Enhancing mechanical and surface properties of eucalyptus wood

Eucalyptus is one of the most fast-growing trees. Therefore, in the last decades it has been extensively planted and harvested so that nowadays Eucalyptus is one of the most popular trees of the planet. There are many genres of this plant and they are often treated as a large bunch of the same timber characterized by moderate mechanical and surface properties which hinder their usage for any sight application (e.g. flooring, cladding, ceiling). In this study four species of Eucalyptus: E. grandis, E. dunnii, E. cloeziana and E. tereticornis were undergone to densification through hydro-thermo-mechanical treatment (HTM) first and then to oil heat-treatment (OHT) in order to improve their mechanical properties and hydrophobicity. It was observed that low density species (E. grandis) reaches higher compression degrees while heavier species (E. tereticornis) reach densities over 800 kg/m³; however, HTM decrease the variability of the properties. Treatments at higher temperature (160 °C) involves higher compression degree, lower set-recovery and higher surface hydrophobization, but also weaker mechanical properties. The hot oil post- treatment helps to contain the springback effect and to reduce the wettability of each specimen. Densified samples present similar surface hardness. The tailored application of the two treatments improves the properties of every Eucalyptus which can gain market also for nobler end-usages

Effect of process parameters in the thermomechanical densification of pinus elliottii and eucalyptus grandis fast-growing wood

Densification parameters were investigated for the fast-growing pine and eucalyptus. Both woods showed optimal results in terms of apparent density and mechanical properties when milder treatments of 150\ub0C were applied. Pine showed mass loss and improved mechanical properties with a longer heating time of 60 min, while eucalypt performed better with shorter treatments of 30 min. Eucalypt has more highly acetylated hemicelluloses, minly composed of xylose units, which degrade more quickly with consequent decrease in mass and mechanical properties. However, apparent densities close to 1.0 g.cm-3 were obtained, and greatly enhanced bending properties, hardness, and impact resistance were observed,especially when the optimal parameters were used. Treatments at 170\ub0C or greater, while resulting in well-densified specimens, yielded inferior mechanical properties. The densified woods also presented initial apparent contact angles greater than 85\ub0, highlighting a considerable increase of hydrophobicity. The densification process therefore allows these less valuable timber species to be used in applications such as flooring and decking

Enhancing mechanical and surface properties of Eucalyptus wood

Eucalyptus is one of the most fast-growing trees. Therefore, in the last decades it has been extensively planted and harvested so that nowadays Eucalyptus is one of the most popular trees of the planet. There are many genres of this plant and they are often treated as a large bunch of the same timber characterized by moderate mechanical and surface properties which hinder their usage for any sight application (e.g. flooring, cladding, ceiling). In this study four species of Eucalyptus: E. grandis, E. dunnii, E. cloeziana and E. tereticornis were undergone to densification through hydro-thermo-mechanical treatment (HTM) first and then to oil heat-treatment (OHT) in order to improve their mechanical properties and hydrophobicity. It was observed that low density species (E. grandis) reaches higher compression degrees while heavier species (E. tereticornis) reach densities over 800 kg/m3; however, HTM decrease the variability of the properties. Treatments at higher temperature (160 \ub0C) involves higher compression degree, lower set-recovery and higher surface hydrophobization, but also weaker mechanical properties. The hot oil post-treatment helps to contain the springback effect and to reduce the wettability of each specimen. Densified samples present similar surface hardness. The tailored application of the two treatments improves the properties of every Eucalyptus which can gain market also for nobler end-usages