Differences in the Behaviour of Hardwood and Softwood Under Heat Treatment. Part 1. Strength Properties

The differences in the mechanical behaviour of hardwood and softwood under heat treatment were investigated. There were 15.8% and 3.3% reduction in modulus of elasticity in the hardwood and softwood respectively while the loss in modulus of rupture is 32.9% and 15.6% in the hardwood and softwood respectively. The lower reductions in the strength properties in the softwood compared to the hardwood indicate that the former is less amenable to heat treatment than the latter. This is probably due to the higher acidity of the former, which could have resulted in higher degree of degradation, higher cellulose crystallinity and consequently higher strength reduction. From the results of this study, it is suggested that the effects of heat treatment on the strength properties of wood is more a function of the chemical composition of the material than its anatomical structure.