Grandis Wood Research Articles

Decay resistance of two-step freezing–heat-treated fast-growing eucalyptus wood

The present study aimed at evaluating the decay resistance of Eucalyptus grandis wood modified by two-step freezing–heat treatments, using brown-rot (Gloeophyllum trabeum) and white-rot (Trametes versicolor) fungi. Five treatments, combining freezing (at − 22 °C) and termorretification (at 180 °C and 200 °C), were performed. The decay resistance tests were conducted as per relevant standard. Both freezing and thermal treatments were effective in reducing the mass losses attributed to the brown-rot fungus. The two-step treatment, in which the freezing was prior to the thermal treatment at 200 °C, yielded the highest decay resistance to the eucalyptus wood, leading to a hindered access to the nutrients in cellulose and hemicelluloses. Only two-step treatments were effective for protecting the wood against the white-rot fungus, which may be due to modifications in both lignin and wood extractives related to synergic effects from both freezing and heat.

Anatomical, Physical and Mechanical Properties of Aerial Roots of <i>Ficus bengalensis</i> L. (Thandlu)

This study reports on radial variations of anatomical parameters of aerial roots Ficus bengalensis (Thandlu) such as fibre length, fibre diameter, fibre lumen diameter, fibre wall thickness, vessel element length, vessel diameter and vessel frequency. Certain important physical and mechanical properties of Thandlu wood such as equilibrium moisture content (EMC), specific gravity, density, flexural strength (modulus of rupture-MOR), flexural stiffness (modulus of elasticity-MOE), compressive strength parallel to grain (maximum compressive stress-MCS), compressive strength perpendicular to grain and surface hardness were also investigated. Average air-dry density of Thandlu wood was found to be 537.6 ± 91.4 kg/m 3 . Moreover, specific gravity exhibited increasing trend from pith to periphery and average values were found to be correlated with anatomical properties. Radial variations of anatomical parameters were observed to be significant. Fibre lumen diameter was negatively correlated while fibre wall thickness was positively correlated with density. Similarly, vessel element length was positively correlated with fibre length and fibre lumen diameter was found to be positively correlated with the fibre diameter. The physical and mechanical properties in air-dry condition of Thandlu wood were compared with Tectona grandis (Teak) wood. Naturally having long cylindrical shape, light to moderately heavy wood and moderate to strong mechanical parameters of Thandlu in dry condition, their traditional applications in different areas are well supported by the observations made in the present study.

Color change and thermogravimetric analysis of thermally treated Eucalyptus grandis wood

Color change and thermogravimetric analysis of thermally treated Eucalyptus grandis wood

INFLUENCE OF TIME AND HEAT TREATMENT TEMPERATURE ON PERMEABILITY OF Eucalyptus grandis WOOD

ABSTRACT Due to the fact that raw timber has permeability characteristics unsuitable for some applications, several processing techniques have been developed, such as hydrothermal treatments and freezing, which aim to improve these properties. The objective of this study was to analyze the effects of treatment temperature and duration on the permeability of Eucalyptus grandis wood. Heartwood samples from three E. grandis trees were utilized, each with the dimensions 30 x 8 x 3 (length, width, thickness). The treatments were carried out at three temperatures (-20°C, 60°C, and 100°C) and three exposure durations (5, 10, and 15 hours). Treatments at -20°C were conducted inside a domestic freezer, while treatments at 60°C and 100°C took place inside a Parr Reactor, while the wood being submerged in water. Extractive removal was only observed at the surface and interior of wood treated at 60°C and 100°C; while all treatment conditions increased permeability with respect to control treatments.

