Investigation of Color Difference in ACQ and CBHDO Treated Wood During Two-year Outdoor Exposure

Abstract

In general, when wood products are used outdoors for a certain period of time the surface color of wood changes due to light, water, heat and so on. This color change can be considered importantly for the product's market value. In this study, the color change of ACQ (Alkaline Copper Quaternary) and CBHDO (CuO⋅ H3BO3⋅N-cyclohexyldiazenium-anion) treated wood and untreated wood was investigated during 2-year weathering test. From this experimental study, it was found that the colors of the treated wood changed more reddish and yellowish from green. Meanwhile, the untreated wood turned to grey color rapidly. Also, the color of the treated wood in short-term exposure changed closer to the inherent color of the fresh natural wood than that of the untreated woods.

Surface characterization of wood treated with boron compounds combined with water repellents

“…The negative values of Δ L * in the test samples were indicative of the depolymerization of lignin . After the first 6 months, the darkening surface of the samples had begun to be noticeable.…”

“…Negative light stability (Δ L *) values were measured on the surface of the control samples as the surface of the wood exposed to outdoor conditions became coarser and darker, caused by the depolymerization of the lignin. In another study, the L * value of the control samples decreased with time, while an increase was observed in the samples impregnated with alkali copper quat . Regarding the chromatic coordinates, the values of the red/green (Δ a *) and the blue/yellow (Δ b *) coordinates showed a negative increase.…”

“…In another study, the L* value of the control samples decreased with time, while an increase was observed in the samples impregnated with alkali copper quat. 26 Regarding the chromatic coordinates, the values of the red/green (Δa*) and the blue/yellow (Δb*) coordinates showed a negative increase. The negative values of ΔL* in the test samples were indicative of the depolymerization of lignin.…”

“…The negative values of ΔL* in the test samples were indicative of the depolymerization of lignin. 26 After the first 6 months, the darkening surface of the samples had begun to be noticeable. Samples impregnated with NB exhibited more light stability than those impregnated with BA.…”