竹材微波-碱蚀作用多维弱相结构失效与孔隙形成机制研究

Poor impregnation is one of the key factors that restrict the functional value-added utilization of bamboo. In this project, moso bamboo is studied as the main object. The project intends to understand the natural pore structure of bamboo and the effects of heterogeneity of moisture and density on the cell-wall weak structure by microwave irradiation. A mathematical model for bamboo microwave treating is developed to simulate the evolution procedure and critical condition of a crack. Furthermore, the variations of chemical structure and ultrastructure are explored under conditions of NaOH complex solution. The effect of cracks on promoting dissolution of compositions and the response relation between the nanopores and dissolved compositions, are illustrated. Combine with nitrogen absorption-desorption, digital image methods and fractal theory, the characteristics of micro to nano pores are analyzed. Finally, the failure mechanism of multi-scale weak structure of bamboo, including tissue structure, cell wall structure and chemical structure, and its pore-formation mechanism are revealed. These studies could offer research foundation for improving bamboo impregnation and facilitate the large and uniform load of functional substances, thereby providing theoretical foundation for bamboo resources developing into multi-functional and value-added materials.

竹材浸注性差是制约其功能性高值利用的关键因素之一。本项目以毛竹为主要研究对象，系统研究竹材生物孔结构特征以及水分、密度非匀质效应对微波破坏竹材内微观弱结构的作用机制，模拟竹材微裂纹形成临界条件及扩展演变过程，解析碱溶剂作用条件对竹材化学组分溶出与超微构造的影响规律，阐明微裂纹对组分溶出行为的促进作用以及纳米孔隙与溶出组分之间的内在响应关系，结合氮气吸脱附法、数字图像相关法和分形理论反馈微-纳多维孔隙结构特征与分形特征，揭示竹材内细胞间、壁层间及化学组分间的多维弱相结构失效与孔隙形成机制，进而为改善竹材浸注性、助力功能物质均匀大量负载提供研究基础，为竹材资源向新型多功能方向绿色高值利用提供重要理论支撑。

竹材生长周期短、蓄积量大、力学性能优异，是重要的室内装饰与家具材料，但竹材结构非匀质且渗透性差，极大限制了高附加值功能化利用。为此，本项目结合多种技术手段解译了毛竹材胞腔至胞壁的孔隙特征、水分分布及径向变异性；利用微波与碱蚀作用破坏竹材细胞壁弱结构，构建了液体渗透新通道，探明了微细裂纹萌生临界条件与扩展演变过程，解析了作用条件对竹材宏微观形貌、孔隙结构与理化性质的影响规律，阐明了微裂纹对木质素溶出的促进作用以及纳米孔隙与溶出组分之间的响应关系，揭示了竹材细胞间、壁层间及化学组分间的多维弱相结构失效与孔隙形成机制；将微波-碱处理材经树脂浸渍、纳米原位生长或高温碳化，制备了透明、导电与吸波等功能型竹基材料，并表征了功能复合材的理化特性。本项目解决了竹材微波-碱蚀处理技术背后的关键科学问题，丰富了竹材预处理技术和功能性研发基础理论，以期为竹材资源高附加值功能化利用提供新思路和新手段。