Decay resistance and weathering properties of thermally-modified amazon woods – Parkia pendula (Willd.) and Simarouba amara (Aubl.)

Abstract

ABSTRACT Thermal modification is a technique that can be used to increase the resistance of wood to the biodeterioration processes. In this context, the objective of this study was to evaluate the durability of Parkia pendula (angelim-saia) and Simarouba amara (marupá) woods thermally modified in rotting field tests and by the action of natural weathering. The tests were carried out in the Brazilian Amazon region, in the Mato Grosso State. The thermal modification of the wood was set with four treatments: control (T1); electric-oven treatment, 180°C for 3 h (T2); combination of autoclave and electric-oven, 125°C for 3 h, and 180°C for 3 h respectively (T3), and immersion in vegetable oil, 180°C for 3 h (T4). The samples were partially buried for the field rotting assays, and the mass loss and deterioration index were seasonally evaluated after the experiment was installed. These analyses were performed on the same samples which has been exposed to rotting essays. The action of natural weathering was assessed through the CIELAB* colour system. T4 was the most efficient for increasing the resistance to biological deterioration, under the tested conditions. T2 and T3 treatments conferred higher colorimetric stability for both types of woods after natural weathering, under the tested conditions.