Caracterização da madeira de três espécies florestais plasticizadas por tratamentos hidrotérmicos.

Abstract

Timber of three forestry species were characterized on its mechanical and physical properties. The present study evaluated the softening potential of hydrothermal pretreatments for solid wood bending. The timber was subjected to boiling, microwave radiation and steaming treatments, with exposure time variation. Were analyzed Luehea divaricata (açoita-cavalo), Carya illinoinensis (nogueira-pecã), e Platanus x acerifolia (plátano) in its mechanical properties, through solid wood bending and static bending (ASTM D143 – 94). Furthermore were evaluated colorimetric parameters on CIEL*a*b* system, surface roughness, apparent specific gravity at 12% moisture content, and the moisture content variation between treatments. Was found that nogueira-pecã timber is more suitable for bending. The Platanus x acerifolia wood presents better flexural resistance. The softening treatments modified the mechanical properties and increased bending quality reducing the modulus of elasticity (MOE), modulus of rupture (MOR), the brittleness and the modulus of resilience. The surface roughness was reduced, as well as the lightness (L). Colorimetric parameter a was increased and was found a slight reducing of b parameter for all species compared treated and untreated groups. Thus, can be concluded that microwave does not presents significant difference comparing to other pretreatments considering softening efficiency. It shows equalized results comparing with steaming and boiling treatments. This way, can be qualified as more favorable as function of its less exposure time and energetic expenses for the same general results.