文献类型：期刊文献

英文题名：Effects of preheating temperatures on the formation of sandwich compression and density distribution in the compressed wood

作者：Li, Ren[1,2] Gao, Zhiqiang[1,2] Feng, Shanghuan[3] Chang, Jianmin[2] Wu, Yanmei[1] Huang, Rongfeng[1]

第一作者：Li, Ren

通信作者：Huang, RF[1]

机构：[1]Chinese Acad Forestry, Res Inst Wood Ind, Beijing 100091, Peoples R China;[2]Beijing Forestry Univ, Coll Mat Sci & Technol, Beijing 100083, Peoples R China;[3]Aalborg Univ, Dept Energy Technol, Pontoppidanstr 111, DK-9220 Aalborg, Denmark

年份：2018

卷号：64

期号：6

起止页码：751-757

外文期刊名：JOURNAL OF WOOD SCIENCE

收录：;EI(收录号：20183605789302);Scopus(收录号：2-s2.0-85052813061);WOS:【SCI-EXPANDED(收录号:WOS:000452340900005)】；

基金：The authors acknowledge the financial support from the National Natural Science Foundation of China: Formation Mechanism and Controllability of Wood Sandwich Compression by Hydro-thermal Control (Grant no. 31670557).

语种：英文

外文关键词：Sandwich compression; Preheating temperature; Position of the compressed layer(s); Thickness of the compressed layer(s); Density distribution

摘要：Sandwich compression of wood that can control the density and position of compressed layer(s) in the compressed wood provides a promising pathway for full valorization of low-density plantation wood. This study aims at investigating the effects of preheating temperatures (60-210 degrees C) on sandwich compression of wood, with respect to density distribution, position and thickness of the compressed layer(s). Poplar (Populus tomentosa) lumbers with moisture content below 10.0% were first soaked in water for 2 h and stored in a sealed plastic bag for 18 h, the surface-wetted lumbers were preheated on hot plates at 60-210 degrees C and further compressed from 25 to 20 cm under 6.0 MPa at the same temperature on the radial direction. The compressed lumbers were characterized in terms of density distribution, position and thickness of compressed layer(s). It was found that depending on preheating temperatures, sandwich compressed wood with three structural modes, namely, surface compressed wood, internal compressed wood and central compressed wood can be formed. Density of the compressed layer(s) in wood increased gradually as a result of the elevated preheating temperatures. Higher preheating temperatures gave rise to bigger distance between compressed layer(s) and the surface, and preheating temperature elevation from 90 to 120 degrees C contributed to a maximal distance increase of 2.71 mm. In addition, higher preheating temperatures resulted in bigger thickness of compressed layer(s) over 60-150 degrees C and temperature elevation from 120 to 150 degrees C lead to the layers integration from two into one. Further temperature elevation over 150 degrees C reduced the thickness of the compressed layer in wood. SEM scanning suggested that cell wall bucking rather than cell wall crack occurred in compressed layer(s) and transition layer(s).