Color changes of wood from Pinus taeda and Schizolobium parahybum treated by in situ polymerization of methyl methacrylate using cross-linkers

Abstract

The aim of this study was to evaluate the colorimetric properties of Pinus taeda and Schizolobium parahybum woods treated by in situ polymerization. The wood samples were impregnated in a vacuum/ pressure system and polymerized in an oven at 90°C for 10h, using benzoyl peroxide at 1,5wt% as the catalyst. The treatments were characterized using attenuated total reflectance infrared (ATR-IR) spectroscopy and weight percentage gain (WPG). The color evaluation was performed using CIEL*a*b* concepts, specular gloss, and UV-Visible spectrophotometry. Treated woods showed increases in band intensity related to polymers (1730, 1460 and 1145 cm -1 ), and WPG ranged from 39 to 164%, depending of the wood species and treatments. Lightness decreased, while the Chroma, gloss and the color coordinates increased. A darkening of the all treated samples was observed, and confirmed by the decrease in the reflectance intensity between 400 and 700 nm.

Discolouration of heat-treated fast-growing eucalyptus wood exposed to natural weathering

“…In this sense, many treatments have been proposed in order to minimize weathering effects on wood surface, with some promising results already reported. These treatments include: thermal treatments, 6,7 acetylation, 8 surface coatings, 2 manufacture of wood composites with wood flour, 9 wood fiber, 10 and in situ polymerization, 11 among other chemical modifications. 10,12,13 In comparison with other treatments, thermal treatment is an eco-friendly treatment capable of improving many wood features without using chemicals.…”

Photochemical Aging of Eco-Friendly Wood Coatings Derived from Vegetable Oils

“…The unprotected wood surface showed a rapid increase in the parameter b * in the first 100 h, followed afterward by its decrease up to 500 h irradiation. The observation reflects the instability of yellow chromophores at high doses of irradiation . However, after 500 h of exposure, the surface of the unprotected wood is yellower than that of the initial one (Δ b * = 14.3).…”

“…The observation reflects the instability of yellow chromophores at high doses of irradiation. 31 However, after 500 h of exposure, the surface of the unprotected wood is yellower than that of the initial one (Δb* = 14.3). In the case of the protected samples after 500 h of exposure, the same variation tendency of parameter b* is noticed (Table S1 in Supporting Information).…”