Finger joint performance of green-glued rubberwood (Hevea brasiliensis) lumber

The feasibility of performing finger jointing of green rubberwood was considered with typical adhesives used for gluing kiln-dried wood. The effect of initial moisture content of rubberwood (12 ± 1.1%, 37.6 ± 3.2%, and 61.2 ± 6.1%), hot air oven-drying temperatures (60 °C, 80 °C, and 100 °C), and types of adhesives (polyurethane (PU) and emulsion polymeric isocyanate (EPI)) on bending and compressive properties of finger jointed rubberwood products were investigated. The controls were manufactured from 12 ± 1.1% moisture content rubberwood. The type of adhesives had no significant effect on the examined properties of the finger-jointed specimens. The initial moisture content had a slight effect on the modulus of rupture (MOR) and modulus of elasticity (MOE) of specimens bonded with EPI adhesive. The MOR of all types of specimens bonded with EPI adhesive were slightly lower, but their MOE tended to be slightly higher than the control. The drying temperature slightly improved the MOE of specimens bonded with EPI adhesive. The result suggests that the finger jointing process of green rubberwood using typical adhesives could be performed without notably reducing the strength of the final products compared with the control.