Oxidation and Cross-Linking in the Curing of Air-Drying Artists’ Oil Paints

In this study, the chemistry of air-drying artist’s oil paint curing and aging up to 24 months was studied. The objective is improve our molecular understating processes that lead conversion fluid binder into a dry film how evolves with time, which at base better comprehension degradation phenomena paintings relevant artists’ manufacturing industry. To aim, methodological approach based on thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), gas chromatography–mass spectrometry (GC–MS), analytical pyrolysis coupled chromatography mass (Py–GC–MS) implemented. Model linseed safflower (a drying semidrying oil, respectively) mixed two historically pigments—lead white through drier) synthetic ultramarine blue pigment often encountered in degraded painting layers)—were investigated. under accelerated conditions (80 °C air flow) followed by isothermal TG analysis. oxygen uptake profiles were fit semiempiric equation allowed study kinetics oxidation estimate oxidative degradation. DSC signal due hydroperoxide decomposition radical recombination used monitor activity over time evaluate stability peroxides formed layers. GC–MS performed 7 natural investigate noncovalently cross-linked fractions Py–GC–MS characterize whole organic fraction model paintings, including network. We show oil–pigment combination may have strong influence relative degree films respect its cross-linking, be correlated literature Undocumented pathways are also highlighted.