Lignocellulosic Materials for Production of Cement Composites: Valorization of the Alkali Treated Soybean Pod and Eucalyptus Wood Particles to Obtain Higher Value-Added Products

Brazil, as a predominantly agricultural country is the second largest world producer of soybean. Consequently, these plantations are responsible for high production of agricultural wastes. For reusing the large volume of one type of this material generated, the soybean pods, one type of waste generated by this crop, could be applied as a raw material for production of higher value-added products. Good examples of value-added product are those applied in the field of construction. The building construction is an intensive activity and it requires a great variety of materials. A great ideal in this field would be the obtainment of a material that relates good mechanical strength and reuse of wastes. In this context, the aim of this study was to produce cement composites with soybean pods associated with eucalyptus wood, both treated with alkaline solution and evaluate their physical properties and mechanical strength. The wood and the wastes particles were submitted to alkaline treatment in NaOH solution (5%) during 48 h in order to removing chemical compounds that could harm the cement solidification. For the composites production, the soybean pods addition was performed in proportions of 0, 25, 50, 75 and 100% and mixed with the complementary percentage of Eucalyptus grandis wood particles until achieve the amount of 100% of lignocellulosic material which constitutes the composite. The lignocellulosic materials were evaluated by basic density and chemical composition. The physical properties of water absorption (WA) (2 and 24 h) and thickness swelling (TS) (2 and 24 h) and the mechanical properties modulus of elasticity (MOE), modulus of rupture (MOR), compression strength and janka hardness of the cement composites were evaluated. Scanning electron microscopy (SEM) images showed the occurrence of cavities in the composites produced with higher proportions of soybean pods. All the properties were analyzed by ANOVA and in case of significance, the regression equation was adjusted to correlate the property with the percentage of soybean waste added. It was noted an increase of WA 24 h in the samples with high insertion of soybean pods. The TS was not affected by the different compositions of the composites. The mechanical properties decreased with the increase of soybean pod in the cement composites. However, the cement composites could be produced with up to 48% of soybean pods associated to eucalyptus wood and applied, for example, as partition walls or thermal and acoustic insulation walls.

Initial study of micronized zinc borate as flame retardant in Eucalyptus grandis from Uruguay

ABSTRACTZinc borate has long been used as a protector for wood products due to its fungicide, insecticide and flame retardant properties. In this initial study, its capacity as a flame retardant when applied to Eucalyptus grandis wood is evaluated; micronized zinc borate, synthesized from zinc oxide and boric acid in our laboratory was used. The methodology used in the study is the use of the Vandersall tunnel, which allowed analyzing parameters such as the flame spread, the carbonization index, the carbonization area and the wood weight loss. The results show a remarkable improvement in these parameters after the application of micronized zinc borate. For the longest fire exposure time, the percentage decrease of each evaluated parameter is, for tangential and radial plane respectively: 31.27-43.00% for flame spread, 36.66-40.86% for carbonization area, 33.01-52.49% for carbonization index and 19.86-57.80% for mass loss.

Mechanical Properties Evaluation of Eucalyptus grandis Wood at Three Different Heights by Impulse Excitation Technique (IET)

Wood is a natural material with great variability in its mechanical properties. This study analyzed the effectiveness of the impulse excitation technique (IET) to characterize the stiffness of 10-year-old Eucalyptus grandis wood at three different heights of 3 m, 6 m, and 9 m from the bottom (height A, B, and C, respectively). A nondestructive testing method—excitation impulse, using Sonelastic® PC-based technology—and a destructive static bending test were used. The mean value for the modulus of elasticity (MOE) in bending was 16.4 GPa and in IET the value was 16.6 GPa. The average values for MOE in static bending were 14.8 GPa at height A, 17.9 GPa at height B, and 17.0 GPa at height C, demonstrating that the greater the height in the trunk of the tree the greater its modulus of elasticity. The correlation equation between static MOE and dynamic MOE was MOESTAT = 0.743.MOEDYN + 4.0983, with the coefficient of determination of R² = 0.85.

