EFFECTS OF SURFACE PRETREATMENT ON WETTABILITY OF ACACIA MANGIUM WOOD

Furniture manufacturers using Acacia mangium wood often experience difficulties in getting high glossy and attractive finished surface. Such problems may be attributed to poor surface wettability as well as the anatomical structure of the wood itself. This study evaluates the effects of surface treatment on the wettability of A. mangium wood. Acacia mangium lumber was segregated into sapwood and heartwood prior to sanding. Two types of solvents, methanol and sodium hydroxide (NaOH) at different concentrations (2, 4, 6, 8, 10, 12 and 14%) were used to treat the wood surface. The treated surfaces were evaluated for surface roughness and contact angle according to ISO 4287 and ASTM D7334-08 respectively. The results showed that untreated sapwood of A. mangium had significantly rougher surface compared with heartwood after treatment with methanol and NaOH. NaOH-treated surface had relatively lower contact angle than methanol-treated wood and experienced complete wetting within 4.2 s for sapwood and 6.8 s for heartwood. The surface was darker and the grain was less visible. Methanol-treated sapwood and heartwood took 6.4 and 12.1 s respectively to be completely wet but retained its original colour. Their wood grain was clearer and much enhanced. Based on both wettability and appearance, the best results were given by 6% methanol for sapwood and 4% methanol for heartwood.