| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Fast-growing trees have been attracting an increased interest as the raw materials for pulp and board industries, and it is quite sure that only fast-growing trees can fulfilll the world-wide demand of woody raw materials in future. To collect full information of the chemical characteristics of fast-growing trees seems to be very important to develop the better utilization of those materials.
In this research, structural characteristics of fast-growing poplar wood lignin will be discussed in comparison with normal poplar wood lignin. Both poplar woods were basically same species and grown in the Tokyo University Forest, Hokkaido under similar environmental conditions. The former is the one which was developed by New Oji Paper Company.
Both trees were felled at the beginning of December, 1992, and the wood samples obtained at the breast height were used for the characterization. The growing rate of the fast-growing poplar was about 1.5 times faster than that of normal one in terms of the height and diameter of those trees. Although those trees didn't show any noticeable difference in lignin content, remarkable differences were found in the chemical structures of lignins in those two trees. Vanillin to syringaldehyde molar ratio in the alkaline nitrobenzene oxidation products of fast-growing tree lignin was 2.0, which was much higher than that of normal wood lignin, 1.5. Potassium permanganate oxidation, other type of lignin degradation reaction, also gave the consistent results. These results suggest that as far as the non-condensed type structural units concerned, lignin in fast-growing tree is apparently rich in syringyl type structures. Molecular weight distribution and contribution of carbon-carbon bonds in lignin macromolecule of fast-growing tree lignin were also evaluated in comparison with those of normal wood lignin.
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