Process optimization of thermal modification of Chilean Eucalyptus nitens plantation wood

Eucalyptus nitens ist eine der wichtigsten schnell wachsenden Plantagenbaumarten in Chile. Sein Holz wird hauptsächlich für Zellstoff und Papier verwendet, seit einigen Jahren gibt es jedoch, durch ein steigendes Interesse an hochwertigen Produkten aus dieser Holzart, einen wachsenden Markt für Massivholzprodukte, wodurch finanzielle Erträge erhöht werden. Thermische Modifizierungstechnologien haben ihr Potenzial bei der Herstellung von qualitativ hochwertigem Material bereits unter Beweis gestellt und wurden schon für andere Eukalyptusarten (zum Beispiel Eucalyptus globulus) verwendet. Temperaturen zwischen 150 und 240 °C und die Begrenzung des Sauerstoffgehalts im Prozess sind die Charakteristika der thermischen Modifizierungen, die aktuell auf dem Markt verfügbar sind. Die Prozesse unterscheiden sich durch die verwendeten Arbeitsgase (zum Beispiel Wasserdampf oder Stickstoff) und den Druck, der in offenen oder geschlossenen Prozessen herrscht. Offene Verfahren arbeiten unter Atmosphärendruck und verwenden häufig überhitzten Wasserdampf. Diese Verfahren gelten als „Trockenprozesse“, da die Holzfeuchte während des Prozesses stark abnimmt. Geschlossene Systeme arbeiten mit Überdruck während der Modifikation, wodurch die Modifikationsdauer reduziert wird. Sie gelten als „Feucht-Prozesse“, da die Holzfeuchte während und nach des Prozesses höher ist als beim offenen Prozessen. Die erhöhte Holzfeuchte bei die geschlossene Prozessen, in Verbindung mit der Akkumulation von Carbonsäuren im Holz, wird als Hauptursachen für die beschleunigte Degradation des Holzes angesehen. Es ist jedoch ungeklärt, ob sich Eigenschaften von thermisch modifiziertem Holz aus offenen und geschlossenen Prozessen signifikant unterscheiden. Diese Unterschiede sollen in der vorliegenden Arbeit untersucht werden, um eine den Eigenschaften entsprechende Verwendung und Anwendung von thermisch modifiziertem E. nitens Holz zukünftig zu gewährleisten. Um die Mechanismen und die Unterschiede zwischen diesen beiden Modifizierungssystemen besser zu verstehen, und das Potential von E. nitens als thermisch modifiziertes Holz zu analysieren, wurde das Material in einem geschlossenen und einem offenen System modifiziert. Beim geschlossenen Verfahren fand die Modifizierung unter hohem Druck, der durch Dampf erzeugt wurde, kontrollierter relativer Feuchtigkeit (30 und 100 % RH), und bei Temperaturen zwischen 150 und 170 °C statt; im offenen System erfolgte sie unter Sattdampf zwischen 160 und 230 °C. Die chemische Zusammensetzung (Hemicellulosen, Cellulose, Lignin, Extraktstoffe, Essigsäure, Ameisensäure, Phenole, Polymerisationsgrad der Cellulose und Kristallinitätsgrad) wurden analysiert. Ausgewählte mechanische Eigenschaften (Elastizitätsmodul (MOE), Biegefestigkeit (MOR), strukturelle Integrität und Durchbiegung und Biegearbeit) wurden bestimmt und der Einfluss chemischer Veränderungen auf diese Eigenschaften diskutiert. Veränderungen in der Holzanatomie nach der Modifikation wurden untersucht und die reversiblen und irreversiblen Effekte auf die Hygroskopizität näher betrachtet. Die so für beide Modifizierungsprozesse erhaltenen Materialkennwerte wurden unter Verwendung des korrigierten Massenverlusts (CML), der dem Masseverlust von extraktfreien Holz entspricht, verglichen. Chemischen Veränderungen zeigten am deutlichsten den Unterschied zwischen dem offenen und geschlossenen Prozess. Die Hemicellulosen (z.B. Xylose), der Säuregehalt und der Polymerisationsgrad der Cellulose unterschieden sich am stärksten. Auch wenn die mechanischen und anatomischen Eigenschaften keine signifikanten Unterschiede zwischen den beiden Systemen aufwiesen, zeigte der Elastizitätsmodul eine Korrelation mit den chemischen Veränderungen, was die Durchbiegung und Biegearbeit beeinflusst und auf ein spröderes Holz nach Modifizierung im geschlossenen System hindeutet. Diese Unterschiede waren beim Vergleich offener und geschlossener Systemmodifikationen mit ähnlicher CML deutlich zu erkennen. Auch bei den reversiblen Änderungen der Gleichgewichtsfeuchte (EMC) und der volumetrischen Quellung (Smax) nach Wassersättigung und Trockungszyklen zeigten sich Unterschiede. Diese Zyklen verringerten teilweise den Einfluss der Modifizierung auf die EMC und Smax. Dies ist im offenen System bedingt durch die Entfernung der trocknungsbedingten Effekte von amorphen Polymeren, und beim geschlossenen Systen durch die Beseitigung des Zellwandfülleffekts bei hohem Druck. Die beschriebenen Effekte beeinflussen auch die mechanischen und chemischen Eigenschaften des modifizierten Holzes. Weiterhin wurde gezeigt, dass thermisch modifiziertes Holz von E. nitens das Potenzial hat, für Terrassendielen verwendet zu werden. Die Ergebnisse zeigten, dass dieses Material alle Anforderungen hinsichtlich Oberflächenhärte, Anti-Schwellungseffizienz (ASE), Gleichgewichtsfeuchtigkeitsgehalt, Volumenquellung und Abriebfestigkeit erfüllt. Es lässt sich somit sagen, dass sich die in dieser Studie erhaltenen Ergebnisse als Richtlinien für die Auswahl des Modifizierungssystems benutzen lassen, die von den gewünschten Eigenschaften des Endprodukts und der Menge des herzustellenden Materials abhängt.Eucalyptus nitens is one of the most important fast growing plantation species in Chile. Currently it is mostly used for pulp and paper, but in recent years there has been a growing market for solid wood products to increase the economic returns, and an increasing interest on producing high quality materials from this species. Thermal modification technologies show potential to produce high quality material and have been used for other eucalypt species. Temperatures vary between 150 and 240°C and the limitation of oxygen content in the process is the most common feature of the thermal modifications currently available on the market. Main differences are the shielding gases used (steam or nitrogen for example) and the pressure applied to open or closed processes. Open processes work under atmospheric pressure, mostly use superheated steam, and are considered “dry processes”, as the wood moisture content (MC) decreases considerably during the process. Closed systems enable elevated pressure levels during the modification, which makes the modification process faster. They are considered “wet/moist processes”, as the MC during the process is higher than in the closed system. The elevated MC, in conjunction with the accumulation of carboxylic acids in the wood, has been suggested as the main cause of the accelerated degradation of the wood during these processes. However, it still remains unclear if the properties of thermally modified wood from open and closed processes are significantly different. These differences need to be explored to avoid the use of thermally modified wood with properties that do not fit for specific products or applications. To further understand the mechanism and the differences between these two types of modifications and to analyse the potential of E. nitens as thermally modified wood, the material was modified in a closed system under elevated pressure generated by steam 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 under saturated steam between 160 and 230°C. The chemical composition (hemicelluloses, cellulose, lignin, extractives, acetic acid, formic acid, total phenols, cellulose degree of polymerization and degree of crystallinity) was measured. Selected mechanical properties (modulus of elasticity (MOE), modulus of rupture (MOR), resistance to impact milling (RIM) and deflection and work in bending) were assessed and the influence of the chemical changes on these properties was analysed. Changes in wood anatomy during modification were examined and the reversible and irreversible effects of the hygroscopicity were investigated. All these properties were compared using the corrected mass loss (CML), which is the oven dry mass loss of extractive free wood, to analyse the differences/similarities between both thermal modification processes. The chemical changes made it possible to differentiate between open and closed system modifications, as the strongest differences between the modifications were specifically the hemicelluloses (xyloses), acid content and cellulose degree of polymerization. Even if the mechanical and anatomical properties showed no significant differences between the open and closed processes, MOR showed a strong correlation with those chemical changes, influencing the deflection and work in bending. These differences could be clearly be seen when comparing open and closed system modifications with similar CML. The differences between open and closed systems were also noticeable in the reversible changes in equilibrium moisture content (EMC) and volumetric swelling (Smax) after continuous water soaking cycles. These cycles partially lessened the reduction in EMC and Smax after the modification processes. This is related in the open system modification to the removal of the drying related effects of amorphous polymers, while the removal of the cell wall bulking effect was the main effect in the closed system modifications at high RH. These effects also influence the mechanical and chemical properties of the modified wood. It was shown in an experimental run that thermally modified E. nitens wood has the potential to be used for decking material, as it fulfils all the requirements regarding the surface hardness, anti-swelling efficiency (ASE), EMC, volumetric swelling, and abrasion resistance to be used as decking material. Overall, the results obtained in this study can be used as guidelines for the selection of the type of modification to be used for this species, which will depend on the desired properties of the final product and the quantity of material to be produced

