| Budget Amount *help |
¥15,700,000 (Direct Cost: ¥15,700,000)
Fiscal Year 2000: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥13,900,000 (Direct Cost: ¥13,900,000)
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| Research Abstract |
Basic features of pyrolysis of cellulose were reexamined in terms of loss of crystallinity and carbon yield. Cellulose crystallite was found to degrade at above 320C in inert atmosphere. Mass yield of resulting carbon was as low as 1/3-1/4 of theoritical value for pure cellulose. Imprivement of carbon yield was achieved by addition of small amounts of sulfuric acid to cellulose, the yield reaching about 80% of theoritical value. Derivatization of cellulose also had remarkable effect in increasing the yield, as observed for periodic acid-oxidized cellulose. Further derivatization of dialdehyde cellulose through reactions with amines caused anomalous explosive decomposition of the material at high level of derivatization.
Highly crystalline cellulose samples from bacteria, tunicate or algae were graphitized at above 1600C, and crystallinity of the resultant material was in accord with that of starting material. The graphitized material contained microfibrillar crystallite apparently derived from the cellulose microfibril. This new form of graphite, carbon nanorod, may lead to novel applications. Hence efforts were made for preparing this material in higher yields, through processing of cellulose by freeze drying, embedding in other materials, and coating of microfibrils. Coating with silver showed some effect, but significant improvement in yield has not been achieved.
As a polymer having cellulose-like structure, poly (vinyl alcohol) was examined for its pyrolytic carbonization with addition fo sulfuric acid. Unlike pure material, PVA with sulfuric acid showed weight loss at around 250C, giving loss levels that correspond to stoichiometric dehydration. The resulting material is considered to contain polyacetylene-like structure and may lead to a novel electroconductive polymer.
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