水/热作用下栓皮栎软木细胞壁的响应机制与应用

The quality of domestic cork harvested from the outer bark of oak (Quercus variabilis) trees is poor and its property of cell wall has not been clarified entirely.The technology of cork cooked in boiling water has severe water pollution and high consumption of energy,and microscopic change of cork is not clear.To solve these problems,the purpose of this project is to explore the change rule of cork cell wall in nature when cork faces the action of water and heat.And a new method of cork softening and expansion is proposed. Taken the virgin and regeneration Quercus variabilis cork from Shaanxi as raw material, the ultra-microstructure and topochemistry of cork cell wall are to be analyzed in the project. By modern instrumental analysis, the microcosmic response mechanism of cork cell wall under the varying conditions of hot water and high temperature processing,respectively,will be explored from different aspects including structural, morphology and dimensional changes of cork cell wall, changes of chemical composition and surface functional group, relationship between color change and mass lose of cork,mechanics of cell wall,viscoelasticity and hygroscopicity of cell wall.According to microcosmic response mechanism of cork cell wall,a new method and technology of softening and expanding cork without boiling water are to be investiaged. The goals of the project are to prove the ultra-microstructure of cork cell wall and the structure of wall layer, to discover the response mechanism in essence of cork cell wall under the hot water and high temperature processing,respectively,to get a new method of cork softening and expansion without water, and to testablish mathematical model bentween color change and mass lose of cork under high temperature processing. The project completion can provide the theoretical foundation and basis for processing and utilization of cork and the cultivation of Quercus variabilis cork resources.

针对栓皮栎软木品质低、细胞壁特性不明确，现有热水蒸煮软化膨化软木方法能耗高、污水多、微观变化机理不清楚等问题，本项目旨在探索水热作用下软木细胞壁的变化规律，研究软木软化膨化新方法。项目以陕西产的初生和次生栓皮栎软木为原料，分析软木细胞壁的超微壁层结构及其主要化学成分在壁层上的分布特点；利用透射电镜、纳米压痕等先进手段从细胞壁结构、形貌、尺寸、化学组成及官能团变化、颜色变化及其与质量损失关系、细胞壁力学、粘弹性、吸湿性变化等角度，研究软木细胞壁在热水处理和高温热处理条件变化下的响应机制，探索软木在高温高含水率条件下软化膨化新方法和最佳工艺。通过研究，探明软木细胞壁的超微壁层结构；从细胞本源上明确水热作用下软木细胞壁的变化响应机制；获得软木软化膨化改性新方法；建立高温作用下软木颜色变化参数与质量损失之间的数学模型。项目研究为栓皮栎软木的高效加工利用和资源培育提供理论基础和依据。

本项目以我国栓皮栎软木为研究对象，根据项目计划书的要求，系统开展了栓皮栎软木细胞壁超微结构与局部化学、热水蒸煮处理软木、高温热处理软木、软木高温高含水率膨化处理四个方面的研究。. 项目探明了国产栓皮栎软木细胞壁超微壁层结构以及胞间连丝的形态特征，利用显微红外成像和拉曼成像获得了软木主要成分软木脂、木质素和多糖在细胞中的分布规律；探明了栓皮栎软木的化学组成、基本物理特性、表面特性、动态黏弹性和细胞壁纳米力学特性；揭示了热水蒸煮处理前后栓皮栎软木尺寸、密度、硬度、压缩回弹、表面色度学参数以及细胞结构的变化规律；探明了纯软木、夹杂、夹砂、软木脂、木质素和综纤维素成分的热降解温度和表观活化能，构建了纯软木、夹杂和夹砂的热动力模型，对烘焙前后的栓皮栎软木进行了工业分析和元素分析，获得了烘焙前后软木的质量得率、能量得率以及高位热值，揭示了不同温度烘焙下软木细胞结构及主要成分的变化规律；利用马弗炉在空气中对栓皮栎软木进行高温热处理，分析软木综合色差变化与质量损失之间的对应关系，构建了两者之间的关系模型；自主研发软木膨化设备一台，获得较好的软木膨化效果。. 本项目探明了栓皮栎软木细胞壁的超微结构特征，揭示了热水和高温热处理下软木特性及细胞结构的变化规律，研究成果为栓皮栎软木细胞壁功能强化和资源培育提供了理论基础，也为我国栓皮栎软木高效加工利用提供理论依据和新思路。