Biological test, AAS and EPR study of copper monoethanolamine complex with quaternary ammonium compounds as a wood preservative
B Mazela, I Polus, S K Hoffmann, J Goslar
Experiments were carried out on the wood preservative with a strong fungicidal activity based on Cu(II) carbonate, 2-aminoethanol (monoethanolamine) and quaternary ammonium compound (QAC). The object of the performed investigations was sapwood of Scots pine (Pinus sylvestris L.) treated with Cu-EA-QAC formulation. Mycological investigations were carried out according to EN 113 and EN 84 standards. The retention of the copper ions in the wood grows nonlinearly with concentration (in %) of the impregnating solution from 0,25 kg/m3 at 0.03% to 1,55 kg/m3 at 0.21% (i.e. nearly 6 times) whereas the copper leachability decreases 2,5 times from 15% to 6% in the same range. These results indicate good fixation of the copper to the wood and high leaching resistance. EPR results and computer simulations of the observed EPR spectra shows that in Cu-EA aqueous solution the Cu(EA)2(H2O)2 complexes exist and the main coordination plane is not destroyed in impregnating solution and in the wood. In Cu-EA-QAC-BA solution the Cu(EA)2(QAC)2 complexes appear whereas EPR spectra of the treated wood indicate coexistence of a few types of Cu-complexes. We have identified strongly fixed Cu(EA)2O2 and Cu(EA)2O complexes with oxygens atoms from wood functional groups.