【作者】 赵喜龙；

【导师】 王喜明；

【作者基本信息】 内蒙古农业大学 ， 木材科学与技术， 2013， 博士

【摘要】 为了进一步探明木材细胞皱缩的恢复机理、木材细胞发生皱缩后皱缩恢复的动力,同时为研究有效恢复皱缩木材变形的干燥工艺提供理论依据,也为高效利用人工林木材提供技术支持。本文以内蒙古地区主要的速生人工林杨树木材为研究对象,研究木材皱缩的可恢复特性和机理、木材细胞皱缩恢复的调控因素和工艺,利用超微图像数字分析法从微观角度分析并评价了皱缩恢复的效果。探明木材干燥过程中木材细胞产生皱缩的机理和过程、皱缩产生的条件的基础上,对比了皱缩恢复前后试样中的水分状态变化以及结晶度变化。本文研究主要结论归纳如下通过杨树皱缩恢复工艺优化试验中得到,北京杨的弦向恢复率为19.83%,径向恢复率为9.12%。100℃弦向恢复率为26.68%,径向恢复率达到9.36%。6h的弦向恢复率21.27%,径向恢复率为8.13%。皱缩恢复工艺参数优化结果为,处理温度100℃,处理时间6h。通过杨树皱缩恢复性能试验得到,北京杨的皱缩深度最大为1.53mm,加拿大杨皱缩因子最大为56.07,小叶杨的体积收缩率最大为3.95%。12h处理后,皱缩深度减小最小为0.20mm。6h处理后,皱缩因子减小到最小为23.79,试样的体积收缩率随着处理时间的增长逐渐增加。通过研究不同位置皱缩恢复性能试验得到,纵向位置中,基部的皱缩深度、皱缩因子体积收缩率较大,横向位置中,心边材交界处的皱缩深度较大,心材的皱缩因子较大,边材的体积收缩率较大由超微图像分析实验可知,杨树木材发生皱缩的主要区域集中于心边材交界附近。皱缩木材经过蒸汽处理后,与处理前相比,木材细胞面积增大明显,恢复比例为32.90%。周长恢复比例为20.65%。皱缩幅度最大的心边交界材的表面区域,恢复的效果也是最明显的。木材长度方向,皱缩性能变化不显著。皱缩恢复细胞模型为薄壁圆柱体模型。木材皱缩恢复机理：木材细胞经过蒸汽或饱和湿空气处理时,皱缩的细胞壁吸收水分和热量,细胞壁刚性下降,在干燥应力作用下,皱缩细胞开始恢复。同时由于细胞腔内部空气受热膨胀,胞腔内压力增大,促使细胞腔进一步恢复形状。更多还原

【Abstract】 In order to further proven recovery mechanism and recovery power of wood collapse,, and to provide theoretical basis for the study of effective recovery collapse, and to provide technical support for efficient utilization of plantation timber. This paper mainly study on the poplar plantation in Inner Mongolia, and the recovery characteristics and mechanism of collapsed wood. And study on the control factors and recovery technology. To evaluate the collapse recovery effect by Using advanced digital image analysis method from the point of view of microscopic. The change of water status and crystallinity were compared before and after recovery.Main conclusions are summarized as follows:By poplar collapse recovery process optimization test, the recovery Ratio of tangential direction of Populus Xbeijingensis W. Y. Hsu.is19.83%, and the recovery Ratio of radial direction is9.12%. The recovery Ratio of tangential direction of100℃is26.68%,and the recovery Ratio of radial direction is9.36%. The recovery Ratio of tangential direction of6h is21.27%, and the recovery Ratio of radial direction is8.13%. the collpae parameters optimization results is100℃for the processing temperature, and6hfor the processing time.Obtained by poplar collpase recovery performance test, the maximum height of collpae is1.53mm of Populus X beijingensis W. Y. Hsu. the collapse factor is up to56.07of Populus X canadensis Moench, the maximum volume shrinkage is3.95%of Populus simonii Cam. After12h treatment, the minimum height of collapse reduced0.20mm. After6h treatment, the collapse factor is reduced to a minimum of23.79. The Sample s’ volume shrinkage ratio gradually increased along with the increase of processing time.By studying the different positions collapse recovery performance test, the height of collapse and volume shrinkage ratio of bottom is bigger In the vertical position, the height of collapse of Heartwood and sapwood border is larger, and the collapse factor of Heartwood is larger, and the volume shrinkage ratio of sapwood is bigger.From ultra-microscopic image analysis experiments shows that the collapse occurs the main area of the junction of the heart wood and sapwood of poplar plantation. After steam treatment, the recovery ratio is32.90%compared with before treatment by wood cell area increases significantly. The recovery ratio of Perimeter is20.65%. The most obvious recovery effect is in the junction of the heart wood and sapwood. As length direction, the degree of shrinkage did not show significantly.It is thin cylinder model about the collapse recovery cell model. The collapse recovery mechanism of wood:the cell walls absorb water and heat undergoes steam or saturated air treatment, the collapse cells began to recover when the rigid of cell wall reduced under drying stress. And the cell cavity further recoved shape by increasing of cell cavity pressure, because of thermal expansion of the air inside the cavity cells.更多还原