Steaming or freezing improves decay resistance, copper leaching and wood/copper interactions of micron CuO/silica sol treated poplar (Populus tomentosa Carr.)

Micro-based wood preservatives have tremendous potential for reducing in-service preservative losses thereby reducing the amounts needed for protection. Enhancing micro-based wood preservatives/wood interactions without negatively affecting performance could help further enhance the properties of these materials. The factors affecting the leaching and decay resistance of the micro CuO/silica sol wood preservative and the mechanism of action of the preservative and wood were analyzed using scanning electron microscopy/energy dispersive X-ray analysis, Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction for both steaming and freezing post-treatment. SEM showed that the preservative had an irregular spherical shape with an average diameter of 0.45 μm. Changes in moisture content and pH were factors affecting preservative leaching and blocks decay resistance. FTIR analysis showed that the interaction between preservative and wood occurred in wood cellulose and lignin, and freezing treatment enhanced this interaction, which was the reason why freezing treatment improved preservative leaching resistance.