Analysis of rigidity loss and deterioration from exposure in a decay test field of thermorectificated Eucalyptus grandis wood

Abstract

The objective was to evaluate the elasticity dynamic modulus reduction (MOEd) and deterioration of E. grandis thermorectificated wood by exposure to environmental weathering. Six trees were used to obtain 14 logs of 2,4m, with seven from external (sapwood) and the others from internal (heartwood) part of the trunk. A total of 84 wood samples of 2,5x 5x 50cm were made, with half from the inner and the other from the external trunk portion. 14 treatments were evaluated with six replicates composed of thermorectificated wood submitted two differents times (2 and 4 hours) and three temperatures (200, 215 and 230˚C). An ultrasound Stress Wave Timer device was used to evaluate MOEd and the mass measured by weighing. Samples remained in the decay test field for ten months, and monthly inspected and recorded to xylophogous organism's occurrence. At the end of this period MOEd and mass were revaluated. The central portion of wood samples were more deteriorated, with mass losses and stiffness losses ranging from (8-56%) and (18-91%), respectively. Lower values were observed in the wood coming from the external portion, with mass losses and stiffness ranging from (3-10%) and (8-20%), respectively. The thermorectificated wood samples were more damaged by action the termites and less by the action of fungi, compared to controls.

Effects on density, shrinking, color changing and chemical surface analysis through FTIR of Tectona grandis thermo-treated

“…Use of these products becomes increasingly limited, calling for the need of research on new techniques to increase durability in wood with low toxicity methods or eliminating the use of chemicals (TREVISAN et al, 2014).…”

Influência dos tratamentos de termorretificação e furfurilação em propriedades tecnológicas de uma conífera

“…A madeira tratada pelo calor possui novas características, como: melhoras na estabilidade dimensional e resistência biológica ao ataque de fungos xilófagos [7,8], maior durabilidade em serviço [9], melhores propriedades térmicas [10], maior valor estético em razão de sua coloração [11], adquirindo assim características parecidas às madeiras tratadas por meio da furfurilação.…”

Determinación del módulo de elasticidad por los métodos dinámico y estático para madera termo-tratada de Gmelina arborea y Tectona grandis

“…Por otra parte, el nuevo surgimiento de leyes ambientales sobre el uso de productos químicos utilizados en la conservación de la madera, han creado la necesidad de investigar sobre técnicas de conservación de baja toxicidad (Trevisan et al, 2014). Un tratamiento alternativo para la preservación de la madera sin utilizar productos químicos, es el tratamiento térmico, implementado en Europa a principios de 1990 y que ha venido despertando un gran interés al permitir modificar la madera con un bajo impacto ambiental y de una manera financieramente viable (Kesik et al, 2014).…”