Abstract

ROMER SCHULZ, H.; PEREIRA ACOSTA, A.; TECHERA BARBOSA, K.  and  GATTO, D. A.. Chemical, mechanical, thermal and optical properties of the heat treated wood of Pinus elliottii planted in Brazil. Quebracho (Santiago del Estero) [online]. 2021, vol.29, n.2, pp.122-131.  Epub July 01, 2021. ISSN 0328-0543.

The aim of this study is to evaluate the properties of Pinus elliottii wood, submitted to heat treatment at three temperatures (T160 °C, T200 °C and T240 °C) respectively, with the same exposure time in each treatment. In order to analyze the change that heat treatment influences on the physical and colorimetric properties of wood, namely, apparent specific mass at 12 % (ρ12 %,), mass loss (%), colorimetric analysis, the determination of strength parameters after heat treatment with Janka hardness analysis (σ Max) and analyze the degradation of the chemical constituents of wood as a function of temperature as it was submitted with thermogravimetric analysis (TGA and DTG) and Fourier transform spectroscopy (FT-IR), As properties analyzed were determined as described in ASTM D 2395-17 (2017), ASTM (2005) and ASTM D 143-94 (2014). noting that with the increase in the temperature of the heat treatment, there were some significant changes, with a loss of mass being evidenced, due to the degradation of the structural components and, therefore, directly affecting the resistance of this material, the treatment T 240 °C, presented the higher mass loss value and lower stress of the Janka hardness test, when compared to the control. Regarding the colorimetric analysis, the control has a whitish-yellowish color and after the heat treatment there was a change to a dark brown tone. The (FT-IR) analysis showed a tendency of reduction in the intensity of the bands of the chemical constituents of the wood, as the temperature increased. The thermogravimetric analysis (TGA) and the first derivative (DTG) showed differences in the T240 °C treatment, when compared to the control, for being more unstable. It is noteworthy that the thermal treatments can be used in wood, given that the treatments T160 °C and T200 °C, showed considerable colorimetric variations and no significant decreases in physical-chemical-mechanical properties, when compared to the control.

Keywords : Thermorectification; FT-IR; TGA; Janka Hardness.