桉树木材微波改性预处理中的应力松弛及破膜/破壁机制研究

项目名称： 桉树木材微波改性预处理中的应力松弛及破膜/破壁机制研究

项目编号： No.30871983

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 李贤军

作者单位： 中南林业科技大学

项目金额： 32万元

中文摘要： 本研究利用矢量网络分析仪，系统研究了微波频段桉树木材介电特性，微波场强及微波辐射方式对木材内部温度动态分布的影响规律，揭示了高强微波场-木材耦合规律；采用高强微波预处理设备，系统研究了微波辐射强度、辐射时间等因素对桉树木材微观构造、干燥特性、渗透特性的影响规律，探明了桉树木材微波预处理基本规律；采用纳米压痕仪、微型材料测试仪研究了桉树木材微观力学和流变特性，构建了桉树木材微波预处理应力松弛模型，解析了微波预处理破膜/破壁机制，模拟了桉树木材微波预处理临界温度与压力条件；采用X射线扫描仪，研究了微波与常规加热过程中木材内部水分的动态分布规律，探明了微波加热过程中木材内的水分迁移机制；采用高强微波预处理设备，系统研究了微波辐射强度、辐射时间和木材初含水率对松木微观构造、脱脂率、温变特性的影响规律，探明了微波脱脂基本规律，揭示了微波脱脂机理，构建了微波脱脂模型，模拟和验证松木微波脱脂临界处理条件。研究成果实现了速生木材高强度微波改性预处理研究领域的重要理论突破，能为木材微波改性预处理专用设备的设计、制造，改性工艺的制定和控制，速生桉树和松树木材的实木高附加值利用提供理论基础。

中文关键词： 微波；改性；破膜/破壁；脱脂；木材

英文摘要： A vector network analyzer was used to investigate the dielectric properties of Eucalyptus wood and the effect of microwave intensity and radiation methods on the temperature profiles within wood,and the coupling law between wood and microwave field was revealed; The effect of mocrowave radiation intensity and duration on the microstructure, drying properties and permeability of Eucalyptus wood was investigated using a specified equipment for microwave modification pretreatment, and the microwave pretreatment law for Eucalyptus wood was revealed; The micromechanics and rheological properties of Eucalyptus wood was studied using the Nanoindentation Tester and the Miniature Materials Tester,a stress relaxation model to explain the breakdown process and mechanism of pit membrane and cell wall during the pretreatment was developed and simulated; The moisture content profiles within wood during microwave and conventional heating was investigated using a X-ray density profiler, and the moisture transfer mechanism within wood during microwave heating was ascertained; The effect of wood initial moisture content, microwave radiation intensity and duration on the microstructure, deresination ration, temperature variation characterists of Pine wood was investigated using the micorwave pretreatment equipment, the microwave deresination law and mechanism was revealed, and a mathematical model to describe the critical conditions of microwave deresination for Pine wood was established and verified by experiments. The research results in this research is the important theoretical breakthroughs in the research field of wood micorwave pretreatment with high radiation intesity, which can be used to provide the theoretical foundations for the design and manufacturing of specified equipments for microwave modification pretreatment; for the establishment and control of modification technologies, and for the high added value use of Eucalyptus and Pine solid wood as well.

英文关键词： Microwave;modification;breakdown of pit membrane and cell wall;desrsination;wood