Chemistry and water-repelling properties of phenyl-incorporating wood composites

Abstract

Abstract The properties of materials are presented, which are resulting from a combined inorganic-organic modification of wood with phenyltrimethoxysilane or phenyltriethoxysilane in a simple one-step impregnation treatment. The permanent swelling of the wood showed that the precursors entered the cell walls. The inclusion of phenyl groups, manifest by nuclear magnetic resonance spectroscopy, made the resulting wood composites highly hydrophobic, as evidenced by their low wettability and antishrink efficiencies of up to 44%. Impedance spectroscopy indicated that wood methylol groups took part in the condensation reactions with hydrated siloxanes, contributing to the high hydrophobicity and making the added phase resistant to leaching. The composites exhibited high weight percentage gains of up to 52% and ash contents up to 19%. The thermal properties of precursor solutions and products were assessed by differential scanning calorimetry and thermogravimetric analysis and compared with the more common silica precursor, tetraethyl orthosilicate.