Study on the surface changes of heat-treated aspen wood due to aging by different techniques

Abstract

Heat-treated wood undergoes degradation induced by weathering factors such as solar radiation, temperature variations, rain, and snow. The aging of heat-treated wood affects significantly its surface properties. In this study, the artificial aging test of heat-treated wood using a UV chamber was carried to see the effect of aging on the wood surface. The net radiative heat transfer to the wood sample surfaces in this chamber was estimated in order to determine the corresponding natural weathering times. A complete understanding of the surface changes during the weathering process would allow the development of new treatments and finishes that would greatly enhance the durability of heat-treated wood against degradation due to weathering. Study of the heat-treated wood surface before and after weathering by different techniques helps provide an insight into the degradation process. The techniques and tools for studying heat-treated wood surfaces include color measurement, contact angle test for wettability analysis, light microscopy, FTIR, XPS, and SEM. Each technique gives information on different aspects such as chemistry, structure, and appearance. In this article, the utilization of these techniques is discussed. A number of results for different cases are presented. The aging affects the color of the tangential and radial surfaces differently. During aging, lignin decreases and OH increases; and this increases the wettability of wood.