Effect of the post-heat treatment on the properties of medium density particleboard of Eucalyptus sp.

Abstract

Heat treatment aims to reduce the compression stresses generated during the panel production, improving its dimensional stability and providing greater resistance to attack by xylophagous organisms, despite decreasing the mechanical properties. This work aimed to evaluate the physical-mechanical properties of medium density particleboard (MDP) of Eucalyptus sp. subjected to post-heat treatment with two temperature levels (200 and 260ºC) and two periods (5 or 10 minutes). The apparent density, water absorption and thickness swelling (TS) after 2 and 24h, internal bonding, MOE and MOR in static bending were evaluated. The post-heat treatment at 200 °C for 5 minutes was the most efficient, improving the TS, with smaller reductions in the mechanical properties. The temperature had a greater influence in the first hours of immersion in water (TS2h), while for a longer period (TS24h) the heat treatment time was more effective. The temperature influenced the mechanical properties more negatively than the heat treatment time.

Effect of thermal treatment on the physical properties of GG100 clone Eucalyptus wood

“…Thermal treatments decrease wood's hygroscopicity due to the degradation of the hemicelluloses that occurs more intensely than to other wood components due to their structural heterogeneity, presence of amorphous regions, and low molecular mass [11]. When properly carried out, the treatments also cause higher dimensional stability and resistance to decay [12,13]. The wood color is also altered, leaving it with darker and more uniform tones [14].…”