Effect of the Brazilian process of thermal modification on the physical properties of Eucalyptus grandis juvenile wood

This study is a continuation of a previous study published in this journal, with the aim of evaluating the effect of the Brazilian industrial thermal modification process on some physical properties of Eucalyptus grandis juvenile wood. Flatsawn boards of juvenile wood were tested for four treatment levels: untreated and thermally modified wood at final cycle temperatures of 140 °C, 160 °C and 180 °C. Physical properties were assessed according to a standard of the Comision Panamericana de Normas Tecnicas and a method proposed by the specialized literature encompassing equilibrium moisture content (a measure of wood’s hygroscopicity), density (oven-dried and air-dried) and radial, tangential and volumetric swelling (from oven-dried to green moisture content). Thermally modified Eucalyptus grandis wood became less hygroscopic, more dimensionally stable (tangential and volumetric swelling) and less dense, even at the lowest temperature tested (140 °C), except for radial swelling, which did not differ from untreated wood.

Colour responses of Eucalyptus grandis wood to the Brazilian process of thermal modification

A study of colour assessment, using the CIEL*a*b* system, was conducted with samples of Eucalyptus grandis wood thermally treated by the Brazilian industrial process of thermal modification, VAP HolzSysteme®, at three different temperatures, i.e. 140, 160 and 180 °C. Previous to the treatment, the samples were classified in three groups according to their distance to the wood pith, on the radial direction. All thermally modified samples presented a noticeable colour change, confirmed by high values of ΔE*. As the intensity of the treatment increased, the eucalypt samples presented an increase of red colour tone (a*) (up to 160 oC) and a decrease of colour lightness (L*). Significant colour differences were found among the classified groups, for both untreated and thermally modified samples. The eucalypt samples groups showed different colour responses when thermally treated at 140 and 160 oC. At 180 oC the groups didn’t show a significant colour response variation.

Wood Permeability in Eucalyptus grandis and Eucalyptus dunnii

ABSTRACT The objective of this study was to evaluate the flow of air and water in Eucalyptus grandis and Eucalyptus dunnii wood. Wood was collected from four trees aged 37 years in an experimental plantation of the Federal University of Lavras, Brazil. Planks were cut off the basal logs to produce specimens for air and water permeability testing. Results indicated that the longitudinal permeability to air and water of E. grandis wood were, on average, 5% and 10% higher, respectively, than that of E. dunnii wood. E. grandis and E. dunnii wood showed neither air nor water flow in the test for permeability transversal to the fibers, and longitudinal permeability to air exceeded that to water by approximately 50 fold in both species.

The Effects of Wood Storage on the Chemical Composition and Indigenous Microflora of Eucalyptus species Used in the Pulping Industry

Lipophilic extractives naturally occurring in wood tend to coalesce during pulping to form pitch deposits, which have particularly undesirable effects on the pulping process and quality of pulp produced. A chemical characterization of different eucalypt species [Eucalyptus nitens, E. grandis, and E. dunnii (of different site qualities)] wood and generated pulp was performed. This study aimed at determining the effects of wood storage at -20 °C (for 6 months), by examining their chemical composition and indigenous microflora. Fatty acids were the main lipophilic compounds among E. dunnii (SQ3 and SQ4) and E. grandis wood extractives. The wood of E. nitens posed the least risk for pitch deposit formation, making it the most suitable Eucalyptus species for pulping. Storage of wood chips at -20 °C had a similar effect as the traditional method of seasoning (storage of wood outdoors prior to pulping) used for the reduction of lipophilic extractives. A 25 to 44% reduction of total extractives was observed in the raw material after storage. Variations in bacterial and fungal communities were observed after storage, and should be taken into consideration when conducting lab scale trials. If storage of wood chips is necessary for lab testing, it should be retained for a maximum of 3 months at -20 °C.

