INFLUENCE OF THERMAL MODIFICATION ON THE PHYSICAL AND MECHANICAL PROPERTIES OF Eucalyptus badjensis MIXED PARTICLEBOARD / OSB PANELS

Abstract

The objective of this research was to evaluate the effects of thermal modifications, at different temperatures and exposure times, on the technological properties of mixed particleboard / OSB panels made out of Eucalyptus badjensis. Using the wood of Eucalyptus badjensis, Particleboard, OSB and mixed Particleboard/OSB panels (control and thermally modified) were manufactured. The mixed panels’ thermal modification was carried out under three temperatures (180ºC, 200ºC and 220ºC) and two exposure times (10 minutes and 12 minutes). For the panels’ manufacturing, 6% of phenol-formaldehyde adhesive and 1% of paraffin were employed, which was calculated based on the particles’ dry mass. The water absorption and thickness swelling properties were evaluated after 2 and 24 hours of immersion, in addition to the panels’ modulus of elasticity, modulus of rupture and internal bond. Based on the results, we were able to conclude that the thermal modification affected most of the physical properties positively. From the different exposure times studied, the most effective one was the period of 12 minutes, especially for water absorption after 2 hours, which caused a reduction of 11.27%. In turn, the most effective temperature was of 220ºC, highlighting the thickness swelling after 24 hours, which caused a swelling decrease of 23.76% in comparison with the control panels. Regarding the mechanical properties, the thermal modification, in terms of the studied exposure times and temperatures, did not affect the results of the mixed particleboard /OSB panels.

Study of the Influence of Heat Treatment on OSB Panels Produced with Eucalyptus Wood in Different Layer Compositions

“…Thus, comparing the present study with the one conducted by Pereira et al [58], it is understood that the differences found in the results obtained between the research are related to the longer time of exposure to temperature during thermal modification. This is in line with what Sinha, Gupta and Nairn obtained [60], who found that heat treatment of OSB caused a significant reduction in flexural strength and stiffness, with the greatest reduction occurring at 200 • C for 2 h compared to the other conditions evaluated (reference, 100 • C at 1 and 2 h, and 200 • C at 1 h exposure).…”

“…In their paper, Pereira et al [58] who also studied the thermal treatment (at 180 • C, 200 • C and 220 • C) in two exposure times (10 and 12 min) in particleboard and OSB produced with eucalyptus wood and phenolic resin, it was concluded that the thermal modification at the exposure times and temperatures studied did not influence the results of the mechanical properties of the panels.…”