摘要：
为探究最佳的巨尾桉汽蒸预处理工艺,分别采用80°C、100°C、120°C对20 mm厚的含水率分别为130%、60%、50%、30%、20%的巨尾桉试件进行汽蒸处理.以汽蒸后可见缺陷为主要评价指标,结合扫描电镜进行微观结构分析,并对其汽蒸前后的含水率、抽提物含量、干燥后可见缺陷进行比较分析.结果表明:巨尾桉气干含水率和汽蒸温度分别为50%, 100°C时汽蒸效果最佳,汽蒸后可见缺陷最少,能有效防止后续干燥过程中干燥缺陷的产生;汽蒸后桉木的部分纹孔膜破裂,导管内壁光滑,水分移动通道畅通;热水、1% NaOH和苯醇抽提物含量减少,有利于渗透性的提高.%To explore the most suitable steaming process,Eucalyptus grandis×E.urophylla boards with thick-ness of 20 mm, whose moisture content of 130%,60%,50%,30%,20% were steamed at 80°C,100°C,120°Crespectively. Visible defects were investigated, combining with scanning electron microscope to analyze the micro structure before and after steaming.Changes of moisture content,the extractives content and defects developing dur-ing kiln-drying were considered. Results showed that the steaming effects were satisfactory when the MC was 50% and temperature was 100°C, respectively. The degree of visible defects of samples steamed in this condition was slighter than other groups,effectively avoiding subsequent drying defects developing. Some of the pit membranes in samples were broken up and ducts were smooth,contributing to improving the permeability. There was a slight re-duction of hot water,1% NaOH and benzene-alcohol extractives after steaming,which provided evidence that duct was clear and the permeability was improved.
