Journal of Fiber Science and Technology
Online ISSN : 2189-7654
ISSN-L : 0037-9875
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  • Toshihiro Motochika, Kenya Morie, Masaki Ohishi, Nobuhiko Matsumoto, A ...
    Article type: Transaction
    2022 Volume 78 Issue 9 Pages 143-152
    Published: 2022
    Released on J-STAGE: September 22, 2022
    JOURNAL FREE ACCESS

    The purpose of this study was to establish design guidelines for the application of intermediate materials for continuous fiber reinforced thermoplastic (c-FRTP) to the molding method using textile preforms, and to investigate the effects of different Partially-impregnated Commingled Yarn (PCY) fabrication processes on textile processability, impregnation properties, and mechanical properties. As a result, it was clarified that there were PCY manufacturing conditions that could achieve both textile processability, impregnation and mechanical properties of PCY using crystalline resin as the matrix used. By setting the temperature at which the amorphous component of the base resin flows predominantly without melting the crystalline component, i.e., immediately before the differential scanning calorimetry (DSC) curve drops, it was shown that PCY formed a multi-layered structure. On the other hand, by setting the temperature at which the crystalline component of the base resin melts, i.e. after the DSC curve drops, it was shown that PCY formed a single-layer structure. A PCY consists with a multi-layer structure had better impregnation properties and textile processability than that with a single-layer structure.

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  • Hideyuki Kajiwara, Ritsuko Murakami, Kenichi Nakajima, Eiichi Kosegawa ...
    Article type: Transaction
    2022 Volume 78 Issue 9 Pages 153-160
    Published: 2022
    Released on J-STAGE: September 22, 2022
    JOURNAL FREE ACCESS

    Though species of insect cocoons were partly discriminated by the shape and colour, silk was not impossible to identify them because no DNA remained on them. The method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was established for the identification of cocoons and silks of the silkworm (Bombyx mori), Eri-silkworm, and wild moth based on the cleaved peptide mass fingerprints (PMFs). This method could be evaluated the oldness based on the peak shift by post-translational amino acid modifications. Insect cocoons and silk fibers were partially hydrolysed by diluted formic acid at room temperature (RT) and the PMFs were used to identify insect species, races, and qualities by MALDI-TOF MS. Silk proteins could be hydrolysed limitedly by acid at RT and several kinds of cleaved peptide fragments were obtained from silk. Cocoons and silk could be analysed by MALDI-TOF MS showing the PMFs during the degumming process and differences among races and species. In addition, peak shifts were observed in old silk comparing newly spanned silk. MALDI biotyping using acid hydrolyzed peptides against cocoons and silks could identify the insect species and discriminated silkworm races and oldness based on the PMFs and by their peak shifts.

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