PEG400预处理枫桦圆盘干燥特性研究

Drying Characteristics of Betula costata Disk Pretreated with PEG400

将木材加工成圆盘是扩大木材、尤其是低质材应用范围,提高其经济价值的一条有效途径。为解决圆盘干燥过程中易于出现的开裂问题,以人工林枫桦圆盘为研究对象,采用PEG400溶液进行预处理,研究了处理对圆盘干燥特性的影响,并对PEG400抑制圆盘开裂的机理进行了分析。结果表明:该处理方法可使圆盘在40mm厚枫桦锯材干燥基准条件下获得良好的干燥质量,提高了对干燥条件的适应性,很好地解决了圆盘的干燥问题;对径向心表层终含水率梯度产生明显影响;指出处理后弦径向干缩系数间差值的变小是PEG400抑制圆盘开裂的主要机制。

In order to expand the application extent of the woods with low quality,and to promote their economic values,one of the effective ways is to process them into disk-shaped timber（DST）.However,DST is easy to be cracked during drying.To solve the problem,a solution called PEG400 was applied for the pretreatment before making the Betula costata DST.The influences of the pretreatment on the drying characteristics of B.costata DST were examined.The mechanism of preventing the occurrence of the cracking was discussed.The results showed that drying quality of pretreated DST with a thickness of 40 mm was satisfactory.The adaptability for the drying conditions was promoted after the pretreatment.The pretreatment significantly affected radial moisture content gradient.To diminish D-value of shrinkage coefficient between radial and tangential direction was the major function of restraining cracking by PEG400.