Weathering of copper–amine treated wood

Abstract

In this study, the effect of ultraviolet light (UV) irradiation and water spray on color, contact angle and surface chemistry of treated wood was studied. Southern pine sapwood ( Pinus Elliottii.Engelm.) treated with copper ethanolamine (Cu-MEA) was subjected to artificially accelerated weathering with a QUV Weathering Tester. The compositional changes and the surface properties of the weathered samples were characterized by Fourier transform infrared (FTIR) spectroscopy, color and contact angle measurements. FTIR indicated that MEA treatment was not found to slow down wood weathering. FTIR spectrum of MEA-treated sample was similar to that of the untreated SP. However, the Cu-MEA treatment retarded the surface lignin degradation during weathering. The main changes in FTIR spectrum of Cu-MEA treatment took place at 915, 1510, and 1595 cm −1. The intensity of the bands at 1510 and 1595 cm −1 increased with the Cu-MEA treatment. Both untreated and MEA-treated exhibited higher Δ E than the Cu-MEA treated samples, indicating that MEA treatment did not retard color changes. However, Δ E decreased with increasing copper concentration, suggesting a positive contribution of Cu-EA to wood color stability. The contact angle of untreated and MEA-treated samples changed rapidly, and dropped from 75 ± 5° to 0° after artificial weathering up to 600 h. Treatment with Cu-MEA slowed down the decreasing in contact angle. As the copper concentration increases, the rate of change in contact angle decreases.