Effect of wood and panel density on the properties of lightweight strand boards

Abstract

The objective of this study is to evaluate the effect of wood and panel density on the properties of lightweight strand boards (SB). For this purpose, we compared lightweight SBs made of low-density kiri wood (Paulownia tomentosa), medium-density pine wood (Pinus sylvestris) and high-density beech wood (Fagus sylvatica). Single-layer non-oriented SBs were manufactured with target densities of 300 and 400 kg m−3. Cohesion of beech boards was insufficient for further testing. The larger compaction ratio of kiri boards resulted in a steep density profile and mechanical properties, namely modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond (IB), superior to those of pine boards. However, Kiri panels exhibited a higher thickness swelling (TS). MOR of kiri boards was 2.6 and 1.6 times higher than that of pine boards at 300 and 400 kg m−3, respectively, while these ratios were only 1.8 and 1.2 for MOE. We conclude that the effect of wood density on bending properties reduces as panel density increases and that the compaction ratio affects MOR more than MOE, which is mainly determined by panel density. Hence, utilization of low-density kiri wood allows reduction of board density with MOE being the limiting factor.