EFFECT OF Eucalyptus grandis WOOD REFINING ON THE FIBER MORFHOLOGY AND ON MDF PANELS PROPERTIES

Abstract

The utilization of eucalypts wood for MDF panels producing is recent in Brazil and presents larger perspective of increase, in relationship to pine wood,          due to the shorter harvesting cycle and integral use of the bark in the productive process, etc,. The present work evaluated the anatomical structure and properties of MDF panels manufactured at laboratory with Eucalyptus grandis fibers obtained in three treatments. It were evaluated the variations in heating time, digester and refining pressure and specific energy. MDF panels obtained in critical refining condition showed darker fibers and cell walls transversely broken and lower resistance to internal bond, surface soundness, withdrawal of screws and swelling in thickness. MDF panels obtained after less intensive refining condition showed better physical properties. Better refining conditions increase the bulk density and hinder the adhesive recover and fiber interlace, with worse physical and mechanics properties. Fiber morphology was evaluated through stereoscope and scanning electronic microscopic (SEM), establishing relationships between chips refining treatments and MDF panels properties.