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권해용,박영판,Gwon, Hae-Yong,Park, Yeong-Pan 한국섬유공학회 1997 한국섬유공학회지 Vol.34 No.2
The flax fiber was treated with various concentrations of NaOH solution for the purpose of removal of hemicellulose. The weight loss, which was mainly due to the decrease of hemi cellulose content, was affected by the conditions of NaOH treatment, such as temperature, time and concentration. The crystallinity and birefringence were increased with the NaOH concentration up to 10c1e. Also, the fiber bundles or fibrils were separated more and more as an increase of concentration upon the examination of fiber surface. The critical concentration was observed at around 12% NaOH concentration, in which the crystallinity and birefringence values were very low. Some cracks were appeared on the fiber surface, indicating that the fiber damage occurred. The presence of lignin and hemicellulose as well as the crack formation and fiber bundle separation are important factors for the breaking strength of flax fiber. Moisture regain, water remention value, degree of swelling and the amount of dye adsorption were also strongly related to the structural characteristics caused by NaOH treatment. These physical values were high for the fiber treated with NaOH concentration more than 1071.
권해용,박영환 한국잠사학회 1994 한국잠사곤충학회지 Vol.36 No.2
The structural characteristics of Antheraea yamamai and Antheraea pernyi silk were investigated by using x-ray diffraction method, IR spectroscopy and polarizing microscopy. The amino acid composition, fiber density, thermal decomposition temperature and glass transition temperature were also measured for relating these physical properties to the structure in comparison with those of Bombyx mori silk fiber. There was no significant structural difference between A. yamamai and A. pernyi silk fiber on an examination of x-ray diffraction curve and IR spectrum. Both of these wild silk fibers showed double diffraction peaks at the Brags angle 2θ?16.7° and 20.5° by x-ray diffraction analysis as well as IR absorption peaks for the bending vibration of specific groups related to ala-ala amino acid sequence. On the other hand, the x-ray diffraction curve and IR spectrum Bombyx mori silk fiber are different from those of wild silk fibers, indicating different crystal structure as well as amino acid sequences. It showed under the polarizing microscope examination that the birefringence and optical orientation factor of wild silk fibers are much lower than those of M. mori silk. Also, the surface of degummed wild silk fibers was characterized by the longitudinal stripes of microfibrils in the direction of fiber axies. The amino acid composition, which is strongly related to the fine structure and properties, was not significantly different between these two wild silk fibers. However, the alanine content was somewhat less and polar amino acid content more for A. yamamai. As a result of fiber density measurement, the specific gravities of B. mori, A. pernyi and A.yamamai were 1.355~1.356, 1.308~1.311, 1.265~1.301g/cm3 in the order, respectively. The calculated crystallinity(%) was 64% for B. mori and 51~52% for wild silk fibers, which showed same trend by IR method in spite of somewhat higher value. The thermal decomposition behaviour was examined by DSC and TGA, showing that the degradation temperature was in the order of B. mori, A, pernyi and A. yamamai at around 350°C. It was also observed by TGA that the decomposition seems to proceed step by step according to their specific regions in the fiber structure, resulting the difference in their thermal stabilities. The glass transition temperature was turned out to be 220°C for B. mori, 240°C A. yamamai and 255°C A. pernyi by the dynamic mechanical analysis. It is expected that the chemical properties are affected by the dynamic mechanical behavior in accordance with their structural characters.