The influence of microwave heating on the mechanical properties of wood

The drying of wood can be a time-consuming process. The timber industry has been using several methods to reduce the drying time of timber for many years; these include drying the wood at elevated temperatures in conventional ovens or kilns, drying in radio frequency or microwave ovens, or a combination of the two. Little attention has been given to quantifying the effect of drying method on the mechanical properties of the wood, especially where this involves microwave energy with its interior to exterior heating characteristics. In this study, Carribean pine timber was dried to pre-determined moisture contents using several drying methods. The wood specimens were then subjected to tensile loading in order to determine the mechanical properties of the dried timber samples. The wood was dried in air at ambient temperature, in a conventional oven at two elevated temperatures and in a microwave oven at two different power settings. The results of the mechanical tests were then compared for the various drying methods. These revealed that microwave drying reduced the strength of the dried timber by as much as 60%.