DEGRADATION OF TBTO PRESERVATIVE IN PINUS-RADIATA

Nuclear magnetic resonance (NMR) spectroscopy and gas chromatography mass spectroscopy (GC - MS) were used to investigate the behaviour of bis(tri-n-butyl)tin oxide (TBTO) in light organic solvent preservative (LOSP) treated radiata pine. Timber samples dried under three different temperature regimes were impregnated with TBTO (2.5% w/v in kerosine) using a Lowry process. The distribution of tin species present in the treated timber varied considerably between air-dried samples and those dried at elevated temperature. TBTO was the predominant species in air-dried timber but high temperature kiln-dried timber contained a large proportion of tributyltin esters. Significant losses of total tin (up to 30%) were recorded from treated timber stored indoors for several months. The long-term effects of this on the durability of treated timber are still unknown.