Wood-bamboo particleboard: Mechanical properties

Mechanical characteristics were evaluated of wood-bamboo-based particleboard having the proportions of 100% wood and 0% bamboo, 75% wood and 25% bamboo, and 50% wood and 50% bamboo. This particleboard used Eucalyptus urophylla × grandis wood, Dendrocalamus asper bamboo, and castor oil-based polyurethane resin. Through destructive testing, the values of perpendicular tensile, static bending, modulus of elasticity, and screw pullout strength in the top and face surfaces were analyzed. For 0%, 25%, and 50% bamboo the values were 1.68 MPa, 1.37 MPa, and 1.4 MPa, respectively, for perpendicular tensile; 15.2 MPa, 17.6 MPa, and 18.5 MPa, respectively, for static bending; 2466 MPa, 2694 MPa, and 2922 MPa, respectively, for modulus of elasticity; 1256 MPa, 1922 MPa, and 1362 MPa, respectively, for screw pullout strength in top; and 1392 MPa, 1342 MPa, and 1414 MPa, respectively, for screw pullout strength in face. These results were superior to those presented by ABNT NBR 14810 (2013) and ANSI 208.1 (1999). After performing a Tukey test at 5%, the values for each treatment did not show a significant difference among them.

Integrated forest biorefineries: Recovery of acetic acid as a by-product from eucalyptus wood hemicellulosic hydrolysates by solvent extraction

The biorefinery concept associated with pulp mills appears to be one of the best options for the valorisation of lignocellulosic biomass. Hemicelluloses can easily be pre-extracted from lignocellulosic biomass under mild operational conditions in order to obtain a hydrolysate that is rich in hemicelluloses, which can be used to produce bioethanol, as well as pretreated chips for further pulp production. However, the release of fermentable monosaccharides (mainly xylose) from the pre-extracted hemicellulose fraction is accompanied by the formation of decomposition products such as acetic acid, which inhibits fermentation by reducing conversion rates and yields. Due to the high level of acetyl groups in eucalyptus woods, acetic acid should be separated before the fermentation process in order to limit its inhibitory effect. Consequently, several studies have been conducted regarding the removal and recovery of acetic acid not only because of its inhibitory nature but also because it is a value-added compound in the chemical industry.In this work, acetic acid recovery via liquid-liquid extraction from hemicellulosic hydrolysates of Eucalyptus grandis wood chips was evaluated. This study was carried out mainly because there are few reported data on the experimental recovery of acetic acid from pre-extracted hemicelluloses of eucalyptus wood, considering that the use of eucalyptus chips in a biorefinery platform is important due to the high commercial relevance of eucalyptus pulp over the last decades. Hemicellulose pre-extractions were carried out using green liquor with varying alkali charges (1–6% w/w), temperatures (100–160▪) and reaction times (30–150min). The acetic acid extraction was performed using ethyl acetate at different pH values (2.0–4.0) for 36min, in order to study the effects of the main experimental variables affecting the extraction process (hydrolysate-to-solvent volume ratio, pH and the coupling of the extraction stages). Under the best pH conditions, a single-stage extraction at an H/S of 1:4 achieved 82.0% removal of acetic acid, whereas by a three-stage extraction at an H/S of 1:2, up to 88.0% of the initial acetic acid was recovered. After a fractional distillation, an acetic acid yield of almost 30L/t of dry eucalyptus wood chips was achieved, given the pre-extraction of hemicelluloses from E. grandis wood prior to the Kraft pulping process.

Combined autohydrolysis and alkali pretreatments for cellulose enzymatic hydrolysis of Eucalyptus grandis wood

