Water-repellent acylated and silylated wood samples and their surface analytical characterization

The interest for chemical modification of wood with the aim of preserving it from physical and biochemical deterioration is rapidly increasing. Among the possibilities, acetylation has a great potential for improving the dimension instability of wood against moisture and the durability of wooden objects. Recently, a new acetylating agent, isopropenyl acetate has attracted attention giving an improved acetylating method. By increasing the size of the acyl group, a positive effect on the wood hydrophobicity can be reached. The anhydrides, however, are less reactive. Another applicable surface modification is the silylation of wood that renders the wood surface hydrophobic.. In this paper, we report about the acylation and silylation of different wood samples. A new manufacturing process is tested in which low-value Eucalyptus wood is mixed acylated. The reagent mixture contains at least two kinds of acyl group. One of them is acetyl group; the other(s) can be user-defined. We also report about a silylation method, in which catalyst facilitates the chemisorption process. The extent of modification of the treated wood samples was evaluated by means of weight percent gain, ATR-FTIR, and pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Methylene blue adsorption of selected samples was also studied. The result of analytical measurements was in agreement with that of wettability studies. (C) 2007 Elsevier B.V. All rights reserved.