Abstract Heat treatment aims to reduce the compression stresses generated during the panel production, improving its dimensional stability and providing greater resistance to attack by xylophagous organisms, despite decreasing the mechanical properties. This work aimed to evaluate the physical-mechanical properties of medium density particleboard (MDP) of Eucalyptus sp. subjected to post-heat treatment with two temperature levels (200 and 260ºC) and two periods (5 or 10 minutes). The apparent density, water absorption and thickness swelling (TS) after 2 and 24h, internal bonding, MOE and MOR in static bending were evaluated. The post-heat treatment at 200 °C for 5 minutes was the most efficient, improving the TS, with smaller reductions in the mechanical properties. The temperature had a greater influence in the first hours of immersion in water (TS2h), while for a longer period (TS24h) the heat treatment time was more effective. The temperature influenced the mechanical properties more negatively than the heat treatment time.

ABSTRACT The present study has the objective of evaluating the physical-mechanical properties of plywood produced with Acrocarpus fraxinifolius wood, as well as the effect of combining their veneer with Pinus veneer. The wood of Acrocarpus fraxinifolius and Pinus oocarpa were used in the production of the panels. The plywood was produced with five veneers; the adhesive used was phenol-formaldehyde, weighing 320 g.m-2. The evaluated properties were: equilibrium moisture (EM), specific mass (SM), water absorption (WA), thickness swelling (TS), shear strength (SS), modulus of rupture (MOR) and modulus of elasticity (MOE) both parallel and perpendicular to the fibers. No statistical difference was observed in the EM and TS, whereas all other properties showed statistical differentiation between the treatments. In general, the use of Acrocarpus fraxinifolius veneers improved the physical-mechanical properties of the compensated ones. Thus, the use of this species in the production of plywood is technically feasible.

RESUMO O Brasil é o segundo maior produtor de soja do mundo, com produções em torno de 96,2 milhões de toneladas por safra. Essa alta produtividade acarreta em um número expressivo de resíduos gerados pelo cultivo da soja, o que pode chegar a aproximadamente 41 milhões de toneladas de resíduos por ano. Este material possui propriedades lignocelulósicas, o que pode possibilitar sua utilização como matéria-prima para a produção de painéis aglomerados. Sendo assim, objetivou-se com o presente trabalho avaliar a utilização da vagem da soja na produção de painéis aglomerados. Para a manufatura dos painéis aglomerados foi utilizado madeira do híbrido Eucalyptus urophylla e Eucalyptus grandis em composição com a vagem de soja, nas proporções de 0%, 25%, 50%, 75% e 100%. Para a avaliação dos painéis utilizou-se de delineamento inteiramente casualizado, com cinco tratamentos e três repetições, utilizou-se a regressão linear e o teste de médias de Scott-Knott a 5% de significância para comparação entre os diferentes tratamentos. Foram avaliadas as propriedades densidade aparente, razão de compactação, absorção de água após 2 h e 24 h, inchamento em espessura após 2 h e 24 h em imersão em água, ligação interna, módulo de ruptura e módulo de elasticidade na flexão estática. O efeito da proporção de resíduo de vagem da soja com partículas de eucalipto nos painéis promoveu aumento nos valores de absorção de água e inchamento em espessura e diminuição das propriedades mecânicas. Os painéis produzidos com aproximadamente 23% de vagem da soja possuem viabilidade técnica de produção.

ABSTRACT Brazil is the second largest soybean producer in the world, with a yield of around 96.2 million tons per crop. This high yield leads to a great amount of waste resulting from soybean cultivation, which can reach approximately 41 million tons of waste per year. This material has lignocellulosic properties, which may enable its use as a raw material for particleboard production. Therefore, the objective of this study was to evaluate the use of soybean pods in particleboard production. For particleboard manufacture, wood of the hybrid Eucalyptus urophylla and Eucalyptus grandis was used, added with soybean pods, at proportions of 0%, 25%, 50%, 75% and 100%. For particleboard evaluation, a completely randomized design was used, with five treatments and three replicates, using linear regression and the Scott-Knott test at 5% significance for comparison among the different treatments. The properties apparent density, compaction ratio, water absorption after 2 and 24 hours, thickness swelling after 2 and 24 hours in water immersion, internal bonding, modulus of rupture and modulus of elasticity in bending properties were evaluated. The ratio soybean pod waste and eucalyptus particles in the panels led to an increase in water absorption values and thickness swelling, in addition to a decrease in mechanical properties. The production of panels with approximately 23% soybean pods is feasible.