Evaluating Vegetable Oil Epoxidation Efficiency on Properties of Eucalyptus Wood: Thermal and Thermo-chemical Processing

Abstract

The applications of wood are limited by its hygroscopicity and resulting dimensional changes, which reduce its service life for outdoor conditions. Modification methods develop the usages of wood-based products by altering the structure. This study compared the effect of oil heat treatment (OHT) with raw (SO) and epoxidized soybean oil (ESO) at different temperatures relative to the practical properties of eucalyptus wood. Fourier transform infrared spectra confirmed hemicellulose degradation with increasing temperatures of ESO-treated specimens. With increasing temperature, ESO darkened the specimens compared to SO. Thermal modification at the highest temperature in ESO resulted in a weight loss of modified specimens and the lowest density, with more hydrophobicity and dimensional stability compared to the SO-modified specimens. Based on bending data, unlike modulus of elasticity (MOE), modulus of rupture (MOR) did not show a statistical difference between the two types of oils, except at 150 °C. At 200 °C, the specimens modified with ESO exhibited lower hardness than SO. The impact resistance of 150 and 175 °C/ESO modified specimens was higher than SO specimens. In summary, functionalized vegetable oil significantly improved physical characteristics compared to SO, with obvious improvement in impact strength at 150 °C.