Microwave Drying of Melia dubia and Its Effect on Mechanical Properties

This study explores the microwave (MW) drying of Melia dubia wood, with a comprehensive approach that addresses various facets. The primary objectives were to examine drying behavior and the evaluation of drying defects. The drying rates for various treatments were calculated both above and below the Fiber Saturation Point (FSP). The most optimal treatment, characterized by minimal defects, exhibited a drying rate of 0.4 g/min above FSP, 0.29 g/min below FSP, and an overall drying rate of 0.35 g/min. There were no observable drying-induced defects in the dried wood, suggesting a promising aspect of MW drying. Static bending and compression tests parallel to the grain were carried out to analyze the impact of MW drying on the mechanical properties. MW-dried wood exhibited reductions of 7 ± 3%, 10 ± 2%, and 9 ± 2% in the modulus of elasticity (MOE), modulus of rupture (MOR), and maximum compressive strength (MCS), respectively. The decline in mechanical properties may be attributed to the micro-cracks or damage in its microstructures. These findings emphasize the need for a balanced approach in optimizing MW drying methods to mitigate the reduction in mechanical properties while capitalizing on the advantages of reduced drying time and uniform drying.