Dynamic Weathering Behavior of Heat-Treated Chinese Fir: Surface Properties, Chemical Composition, and Microstructure

Area of Science:

• Wood Science
• Materials Science
• Surface Chemistry

Background:

• Heat-treated wood offers eco-friendly aesthetics but degrades under UV radiation.
• Understanding UV degradation mechanisms is crucial for wood protection.

Purpose of the Study:

• To investigate the performance evolution and degradation mechanisms of heat-treated Chinese fir under artificial weathering.
• To quantify the impact of heat treatment on wood's surface appearance and chemical stability.

Main Methods:

• Chinese fir samples were heat-treated at 190 °C under vacuum.
• Samples underwent artificial weathering to simulate environmental exposure.
• Surface appearance, chemical composition, and microstructure were monitored dynamically.

Main Results:

• Heat treatment significantly inhibited color changes (ΔE = 24.05 vs. 37.78) and reduced yellowness (b* = 58.93% vs. 119.85%) compared to untreated wood.
• Gloss of heat-treated wood increased by 17% during weathering.
• Heat treatment's protective effect waned over time, not preventing long-term structural breakdown.

Conclusions:

• Improved color stability in heat-treated wood is linked to condensed lignin and phenolic chromophores.
• Hemicellulose decomposition creates "weathering-vulnerable zones", impacting long-term durability.
• Findings provide a basis for optimizing wood protection technologies against UV weathering.