Water Absorption and Thickness Swelling behavior of Medium Density Fiberboard Manufactured by Hydrothermally Treated Fibers

In this research، water absorption and thickness swelling behavior of hydrothermally modified fiberboard (MDF). Were evaluated Fibers were treated in a stainless steel reactor at temperatures of 120، 150 and 180°C for holding times of 0، 30 and 90 min. Test boards were prepared based on the target density of 0. 7g/cm3 at the press temperature of 175°C as well as the pressure of 30 bar and the press time of 5 min. Urea formaldehyde (UF) resin was applied at 10% based on the fibers dry weight. Test samples (10×20×20mm) were cut from the boards، dried in an oven and soaked in the water. Water absorption، thickness swelling and their rates were measured in the soaked samples. Results revealed that increase of the treatment temperature caused decrease of water absorption and thickness swelling in the treated boards except in samples treated at 120°C. It was also indicated that increase of the holding time did not significantly affect water absorption and thickness swelling.