WATER UPTAKE, MOISTURE ABSORPTION AND WETTABILITY OF BEECH VENEER TREATED WITH N-METHYLOL MELAMINE COMPOUNDS AND ALKYL KETENE DIMER

Abstract

With Beech veneers being treated with 10% solid content of the chemicals from paper (Alkyl ketene dimer, AKD), wood (N-methylol melamine, NMM-1) and textile industry (fatty acid modified N-methylol melamine, mNMM-2), the results showed that the treatments with these chemicals considerably increased the water repellence effectiveness (WRE) of veneers in the initial submersion phases; Then, WREs reduced significantly from 4 h of immersion to water saturation state (full-water). Moreover, with the WREs at water saturation state ranged from AKD (5.0%) to mNMM-2 (19.3%), there must be some certain chemical deposited in the cell lumen and cell wall of the treated veneers. The water repellence of the treated veneers was stable after the wetting-drying cycles. The chemicals NMM-1 and mNMM-2 that could react with hydroxyl groups or deposit into the cell wall, may induce the reduction in equilibrium moisture content (EMC_R) and radial swelling (RS) for the treated veneers, while large AKD particles could not penetrate and modify the cell wall therefore did not reduce EMC_R and RS in humid environment for the treated veneers. Wettability of veneers treated with AKD, NMM-1 and mNMM-2 was much lower than the untreated and control veneers.