Influence of temperature on fixation of copper–ethanolamine-based wood preservatives

Abstract

Market share of copper–ethanolamine-based wood preservatives is increasing in the past decade; despite of the fact that copper fixation is still not comparable to fixation of copper–chromium-based ones. One of the reasons for increased emissions originates in ethanolamine. Ethanolamine excesses depolymerizes lignin macromolecule, what consequence in higher leaching rates. In order to eliminate this negative influence of ethanolamine, Norway spruce wood blocks were impregnated with three different copper–ethanolamine solutions of three concentrations. After impregnation, specimens were dried at four different temperatures (25, 50, 75 and 103 °C) and, afterwards, leached according to the modified ENV 1250 procedure. The results showed that increased temperatures during fixation did not decrease but increased copper leaching. It is presumed that the main reason for observed fact is ethanolamine, which did not evaporate from wood. Unfortunately, increased temperatures dramatically increase lignin depolymerization, as well as copper leaching.