Strength of particleboard produced with mixed wood traditional and nontraditional forest species/Resistencia de paineis aglomerados produzidos com mistura de madeira de especies florestais tradicionais e nao tradicionais

The objective of this work was to investigate the strength of particleboards made with wood of Pinus taeda, Eucalyptus saligna, Mimosa scabrella and Hovenia dulcis and mixtures in different proportions and two board compositions. The boards were produced in mixtures of two, three and four species for monolayer boards and proportions of the two species for multilayer boards. Panels were also produced with pure pine wood. The adhesive used was based on urea-formaldehyde and the nominal density was 0.65 g/[cm.sup.3]. We evaluated the properties of density, moisture content, static bending, internal bond and screw withdrawal. The analyzes allowed to evaluating the use of different species wood mixtures in particleboards. The results were also compared the requirements of applicable ANSI A 208.1. The values of static bending, internal bond and screw withdrawal increased with increasing proportion of Pinus taeda and Hovenia dulcis and decreased with increasing proportion of Mimosa scabrella and Eucalyptus saligna. Therefore, it can be concluded that better species were the Pinus taeda and Hovenia dulcis. Regarding the composition, multilayer boards, mostly showed themselves superior to monolayer boards. Keywords: Hovenia dulcis; Mimosa scabrella; mechanical-properties. Este trabalho teve como objetivo avaliar a resistencia de paineis aglomerados fabricados com particulas de madeira de Pinus taeda (pinus), Eucalyptus saligna (eucalipto), Mimosa scabrella (bracatinga) e Hovenia dulcis (uva-do-japao) em diferentes proporcoes de misturas e em duas composicoes de camadas. Os paineis foram produzidos em misturas de duas, de tres e das quatro especies para paineis monocamada, e nas proporcoes de duas especies para paineis multicamadas. Foram tambem produzidos paineis com madeira de pinus pura. O adesivo usado foi a base de ureia-formaldeido e a massa especifica nominal estabelecida foi de 0,65 g/[cm.sup.3]. Foram avaliadas as propriedades fisico-mecanicas de massa especifica, teor de umidade, flexao estatica, ligacao interna e arrancamento de parafusos. As analises permitiram avaliar o efeito da utilizacao da madeira das diferentes especies em misturas na fabricacao dos paineis aglomerados. Os resultados foram tambem comparados aos requisitos das normas ANSI A 208.1. Verificaram-se aumentos nos valores das propriedades de flexao estatica, ligacao interna e arrancamento de parafusos com o aumento da proporcao de pinus e uva-do-japao e diminuicao com aumento da proporcao