A wood treatment based on siloxanes and boric acid against fungal decay and coleopter Hylotrupes bajulus

A wood preservative based on tetraethyl orthosilicate (TEOS), 3-aminopropyltriethoxysilane (APTES), andboric acid (BA) in volume ratio TEOS/APTES 1:1 and in molar ratio APTES/BA 50:1 was applied to wood bythe solegel process. Standard EN 113 and mini wood block tests were carried out to determine theeffectiveness against fungal decay. The same formulation applied by immersion was tested against larvaeof the wood-borer insect Hylotrupes bajulus. This formulation showed good efficacy against Coniophoraputeana, Poria placenta, and Trametes versicolor, even after a leaching procedure. It was also effectiveagainst the coleopter H. Bajulus. Different molar ratios of APTES/BAd2.5:1, 5:1, and 10:1dwere testedwith a leaching procedure in accordance with EN 84 to determine the best fixation of boric acid into thewood. The ratio APTES/BA 5:1 was found to be the most effective for fixing boron into wood.