Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The objective of this study was to evaluate the surface coating performance using water base, solvent base and powder coating on medium density fiberboard. Samples were coated using water-base, solvent-base and powder coating. Coating performance was performed by using adhesion strength, surface coating hardness, layer thickness and rapid deformation test. The results were analyzed with two different statistical methods. Adhesion strength, layer thickness and surface hardness were determined by using ANOVA analysis, while results of rapid deformation test were analyzed by using Kruskal-Wallis method. According to these results, coating type was effective factor on the adhesion strength, surface coating hardness, layer thickness and rapid deformation test. Water-based painting application for adhesion strength and impact deformation resistance was higher than solvent-based coating. In the powder coating application, although surface coating hardness was higher than solvent and water base coating application, rapid deformation results were lower than solvent and water base coating applications. Adequacy of models was performed R-square (R²) and Adjusted R-square (Adj-R2) values. R2 values of adhesion strength, layer hardness and film layer thickness were 93.60 %, 95.33 % and 73.90 %, respectively. Adj-R2 values of adhesion strength, layer hardness and film layer thickness were 93.45 %, 95.23 % and 73.30 %, respectively.

In this study, influence of combined heat treatment and densification on mechanical properties of poplar wood (Populus usbekistanica) such as density, EMC, compression strength, modulus of elasticy, modulus of rupture and static bending strength were investigated. Poplar samples were subjected to a temperature of 120oC, 160oC and 200oC for 1 and 3h. After the heat treatment, the heat treated samples were compressed in a hot press at a temperature of 120oC, press pressure of 50 bar and press time of 30 minutes for densification. The results showed that the heat treatment affected the densification with increasing density. Additionally, the heat treatment decreased modulus of rupture (MOR), modulus of elasticity (MOE) and impact bending strength (IBS) with increasing temperature for undensified poplar wood. In conclusion, densification process has improved all the mechanical tested properties.

Nanoparticles have addressed many challenges in science and technology and wood science research is one such field that has benefitted from application of metal nanoparticles. The metal nanoparticles that are commercially available for wood protection are synthesised by physical and chemical methods which produces toxic by-products and are expensive. The current study deals with a new approach for utilization of metal nanoparticle for wood protection in an ecofriendly and cost effective way. Metal nanoparticles were synthesised using plant extracts that are known to have wood preservative properties. The synergistic effects of the intrinsic property of plant extracts along with the biocidal property of metal nanoparticles were utilized. Copper oxide nanoparticles were synthesised using leaf extracts of Neem (Azadirachta indica), Pongamia (Pongamia pinnata), Lantana (Lantana camara) and extract of orange peel (Citrus reticulata). The effectiveness of the synthesised plant extract and copper oxide nanoparticle formulation is tested against wood decay fungi using agar mixed with the test substance.  Graveyard test is employed to assess the effect of the copper oxide nanoparticle formulation against termites. Preliminary results are promising and studies are progressing to develop a stable and environmentally benign wood preservative formulation of metal nanoparticles and plant extracts.

La oferta actual de maderas uruguayas ha incentivado la producción de vigas de madera laminada encolada sin adaptar la tecnología original destinada a elementos de carpintería. La inexistencia de normativa sobre requisitos de fabricación permite producir y comercializar componentes que siendo no estructurales, son consumidos como tales por usuarios desconocedores de las características del producto. El objetivo del trabajo fue establecer la relación entre los parámetros de fabricación de madera laminada encolada de Eucalyptus grandis y sus propiedades estructurales, adaptando la tecnología en Uruguay. La metodología involucró modificar los parámetros de producción de una empresa y ejecutar ensayos de caracterización. Los parámetros adoptados incluyeron: adhesivo poliuretánico; diente estructural de longitud 15 mm; presión de ensamble de 10 MPa y de 1,2 MPa en uniones dentadas y vigas respectivamente; y control de tiempos de prensado en láminas y vigas. Los resultados de los ensayos mecánicos y de integridad de encolado indicaron que fue posible fabricar madera laminada estructural. Las propiedades de flexión y densidad de las vigas se correspondieron con las respectivas de la clase resistente GL24h de la norma europea EN 14080. Estos resultados contribuyen a la redacción de una norma uruguaya de madera laminada encolada estructural de Eucalyptus grandis. 

Uruguay has a forest resource of 1 million ha plantation of fast-growing eucalyptus and pine. Short-fiber pulp is the country second export product in value, but there is also a significant production of plywood and graded kiln-dried timber from both species, used mainly for appearance applications. However, the value chain of the wood industry is not yet fully developed, particularly for pine. This study classified different existing and potential wood products using added value as criteria, calculated at the industry level by adopting a system of inputs and outputs. Hypothetical plants to manufacture these products were technical and economically analyzed: thermally modified timber, cross laminated timber, laminated veneer lumber, pine timber, bleached Eucalyptus kraft pulp, pine bleached chemical thermo-mechanical, medium density fiberboards, oriented strand board and a power plant fueled with forest biomass. The data used for this study was obtained from the final project of undergraduate engineer students of the Faculty of Engineering, Universidad de la República, Uruguay, except for the eucalyptus pulp mill, which was proposed by the authors. The results showed that wood products obtained from logs that are the main objective of the plantation presented a higher added value than those manufactured from forest residues, thinnings or chips from the sawmilling industry. Solid wood products for appearance or structural applications are at the top of added value list, considering value added per product, unit of biomass or unit of forest land per year. The integration of the value chain of the products analyzed, linking solid wood products with panels or pulp, has the potential to boost the addition of value of the forest biomass in Uruguay.

