STUDIES ON EQUILIBRIUM WATER CONTENTS OF MDF AND PARTICLE BOARDS

Investigations into dimensional stability of MDF and particleboards Th e dimensional stability of MDF and FPO-particleboards was investigated after installation into a double climate testing chamber under inside climatic conditions. Using difference climate testing with realized h umidity gradient at a constant temperature of 20 degrees C, the fundam ental phase of deformation was reached after only 48 hours operating t ime. With the beginning of re-conditioning a prompt reverse material d eformation was observed. As a result of its structure and relatively l ow potential of sorption the investigated MDF boards were less sensiti ve to the affecting climatic differences than particleboards, therefor e both lower deformation and better deformation reversibility were att ained. Coated wood materials were significantly less affected by humid ity gradients in difference climate testing due to diffusion impedimen t. In temperature gradient affected deformation, a ten times lower mag nitude was noted.