Changes in dimensional stability and mechanical properties of Eucalyptus pellita by melamine–urea–formaldehyde resin impregnation and heat treatment

This study investigated the influence of heat treatment on the dimensional stability and mechanical properties of untreated and low molecular weight melamine–urea–formaldehyde (MUF) resin treated Eucalyptus pellita wood. Wood samples were heat treated under vacuum atmosphere in laboratory conditions at temperatures between 160 and 240 °C for 2–10 h. The results showed that anti-shrink efficiency and anti-swelling efficiency of MUF resin-impregnated heat-treated eucalypt wood were improved by up to 47 and 49 % at 240 °C for 10 h separately, which were greater than those of heat-treated wood. In relation to mechanical properties, the modulus of elasticity and modulus of rupture decreased with increasing temperature and time, but the reduction of properties appeared to be smaller for MUF resin-impregnated heat-treated wood. Therefore, heat treatment combined with resin treatment of eucalypt wood shows potential to improve the wood quality of solid wood products.