Effects of heat treatment, on praoperties of medium density fiberboards (MDF)

In this study, The Eastern Anatolian Black Pine (Pinus nigra var. pallasiana) and oriental beech (Fagus orientalis Lipsky) wood fibers produced using a medium density fiberboard (MDF) some of the physical properties (thickness increased, water absorption, rate of release of formaldehyde) and mechanical properties (bending, bending modulus of elasticity, tensile strength fibers perpendicular and parallel) on the properties fiber board density, heat treatment and pressing after the waiting period was investigated.Fiberboard samples, including in a 50-50 % mixture of wood, as a urea formaldehyde adhesive glue, using the two different intensity level (700-740 kg/m3), three different heat treatment temperature (155, 165, 175 °C), three different heat treatment time (2.5 h, 3.5 h, 4.5 h) and three different waiting times After pressing (30 min, 120 min, 600 min) were obtained using. As a result, the temperature of heat treatment (155, 165, 175 °C) with the alteration of tensile strength, flexural strength, flexural modulus of elasticity values negatively affected, and the thickness swelling and water absorption increase in a positive way with the observed quantities of free formaldehyde. Thermal processing times (2.5, 3.5, 4.5 hours) with the alteration of tensile strength values are affected negatively, flexural strength, flexural modulus of elasticity, thickness swelling and water absorption increase in a positive way with the observed quantities of free formaldehyde. After pressing, waiting times (30, 120, 600 min) with the alteration of tensile strength, flexural strength, flexural modulus of elasticity values negatively affected, and the thickness swelling and water absorption and the amounts of free formaldehyde observed increase in the positive direction. Fiberboard densities (700 to 740 kg/m3), together with the change of tensile strength, flexural strength, flexural modulus of elasticity, thickness swelling and water absorption with increasing density of the amounts of free formaldehyde levels observed increase in the positive direction.Key words: Medium Density Fiberboard, Heat Treatment, Mechanical Properties, Physical Properties, Density