Efeito da modificação térmica nas propriedades da madeira juvenil de Eucalyptus grandis W. Hill e Tectona grandis L. f.

Abstract

The process of thermal modification presents itself as a viable alternative for an improvement of real estate of the wood. In this context, there is a possibility of technical production in woods from young forest stands, thus increasing the viability of enterprises. The objective of this study was to evaluate the effect of the Brazilian process of thermal modification on the chemical composition, on some physical and mechanical properties, and on the biodeterioration resistance of Eucalyptus grandis and Tectona grandis juvenile wood. Four treatments were investigated, resulting from the interaction between species and species. In addition, chemical solutions (soluble and insoluble lignin, hemicelluloses, total extractives and solubility in acetone, chloroform, dichloromethane and ethanol: toluene), physical (apparent density at 12%, hygroscopicity and total swelling), mechanical (compression parallel to Fibers and static flexion) and resistance to biodeterioration by fungi Postia placenta and Trametes versicolor, termites Nasutitermes corniger and Cryptotermes brevis. Thermal modification process at 160 °C, increase in total consumption, total extractives and hot water, and better solubility for polar solvents (acetone and ethanol: toluene); Hygroscopicity was reduced in both species, due to the loss of mass of hemicelluloses; The mechanical resistance to the static flexion and the compression parallel to the fibers were reduced; And increase in the resistance of the companies like species to the biodeterioration caused by subterranean termites; The same for Eucalyptus grandis wood exposed to dry wood termites. Analyzing the pros and cons of the process, it is more advisable to modify thermal at 160 °C of juvenile Eucalyptus grandis wood than that of Tectona grandis juvenile wood.