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No presente estudo, foram analisadas as propriedades fisico-mecânicas de paineis de madeira aglomerada, de tres camadas, produzidos em laboratorio, com a adicao de dois tipos de serragem obtidas em serrarias, as quais foram classificadas como tipo “fino” e “grosso” por meio de analise granulometrica. Tres proporcoes de serragem (10, 20 e 30%) foram adicionadas as particulas de madeira de Pinus taeda para a confeccao dos paineis. Foram, tambem, confeccionados paineis sem residuo, constituindo um experimento fatorial com sete tratamentos e tres repeticoes. Utilizou-se adesivo de ureia-formaldeido na proporcao de 10% e parafina na proporcao de 1%. Os paineis foram produzidos com densidade nominal de 0,65 g/cm³ temperatura dos pratos da prensa de 160°C, pressao de prensagem de 40 Kgf/cm², tempo de prensagem de 8 minutos e tempo de fechamento da prensa de 40 segundos. Apos a confeccao, os paineis foram esquadrejados ficando com dimensoes de 40 x 40 x 1,5 cm. Os ensaios de densidade aparente, estabilidade dimensional, flexao estatica, tracao perpendicular a superficie dos paineis e arrancamento de parafusos foram realizados de acordo com a norma norte-americana ASTM D 1037 – 93. Os resultados foram submetidos a analise estatistica entre tratamentos e entre fatores. Verificou-se que os paineis produzidos com adicao de ate 10% de serragem apresentaram qualidade semelhante aos produzidos apenas com  particulas obtidas de madeira rolica, sendo assim uma alternativa para um melhor  aproveitamento da serragem como materia prima. Para maiores proporcoes, foi observado que um aumento da proporcao de serragem causou diminuicao das  propriedades mecânicas e efeito negativo na estabilidade dimensional dos paineis. Abstract In this paper we analyzed the quality of three layers particleboard, produced in  the laboratory with addition of two types of sawdust collected in the sawmills. The  sawdust was classified as type a “thin” and a type a “thick”, using sieve analysis.  Three ratios of sawdust (10, 20 and 30%) were added to the particles Pinus taeda wood for making the panels. Panels were also made without residue, constituting  a factorial design with seven treatments and three replications. It was used for  urea-formaldehyde adhesive in a proportion of 10% and paraffin at a ratio of 1%.  The panels were produced with nominal density of 0.65 g/cm³, temperature of  the press platens to 160 oC, pressing pressure of 40 kg/cm², pressing time of 8  minutes and closing time of the press 40 seconds. After fabrication, the panels  were squared up with dimensions of 40 x 40 x 1.5 cm. Tests of apparent density,  dimensional stability, bending strength, tensile strength perpendicular to surface  and screw withdrawal were performed according to standard American ASTM D  1037 - 93. The results were statistically analyzed between treatments and between  factors. It has been found that panels produced with addition 10% sawdust had a  similar quality to those produced only by particles obtained round wood, therefore  an alternative to a better use of sawdust as raw material. To highest ratios it was  observed that increased proportion of sawdust caused a decrease of mechanical  properties and adverse effect on the dimensional stability of the panels.

ambiência

Influência da adição de serragem nas propriedades tecnológicas de painéis de madeira aglomerada de Pinus taeda / Influence of sawdust addition in the technological properties of Pinus taeda particleboards