In order to investigate the effect of removing chemical components on moisture sorption and hygroexpansive behavior of wood, Cunninghamia lancolata Hook specimens, with the size of 20 mm(T)×20 mm (R)×4 mm(L) were divided into three groups as untreated, extractives removed, and delignificated. The samples were exposed to successive adsorption in three relative humidity conditions of 45%, 60% and 75% at 25℃, and moisture and dimensional changes in radial and tangential directions were measured during the processes. The results showed that: moisture and dimensional changes of all the three groups increased rapidly at the initial stage during adsorption and the adsorption rate gradually decreased as the sorption proceeded until equilibrium state was reached. Among the three groups, the delignificated samples exhibited the highest hygroscopicity, followed by the extractives removed samples and untreated wood. After removal of extractives, Cunninghamia lancolata specimens showed a slight increase in both radial and tangential dimensional changes, which did not affect transverse anisotropy much; whereas, radial and tangential dimensional changes of the delignificated samples increased considerably with an obvious reduction in transverse anisotropy. In addition, moisture content of the samples was linearly related to dimensional changes during the continuous adsorption processes as well as at equilibrium state. Furthermore, the delignificated samples had the greatest value of moisture sorption coefficient and humidity expansion coefficient, followed by the extractives removed samples and untreated wood.
Key words
wood; adsorption; extractives removal; delignification; moisture content; dimension
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] 马尔妮,赵广杰.木材物理学专论[M].北京:中国林业出版社,2012: 19-39.
[2] Hosseinaei O, Wang S, Enayati A A, et al. Effects of hemicellulose extraction on properties of wood flour and wood-plastic composites [J]. Composites Part A: Applied Science and Manufacturing,2012,43 (4):686-694.
[3] Hosseinaei O, Wang S, Taylor A M, et al. Effect of hemicellulose extraction on water absorption and mold susceptibility of woodplastic composites[J]. International Biodeterioration & Biodegradation,2012,71:29-35.
[4] Ou R, Xie Y, Wolcott M P, et al. Morphology, mechanical properties, and dimensional stability of wood particle/high density polyethylene composites: Effect of removal of wood cell wall composition[J]. Materials & Design,2014,58:339-345.
[5] 张文博,德本守彦,武田孝志,等.木材のメカノソープテイブクリープ及ぼす脱リグニン处理の影响Ⅰ[J].木材学会志,2006a,52 (1):19-28.
[6] 张文博,德本守彦,武田孝志,等.木材のメカノソープテイブクリープ及ぼす脱リグニン处理の影响Ⅱ[J].木材学会志,2006b,52 (1):29-36.
[7] 张文博,德本守彦,武田孝志等.木材のメカノソープテイブクリープ及ぼす脱リグニン处理の影响Ⅲ[J].木材学会志,2006c,52 (4):206-214.
[8] 谢满华.化学处理木材的应力松弛[D].北京:北京林业大学,2006.
[9] 张双燕.化学成分对木材细胞壁力学性能影响的研究[D].北京:中国林业科学研究院,2011.
[10] Hailwood A J, Horrobin S. Absorption of water by polymers: Analysis in terms of a simple model[J]. Trans Faraday Soc,1946,42 (B):84-102.
[11] Macromolecule Academy. Physical properties of macromolecule(Ⅲ) [M]. Tokyo: Kyoritsu Press,1958:240-260.
[12] 杨甜甜,马尔妮.水分周期性作用下木材的动态吸着和干缩湿胀[J].功能材料,2013,44(24):3055-3059.
[13] Noack D, Schwab E, Bartz A. Characteristics for a judgment of the sorption and swelling behavior of wood[J]. Wood science and technology,1973,7(3):218-236.
[14] 刘一星,赵广杰.木质资源材料学[M].北京:中国林业出版社,2004: 141-142.
[15] S tevens W C. The transverse shrinkage of wood[J]. For Prod J, 1963,13(9):3886-3891.
[16] 刘培义,孟国忠.木材的尺寸稳定性处理[J].木材工业,2003,17(2): 24-26.
{{custom_fnGroup.title_en}}
Footnotes
{{custom_fn.content}}
