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中国农学通报

中国农学通报 ›› 2014, Vol. 30 ›› Issue (25): 49-54.doi: 10.11924/j.issn.1000-6850.2014-1027

• 林学 园艺 园林 • 上一篇    下一篇

吸湿过程中脱化学成分木材的水分及尺寸变化

周海珍 许若 马尔妮   

  • 收稿日期:2014-04-10 修回日期:2014-07-10 出版日期:2014-09-05 发布日期:2014-09-05
  • 基金资助:
    北京高等学校青年英才计划“静、动态条件下木材主成分的水分吸着与变形响应”(YETP0762)；国家自然科学基金项目“水、热周期作用下木材的变形响应及吸附热力学特性”(31200435)。

Moisture and Dimensional Changes of Chemical Component-Removing Wood During Adsorption Processes

  • Received:2014-04-10 Revised:2014-07-10 Online:2014-09-05 Published:2014-09-05

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摘要： 为了考察脱化学成分木材的水分吸着和变形行为，本研究以尺寸20mm(T)×20mm(R)×4mm(L)的杉木（Cunninghamia lanceolata Hook.）为试材，将未处理材及脱抽提物材、脱木质素材先后置于25℃、45%→60%→75%相对湿度的环境中达到吸湿平衡，在该过程中测量了试材含水率及弦、径向尺寸的变化情况。主要结论如下：各种试材的含水率和横向尺寸变化在吸湿初期快速增加，随着吸湿过程的进行，变化速率逐步降低并最终达到平衡状态；其中，脱木质素材的吸湿性最强，脱抽提物材次之，而未处理材的吸湿性最低；相比较于未处理材，杉木脱除抽提物后，弦、径向尺寸变化率有微小的上升，但对其横纹方向上变形各向异性的影响不大，而脱木质素材的弦、径向尺寸变化率明显增大，且横纹变形各向异性有所下降；各种试材无论在连续吸湿过程中还是达到吸湿平衡状态下，其含水率与弦、径向尺寸变化率均成近似线性关系；脱木质素材的水分吸着系数和湿度膨胀系数最大，脱抽提物材次之，未处理材最低。

关键词: 正交试验, 正交试验

Abstract: 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.