Lignocellulosic materials represent a promising low-cost and abundant raw material which does not compete with foodstuffs, but an appropriate pretreatment is required to make sugars easily available. In this work, Eucalyptus grandis wood was subjected to autohydrolysis pretreatment under mild operational conditions (6–10 g/g liquid to solid ratio, 140–160 °C, reaction times up to 150 min) in order to recover and preserve hemicelluloses, while enhancing enzyme accessibility to cellulose. The severity of the pretreatment should be chosen depending on the subsequent use of the separated products. Pretreatment at 160 °C for 150 min using a liquid to solid ratio of 6 g/g was the best condition for hemicellulose recovery (mostly as xylose) in the liquid fraction. Under these autohydrolysis pretreatment conditions, an additional alkaline pretreatment applied to the autohydrolyzed solids was evaluated in order to improve the enzymatic hydrolysis of pretreated wood. Also, the addition of surfactant was assessed in order to enhance the enzymatic hydrolysis. The highest cellulose hydrolysis was obtained in the presence of PEG 6000. For the autohydrolysis-pretreated solids, a cellulose conversion of 39% was obtained, corresponding to an overall glucose yield of 18.7 kg per 100 kg of dry raw material. Additionally, for the autohydrolysis-alkaline-pretreated solids, a cellulose conversion of 43% was achieved, which corresponds to an overall glucose yield of 15.4 kg per 100 kg of dry raw material.

Secondary metabolites from Eucalyptus grandis wood cultivated in Portugal, Brazil and South Africa

The composition of the lipophilic and phenolic fractions of the wood of Eucalyptus grandis cultivated in Portugal, Brazil and South Africa, was studied. The lipophilic fraction of the studied E. grandis wood is mainly composed of sterols, fatty acids and phenolic compounds. Three triterpenic acids were detected for the first time in the wood extracts from Brazil. E. grandis wood from Portugal presents the largest lipophilic content (1.67gkg−1 of dry wood), followed by South Africa (1.56gkg−1 of dry wood) and Brazil (1.05gkg−1 of dry wood). 51 Phenolic compounds were identified in E. grandis wood MeOH:H2O extracts, from which 11 are reported for the first time as E. grandis constituents and 4 phenolic compounds are firstly reported as Eucalyptus genus components. E. grandis wood from Brazil shows the highest phenolic content (∼2.36gkg−1 of dry wood), followed by South Africa (∼1.90gkg−1 of dry wood) and Portugal (∼1.30gkg−1 of dry wood), demonstrating the influence of the geographic origin over E. grandis wood extractives composition and abundance, as well as on the antioxidant activities of the phenolic fractions. The detailed knowledge of these E. grandis extracts can contribute on the one hand to prevent their impact in the bleaching process, and, on the other demonstrates the potential of this species as a source of bioactive phytochemicals for nutraceutical applications.

Upscaled Production of Sugarcane Vinegar by Adsorbed Cells of Acetobacter aceti Under Semi-Continuous Fermentation Conditions

Natural vinegar is a food supplement, tonic and nutraceutical produced by twin fermentation of sugar to acetic acid via ethanol. The fermentation of sugarcane juice carried out with Saccharomyces cerevisiae MTCC 11815 produced 9.11 % (v/v) of ethanol with a fermentation efficiency of 89.8 % in 72 h. Statistical optimization of acetic acid fermentation revealed that immobilized cells of Acetobacter aceti (grown in 2 g/L DAHP supplemented jaggery solution) adsorbed on 15-mm-sized Melona grandis wood shavings for 15 h had the highest adsorption rate (66.6 %) followed by Tectona grandis (44.4 %) and Castania sativa (21.4 %) with maximum viable count of 12.76 × 107 and 6.0 × 107 cfu/g in absence or presence of substrate, respectively. A 1L plastic fermenter packed up to half of its length produced sugarcane vinegar with 5.0 % (w/v) volatile acidity in 6 days. These optimized conditions scaled to 5 L in PVC column reactors and 50 L plastic fermenter produced 7.0 % (w/v) and 4.0 % (w/v) volatile acidity in 6–7 days and 7–10 days, respectively. The sugarcane vinegar had a mean sensory score of 8.61 ± 0.52 in comparison to commercial brands with sensory scores of 7.22 ± 0.76 and 7.47 ± 1.02.

