Durabilidade natural de painéis aglomerados confeccionados com Eucalyptus grandis e Bambusa vulgaris em ensaio de apodrecimento acelerado

O conhecimento acerca da resistencia dos compostos ligno-celulosicos ao ataque de microrganismos e primordial para servir de base a prevencao da deterioracao e a correta destinacao de emprego do material. Nesse sentido, avaliou-se a resistencia natural a fungos apodrecedores de paineis aglomerados confeccionados com particulas de madeira (Eucalyptus grandis) e/ou bambu (Bambusa vulgaris). Foram produzidas, em laboratorio, chapas aglomeradas nas dimensoes 50x50x0,95cm e massa especifica pre-estabelecida em 0,70g cm-3, nas proporcoes de 100:0, 75:25, 50:50, 25:75 e 0:100 de madeira e bambu, respectivamente. A massa de particulas representou 91 por cento da massa seca de cada painel, sendo, o restante, formado pelo adesivo ureia-formaldeido (8 por cento) e parafina (1 por cento). Para determinacao da resistencia natural ao ataque de fungos xilofagos, os paineis foram testados em laboratorio e utilizados os fungos Gloeophyllum trabeum (podridao parda) e Trametes versicolor (podridao branca), de acordo com a ASTM D 2017 (2005). Quanto aos resultados, foi observado que os paineis confeccionados com mistura de particulas de madeira e bambu apresentaram menor resistencia ao ataque dos fungos apodrecedores. Paineis que utilizaram apenas bambu ou madeira apresentaram resistencia biologica semelhante. Dentre os fungos, T. versicolor atacou mais severamente os paineis.(AU) The knowledge about lignocellulosic compounds strength to the attack of microorganisms is essential for preventing deterioration and also for knowing the correct usage of the material. Accordingly it was evaluated the natural resistance of wood panels made of particles of wood (Eucalyptus grandis) and/or bamboo (Bambusa vulgaris) to decay fungi. Particleboards were produced in laboratory, each of them with dimensions 50x50x0.95cm and density pre-set at 0.70g cm-3, in proportions of 100:0, 75:25, 50:50, 25:75 and 0:100 of wood and bamboo, respectively. The particles mass represented 91 percent of the dry mass of each panel while the remainder was formed by the urea-formaldehyde adhesive (8 percent) and paraffin (1 percent). The panels were tested in the laboratory and Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) were used to determine the natural resistance to attack by wood decay fungi. It was observed that panels which were made with a mixture of particles of wood and bamboo were less resistant to attack by decay fungi. Panels that were made from bamboo or wood only showed similar biological resistance. Among fungi, T. versicolor was the one that attacked panels more severely.(AU)