Evaluating the Effect of Thermal Treatment on Some Mechanical Properties of Two Lesser Used Wood Species Grown in Ghana

Abstract

Some lesser used wood species from the forests in Ghana are non-durable and have low dimensional stability. These wood species can be modified to improve such properties. Thermal treatment of wood can improve wood properties such as resistance to wood-destroying fungi and dimensional changes depending on the treatment period and the temperature intensity, but has adverse effect on strength properties. The objective of this study was to evaluate impact of thermal modification on Modulus of elasticity (MOE), Modulus Of Rupture (MOR) and compression parallel to the grain (CP) of two Ghanaian Lesser-Used wood species Wawabima (Sterculia rhinopetala) and Niangon (Heritiera utilis. Thermal treatment of the two species showed that the MOE, MOR and CP decreased with increased heating temperature. The MOE of Sterculia rhinopetala decreased from 17,850.658 N/mm2 to 16,520.002 N/mm2 after thermal treatment from 150oC to 240oC. MOR decreased from 172.334 N/mm2 to 70.181 N/mm2 and CP from 75.246 to 57.934 N/mm2. The MOE of Heritiera utilis decreased from 15,604.142 N/mm2 to 9,155.977 N/mm2, MOR from 144.465 N/mm2 to 58.293 and CP from 52.842 to 39.103 N/mm2. The thermal modification of Sterculia rhinopetala) and Heritiera utilis had negative impact on three mechanical properties of the two species.