Diffusion and reaction of chemical impregnants in solid wood cell walls

木基产品的可持续使用取决于它们在广泛的环境暴露中的长期和有效性能。影响木材性能的特性，如耐腐性、尺寸稳定性、耐火性和风化性能，取决于中空木纤维的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将溶液中的无机或有机物质加压浸渍到细胞腔或空隙中来改变，其中一些溶解的物质可能会从中扩散到细胞壁中。通过策略性反应或将物质固定在细胞壁结构内，可以提高治疗的长期疗效。有效的无机处理的例子是用硼酸盐对付真菌、昆虫和火，用磷酸盐对付火，用铜和锌对付微生物。非金属物质，如有机木材防腐剂和可溶性单体和聚合物，也可以有效地保护或稳定木材。由于木材变质的所有模式都与细胞壁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会影响其性能。然而，对于这些物质从木材穿透的空隙空间向细胞壁材料扩散的相对速率，以及它们在细胞壁基质中的平衡分布和构型，人们所知相对较少。这项工作的目的是了解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分布和配置，这些都受到木材的化合物或离子类型、加工条件和化学性质的影响。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.