Abstract:
Samples from the two most common pines grown in Portugal (Pinus
pinaster Ait) and Spain (Pinus radiata, D. Don) were heat-treated in
industrial facilities in accordance with ThermoWood ® class D. For both
species, the variation in surface properties, of untreated and heat-treated
wood after artificial weathering from 75 to 750 h, is presented. The
analysis included the determination of color, roughness, gloss, and
wettability before exposure and after each artificial weathering period.
Untreated woods became darker faster, while in heat-treated woods,
lightness remained approximately constant until 750 h of artificial
weathering. Both untreated and heat-treated wood became more reddish
in the beginning of the weathering process, turning greener for longer
exposure times. Untreated woods became yellower in the beginning,
turning into blueish tones later. Heat-treated wood turned slightly yellower
until 750 h of weathering. Gloss decreased for untreated wood with no
significant changes in heat-treated wood. Despite the changes, the gloss
of both untreated and heat-treated wood converged to similar values.
Roughness increased for both untreated and heat-treated woods. Artificial
weathering increased the wettability of heat-treated wood.
