Do wood preservatives change the strength, hardness or other physical properties of wood?

Wood preservatives are widely used, especially in protecting wood from natural factors such as rot, insects, fungi, etc. However, while the use of wood preservatives can significantly extend the service life of wood, it may have some impact on the physical properties of wood, such as strength, hardness and other performance.
The use of wood preservatives will have some impact on the strength of wood. Preservatives usually penetrate into the cell structure of the wood, fill the pores of the wood, prevent water from entering and keep the wood dry. This penetrating treatment may change the structure and strength of the wood. For some types of preservatives, especially water-based preservatives, the penetration process may cause certain changes in the fiber structure of the wood, which in turn affects its load-bearing capacity. The bending and compressive strength of the wood may be affected, especially after long-term contact with the preservative. This change in strength does not have a consistent effect on all woods, and the specific situation often depends on the type of wood, density and type of preservative used.
The penetration of preservatives may also change the hardness of the wood. Wood hardness refers to the ability of wood to resist external forces and is usually closely related to the fiber structure and moisture content of the wood. Preservatives, especially chemicals containing solvents, can form a protective film on the surface of wood, which can increase the surface hardness of wood to some extent. However, this hardness improvement is often limited to the surface layer, and the hardness of the internal structure may decrease. Because the penetration of preservatives may affect the cell wall of wood, resulting in a decrease in the toughness of some woods, thus affecting the overall hardness of wood.
In addition to strength and hardness, other physical properties of wood may also be affected by preservatives. The hygroscopicity, swelling and wear resistance of wood may all change due to the use of preservatives. The penetration of preservatives may change the structure of the cell wall of wood, making it less able to absorb water, and this change may reduce the swelling of wood. In some cases, changes in the humidity of wood have an important impact on the shrinkage and expansion of wood, and the use of preservatives sometimes helps wood better adapt to different environmental conditions. This change may also affect the natural elasticity of wood, especially in high humidity environments, where wood may become more brittle and prone to breaking or cracking.
The accumulation and distribution of preservatives in wood will also directly affect the physical properties of wood. Some preservatives have a more uniform penetration effect and can better protect the wood, while some preservatives may cause uneven distribution inside the wood, which may cause local weakening of the wood structure. For example, the over-treated part of the wood surface may become more fragile, while the untreated part maintains its original performance, resulting in an imbalance in the overall physical properties of the wood.