EFFECT OF MODIFICATION WITH MELAMINE–UREA–FORMALDEHYDE RESIN ON THE PROPERTIES OF EUCALYPTUS AND POPLAR

Fast-growing eucalyptus (Eucalyptus robusta Smith) and poplar (Populus tomentosa Carr.) were impregnated with melamine–urea–formaldehyde (MUF) resin by vacuum. The weight percent gain (WPG), water absorption, bulking rates, anti-swelling efficiency (ASE), and density distribution of the impregnated wood were examined. The characterization of eucalyptus and poplar was performed by Fourier transform infrared spectroscopy and scanning electron microscope. WPG of the impregnated wood increased with increasing concentrations of MUF resin, however, rate of water absorption was nearly the reverse. The impregnated eucalyptus wood showed low WPG (at most 23.03%) but achieved high ASE (52.02%) values. Although a relatively high WPG (up to 59.02%) was achieved by modified poplar, the ASE (50.21%) value was not high. This was owing to the differences in the microstructure of eucalyptus and poplar. The density of impregnated wood was remarkably increased (eucalyptus from 0.48 to 0.54 g/cm3, poplar from 0.38 to 0.49 g/cm3).