Tensile stress relaxation of copper-ethanolamine (Cu-EA) treated wood

The tensile stress relaxation of Chinese fir wood treated with copper-ethanolamine (Cu-EA) was compared with that of untreated control to investigate the influence of Cu-EA treatment on the dimensional stability of wood in long-term application, and also for a better understanding of copper-wood-water interactions in copper containing water-borne preservative systems. The results showed that temperature and moisture conditions play important roles in the stress relaxation behavior of wood with or without Cu-EA treatment. At 25 degrees C, Cu-EA treatment has little influence on stress relaxation; while at 35 degrees C, Cu-EA treatment can significantly reduce the stress relaxation of wood, suggesting that Cu-EA treatment can increase dimensional stability of wood at high atmospheric temperature in long-term application. The complicated effect of copper retention on stress relaxation further confirms that copper competes for hydroxyl groups as adsorption sites with water molecules, as put forward in the previous report.