Amélia Guimarães Carvalho

IMPORTANCE OF WOOD DRYING TO THE FOREST TRANSPORT AND PULP MILL SUPPLY

The forest transportation represents a great proportion of raw material cost for pulp and paper production and, for this reason, the wood moisture content should be low to reduce these cost. The objective was to relate the wood moisture with fuel consumption per kilometer in each vehicle and the number of trips to supply a pulp mill. Three trees of

Effect of Post-production Heat Treatment on Particleboard from Sugarcane Bagasse

This study aimed to evaluate the effect of heat treatment on the physical and mechanical properties of particleboard from sugarcane bagasse. The experiment consisted of seven treatments arranged in a 2 × 3 factorial arrangement (two heat treatment times – 8 and 12 min, and three heat treatment temperatures – 200 °C, 230 °C, and 260 °C) and treatment control (without heat treatment). We evaluated the properties such as apparent density, water absorption after 2 and 24 h (WA2h andWA24h), thickness swell after 2 and 24 h (TS2h and TS24h), irreversible thickness swelling rate (ITS), internal bond, Modulus of Elasticity (MOE), and Modulus of Rupture (MOR) in static bending. In general, the use of heat treatment appeared very promising for improving the dimensional stability of sugarcane bagasse particleboard, without being made unviable by the mechanical properties reduction.

Properties of osb panels with veneer inclusion

This work aimed to evaluate the effect of veneer inclusion with different wood species, and also different levels of pressing pressure applied in the moment of the veneer inclusion over physicalmechanical properties of already consolidated OSB (Oriented Strand Board) panels. Treatments were arranged in factorial scheme 4 x 2 (four wood types for veneer inclusion – Pinus oocarpa, Eucalyptus urophylla, Parkia gigantocarpa and Brosimum parinariodes; and two pressing pressures – 1 and 2 MPa) and also a control (without veneer inclusion). Veneer inclusion was made with 180 g.cm-2 phenol formaldehyde adhesive, in a simple glue line, perpendicular to the external layer of panels. The pressing cycle used was 150oC for 4 minutes under pressure 1 or 2 MPa pressure depending on the pre-established treatment. It was possible to conclude that: 1) Veneer inclusion with pines, eucalypt and amapa promoted significant improvements for physical-mechanical properties of OSB panels, highlighting eucalypt and amapa; 2) There was not a significant effect of the level of pressing pressure over mechanical properties of OSB with veneer inclusion; and 3) Regarding physical properties, the highest pressure level (2 MPa) promoted a negative effect in some properties, while veneer inclusion the pressure of 1 MPa generally promoted significant improvement of all physical properties.

Prediction of the physical, mechanical and colorimetric properties of Eucalyptus grandis heat-treated wood using artificial neural networks

Heat treatment is important to change wood color and increase its dimensional stability, though the quality control and modeling during this process need to be further studied. The aim of this study was to evaluate the efficiency of artificial neural network based in temperature to predict the Eucalyptus grandis wood properties after heat treatment. The physical, mechanical and colorimetric properties of the wood samples after heat treatment at 140, 170, 200 and 230°C for three hours under atmospheric pressure and the presence of air were evaluated. An artificial neural network based on the heat treatment temperature was established to predict the equilibrium moisture content, total volumetric swelling, modulus of rupture, modulus of elasticity, lightness (L*), green-red coordinate (a*) and blue-yellow coordinate (b*) of the wood. The equilibrium moisture content, total volumetric swelling and modulus of rupture (MOR) were affected from 170°C, the modulus of elasticity from 200°C, the oven-dry density from 230°C and colorimetric parameters from 140°C onward. The artificial neural network estimated results with precision, showing its potential for quality control in the wood heat treatment process.

UMIDADE DE EQUILÍBRIO DE PAINÉIS OSB EM FUNÇÃO DA UMIDADE RELATIVA E DA TEMPERATURA AMBIENTE

The study aimed to obtain statistical models to estimate the equilibrium moisture content of OSB panels as a function of temperature and relative humidity of air, as well as evaluate the effect of some production variables on the equilibrium moisture content of the panels. The experimental design consisted of six processing conditions, three air temperature and six relative humidity of air. In the processing conditions, were evaluated three different thicknesses of the strand particles (0.4, 0.7 and 1.0 mm), two apparent densities of panels (0.65 and 0.90 g/cm³) and three levels of pressure in the pressing of the panels (40, 60 and 80 kgf/cm²). For each treatment four panels were produced with the wood of Pinus taeda and 6% of phenol formaldehyde adhesive. In the evaluation of the experiment was considered a completely randomized design arranged in a factorial triple 6 x 6 x 3, in order words, six production variables (processing conditions), three air temperatures (30, 40 and 50°C) and 6 relative humidity (40, 50, 60, 70, 80, 90%). The means were compared statistically by Scott-Knott test at the 5% level of significance. The modeling the equilibrium moisture content of OSB panels was performed with fit the multiple polynomial models for each treatment. Based on measurements of accuracy and the results can be concluded that: 1) it is recommended to use the model UEQ = β0 + β1UR + β2UR² + β3UR³ + β4Temp + e for indirect estimation of equilibrium moisture content of OSB panels 2) The temperature shows linear influence on the equilibrium moisture content of the panels, while the relative humidity of air shows behaving of third order polynomial, and the relative humidity of air affects more pronouncedly the equilibrium moisture content of OSB panels than the ambient temperature; 3) In respect of the effect of production variables, the pressing of pressure of 80 kgf/cm² and the increased the thickness of the strand particles to 1.0mm thick promoted trend of reductions in average of the equilibrium moisture content of OSB panels. But the increased density of the panel promoted the trend of increasing of equilibrium moisture content of OSB panels; and 4) The use of multiple polynomial models allows that are produced contours to obtain the values of equilibrium moisture content of OSB as a function of relative humidity and temperature of the place where the panel is exposed, standing out for its convenience of use.

AVALIAÇÃO DE ADESIVOS À BASE DE TANINOS DE Pinus caribaea var. bahamensis E DE Acacia mearnsii NA FABRICAÇÃO DE PAINÉIS AGLOMERADOS

This work aimed to evaluate the methods for extraction of tannin from the bark of Pinus caribaea var. bahamensis, as well as to evaluate the technical feasibility of using tannins from the barks of Pinus caribaea var. bahamensis, of Acacia mearnsii, the mixtures of black wattle and pine tannins and the mixture of adhesive urea formaldehyde (UF) with black wattle and pine tannins in the production of adhesives for particleboard. The barks of Pinus caribaea var. bahamensis were fragmented in hammer mill, sieved and extracted under reflux for 2 hours, using a bark: liquor relation of 1:15, in nine treatments. The best extraction was used to obtain large quantities of extracts, which were used in the manufacture of adhesives and mixtures with UF adhesive and tannins of black wattle and the manufacture of particleboard. The addition of sodium sulfite gave higher extraction of tannin, which was extracted with the addition of 5% sodium sulfite. The results showed that both the black wattle tannin, as the bark of Pinus caribaea var. bahamensis have good bonding properties. It is possible to add pine tannin solution to the solution of black wattle and to replace part of the UF adhesive for the wattle tannins up to 25%, without compromising the glue quality. Replacing 10% of UF for tannic extract, both pine and black wattle, did not alter the values of thickness swelling (TS) of the panels. It is possible to obtain good mechanical properties with UF adhesives modified with tannic extracts at a ratio of 10%. The high values found for the internal bond (IB) panels containing tannin extracts showed the potential of these tannic extracts for bonding wood materials.