CURING CHARACTERISTICS OF LOW EMISSION UREA-FORMALDEHYDE ADHESIVE IN THE PRESENCE OF WOOD

Urea-formaldehyde (UF) resin presents, by far, the most utilized adhesive system in the manufacture of particleboard and fiberboard. At the temperatures above 100 degrees C in the presence of catalyst, this resin undergoes cross-linking reaction and bonding of wood particles in a hot press. In this work the cross-linking of the new type of commercial UF adhesive for E1 type of wood based panels was studied using infra red (IR) spectroscopy and differential scanning calorimetry (DSC). IR spectra of examined UF adhesive showed distinctive characteristics in comparison to the older types of UF adhesives. The influence of different industrial wood species (obtained from beech, fir and poplar) on the curing behavior of wood-flour/adhesive mixtures has been evaluated using DSC method. The peak temperature and enthalpy of the curing reaction were evaluated from scans obtained with different heating rates. The activation energy for the curing reaction of pure adhesive and for wood-flour/adhesive mixtures was calculated using the Kissinger method.