1998 Fiscal Year Final Research Report Summary
A new model for cellulose microfibril
| Project/Area Number |
08306009
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OKANO Takeshi Grd.School of Agr.& Life.Scis., Dept.of Biomaterial Sci., The Univ.of Tokyo, Professor, 大学院・農学生命科学研究科, 教授 (30011927)
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| Co-Investigator(Kenkyū-buntansha) |
SAMEJIMA Masahiro Grd.School of Agr.& Life.Scis, The Univ.of Tokyo, Associate Professor, 大学院・農学生命科学研究科, 助教授 (30162530)
OKUYAMA Takashi Dept of Appl.Bioscience, Nagoya Univ., Professor, 農学部, 教授 (00023482)
WADA Masahisa Grd.School of Agr.& Life.Scis., The Univ.of Tokyo, Assistant Professor, 大学院・農学生命科学研究科, 助手 (40270897)
SAITO Yukie Grd.School of Agr.& Life.Scis., The Univ.of Tokyo, Assistant Professor, 大学院・農学生命科学研究科, 助手 (30301120)
SUGIYAMA Junji Wood Res.Inst., Kyoto Univ., Associate Professor, 木質科学研究所, 助教授 (40183842)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Cellulose microfibril / Cellulose I_<beta> / Celulose I_<alpha> / Parallel packing structure / beta chitin / Cellulase / Valonia Cellulose / Non-crystalline region |
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| Research Abstract |
(1) Structure and morphology of cellulose microfibril :
Cellulose chain was found to be in the unit cell with "parallel up" packing, and its reducing end coincides with the c-axis. Consequently, cellulose chain is synthesized on the non-reducing ends. Cellulose I beta crystal distorts some extent and, strictly speaking, it is imperfect crystal. Surface of the cellulose I alpha crystal might be different from that of I beta. It is likely that polymorph of native cellulose comes from with or without stress in the forming stage of the crystal. We succeeded in making a highly oriented film of cellulose microfibril. Neutron diffraction of this film revealed probable position of hydrogen in the cellulose crystal. Consequently, cellulose II crystal is an anti-parallel packing which is favorable to hydrophobic surfaces of the molecule. Beta chitin with parallel chain packing transforms into alpha form of anti-parallel one through swelling by HC1 solution in the similar process of cellulose I to II by alkali treatment.
(2) Properties of cellulose microfibril
Thermal expansion of cellulose crystal gave several new knowledges. The crystal expands to only aaxis direction. Resistibility of thermal decomposition depends on cellulose microfibril. We can estimate Poison's ratio of the cellulose crystal. Mechanical phenomena suggest an unstable crystalline region. Young's modulus of wood in the longitudinal direction indicates that orientation and density of non-crystalline cellulose is very similar to those of crystalline one. In case of ramie fibers non-crystalline parts exist in the both directions.
(3) Susceptibility of cellulose microfibril for enzyme :
Susceptibility of cellulose microfibril for enzyme depends on its morphology : Typical crystal of valonia also has some defects on its surface.
Cellulose microfibrils have their own morphology coming from their origin.
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