Thinning wood properties of Nothofagus alpina under three different silvicultural conditions

The main objective of this study was to assess the properties of Nothofagus alpina wood from thinning that originates from two sites with intensive silviculture and one similar to a secondary growth forest, with different soil, climatic conditions and age. To achieve this, some mechanical, physical and chemical-crystalline properties were characterized; studying the differences from pith to bark and between the selected trees that were taken from the thinning of the three plantations. Among the studied plantation sites, there were statistical differences in equilibrium moisture content, density and modulus of elasticity. Furthermore, FT-IR was able to differentiate the chemical-crystalline compositions from pith to bark and between plantations, while the X-Ray Diffraction showed differences in the crystallinity index. It was possible to differentiate between the sites with a more intense silvicultural intervention and the one with more variable growth conditions

Fizička i mehanička svojstva toplinski modificiranog drva Eucalyptus nitens za vanjske podne obloge

Eucalyptus nitens is a fast growing plantation species that has a good acclimation in Spain and Chile. At the moment it is mainly used for pulp and paper production, but there is a growing market for solid wood products made from this species. Thermal modification offers a good alternative to produce high quality material to manufacture products with high added value. This study used unmodified and thermally modified E. nitens wood from Spanish and Chilean plantations to elaborate external decking and examine if it complies with the necessary properties to be a competitive product. A process similar to ThermoWood® was applied at the following temperatures: 185 °C, 200 °C and 215 °C. For each modification and for an unmodified specimen mass loss, volumetric swelling, anti-swelling efficiency (ASE) and equilibrium moisture content (EMC) were determined. Brinell hardness, dynamic hardness, screw and nail withdrawal resistance, and abrasion resistance according to the Shaker method and the Taber Abraser method were also determined. According to this study, thermally modified E. nitens from both countries showed high potential to be used as decking material, particularly when modified at 200 °C.Eukaliptus nitens brzo je rastuća plantažna vrsta koja se dobro prilagodila klimi u Španjolskoj i Čileu. Trenutačno se uglavnom iskorištava za proizvodnju celuloze i papira, ali sve je veće tržište proizvoda izrađenih od masivnog drva te vrste. Toplinskom modifikacijom dobiva sa dobra alternativa za proizvodnju visokokvalitetnih proizvoda s visokom dodanom vrijednošću. U ovom je istraživanju kao materijal za vanjske podne obloge upotrijebljeno nemodificirano i toplinski modificirano drvo E. nitens sa španjolskih i čileanskih plantaža te je ispitana njegova sukladnost sa svojstvima potrebnima za postizanje konkurentnosti. Primijenjen je postupak sličan procesu ThermoWood®, i to pri temperaturama 185, 200 i 215 °C. Za svaki modificirani i nemodificirani uzorak određen je gubitak mase, volumno bubrenje, učinak smanjenja bubrenja (ASE) i ravnotežni sadržaj vode (EMC). Određene su i tvrdoća prema Brinellu, dinamička tvrdoća, otpornost na izvlačenje vijaka i čavala te otpornost na habanje prema metodama Shaker i Taber abraser. Na temelju ovog istraživanja može se zaključiti da su toplinski modificirani uzorci drva E. nitens iz obje zemlje pokazali visok potencijal za uporabu u obliku vanjskih podnih obloga, posebice ako su modificirani pri 200 °C

Dynamic and static mechanical properties of eucalyptus nitens thermally modified in an open and closed reactor system

