIhttps://doi.org/10.2115/fiber.66.51
    JOURNAL FREE ACCESS
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    In order to establish the bleaching process for cotton fabrics under the neutral condition, cotton fabrics were bleached by hydrogen peroxide with urea. It was revealed that hydrogen peroxide bleaching with urea showed the higher whiteness of bleached fabrics than that without urea at more than 70 degrees Celsius. Tensile strength did not decrease after bleaching. Some radicals were observed by ESR measurement when urea was added into hydrogen peroxide aqueous solution. The effects of urea on hydrogen peroxide bleaching seems to be caused by active oxygen ; hydroxyl radical, perhydroxyl radical and superoxide anion radical as well as perhydroxyl anion. The residual hydrogen peroxide concentrations in bleaching baths were measured. When urea is added to the bleaching baths, the decomposition of hydrogen peroxide is accelerated even in the neutral bath.
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  • Decoloration of Dye with Peroxidase-H2O2 System in the Presence of Sodium Percarbonate
    Manami Morisaki, Miyuki Morita, Takako Watanabe
    2010 Volume 66 Issue 2 Pages 56-62
    Published: 2010
    Released on J-STAGE: April 10, 2010
    DOIhttps://doi.org/10.2115/fiber.66.56
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    Decoloration reaction of Orange II and Reactive Blue 2 were investigated to rice hull peroxidase (RPO) bleaching system in the presence of sodium percarbonate (PC) system by measuring the decoloration rate, decoloration rate constants and the color difference of transfer to fabrics. Decoloration rate constant of Orange II in the RPO-PC system increased 2.2 times higher compared with that of RPO single system, when H2O2 concentration is high such as 300 mM in the model bleaching system. Decoloration rate of Orange II also increased in the RPO-PC system, it occurred 100% in the RPO-PC system in comparison with 95 % that of RPO single system. HPLC analyses of decoloration products of the Orange II in RPO-PC system, peaks of all colored products disappeared. In addition, using RPO-PC system, it is possible to decompose Reactive Blue 2 dye having a refractory structure. In the nylon fabric washing model, it is possible to inhibit for dye transfer with RPO-PC system, no matter how low PC concentration of 10 mM is added.
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