Screw withdrawal resistance of moulded laminated veneer oil palm (MLVOP) Bonded with formaldehyde resins

Abstract

A research was conducted to discover the screw withdrawal resistance of moulded laminated veneer lumbers made from oil palm trunks (MLVOP). The MLVOPs were manufactured separately with three different veneer arrangements namely S100% (each ply came from the superior part), SS-CI (surface superior and core inferior) and S-I (alternate superior and inferior parts). The veneers were divided into two groups. One group of veneers was bonded with urea formaldehyde (UF) resin to MLVOPs and the other was bonded with phenol formaldehyde (PF). The veneers were pressed at a temperature of 110°C for 20 min. The pressures applied to press the veneers to MLVOPs were 1500 psi, 2000 psi and 2500 psi. The study showed that the pressures and S-I veneer arrangement gave significant effects to the screw withdrawal resistance of UF-bonded and PF-bonded MLVOPs. MLVOPs with S-I veneer arrangement achieved the highest mean screw withdrawal resistance values when they were bonded with UF resin then pressed with 1500 psi and 2500 psi and bonded with PF resin and pressed with 1500 psi. The values were 848 N, 884 N and 496 N respectively. Overall, UF-bonded MLVOPs were better than those bonded with PF resin.