An experimental study on efficient physical wood modification for enhanced permeability–focusing on ultrasonic and microwave treatments

This study discusses efficient physical wood modification to enhance permeability. Ultrasonic and microwave treatments were chosen as methods for physical wood modification. Indonesian momala (Homalium foetidum) and Korean red toon (Toona sinensis) were supplied for this study. We conducted 150-Wh microwave and ultrasonic treatments of two species. Then, specimen pore size and porosity were analyzed. After treatment of momala and red toon with ultrasonic and microwave, their pore sizes and through-pore porosities significantly increased, leading to their enhanced gas permeability. After ultrasonic and microwave treatments, the gas permeability of momala increased by 57.9% and 82.8%, respectively. In red toon, the gas permeability increased by 98.7% for ultrasonic treatment and 132.9% for microwave treatment. These results show that microwave treatment was more effective in improving permeability than was ultrasonic treatment when the same amount of electricity was used.