Manufacture of medium density fiberboard (MDF) panels from rhododendron (R. ponticum L.) biomass

Rhododendron has invaded the understory layer of the forests throughout the Black Sea Region of Turkey with substantial biomass potential. This study was conducted to evaluate the suitability of Rhododendron fiber for medium density fiberboard (MDF) production.For the evaluation, rhododendron and industrial wood compositions at different mixture rates were compared for some of the chemical properties, such as holocellulose, alfa-cellulose, lignin and ash contents, alcohol–benzene, solubility in dilute alkali (1% NaOH), and hot- and cold-water solubility. In addition, rhododendron fiber properties such as fiber length, diameters and cell wall thickness were determined.For the experiment rhododendron and commercially manufactured chip (Pinus sylvestris L. and Quercus robur L.) with 11% moisture content were used. The mixing ratios of rhododendron with commercially manufactured chip were 100:0%, 75:25%, 50:50%, 25:75% and 0:100%, respectively. A commercial urea-formaldehyde (UF) adhesive was used as a binder. Chemical properties including; holo-, alfa-cellulose, lignin and ash contents, alcohol–benzene solubility in dilute alkali (1% NaOH), hot- and cold-water solubility were determined. In addition, some of the physical and mechanical properties such as density, thickness swelling (TS), bending strength (BS), modulus elasticity (MOE), internal bond (IB), screw-holding ability perpendicular to the plane of panel, janka hardness perpendicular to the plane of panel properties of MDF were also measured.Chemical composition, solubility of rhododendron-wood are similar to those of hardwoods in general. More over, the values of rhododendron-wood fiber lengths, diameters and cell wall thickness are also in the range of values reported for hardwoods.The results indicated that all the panels met the general-purpose use requirements of TS-EN. Thus, our results suggest that rhododendron biomass can be an alternative raw material for MDF manufacturing.