THE EFFECT OF MAT MOISTURE CONTENT GRADIENT ON PHYSICAL & MECHANICAL PROPERTIES OF PARTICLEBOARD

In this investigation, experimental boards were produced using beech wood particle, mat moisture content gradient at 0,3 and 6%, two press temperature sat 165and 1850 C and two press times at 3 and 5 minutes. 36 sample boards produced and the physical and mechanical properties of those tested.The results indicated that mat moisture content gradient had significantly effected on modified of modulus of elasticity of boards, and with increasing mat moisture content gradient, the MOE of boards increased. Also in 0% mat moisture content gradient, increasing of press time, modulus of rupture and modulus of elasticity decreased. However with increasing mat moisture content gradient, increasing of press time caused of these properties modified.On the other hand an inverse relationship observed between mat moisture content gradient and internal bond of boards that due to of negative effect of increasing of vapor pressure were on resin bond quality in middle layer. But with increasing press time from 3 to 5 minutes, the internal bond of boards increased. The results of thickness swelling measurement indicated that with increasing mat moisture content gradient, the thickness swelling of boards increased. However, when press time increased, the thickness swelling of boards decreased