Qualidade da adesão de juntas coladas expostas a condições de serviço externo e interno

Abstract

The present paper had as objective to test the glued joints quality and strength before and after simulated exterior exposure conditions. The woods quaruba and pinus were glued with the Adhesives resorcinol, resorcinol with 10% de tannin and resorcinol with 20% de tannin were used in the 25°C e 60°C temperature, with 10% of methanol and without methanol. The strength tension perpendicular to grain and shear before and after exposure tests was made and with the better results of the shear strength tests was did a delaminating test in the glued joints. The two wood species presented restriction on tension perpendicular to grain strength, been necessary the device use to prevent the structure break. In both woods before and after exposure the 25°C temperature presented better results. Methanol improves de strength at the 60°C glued. The resorcinol adhesive when glued in pinus wood didn t presented significant differences between with and without heat and methanol, when was used in the quaruba wood the adhesive had a lower strength at 60°C. The adhesives with tannin in the composition presented better results without methanol in bath temperatures and with methanol at 60°C. The compositions glued in Pinus shown results acceptable in the delaminating test, but in the quaruba wood these results presented very high percentage.