Impact of thermal modification combined with silicon compounds treatment on wood structure
In the present study silicon containing formulations were investigated for their applicability in solid wood modification. Black pine sapwood was thermally modified at 180oC and 200oC (3, 5 and 7 hours) and afterwards, an additional chemical treatment with silicon containing systems (N-2-aminoethyl-3-aminopropyltrimethoxysilane) followed, in an attempt to invigorate hydrophobicity and durability of wood. Infrared spectroscopy (FTIR) was used to examine the formation of new bonds in the treated materials and atomic absorption spectrometry (AAS) to measure the silane concentration. The results showed a high reactivity between thermally modified wood and organosilicon compounds. The presence of bands representing vibrations of the Si–O–CH3 group in IR spectra of modified wood and after extraction confirms the stable character of the formed bonds between the hydroxyl group of wood and the methoxy groups of organosilanes. Furthermore, reactivity between wood and AE-APTMOS and alkyd resin solution was confirmed by the AAS results. Alkyd resin caused a higher concentration of silica in wood mass, which increases as the thermal treatment temperature increases. The organosilicon compounds caused a much higher resistance to water washout, revealing permanent binding of silanes to wood mass.