Stabilization of copper- and iron-containing papers in mildly alkaline environment

Oxidative processes lead to enhanced degradation of cellulose in alkaline environment, especially in the presence of transition metals, such as iron and copper. Considerable parts of collections of manuscripts, drawings, maps and archival materials throughout the world are seriously damaged as the result of the use of iron gall inks and copper based pigments. The research on cellulose degradation and stabilization in the presence of transition metals is therefore crucial for the development of paper stabilization methods. The aim of this study was to evaluate the possibility of slowing down oxidative degradation of papers containing transition metals by their contact with paper folders containing antioxidant. The paper discusses the degradation rate constants of paper samples with elevated amounts of copper and iron ions and their mixtures during accelerated thermal ageing in contact with papers containing none or various amounts of quaternary ammonium salt. Their efficiency in respect to concentration of the antioxidants is presented. The research demonstrates that effective stabilization of paper samples with higher amounts of iron and copper ions in mildly alkaline environment by interleaving with papers, impregnated with antioxidant tetrabutylammonium bromide can be achieved under given conditions. Simple conservation procedure was proposed and evaluated for iron gall ink containing paper samples. (C) 2011 Elsevier Ltd. All rights reserved.