The feasibility of using oil palm veneers in LVL with respect to its wettability, adhesives penetration and bending strength / Siti Zalifah Mahmud

The depletion of our tropical timber has encouraged the Malaysian wood based industry to seek alternative lignocellulosic materials for board production. Oil palm (Elaeis guinensis) from agricultural residues is a potential alternative. Oil palm trunk (OPT) appears to have great potential use after rubberwood, as a source of valueadded products such as plywood, laminated veneer lumber (LVL) and parallel strand lumber (PSL). Due to the potential of using OPT as raw a material for panel product, it is necessary to investigate its properties. Therefore, the main objective of this study is to determine the general properties of OPT veneer and its interaction with adhesives. The properties investigated were moisture content, relative density, pH, buffer capacity, wettability, surface tension, adhesive penetration and bending strength and stiffness. The moisture content of dry veneer was approximately 8%. The results of relative density of OPT veneer increased significantly from the bottom portion to the top portion and declined significantly inward from the outer part to the inner part. The average mean pH value and buffer capacity of OPT veneer were 4.52 and 0.12 me., respectively. Contact angle of the surface using deionised distilled water was 49.78°. Surface tension parameter of OPT veneer for Lifshitz van der Waals’ (γSLW) component was 39.40 mJ/m², acid or electron accepting (γS+) was 1.65 mJ/m², base or electron donating (γS-) was 38.37 mJ/m² and total surface tension (γS total) was 55.20 mJ/m². In general, the adhesive penetration properties when using PF and UF resins were significantly different between parts and temperatures, but only slightly significant at different portions. Bending strength properties of laminated OPT veneer when using PF and UF resins mostly gave a higher significance value for comparison at different temperatures, portions and parts. A Pearson correlation coefficient was computed between bending strength and adhesive penetration properties of laminated OPT veneer using PF and UF resins. Generally a weak, positive correlation was established and found to be significant.