Evaluation of the weathering intensity of wood-based panels under outdoor exposure

Abstract

In this study, the deterioration of wood-based panels at eight sites in Japan was investigated using outdoor exposure tests. In particular, the modulus of rupture (MOR) retention and internal bond strength (IB) retention after 5-year exposures were compared among panels and sites. The deterioration of panels located in southern Japan was higher than that of panels in northern Japan. To quantify the regional differences, the deterioration rates were calculated; the values showed clear regional differences. The deterioration rate for areas that receive much rain in the summer was higher than the rates for other sites. To eliminate regional differences, we carried out an analysis in terms of the "weathering intensity," a factor which combines weather conditions (precipitation and temperature). Panels for which deterioration progressed extensively during exposure periods showed a strong correlation between strength retention and the weathering intensity. The signifi cance of these parameters is discussed.

Changes in chemical composition of decayed Scots pine and beech wood

“…The peak intensities at 1316 cm -1 (10) and 664 cm -1 (18) decreased in aged samples after P. placenta attack; however, those peaks showed an increasing tendency in unaged samples. In the case of beech samples, the peaks responsible for wood carbohydrates at 1370 cm -1 (9), 1027 cm -1 (15), and 897 cm -1 (16) decreased for both aged and unaged samples after fungi attack. The reduction at 1370 and 897 cm -1 was greater in aged beech samples after P. placenta attack than C. puteana attack.…”

“…For such applications, information on long-term durability of wood and wood-based composites under realistic environmental conditions is gaining an importance. Long-term tests known as outdoor exposure tests take long time for evaluation and are difficult to carry out in many times [15]. Short-term test generally known as laboratory accelerated aging offers some advantages, as it is easy to perform and more standardized than long-term tests [16].…”

“…Short-term test generally known as laboratory accelerated aging offers some advantages, as it is easy to perform and more standardized than long-term tests [16]. Reduction in strength properties of wood-based composites [15][16][17][18] and reduction in biological resistance of wood-based composites and solid wood [19] were reported after accelerated aging treatments such as water immersion, boiling, steaming, freezing, and drying.…”

Surface deterioration of wood plastic composites under outdoor exposure

“…A large scale outdoor exposure test is effective for evaluating the influence of weather factors on the durability of wood-based composites [12][13][14]. However, there have been few examples of such tests using WPCs [15].…”

Modified method for evaluating weathering intensity using outdoor exposure tests on wood-based panels

“…We attempted to eliminate regional differences in the deterioration of panels by defining "weathering intensity," based on weather parameters. 5,6 In previous studies, weathering intensity was defined as a weather-based force exerted on panels during outdoor exposure tests, considering only average daily temperature and daily precipitation as weather parameters. However, this method ignored other important factors that influence panel deterioration (e.g., sunlight hours), and calculations of daily parameters become cumbersome over a period of several years.…”