Produção de chapas de madeira compensada de cinco espécies de pinus tropicais.

Abstract

RESUMOEste trabalho teve como objetivo avaliar o potencial de utilização de 5 espécies de pinus tropicais para produção de painéis compensados. As espécies estudadas foram: Pinus caribaea, Pinus chiapensis, Pinus maximinoi, Pinus oocarpa, Pinus tecunumannii e Pinus taeda, sendo esta última espécie como testemunha. Foram produzidos compensados de 5 lâminas com resinas uréia--formaldeído e fenol-formaldeído. Os resultados de inchamento e recuperação em espessura foram estatisticamente iguais entre as espécies estudadas, com exceção para inchamento em espessura das chapas coladas com resina fenol-formaldeído. As chapas de Pinus maximinoi e Pinus oocarpa, apresentaram melhores resultados de módulos de elasticidade. Para o módulo de ruptura, as chapas de Pinus maxininoi, Pinus oocarpa e Pinus taeda, coladas com resina fenol-formaldeído, apresentaram valores estatisticamente superiores em relação às demais espécies. Quanto a resistência da linha de cola, as chapas de Pinus maximinoi, Pinus taeda e Pinus chiapensis, foram as que apresentaram melhor desempenho. Com base nos resultados gerais da pesquisa, pode-se destacar a potencialidade da madeira de Pinus maximinoi e Pinus oocarpa para produção de chapas de madeira compensada. Palavras-chave:Pinus tropicais, compensados, resistência da linha de cola. ABSTRACTThis research was developed aiming at evaluating the feasibility of the use of 5 species of tropical pine to plywood manufacture. The following species were studied: Pinus caribaea, Pinus chiapensis, Pinus maximinoi, Pinus oocarpa, Pinus tecunumannii and Pinus taeda, being the last used as the referential species. Plywood were manufactured with 5 plies, bonded with ureaformaldheyde and fenol-formaldheyde resin. The results of thickness sweeling and recovering were the same for all species studied, with exception to thickness sweeling for the boards glued with fenolformaldheyde resin. The boards made from Pinus maximinoi and Pinus oocarpa, showed the higher values in modulus of elasticity. The boards of Pinus maximinoi, Pinus oocarpa and Pinus taeda, glued with fenol-formaldheyde resin, resulted in higher values of the modulus of rupture, in comparison to other species. For the glue line strength, the boards of Pinus maximinoi, Pinus taeda and Pinus chiapensis, showed the better results. Based on the general results of this research it, could be said that the Pinus maximinoi and Pinus oocarpa present the high potentiality to plywood manufacture.

Use of wood from Pinus caribaea var. caribaea and Pinus caribaea var. bahamensis for production of particleboard panels

“…bahamensis and between combinations of these two varieties. Mean values of 83.74% to 92.00% for water absorption are compatible with values found by Iwakiri et al (2001) while studying panels from five species of tropical pine with no paraffin emulsion applied, which ranged from 75.04% to 80.05%. Dacosta et al (2005a) found mean values of 75.67% to 90.85% for water absorption after 24 hours while studying particleboard panels from Pinus elliottii with densities of 0.60 and 0.70 g/cm³.…”

“…With panels from the above mentioned five species of tropical pine, Iwakiri et al (2001) found mean values of 32.70% to 39.74% for thickness swell after 24 hours. Dacosta et al (2005a) found mean values of 23.50% to 40.04% for thickness swell in particleboard panels from Pinus elliottii with densities of 0.60 and 0.70 g/cm³.…”

“…As reference parameters in existing literature, Iwakiri et al (2001) found mean values of internal bond of 0.72 MPa to 1.05 MPa for panels made with five species of tropical pine. Cabral et al (2007) found mean values of internal bond of 0.45 MPa and 0.56 MPa for panels made with combinations of Eucalyptus urophylla and Pinus elliottii, and Eucalyptus cloeziana and Pinus ellotti respectively.…”

“…Iwakiri et al (1996) found mean values of 2.208 MPa to 2.530 MPa for panels made with combined Pinus taeda and Eucalyptus dunnii at rates 75%, 50% and 25%. In another study with five species of tropical pine, Iwakiri et al (2001) obtained mean values of MOE of 2.563 Mpa to 3.214 MPa. Dacosta et al (2005b) found mean values of MOE ranging from 522 MPa to 650 MPa for particleboard panels from Pinus elliottii with densities of 0.60 and 0.70 g/cm³.…”

Particleboard Panels Produced with Different Radial Positions of Pinus oocarpa Wood

“…Iwakiri et al (2001) evaluated the potential use of five tropical pine species for production of particleboard panels with nominal density of 0.70 g/cm 3 and 8% of urea-formaldehyde adhesive. They found mean values for water absorption after two and 24 hours of immersion ranging from 68.80 to 83.60% and from 78.69 to 93.81%, respectively.…”