Thermal Decomposition of Cellulose Crystallites in Wood

• Published in: Holzforschung Vol. 55; no. 5; pp. 521 - 524
• Main Authors: Kim, Dae-Young, Nishiyama, Yoshiharu, Wada, Masahisa, Kuga, Shigenori, Okano, Takeshi
• Format: Journal Article
• Language: English
• Published: Berlin Walter de Gruyter 19.09.2001; New York, NY de Gruyter
• Subjects: Applied sciences; Exact sciences and technology; Hydrolysis, pyrolysis and by-products; Polymer industry, paints, wood; Wood; Wood. Paper. Non wovens; Pyrolysis; Crystallites; Hardwood; Experimental study; X ray diffraction; Cellulose
• ISSN: 0018-3830; 1437-434X
• DOI: 10.1515/HF.2001.084

Decomposition of cellulose crystallites in wood during pyrolysis was studied by X-ray diffraction using a tension wood of Populus maximowiczii (cottonwood), which contains highly crystalline cellulose. X-ray diffraction profiles were recorded at varied temperature up to 360°C. By one-hour isothermal treatments, the cellulose crystallites did not decompose at 300°C, but completely decomposed at 340°C. The change in equatorial diffraction profile was studied by temperature scan up to 360°C and by isothermal treatment at the critical temperature of 320°C. Along with the changes by thermal expansion, the changes in diffraction diagram revealed a characteristic discrepancy between the diminishment of crystalline order and the reduction in crystallite size; i.e., the intensity of crystalline reflections diminished steadily while the crystallite size decreased much more slowly. A model of highly heterogeneous decomposition is proposed to explain this behavior.