Influência do tratamento térmico sobre as propriedades físicas e mecânicas da madeira de angelim pedra

Abstract

The objective of this study was to evaluate the effect of heat treatment on the behavior of physical and mechanical properties Hymenolobium petraeum Ducke wood. The treatment was performed in wood Technology Laboratory at the Federal University of Mato Grosso Campus of Sinop, the H. petraeum samples were obtained from the local market. 50 pieces were fabricated with dimensions (25.0 x 10,0 x 1.7 cm) and randomly divided into five groups, and one of these used as a witness and the other submitted to term rectification process in a circulation oven forced air, at different times and temperatures. They were used of temperatures of 180 ° C and 200 ° C with exposure times ranging from 2 to 4 hours. After the heat treatment of each repetition were withdrawn different bodies of the test piece to carry out the physical tests (weight loss specific and dimensional stability) and mechanical (Ultrasound, bending and compression parallel fibers). Before testing, the bodies of the test piece was subjected to bending ultrasound test to determine the dynamic modulus of elasticity and later correlated with the elastic modulus obtained by destructive tests conducted in the universal test machine. The heat treatment provided a mass loss of the wooden Angelim pedra, and the higher temperature treatments showed may loss percentage. For dimensional stability heat treatment was effective as this improved this property. The ultrasound method proved effective to correlate the dynamic elastic modulus with the MOR and MOE obtained in bending test static. Thermal treatment did not affect significantly the mechanical properties of wood Angelim pedra, since there was no significant reduction of MOR and MOE found in the bending test and compression parallel fibers.