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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.

The thermal modification of wood is a potential alternative method for improving wood dimensional stability and increasing the resistance of wood to decay. However, during thermal modification, morphological changes occur within the microstructure of the cell, and these confer different properties to the wood. This study investigated the effects of the thermal modification process on the microstructure of radiata pine juvenile wood. Therefore, anatomical measurements were performed via optical microscopy in selected earlywood and latewood samples after each treatment, and the results were compared to untreated wood samples. In this study, two temperatures (190 °C and 210 °C) were considered for the thermal modification process. The results showed that the level of temperature of modification affected to microstructure of cell wall. The cell wall thickness decreased as treatment temperature increased, whereas the average lumen diameter increased slightly as temperature increased. Thermally modified radiata pine showed signs of damage (cracks, broken cells and deformations in the wood cell wall). The proportion of destroyed area increased as temperature increased, and significant differences were evident for the thermal treatment at 210 °C.

An eco-friendly agent mainly consisting of activated glucose (AG) and citric acid (CA) was investigated for its potential wood modification applications. Scots pine (Pinus sylvestris L.) sapwood was treated with AG and CA both individually and in combination. The treatments with the combined agent resulted in an increase in the weight percent gain and decrease in the leaching ratio, which suggested a synergy between the two components for their fixation in wood. The dynamic vapor sorption behavior indicated an increased sorption at a higher AG concentration. Compared with the AG treatment, the CA treatment more effectively improved the dimensional stability of the wood. The modulus of elasticity was not influenced by the treatments, and the modulus of rupture was slightly reduced. Incorporation of AG in the CA inhibited the decrease in impact strength of wood compared to treatment with CA alone, which was a result of reduced crosslinking from the CA within the wood matrix. Fourier transform infrared (FTIR) spectroscopy revealed an enhanced absorbance, indicating development of ester bonds due to the treatment.

Eucalyptus nitens specimens were thermally modified under open and closed systems. The anatomical characteristics from selected modifications that presented similar mass losses were investigated by...

In the present work, Eucalyptus nitens was thermally modified in an open (atmospheric pressure) and a closed (under pressure) reactor system. The effect of the changes of the chemical composition on the mechanical properties was investigated. Hemicelluloses, cellulose, lignin, extractives, acetic acid, formic acid, total phenols and the cellulose degree of polymerization (DP) as well as modulus of elasticity (MOE) and modulus of rupture (MOR) were measured for each modification. The results indicated that the closed system modification, particularly at high pressure, presented stronger variations on the chemical structure of the modified wood than the modifications in the open system. In both modifications, MOR showed a better correlation with the chemical changes than the MOE, especially xylose, cellulose DP, lignin and total phenols. These correlations suggest a tendency of a more brittle wood in the closed system modification at high pressure than in the modifications in the open system. Result...

Bordered pits are a major determinant for the hydraulic function of wood tissues. Unlike microscopic imaging (e.g. light and electron microscopy) that is constrained to two-dimensional (2D) information, X-ray micro-computed tomography (XμCT) contributes to three-dimensional (3D) analysis. This advantage was used to estimate the volume of bordered pits in Pinus sylvestris. The 3D data obtained by XμCT were compared with two mathematical models (ellipsoid model and spherical cap model) using 2D data obtained by transmission light microscopy and XμCT. The findings of this study showed that the volume approximation using the ellipsoid model revealed values close to the volumes, which were three-dimensionally obtained by XμCT. This trend, however, is more pronounced for pits in earlywood than in latewood. Nevertheless, this study demonstrated that microscopic images can also be used for the approximation of pit volumes to some extent. Researchers should be aware of limitations that come with the 3D method (e.g. resolution, image analysis) and 2D method (unknown location of the section in the pit) as well as the natural variation of the pit morphology.

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.

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.

Near infrared (NIR) spectroscopy calibrations was used to predict radial profiles of cellulose content, wood density, cellulose microfibril angle (MFA) and modulus of elasticity (MOE) in 20-year-old plantation Eucalyptus globulus to identify non-recoverable collapse zones associated with tension wood. Radial (cambium-to-pith) wood cores were extracted at a height of 1.0 m from trees selected to represent a range of silvicultural treatments. NIR spectra were measured at 1 mm intervals along the radial-longitudinal face of each core after drying to 12 % equilibrium moisture content (EMC) at 40 °C. Tangential shrinkage was measured at eight points along each core, following steam reconditioning and re-drying to 12 % EMC. Additional cores from 20 of the sample trees were collected. Radial profiles of density, MFA and MOE were obtained for wood strips prepared from these cores, using the SilviScan 3 wood assessment system. Trait profiles were matched to radial NIR scans of these cores, enabling the development of NIR calibrations using partial least squares (PLS) regression. These, and an existing NIR calibration for cellulose content, were used to predict the radial profiles of the four wood properties for the first set of cores. Predicted wood properties were then related to actual tangential shrinkage measurements and the occurrence of visible bands of non-recoverable collapse. A regression model was developed to reliably predict regions of non-recoverable collapse from NIR-predicted cellulose content and MOE. Micrography of stained wood sections indicated that the collapse was caused by the presence of tension wood.