Papers by toshiro morooka
Holzforschung, 2000
Summary Creep compliance curves in the radial compression were measured under steam for sugi (Cry... more Summary Creep compliance curves in the radial compression were measured under steam for sugi (Cryptomeria japonica D. Don) at temperatures up to 200°C. The creep compliance curves for 30 min (I) and those with pre-steaming for 30 min (II) were well connected at 30 min when the structural changes due to the degradation of hemicelluloses or the decomposition of lignin as well as hemicelluloses occurred. However, the creep curves (I) at 30 min differed markedly from creep curves (II) when the structural changes due to the increase in regularity of crystalline lattice spacing of the microfibrils or the formation of cross-linkages between the cell wall polymers occurred. It was concluded that two kinds of structural changes could be detected well by creep measurement.
Journal of Applied Polymer Science, 1988
A series of (cellulose oligo-oxymethylene ether) acylates (COAs) are characterized by the presenc... more A series of (cellulose oligo-oxymethylene ether) acylates (COAs) are characterized by the presence of the micro-Brownian motion of the side chain (β process) which appears separately from that of the main chain (α process). Both the alpha; and β processes are largely affected by the kind of acyl groups introduced in the side chain. To clarify the effect of the acyl group on these processes, we investigated the dynamic mechanical properties of newly prepared COAs with acyl side chain, bulky in chemical structure (iso-butyrate, privalate, and benzoate) in relation to those for COAs with linear acyl side chain (acetate, butyrate, and valerate). By substituting bulky acyl isomer for linear acyl group in COAs, we observed that the temperature region of both the α and β processes moved to higher temperature. Furthermore, with an increase in molecular size of bulky acyl group, the β region shifts were much larger than the α region, indicating that the mobility of the side chain became comparable to that of the main chain. Finally, when such a large bulky group, for example, benzoate was introduced, the micro-Brownian motion of the side chain prior to that of the main chain ceased. The apparent activation energy for a third process (γ) due to the motion of the oligo-oxymethylene parts in the side chain was estimated to be 10.3 kcal/mol.
Nihon Reoroji Gakkaishi(Journal of the Society of Rheology, Japan)
Journal of the Japan Society for Technology of Plasticity
Journal of the Society of Materials Science, Japan, 1979
Wood Research Bulletin of the Wood Research Institute Kyoto University, Sep 30, 1998
Sustainable Humanosphere Bulletin of Research Institute For Sustainable Humanosphere Kyoto University, Aug 1, 2007
Wood Research Bulletin of the Wood Research Institute Kyoto University, Mar 25, 1983
ABSTRACT 2,3-Dialdehyde celluloses were prepared by homogeneous periodate oxidation in an aqueous... more ABSTRACT 2,3-Dialdehyde celluloses were prepared by homogeneous periodate oxidation in an aqueous solution of methylol cellulose. Since methylol cellulose stays dissolved in water for a certain time before decomposing gradually into regenerated cellulose, the oxidation reaction progressed homogeneously throughout the period. The resulting dialdehyde cellulose achieved an oxidation level of over 90 % in as little as 12 h. Reducing the dialdehyde celluloses with NaBH4 resulted in water-soluble dialcohol celluloses, which have an open-ring structure at the C2–C3 position. The dialcohol celluloses were characterized using nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The Tg of the products decreased with increasing oxidation levels. The products might be processable, and unique tensile properties were obtained by cutting the C2–C3 bonds in the glucopyranose rings. The dialcohol celluloses prepared using a cast method yielded clear and transparent films which showed unique mechanical properties by tensile tests depending on the values of oxidation level.
Wood Research Bulletin of the Wood Research Institute Kyoto University, Sep 30, 2002
Wood Research Bulletin of the Wood Research Institute Kyoto University, Sep 30, 1999
Wood Research Bulletin of the Wood Research Institute Kyoto University, 1986
Wood Research Bulletin of the Wood Research Institute Kyoto University, Sep 30, 1998
Forest Products Journal, 2007
The characteristics of tangential stresses experienced by Japanese sugi (Cryptomeria japonica D. ... more The characteristics of tangential stresses experienced by Japanese sugi (Cryptomeria japonica D. Don) during drying under superheated steam with high temperature and pressure were examined in this study. A load cell capable of operating under high temperature and pressure inside an autoclave was used to measure the shrinkage stresses of water-saturated specimens under various drying conditions. The results showed that
Wood Research Bulletin of the Wood Research Institute Kyoto University, Feb 29, 1984
Wood Research Bulletin of the Wood Research Institute Kyoto University, Feb 28, 1986
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Papers by toshiro morooka