Brazilian productivity of eucalyptus trees is one of the highest in the world, and it has sustainable and viable conditions to supply the demand for woody biomass in a large quantity and diversity. This favorable situation makes Brazil one of the countries with the greatest potential for the production development of torrefied woody biomass on a commercial scale. Torrefaction is a mild pyrolysis applied to increase the energy quality of the feedstock. The aim of this study was to evaluate the Brazilian potential of woody biomass torrefaction for energy purposes. An experimental study was performed evaluating this thermal treatment of eucalyptus wood chips on a semi-continuous screw reactor developed by a Brazilian university. The results showed the increases in the energy quality of eucalyptus wood chips as a function of torrefaction temperature and time. This thermal treatment was technically feasible for the hygroscopicity reduction and the increases of fixed carbon and calorific values of the woody biomass.

The concentration of atmospheric carbon dioxide is constantly rising, with severe effects on global climate change. To mitigate impacts of climate change, the role of forest in terms of carbon sequestration are well-known as trees naturally pull CO2 from the atmosphere as they grow. Contrarily, only recently the carbon mitigation value of wood-based products in buildings has been recognized. Buildings are a fundamental sector for wood-based products, both in terms of volume and service life length. In particular, furnishings in housing include high quantities of wood-based products; they are usually made, partly or entirely, by solid wood or by wood-based panels such as plywood, particleboard and medium density fiberboard. These wood furnishings store biogenic carbon during their service life. In this context, the present study investigated the amount of carbon stored by furnishing wood-based products for an apartment in Torino, Italy. The overall amount, determined according to European Standard, resulted in 3531 kg of CO2-equivalents stored. This corresponds to 45,8 kg/m2 of indoor walkable area; simulating lower and higher intensity usages of wood-based products provided carbon storage values of 35,1 and 55,3 kg/m2, respectively. On the whole, the present study gave an order of magnitude of the role played in carbon storage by furnishing wood-based products in building and illustrates their relevance in mitigating climate change.

Furniture from wood material is exposed to various external effects. Impact has negative influence on these materials. Surface treatment is effective on wood material’s durability. This may change due to layers of paint and the property of the paint used on the material. The aim of this study is to determine the differences by investigating the deformations occurring on Medium Density Fiberboard (MDF) with various surface treatments due to impact. Determination of the deformation values were performed by pendulum hardness test and rapid deformation test on MDF using polyurethane and cellulosic paints with different number of application layers. Impact tester was used for determining the effect of rapidly deforming sudden impacts. Pendulum hardness tester was used to determine the layer hardness of the surfaces. Statistical assessment was performed for determining and revealing the impacts. As result of the study, paint type, layer thickness and the interaction between them were significant. Highest layer hardness values for cellulosic paint application type 1 and polyurethane paint type 2 were 241.667 sec. and 222.133 sec. respectively. According to rapid deformation test it was determined that polyurethane paint application had better results than cellulosic paint application.

The wood of poplar species are generally perceived as susceptible to decay, however, poplar is still widely used as columns in traditional Chinese buildings. Understanding how decay affects the compressive properties of this material will help engineers better assess wood condition during routine inspection and maintenance. The effects of decay on compressive properties of Chinese poplar were explored using a brown rot decay fungus (Gloeophyllum trabeum). Changes in compression strength were fairly linear and more closely correlated with mass loss (R2= 0.75). The results suggest that residual compressive strength could be roughly predicted using wood density as a surrogate measure.

This work proposes a sequential combination of steam explosion and organosolv delignification for Pinus radiata fractionation. An efficient pretreatment to fully optimize the use of lignocellulosic materials is the key to make a biorefinery profitable, especially for softwoods, known to be more recalcitrant than other lignocellulosic raw materials. Steam explosion has a dual effect on biomass as morphological and chemicalchanges are introduced. A delignifying stage has been stated to be necessary in order to ease hydrolytic enzymes accessibility to cellulose while avoiding non-productive bonds with the lignin present. Three steam explosion conditions were tested (170°C, 5 min; 180°C, 10 min; 170°C, 5+5 min) followed by an organosolv delignification stage, carried out at two different conditions (170°C, 60 min; 170°C, 90 min). All treatmentyields, delignification extent, and hydrolysis yields were determined to evaluate each stage. The steam explosion treatment did not produce high delignification extent. Maximum global delignification (50,4%) was achieved when combining the two-cycle steam explosion with the most severe post-treatment condition tested. Enzymatic hydrolysis of the cellulosic residue improved after organosolv delignification; however, hydrolysisyields did not exceed 35%. The chemical changes undergone by softwood lignins are presumably responsible for the low digestibility.