Establishment of Method for Measuring Molecular Orientation in Wood by Fluorescence Method and Its Application

Research Project

Project/Area Number	61560186
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	林産学
Research Institution	Tokyo University of Agriculture and Technology
Principal Investigator	FUSHITANI Masami Tokyo University of Agriculture and Technology Professor, 農学部, 教授 (80014950)
Co-Investigator(Kenkyū-buntansha)	SATO Keiichi Tokyo University of Agricultre and Technology Assistant Professor, 農学部, 助手 (90178723) KUBO Takafumi Tokyo University of Agriculture and Tecnology Associate Professor, 農学部, 助教授 (00015091)
Project Period (FY)	1986 – 1987
Project Status	Completed (Fiscal Year 1987)
Budget Amount *help	¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords	Fluorescence method / Wood / Lignin / Ratio of polarized component of fluorescence intensity / Degree of molecular orientation / Fluorescence microscope / Acetylating treatment / 細胞壁
Research Abstract	1. We investigated the method for measuring the molecular orientation of lignin by the use of the fluorescence emitted from wood itself. The corrected ratio of each polarized component of fluorescence intensity to that with the polarizer and the analyzer aligned parallel to the longitudinal direction was obtained by extrapolating a straight line of sample thickness vs. its ratio to zero. The degree of molecular orientation calculated from these ratios ranged from 0.003 to 0.094. 2. The uncorrected value of degree of molecular orientation of hardwood native to Japan which was obtained from the orientation of fluorescent molecules introduced into wood was hardly varied by a highly acetylating treatment, whereas that of softwood and lauan was markedly decreased by it. This marked increase resulted from the increase in fluorescence intensity of lignin itself due to the highly acetylating treatment. The introduction of fluorescent molecules into wood was inhibited by the treatment, but it is unclear whether wood components dyed with the fluorescent molecules change or not. 3. The distribution of fluorescence intensity in the cell wall of wood was observed with a fluorescence microscope. The fluorescence emitted from wood itself near the compound middle lamella and outer layer of secondary wall was strong, and the fluorescence intensity in the middle lamella was hardly increased by the introduction of fluorescent molecules into wood. The acetylated woo had a similar tendency. 4. The relationship between structure factors and softening of wood due to heat and water was investigated. The degree of molecular orientation in the amorphous area had the greatest effect on the specific Young's modulus under every condition. Woods with small values of the degree of crystallinity and Klason lignin content have small values of specific Young's modulus and large values of breaking strain when they are softened with heat and water.