The Rate of Solvent Action on Modern Oil Paint

Abstract

The physico-chemical behaviour of modern oil paints used in artworks from the early twentieth century can be quite different to classical oil paint systems due to variations in paint formulation. There are many modern paint products that are sensitive to solvent exposure, which can prove challenging with respect to conservation treatment. Specific behaviours can be linked to ageing reactions; particularly oxidative cross-linking, oxidative fragmentation, hydrolysis and carboxylate formation. Hence, the lack of multivalent ions in modern oil paints (e.g. containing organic colorants) can lead to a different ageing behaviour. This is relevant, as the chemical nature of the glyceride network and the low molecular weight ageing products influences solvation properties, swelling behaviour and the leaching capacity of a modern oil paint. The efficiency of these processes within the first thirty seconds of solvent immersion was investigated, based on a set of 42 solvents with characteristic interaction properties. The data indicates that the kinetics of swelling and leaching does not primarily depend on the intermolecular interactions; but is essentially driven by the physical properties of the solvent.