Phenylethanoid Glycosides from Teak Wood Knots and Their Antioxidant Activity

Two phenylethanoid glycosides previously not observed in Tectona grandis (teak) wood knots were isolated from 30% aqueous isopropanol extract, purified by HPLC and identified as forsytoside B and isoacteoside by methods of NMR spectroscopy and mass-spectrometry. These compounds displayed notable antioxidant capacity determined using amperometric method.

RESISTÊNCIA DA MADEIRA MODIFICADA TERMICAMENTE DE <i>Eucalyptus grandis</i> W. Hill ex Maiden AO TÉRMITA DE MADEIRA SECA <i>Cryptotermes </i>sp.

Existem atualmente cinco principais processos de modificação térmica em operação na Europa, que aumentam a estabilidade dimensional e a resistência da madeira à biodeterioração, porém, não são eficientes contra o ataque de térmitas. Na verdade, existe pouca pesquisa a respeito do efeito da modificação térmica da madeira na resistência à biodeterioração por térmitas, sejam subterrâneos ou de madeira seca. O objetivo desta pesquisa foi avaliar o efeito do processo brasileiro de modificação térmica VAP HolzSysteme® na resistência da madeira de Eucalyptus grandis ao ataque de térmitas de madeira seca Cryptotermes sp. Para tanto, foram testados cinco tratamentos: madeira não tratada de eucalipto, madeira de eucalipto modificada termicamente a três temperaturas finais (140, 160 e 180°C) e madeira de pinus (controle). O ataque foi avaliado em termos de perda de massa, escore médio das notas do desgaste, número de orifícios e mortalidade dos térmitas, de acordo com o método proposto pelo Instituto de Pesquisas Tecnológicas de São Paulo. Semelhante aos processos europeus de modificação térmica, o processo brasileiro VAP HolzSysteme® também não foi eficaz para melhorar a resistência da madeira de eucalipto ao ataque dos térmitas de madeira seca, pelo menos nas condições avaliadas.

Supercritical water gasification of Eucalyptus grandis and related pyrolysis char: Effect of feedstock composition

Eucalyptus grandis (E. grandis) wood and char products derived from pyrolysis of E. grandis wood, were gasified in supercritical water at 450°C – with and without the use of a homogeneous (K2CO3) and heterogeneous (Ni/Al2O3-SiO2) catalyst. Gas yields and gasification efficiencies were measured experimentally and compared to calculated thermodynamic equilibrium values, specifically considering the effects of the O/C ratio and volatile matter content of the feed material. Thermodynamically, feed material with lower O/C ratios (0.22) typically resulted in higher CH4 yields (30mol/kgfeed,dry) and gasification efficiencies (188%). However, experimentally, feed material with lower O/C ratios and lower volatile matter resulted in the lowest CH4 yields and gasification efficiencies. Furthermore, a linear relationship between the carbon efficiency (CE) and both the volatile matter content and O/C ratio of the feed material was found to hold true in both catalytic and non-catalytic experiments.

Nitric acid functionalization of carbon monoliths for supercapacitors: Effect on the electrochemical properties

Activated carbon monoliths and oxidized carbon monoliths are prepared from Eucalyptus grandis wood by pyrolysis and subsequent activation under CO2 (aCMs) and further functionalization using nitric acid (ox-aCMs). Their textural and chemical properties are compared and the electrochemical characteristics as supercapacitor electrodes are tested. The nitric acid treatment does not produce substantial changes in the textural properties of the monolith obtained. Elemental analysis and X-ray photoelectron spectroscopy (XPS) reveal that the oxidized monolith presents a high content of oxygenated functional groups that can participate in pseudocapacitive reactions. This determines that the oxidized monoliths have higher electrical capacitance (80 F cm−3) at low current densities and higher energy density (up to Wv = 2.7 W h L−1) than the non-oxidized ones. The supercapacitor cell containing the oxidized monoliths presents higher total resistance values and response time compared to the non-oxidized monolith. The non-oxidized monolith showed the highest power density (up to PV = 94.5 W L−1).