Diffusion and reaction of chemical impregnants in solid wood cell walls

木质产品的可持续使用取决于其在各种环境暴露下的长期和有效性能。影响木材性能的性能，如耐腐蚀性、尺寸稳定性、耐火性和耐候性，取决于中空木材纤维细胞壁成分的物理和化学性质。这些物理和化学性质可以通过处理改变，即溶液中的无机或有机物质被压力浸渍到细胞腔或空隙中，一些溶解的物质可能从这些空隙扩散到细胞壁。通过策略性地反应或固定细胞壁结构内的物质，可以提高治疗的长期疗效。有效的无机处理的例子有：防真菌、防虫、防火灾的硼酸盐，防火灾的磷酸盐，以及防微生物的铜和锌。非金属物质，如有机木材防腐剂和可溶性单体和聚合物，也可以是保护或稳定木材的有效处理方法。由于木材的所有退化模式都与细胞壁中发生的物理化学变化有关，因此木材物质中保护化学物质的数量和分布显然应该影响它们的性能。然而，关于这些物质从木材渗透的空隙到细胞壁材料的相对扩散速度，以及它们在细胞壁基质中的平衡分布和构型，人们知之甚少。这项拟议工作的目的是加深对木材微观结构中不同成分的扩散和反应以及它们在细胞壁中的微观分布和配置的了解，这些成分受到化合物或离子类型、加工条件和木材化学性质的影响。拟议工作的潜在好处包括开发提高化学处理木材的性能和有效性的方法，以及提高我们对细胞壁结构和细胞壁中物质构象的理解。

The sustainable use of wood based products depends on their long term and effective performance in a wide range of environmental exposures. Properties of wood that affect its performance, such as decay resistance, dimensional stability, fire resistance and weathering performance, depend on the physical and chemical nature of the cell wall components of the hollow wood fibres. These physical and chemical properties can be changed through treatments whereby inorganic or organic substances in solution are pressure impregnated into the cell lumens or void spaces from which some of the dissolved substances may diffuse into the cell walls. The long-term efficacy of the treatments may be enhanced by strategically reacting or fixing the substances within the cell wall structure. Examples of efficacious inorganic treatments are borates against fungi, insects and fire, phosphates against fire and copper and zinc against micro-organisms. Non metallic substances such as organic wood preservatives and soluble monomers and polymers can also be effective treatments to protect or stabilize wood. Since all modes of wood deterioration are related to physico-chemical changes occurring in the cell walls, it is evident that the amount and distribution of protecting chemicals in the wood substance should affect their performance. However, relatively little is known about the relative rates of diffusion of these substances from the penetrated void space of the wood, into the cell wall material nor of their equilibrium distributions and configurations in the cell wall matrix. The objective of the proposed work is to develop an understanding of the diffusion and reaction of different components in the wood microstructure and their micro-distribution and configuration in the cell walls, as affected by compound or ion type, processing conditions and chemical properties of the wood. Potential benefits of the proposed work include developing approaches to enhancing the performance and effectiveness of chemically treated wood and improving our understanding of cell wall structure and conformation of substances in the cell walls.