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

Use of near infrared spectroscopy to detect non-recoverable collapse caused by tension wood in Eucalyptus globulus

© 2012 Maximilian Wentzel-VietheerEucalyptus globulus is widely planted around the world. The wood is mainly used for fibreboard, paper and firewood. Use for sawn and engineered wood products can be limited because of the development of non-recoverable collapse caused by tension wood, which can severely distort wood surfaces and affect sawing and drying performance, leading to increased processing costs, lower yield (recovery) and thus reduced product value. In tension wood, cellulose content, microfibril angle (MFA), density, and stiffness (MOE) are altered compared to normal wood. The study investigated the calibration and application of near infrared (NIR) spectroscopy to measure these wood properties and detect non-recoverable collapse. Radial, bark to pith, wood cores were sampled from 175 trees in a 20 year old E. globulus silvicultural trial at Tostaree, Victoria, Australia. NIR spectra were measured at 1 mm intervals along the cores after drying to 12% estimated moisture content (EMC). Tangential shrinkage of the cores was measured at 8 points across each core after reconditioning to 12% MC. Spectra were measured on an additional 20 cores that were also analysed using SilviScan-3 to measure MFA, density and MOE, and NIR Partial Least Squares (PLS) Regression calibrations were developed. The calibrations were used to predict wood properties in the 175 cores, which were then related to the measured tangential shrinkage and non-recoverable collapse. NIR-predicted wood properties at points of non-recoverable collapse were consistent with the presence of tension wood (i.e. high cellulose, low MFA, high density and high MOE). Cellulose content and MOE were the best multiple regression predictors of tangential shrinkage. An NIR calibration developed to directly predict tangential shrinkage qualitatively identified zones of high shrinkage, but tended to under-predict measured shrinkage values. Tangential shrinkage, or the incidence of high tangential shrinkage, was not or only weakly correlated with tree size, height to diameter ratio, or lean. Silvicultural treatments (thinning intensity, fertilizer application) did not affect tangential shrinkage or tension wood formation. Generally, the incidence of non-recoverable collapse was greater in the wood grown since age 10 years. The study demonstrated that NIR predicted wood properties can be used to detect non-recoverable collapse caused by tension wood. The methodology has potential use in plantation and log assessment, wood processing, and tree breeding

Dynamic and static mechanical properties of "eucalyptus nitens" thermally modified in an open and closed reactor system

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

Wood sanitization protocol for export packaging of Pinus radiata wood using a radiofrequency heat treatment

A treatment is proposed to sanitize wood for export packaging using radio frequency equipment that is capable of treating wood. This was achieved by optimizing the sanitization process and developing an equation to predict the total sanitization time. Statistical analysis determined that the separation of plates and the power density of the equipment significantly influenced the duration of a sanitization process using radio frequency heating, whereas the thickness of the material was not as influential for the overall process. Furthermore, the sanitization process did not influence the quality of the wood; therefore, the proposed sanitization protocol provided a balance between duration and the quality of the finished radiata pine packaging material

A Roadmap for Transforming Research to Invent the Batteries of the Future Designed within the European Large Scale Research Initiative BATTERY 2030+

This roadmap presents the transformational research ideas proposed by “BATTERY 2030+,” the European large-scale research initiative for future battery chemistries. A “chemistry-neutral” roadmap to advance battery research, particularly at low technology readiness levels, is outlined, with a time horizon of more than ten years. The roadmap is centered around six themes: 1) accelerated materials discovery platform, 2) battery interface genome, with the integration of smart functionalities such as 3) sensing and 4) self-healing processes. Beyond chemistry related aspects also include crosscutting research regarding 5) manufacturability and 6) recyclability. This roadmap should be seen as an enabling complement to the global battery roadmaps which focus on expected ultrahigh battery performance, especially for the future of transport. Batteries are used in many applications and are considered to be one technology necessary to reach the climate goals. Currently the market is dominated by lithium-ion batteries, which perform well, but despite new generations coming in the near future, they will soon approach their performance limits. Without major breakthroughs, battery performance and production requirements will not be sufficient to enable the building of a climate-neutral society. Through this “chemistry neutral” approach a generic toolbox transforming the way batteries are developed, designed and manufactured, will be created. © 2022 The Authors. Advanced Energy Materials published by Wiley-VCH GmbHpublishedVersio