FT-IR Studies of Weathering Effects in Western Redcedar and Southern Pine

Abstract

Diffuse reflectance infrared spectroscopy has been used to monitor the changes in functional groups on the surface of two woods (western redcedar and southern pine) when they are subjected to a range of artificial weathering conditions. The effects of light only, water only, and light plus water have been studied for a variety of exposure times. The changes in the chemical composition of the wood caused by light plus water is considerably greater than that caused by light only, whereas water alone causes no permanent chemical changes. The effects of some of these weathering conditions have been investigated for wood protected by varnish, for earlywood and latewood and for tangentially, radially, and cross-sectionally cut wood samples. The application of two coats of varnish was found to considerably reduce the weathering effects caused by UV radiation; earlywood undergoes light-only degradation faster than late wood; and the effect of weathering was found to be greatest for cross-sectional cut samples and least for radially cut samples. The weathering profile with depth of penetration has been studied in some detail for western redcedar, and our results show that, after 300 h of continual artificial weathering, the chemical changes are confined to the first 200 μm.

Protection of Wood from Microorganisms by Laccase-Catalyzed Iodination

“…We used the FTIR-ATR technique for evaluation of a possible modification of lignocellulose by laccase-mediated wood iodination. The impact of leaching on native wood has already been investigated by several authors (31,55), and their results are in good agreement with our observations. Water-soluble phenolic moieties in lignin were washed out during the leaching procedure, resulting in a decrease of absorption of mostly lignin-associated bands, especially of the band at 1,590 cm…”

Influence of wood extractives on the photo‐discoloration of wood surfaces exposed to artificial weathering

“…This was confirmed by a previous study that found that changes on the surface of western red cedar and southern pine after artificial weathering were considerably greater when irradiation and water were used together, compared with water or irradiation only. 13 Specimens were removed for color measurement after 2, 6, 12, and 24 h during the first 24 h, and then at 48, 96, 200, 400, 800, 1600, and 2400 h. Special attention was made to always remove the sample for color measurement at 1 h and 55 mn into the UV exposure cycle to ensure similar moisture and temperature conditions for the specimens.…”

Preparation and Characterization of Outdoor Bamboo-Fiber-Reinforced Composites with Different Densities

“…The higher density of these products makes it difficult for water and light to reach the wood . The depth of the photodegradation and the rate of erosion of the wood during weathering depends greatly on the density (Horn et al 1994;Evans et al 2005). Many previous studies of anti-aging treatments have focused on the changes in the physical and mechanical properties, color characteristics, and chemical composition of bamboo and bamboo-based composites (Beckers et al 1998;Cristea et al 2010;Lesar et al 2011;Tolvaj et al 2011;Srinivas and Pandey 2012;Tomak et al 2012;Baysal et al 2014;Tolvaj et al 2014;Li et al 2015;Zhu et al 2015;Shangguan et al 2016).…”