Interaction of copper-containing preservatives with wood. Part 1. Mechanism of the interaction of copper with cellulose

In the present work. the stare of the copper ions absorbed by cellulose from aqueous solutions with different pH values has been studied by electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray analysis (EDXA) methods, It has been shown that the curve of copper sorption has a S-like shape characteristic for weak acid sorbents. At all pH values in ESR-spectra, an anisotropic Cu(II)-signal is registered. At pH >4, the anisotropy of ESR-spectra decreases. At pH = 10, complexes connected by exchange interactions and diamagnetic clusters are formed. After the leaching of specimens, the ESR-signal practically disappeared. The decrease of the copper content in cellulose did not correlate with the change of the integral intensity of the spectra. The changes in ESR-spectra of copper-containing cellulose after leaching were explained by the formation of the Cu(II) diamagnetic clusters.