Abstract
Eucalyptus nitens is a fast growing plantation species that has a good acclimation in Chile. It is commonly used for pulp and paper, but there is a growing market for solid wood products made from this species and an interest on producing high quality material. Thermal modification technology have been used to obtain high quality product out of fast growing plantation species. In this study we modified Eucalyptus nitens to analyse the influences of the process conditions and evaluated its mechanical properties under several process conditions. The material was modified in a closed system under elevated pressure and controlled relative humidity (30 and 100% relative humidity) 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, modulus of rupture, deflection and work in bending (in elastic and inelastic proportions) and the resistance to impact milling in high energy multiple impact tests were determined. Mass loss after each modification was also measured and correlated with the mechanical properties. Anatomical properties of selected modifications were analysed. There were no significant differences between open and closed system modifications in both mechanical and anatomical properties.
Highlights
Eucalyptus nitens plantation wood is mostly used for pulp and paper or biofuels, but there is an interest to widen the use of this fast growing tree species in Chile
Thermal modification technologies show potential to produce high quality material and open new markets for the use of this species. These processes use treatment temperatures between 150°C and 240°C under different operating conditions, either steam, vacuum, nitrogen that limit the presence of oxygen in the process (Hill 2006, Militz and Altgen 2014). They can be separated in open systems, in which the modification happens at atmospheric pressure (ThermoWood (Mayes and Oksanen 2002), and closed systems, where the processes work under steam pressure, such as FirmoLin (Willems 2009) and WTT (Dagbro et al 2010), or vacuum (TERMOVUOTO (Allegretti et al 2012)), to name a few examples
At corrected mass loss (CML) above 10% the modulus of rupture (MOR) ratio decreased up to 0,71 at 170°C and 100% relative humidity (RH), while at 230°C in the open system modification showed the highest decrease in the ratio (0,74)
Summary
Eucalyptus nitens plantation wood is mostly used for pulp and paper or biofuels, but there is an interest to widen the use of this fast growing tree species in Chile. Thermal modification technologies show potential to produce high quality material and open new markets for the use of this species These processes use treatment temperatures between 150°C and 240°C under different operating conditions, either steam, vacuum, nitrogen that limit the presence of oxygen in the process (Hill 2006, Militz and Altgen 2014). The wood composition changes when it is exposed to high temperatures, and as a consequence, it improves the biological durability (Boonstra et al 2007, Hakkou et al 2006), and its dimensional stability (Boonstra and Tjeerdsma 2006, Tjeerdsma and Militz 2005), changing its mechanical properties (Esteves and Pereira 2009, Kubojima et al 2000) These variations are closely related to the species and the process conditions. Other authors showed that MOE of thermally modified wood can de higher than the reference values increased in certain thermal modifications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
