Acceleration of Moisture Migration in Larch Wood Through Microwave Pre-Treatments

Abstract

This study investigates the effects of microwave pre-treatments on moisture migration in larch wood. Two groups (high and low moisture contents) of specimens were treated in a microwave drier at a fixed output power of 0.8 kW for three different durations (1, 3, and 5 min). Changes of microscopic structure in larch wood after microwave treatments were then examined using scanning electron microscopy. The percentage of aspirated pits was estimated and water absorption was measured using a cylinder with a vacuum pump. In addition, drying rates after the treatments were also evaluated. The results show a significant reduction in the number of aspirated pits in larch wood and a sizable increase in water absorption and drying rate after a 3-min or 5-min microwave treatment. More ruptures and water absorption have been found in the group with lower moisture content. It is concluded that microwave pre-treatments can open some water pathways and accelerate moisture migration in larch wood.