Stefânia Lima Oliveira

Particleboard Panels Made from Sugarcane Bagasse: Characterization for Use in the Furniture Industry

The objective of this study was to evaluate the physical and mechanical properties of commercial panels produced with sugarcane bagasse to investigate the possibility of us for the production of furniture. We evaluated industrial MDP (Medium density particleboard) panels made of Eucalyptus and Pinus by two Brazilian companies and an industrial MDP panel made from sugarcane bagasse, produced in China. We tested the physical characteristics of water absorption and thickness swelling of the panels after 2 and 24 h of immersion in water. To estimate the moisture content and density, we followed the procedure detailed in NBR 14810-3¹. The mechanical properties were characterized by performing bending (moduli of elasticity and rupture), compression (moduli of elasticity rupture), internal bonding, screw pullout and Janka hardness tests. We found that panels made from sugarcane bagasse showed comparable with or superior physical and mechanical properties to those made from Eucalyptus and Pinus.

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.

Use of Sugarcane Bagasse for Particleboard Production

The use of agricultural residues for particleboard manufacturing increases their value-add and help meet the growing demand of raw materials for the panel industry. Accordingly, the aim of this study was to assess the quality of particleboards produced only with sugarcane bagasse or along with Pinus and Eucalyptus wood. The experimental design consisted of 5 treatments: T1) Eucalyptus panels, T2) Pinus panels, T3) sugarcane bagasse panels, T4) 50% Eucalyptus and 50% sugarcane bagasse panels, and T5) 50% Pinus and 50% of sugarcane bagasse panels. For each treatment, three panels were produced using 8% urea-formaldehyde adhesive, with 0.65 g/cm3 apparent density, 160°C pressing temperature, 4 MPa pressure, and 8 min of pressing time. The analyses revealed that use of sugarcane bagasse for particleboard manufacturing resulted in improved water absorption and thickness swelling properties after 2 h of immersion in water. In addition, the panels produced with bagasse only showed significant reductions in the mechanical properties. However, the use of sugarcane bagasse along with Pinus or Eucalyptus wood allowed the manufactured panels to meet all the conditions required by the CS 236-66 [1], ANSI A208.1 [2], and EN 312 [3] standards.

Umidade de equilíbrio de painéis OSB produzidos com inclusão laminar e com diferentes tipos de adesivos

Neste trabalho, objetivou-se avaliar diferentes modelos estatisticos para a estimativa da umidade de equilibrio de paineis OSB expostos a diferentes condicoes de temperatura e umidade relativa do ar, bem como avaliar a influencia do adesivo e do reforco laminar na umidade de equilibrio. Os paineis foram produzidos com tres diferentes tipos de adesivos (fenol-formaldeido - FF, melamina-ureia-formaldeido - MUF, e fenol-melamina-ureia-formaldeido - PMUF) e, ainda, com e sem a inclusao laminar. A avaliacao da umidade de equilibrio dos paineis foi efetuada nas temperaturas de 30, 40 e 50°C e nas umidades relativas de 40, 50, 60, 70, 80 e 90%. A modelagem da umidade de equilibrio foi realizada por meio do ajuste de modelos estatisticos nao lineares e polinomiais. De forma geral, os modelos polinomiais sao os mais indicados para a estimativa da umidade de equilibrio dos paineis OSB. Os modelos ajustados apenas com a umidade relativa do ar foram os que obtiveram as melhores medidas de precisao. O tipo de adesivo afetou a umidade de equilibrio dos paineis, sendo observada para os adesivos PMUF e FF a mesma tendencia de variacao, e os maiores valores medios obtidos para os paineis produzidos com adesivo MUF. A inclusao laminar promoveu a diminuicao da umidade de equilibrio apenas para os paineis produzidos com o adesivo MUF.

SELECTION OF CLONES OF Eucalyptus urophylla FOR PLYWOOD PRODUCTION

This work aimed at the evaluation of six (6) Eucalyptus urophylla clones of Companhia Mineira Metais - Unidade Agroflorestal (VM-AGRO) for making particleboard panels. Six (6) panels to each clone studies were produced. About 320g/m² of Phenol phormol aldehyde adhesives Were utilized. The pressing cycle parameters were: pressure of 1.47MPa, temperature of 150oC and 10 minutes of pressing time. It was concluded that clones of Eucalyptus urophylla show a great potential for production of particleboard panels, since they presented values of physical and mechanical properties above the ones referenced in literature and highly superior to those required by the ABNT Standards 31:000.05-00/2 (static bending) and EN 314-2 (shearing resistance), the tested clones can be used for producing concrete mold (FOR). The clone which stood out the most in all the properties tested was the clone 36.This work aimed at the evaluation of six (6) Eucalyptus urophylla clones of Companhia Mineira Metais - Unidade Agroflorestal (VM-AGRO) for making particleboard panels. Six (6) panels to each clone studies were produced. About 320g/m² of Phenol phormol aldehyde adhesives Were utilized. The pressing cycle parameters were: pressure of 1.47MPa, temperature of 150oC and 10 minutes of pressing time. It was concluded that clones of Eucalyptus urophylla show a great potential for production of particleboard panels, since they presented values of physical and mechanical properties above the ones referenced in literature and highly superior to those required by the ABNT Standards 31:000.05-00/2 (static bending) and EN 314-2 (shearing resistance), the tested clones can be used for producing concrete mold (FOR). The clone which stood out the most in all the properties tested was the clone 36.

Particleboard Panels Produced with Different Radial Positions of Pinus oocarpa Wood

The aim of this study was to evaluate the effect of different radial regions of Pinus oocarpa wood on the physical and mechanical properties of particleboard panels. Three different radial regions (internal, intermediate and external) and the mixture (integral log) were assessed. Experimental panels were produced with a nominal density of 0.70 g/cm3 using 8% urea-formaldehyde adhesive; they were compressed at a specific pressure of 40 kgf/cm2 and temperature of 160 °C, for 8 minutes. Wood radial position affected particleboard quality and a direct influence of the chemical composition and density of the material used was observed. Only the panels produced the mixture (integral log) and with the internal region met all the requirements stipulated by the marketing standard.

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.

Natural Aging in Heat-Treated Medium-Density Fiberboard Panels

Heat treatment of wood is a promising alternative in improving its dimensional stability. The action of heat ensures the good quality of the treated wood product, with better performance in environments with high humidity. To prove the positive effect of this treatment, a test in which the specimens are weathered for a certain period of time termed as natural aging was performed. The aim of this study was to evaluate the effect of aging on heat-treated medium-density fiberboard (MDF) panels. Commercial MDF panels produced with pinewood adhesive and urea-formaldehyde were used. The experiment included seven test treatments [at 200, 225, and 250°C heat temperatures for 5 and 10 min] and a control treatment (without heat treatment). The products subjected to these treatments were weathered for 40 days, and climatological data were monitored daily. The results suggested that: 1) There is a decreasing trend in density with increasing time and temperature; 2) the treatment time and temperature had no effect on the ownership of the static bending for modulus of elasticity (MOE); 3) the time period is correlated with the treatment temperature for modulus of rupture (MOR) property; and 4) the thermal treatment of MDF panels did not allow the maintenance of the properties of MOR and MOE static bending strength after natural aging.