Eucalyptus nitens was thermally modified in a closed system under elevated pressure and controlled relative humidity (30 and 100% RH) at temperatures between 150 and 170°C, and in an open system with a standard thermal modification procedure between 160 and 230°C. Modulus of elasticity (MOE), modulus of rupture (MOR), deflection and work in bending (in elastic and inelastic proportions) were measured after acclimatizing the wood at 20°C/65% RH. Mass loss after each modification was also measured and correlated with mechanical properties. MOR and MOE tend to be lower at higher temperatures and higher pressure in the closed system modification, while there was a slight increase in MOE and MOR after modifications between 160 and 200°C, followed by reduction of these properties at increasing temperatures up to 230°C in the open system. The inelastic deflection and inelastic work in bending was at its lowest at the modification process at 170°C and 100% RH, whereas in the open system the modification that led to the lowest inelasticity values was at 200°C. The results obtained can be used as a guide for future applications of thermally modified Eucalypt and heat treatment process optimization.
Keywords: Eucalyptus nitens, thermal modification, MOE, MOR
Authors
Wentzel M.
PhD Student, Department of Wood Biology and Wood Products, Georg-August-University Göttingen, Göttingen, Germany
Militz H.
Professor, Department of Wood Biology and Wood Products, Georg-August-University Göttingen, Göttingen, Germany
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