Eficiência de preservantes fungicidas em madeiras de Eucalyptus dunnii e Pinus elliottii

Abstract

This study aimed to evaluate the influence of fungicides products on physical, mechanical, chemical and biological properties in Eucalyptus dunnii and Pinus elliottii woods. For this, there were obtained specimens with 2.5 x 2.5 x 0.9 (tangential, radial and longitudinal, respectively) dimensions, which were treated with chromated copper borate (CCB), synthetic pyrethroids and carbamates (PSC), and copper chelate carbamate (QCC), being used 2%, 4% and 6% concentrations for each produtc. The autoclave impregnation process applied was the vacum pressure, during 90 minutes period, with 8kgf/cm² of pressure. Subsequently, it was verified the influence of the treatments on the basic (µb) and apparent specific mass (12% moisture) – (µap12%), on the equilibrium moisture content (TUE) and on the Janka hardness. Other variables evaluated were the mass loss (PM) and changes on hardness and moisture content properties caused by the deteriorations of the samples submetted to the accelerated rotting decay test with the white rot fungus Ganoderma applanatum. It was used the infrared spectroscopy (FTIR) analysis, in the region between 1800cm-1 and 600cm-1, to verify the influence of preservatives treatments and deterioration caused by the fungus in the variations of wood chemical composition. The use of preservative treatments influenced significantly the specific mass of the wood, and the synthetic pyrethroids and carbamates product caused a decrease the specific mass for both species. The treatments with chromated copper borate showed the highest increases on moisture content and Janka hardness. As for fungus deterioration, mass loss were 4.6% for Eucalyptus dunnii and 11.9% for Pinus elliottii, in there control groups treatments. This deterioration caused an icrease in the equilibrium moisture content of the wood and decrease in the woods Janka hardness. Eucalyptus dunnii showed a high, directly proportional and significant correlation between the loss of mass with the moisture content (99%), and high and inversely proportional to the hardness (85%). For Pinus elliottii wood was found a high, directly proportional and significant correlation for mass loss and moisture content (99%), while the relationship between mass loss and hardness was not significant. The FTIR technique proved to be an important tool in the characterization of the materials, since it presented spectra consistent with the degradation occurring in both species, both by treatments and fungus. Visualizing the results obtained it was noted the importance of the knowledge acquired about of the products active ingredient efficiency on the wood preservation, as well as the possibility of causing some changes in the technological properties of Eucalyptus dunnii and Pinus elliottii woods, in relation to the treatments of the control groups.