Diffusion and reaction of chemical impregnants in solid wood cell walls

木基产品的可持续使用取决于其在广泛的环境暴露中的长期有效性能。 影响木材性能的木材性质，如耐腐性、尺寸稳定性、耐火性和耐候性，取决于中空木纤维细胞壁组分的物理和化学性质。 这些物理和化学性质可以通过处理来改变，其中溶液中的无机或有机物质被压力浸渍到细胞腔或空隙空间中，一些溶解的物质可以从细胞腔或空隙空间扩散到细胞壁中。可以通过策略性地使物质反应或固定在细胞壁结构内来增强治疗的长期功效。 有效的无机处理剂的实例是针对真菌、昆虫和火的硼酸盐，针对火的磷酸盐以及针对微生物的铜和锌。非金属物质，如有机木材防腐剂和可溶性单体和聚合物，也可以有效地处理，以保护或稳定木材。 由于木材的所有劣化模式都与细胞壁中发生的物理化学变化有关，因此很明显，木材物质中保护化学品的数量和分布应影响其性能。 然而，对这些物质从木材的渗透空隙空间扩散到细胞壁材料中的相对速率以及它们在细胞壁基质中的平衡分布和构型知之甚少。 拟议的工作的目的是发展的扩散和反应的不同成分的木材微观结构和它们的微观分布和配置在细胞壁中的理解，受化合物或离子类型，加工条件和木材的化学性质。 拟议工作的潜在好处包括开发方法来提高化学处理木材的性能和有效性，并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.