This paper discusses the chemistry of the reaction of alkaline copper and micronized copper with wood. The objective of this study is to examine the copper species produced in wood during the fixation reaction using electron paramagnetic resonance (EPR) spectroscopy. The initial experiments (phases 1 to 2) were designed to confirm the effect of time of treatment and solution concentration on the spectral parameters of copper in sawdust treated with copper sulphate solutions. The relative ease of distinguishing the copper produced from alkaline copper treatments with those produced during treatment of aqueous copper solutions was the focus of phase 3 while phase 4 examined the chemistry of sawdust treated with aqueous suspensions of copper carbonate. In the final phase, the focus was on determining whether a soluble copper species could be identified in wood treated with micronized copper preservatives. The spectra were compared to those of sawdust treated with aqueous suspensions of basic copper carbonate. The results of the study clearly show that soluble copper is produced relatively rapidly in wood treated with aqueous suspensions of basic copper carbonate and that this copper reacts with wood to produce similar copper complexes to that formed between wood and copper sulphate. These copper complexes resist leaching. This would support the premise that soluble copper formed by the reaction between basic copper carbonate and wood, can migrate into the wood cell wall in a manner similar to other soluble copper chemicals, and bind to wood cell components. Further research is in progress to further identify the chemistry of these reactions.

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