Extratos de resíduos industriais da madeira de teca para proteção da madeira a organismos xilófagos

Abstract

The aim of this study was to evaluate the efficacy of extracts from the waste of industrial processing of teak wood (Tectona grandis) as a natural wood preservative. The obtained wastes were quantified as to solubility and subjected to extraction in hot water, acetone, ethanol and methanol. The crude extracts were used in concentrations of 0.5; 1; 2; 4 and 8% in inhibition test to brown-rot (Postia placenta, Gloeophyllum trabeum, Neolentinus lepideus) and white-rot fungi (Irpex lacteus). From the result of fungal inhibition, the concentration for vacuum impregnation in Pinus taeda wood was selected. The selected extracts were characterized by gas chromatography coupled to mass spectrometry (GC-MS). Treated wood was subjected to accelerated aging conditions and color changes and stability were verified by colorimetric readings (CIE-Lab*). To test the effectiveness of extracts in wood protection, tests were carried out with brown- and white-rot fungi, and Nasutitermes corniger termite. The concentration of 8% showed better fungal inhibition results. The impregnation process provided adequate retention of extracts. The extracts were characterized as quinones derivates (35-37%), mainly tectoquinone (26-29%), as well as others such squalene (8-12%) and phenolic compounds (6%). The concentration used ensured a remarkable darkening in the Pinus taeda and high resistance to the xylophagous tested. The aging conditions tested affected wood color and biological resistance, and the best results were obtained for the acetone extract.