白橡热压干燥材等温吸湿特性研究  

Study on Water Sorption Isotherms of White Oak Lumber by Press Drying

作　　者：刘颖 谢杰[1] 全鹏[1] 李贤军[1] LIU Ying;XIE Jie;QUAN Peng;LI Xian-jun(College of Material Science and Engineering,Central South University of Forestry and Technology,Changsha 410004,China)

机构地区：[1]中南林业科技大学材料科学与工程学院

出　　处：《林产工业》2019年第7期16-22,共7页China Forest Products Industry

基　　金：压干法处理实木地热地板技术研究(ZSYF2016-05);湖南省林业科技计划项目“速生人工林木材增强与调色改性处理技术研究”(XLK201634);广东省科技计划项目(2017A090905019)

摘　　要：以白橡热压干燥材为研究对象,利用动态水分吸附仪研究了不同热压温度干燥处理后白橡木材和未处理对照材的等温吸湿特性,并采用H-H模型拟合;分析热压干燥对木材吸湿特性的降低机理。结果表明:白橡木材等温吸湿线皆为IUPAC Ⅱ型等温吸湿线。在任意相对湿度下,热压干燥材平衡含水率均明显低于对照材,且热压温度越高,平衡含水率降低越明显。H-H模型对白橡木材等温吸湿数据表现出良好的拟合效果。单分子层和多分子层含水率降低共同作用使得热压干燥材吸湿性降低,且相对湿度越高,多分子层水的减少对吸湿性的降低作用越大。与对照材相比,热压干燥材(140、150 ℃和160 ℃)的纤维饱和点推测值分别降低8.89%、11.76%和13.62%。白橡热压干燥材吸湿性降低机理主要为游离羟基等亲水基团含量减少和细胞壁刚度增加等。The moisture sorption isotherms of white oak (Quercus robur) wood press drying at different temperatures and untreated wood were studied by means of a dynamic vapor sorption(DVS) apparatus, and fitted with Hailwood-Horrobin model. And the modification mechanism of hygroscopicity of wood by hot-pressing drying was analyzed. The results showed that all DVS isotherms of white oak were IUPAC type Ⅱ curves. Under any relative humidity conditions, the equilibrium moisture content (EMC)of hot-pressed dry wood was significantly lower than that of the untreated wood, and the higher the hot-pressing temperature was, the more obvious the decrease of EMC was. The H-H model greatly fitted to the isothermal water absorption experimental data of white oak wood. The moisture content of the monolayer and the polylayer reduced, which lead to the decrease of hygroscopicity of wood press dried, and the higher the relative humidity, the greater the reduction of polylayer moisture content on the hygroscopicity. Compared with the untreated wood, the predicted values of fiber saturation point of wood press dried(140, 150 ℃ and 160 ℃) were reduced by 8.89%, 11.76% and 13.62%, respectively. The decreasing mechanism of hygroscopicity of white oak wood press dried was mainly considered to be the reduction of hydrophilic groups such as free hydroxyl groups and the increase of cell wall stiffness.

关 键 词：热压干燥 白橡 动态水分吸附 等温吸湿线 H-H模型 平衡含水率 

分 类 号：TS65[轻工技术与工程] S781.7[农业科学—木材科学与技术]