Medium Density Fiberboard (mdf) Manufacturing

In this study wheat straw was taken from Ankara province. In order to produce dry process MDF, urea formaldehyde resin was used at the ratio of 8 %, 10 % and 12 %, 1 % ammonium chloride was used as hardening agent on the basis of dry fiber weight. On the other hand, 5, 6 and 7 min. pressing times were applied. Alcohol benzene, cold water, hot water and 1 % NaOH solubility of wheat straw were 5.15 %, 7.31 %, 9.84 % and 40.79 % respectively. In addition, holocellulose, cellulose, lignin and ash contents were found as 74.79 %, 52.67 %, 20.17% and 4.21 % respectively. Optimum fiber morphology values were as follow; fiber length 1.2-1.5 mm, fiber width 12-16 μm, lumen diameter 4-6 μm and double wall thickness 7.5 -11.5 μm Optimum fiber production conditions for MDF manufacturing were as follows; Vapor pressure : 10.5 atm, steaming time : 4 minutes, defibration time : 2 minutes. 0.700 g/cm, 0.800 g/cm density straw MDF boards and 0.800 g/cm density wood fiber MDF boards were manufactured. On the other hand, 0.800 g/cm straw-wood fiber mixture MDF boards were produced at the rates of 70% -30%, 50%-50% and 30%-70%. Modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding (IB), thickness swelling and water absorption of the boards were measured. After the evaluations of the results obtained, optimum straw MDF boards manufacturing conditions were as follows; Adhesive ratio : 12 %, pressing time : 6 minutes, press temperature : 150 °C, pressure : 200-220 kp/cm, hardening agent : 1 % and straw wood ratio 50 %50 %.