Effect of quat- and amino-silicones on fungal colonisation and decay of wood

Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) wood samples treated with quaternary (quat)and amino-silicone (QS and AS) solutions of different chain lengths were tested against brown-rot and white-rot fungi as well as with regard to blue stain colonisation. The treatment with short-chained silicones bearing quat and amino functional group reduced the mass loss (ML) by decay fungi at 15% treatment concentration. The release of metabolic heat by decayed samples determined in a microcalorimeter corresponded with the ML of the samples, i.e., samples with high ML produced more heat indicating higher fungal activity. Short-chain ASs reduced the blue staining more strongly than long-chain ones. However, the opposite was true in the case of QS. It was assumed that the combined effect of hydrophobation, cell wall bulking and change of the wood surface energy are responsible for a successful performance of silicone compounds as wood preservatives.