AbstractThe objectives of this research were to investigate surface characteristics and overlaying properties of medium density fiberboard (MDF) panels, as affected by thermal treatment of the fibers. MDF panels were manufactured from untreated rubberwood fibers and fibers treated at three different temperatures (120, 150, or 180°C) for 15 or 30 min. Contact angle measurements were obtained by using a goniometer connected with a digital camera and computer system. Roughness measurements, average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Ry), were taken from the sanded samples along and across the sandmarks using a fine stylus tracing technique. With the increasing thermal treatment temperature and time of the fibers, surface roughness of the panels decreased, while their wettability and adhesive bonding strength decreased. Statistical analyses showed significant differences in the surface roughness, contact angle, and adhesive bonding strength of the panels following thermal treatment. Based on the findings obtained from this study, the contact angle and surface roughness parameters of the MDF panels made from thermally treated rubberwood fibers can provide a good information on their ability to bond.