Resistance of scots pine (Pinus sylvestris L.) wood modified with functionalized commercial silicone emulsions against subterranean termites

Abstract

Scots pine (Pinus sylvestris L.) sapwood was treated with quat-silicone micro-emulsion (<40 nm), amino-silicone macro-emulsion (110 nm), alkyl-modified silicone macro-emulsion (740 nm) and solutions of inorganic water glass. Three treatment concentrations of 5, 15 and 30% (w/w) were used for the impregnation of the test specimens. Termite resistance was assessed following a 16-week field trial conducted in northern Queensland, Australia. Two different field sites were chosen for exposure to feeding by Coptotermes acinaciformis (Froggatt) and Mastotermes darwiniensis (Froggatt). Following exposure, the test and feeder specimens were inspected and assessed for termite damage using a visual rating system (from 10 sound to 0 completely destroyed) and individual mass losses. The specimens treated with quat- and amino-silicone emulsions resisted damage by both termite species, even at less than 15% weight percent gains (WPGs). Alkyl-modified silicone macro-emulsion and water glass treatment induced somewhat less resistance to termite damage, but imparted protection at higher WPGs.