The examination of preservative-treated radiata pine using electron spin resonance spectroscopy
D V Plackett, E W Ainscough, A M Brodie
Electron spin resonance spectroscopy (ESR) may be used to characterise the molecular environment of chemical species containing unpaired electrons. These species include free radicals, bi-radicals, point defects in solids, localised crystal imperfections and many transition metal ions. ESR has previously been applied to the examination of wood weathering or wood pyrolysis and now FRI and Massey University are collaborating on the use of ESR to characterise CCA-treated radiata pine. Samples examined to date have included Tanalith C-, Tanalith NCA-, and CuSO4-treated radiata pine. ESR spectra of treated wood give signals indicative of hydrated Cu2+ ions regardless of whether samples are examined in whole splinters or in ground form at room temperature or at -160°C. Comparison of the ESR spectrum of CuSO4-treated lignin with that of CuSO4-treated wood provided no evidence for copper complexation with lignin in treated wood.