Weathering of copper-amine treated wood

IRG/WP 00-40155

J Zhang, D P Kamdem

Copper ethanolamine (Cu-EA) treated southern pine (SP) were artificially weathered with a QUV Weathering Tester. The weathering regime was composed of a continuous UV-light irradiation for 2 hours followed by a water spray for 18 minutes for a total time of 1200 hours. The changes on the surface of the weathered samples were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, color and contact angle measurements. FTIR indicates that Cu-EA treatment can retard the surface degradation during weathering. The reduction of the peak intensity at 1510 cm-1, characteristic of the wood lignin was less pronounced for Cu-Ea treated wood than for untreated or ethanolamine treated wood. This reduction in 1510 cm-1 intensity decreases with the increase of copper EA retention in treated wood. The color change expressed by the value of DE indicated that untreated and Cu-EA treated wood change color rapidly during the first 200 hours irradiation and the color change remained relatively constant thereafter. The values of DE for untreated and ethanolamine treated sample were higher than the values of Cu-Ea treated. Changes in the lightness of wood samples were also observed with the duration of irradiation. The lightness of untreated and Cu-MEA treated samples decreased during the first 100-hour weathering. These samples regained their lightness after 100 hours irradiation. For samples treated with copper concentration above 0.25%, the change in lightness was rather small. The contact angle measurement indicates that the wettability of wood surface increases with the duration of QUV exposure. Untreated and MEA treated wood samples changed contact angles rapidly, and The contact angle of untreated and ethanol amine treated samples dropped from about 75"5 degree to zero after 600 hours artificial weathering. Treatment with Cu-MEA can slow the decreasing in contact angle. After 1200 hours, the contact angle of Cu-EA treated wood dropped from 100 to a minimum between 25 and 60 degree. As the copper concentration increases, the rate of changing contact angle decreases. This study suggests that a copper amine treatment increases the hydrophobic and the resitance to photodegradation.


Keywords: CIELAB; FTIR; QUV; CONTACT ANGLE; COPPER AMINE; CU-EA; ETHANOLAMINE; WEATHERING; LIGNIN; HEMICELLULOSE; CELLULOSE; QUINONE

Conference: 00-05-14/19 Kona, Hawaii, USA


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