Effects of oil heat treatment on poplar wood properties: A pilot scale study

Abstract

Pilot-scale oil heat treatment was conducted to enhance the quality of poplar wood obtained from a fast-growing plantation. Three target temperatures, namely 180, 190, and 200 ˚C, were chosen for the oil heat treatment process. Clear, small specimens were cut from the lumber, following the prescribed standards for assessing wood quality. Light microscopy revealed the ruptures and deformation of the wood cell wall as the treatment temperature increased. The volumetric swelling of the treated specimen decreased proportionally with the increase in treatment temperature. The impact of oil heat treatment on the mechanical properties of wood varied depending on the specific type of mechanical strength and processing temperature. The modulus of rupture, toughness, and hardness of the treated specimens drastically decreased at 200°C. However, the specimens treated at 200°C exhibited much lower mass loss during the fungal decay test. The results of the analytical test showed an increase in the crystalline cellulose content and thermal stability of the treated wood, due to the thermal degradation of hemicelluloses and amorphous regions of cellulose. Overall, it is concluded that oil heat treatment of poplar wood in the optimal temperature is an efficient approach to upgrade its quality with minimal reduction in mechanical strength.