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 ye ars; these include drying the wood at elevated temperatures in conventional ovens or kilns, drying in radio frequency or microwave ovens, or a combina tion 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 chara cteristics. In this study, Carribean pine timber was dried to pre-determine d moisture contents using several drying methods. The wood specimens were t hen subjected to tensile loading in order to determine the mechanical prope rties of the dried timber samples. The wood was dried in air at ambient tem perature, in a conventional oven at two elevated temperatures and in a micr owave oven at two different power settings. The results of the mechanical t ests 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 %. (C) 2000 Elsevier Science S.A. All rights reserved.