Jump to main content
Jump to site search

Issue 17, 2013
Previous Article Next Article

Interactions between inorganic pigments and proteinaceous binders in reference paint reconstructions

Author affiliations

Abstract

The degradation of the proteinaceous binders, ovalbumin (OVA) and casein, and their interactions with azurite (Cu3(CO3)2(OH)2), calcium carbonate (CaCO3), hematite (Fe2O3) and red lead (Pb3O4) pigments were studied. A multi-analytical approach based on Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Size Exclusion Chromatography (SEC) was used. The research was carried out on a set of paint reconstructions, which were analysed before and after artificial light ageing. We highlighted that in most cases the inorganic pigments interact with both proteins by decreasing their thermal stability and their intermolecular β-sheet content, and that ageing induces aggregation. We hypothesized that pigments intercalate between protein molecules, producing a partial disruption to the proteinprotein intermolecular interaction. In the case of casein, these phenomena continued during ageing. In fact, we observed a complete disappearance of intermolecular β-sheets and an increase in intramolecular β-sheets and random coil during ageing. This result is in agreement with the structural properties of casein, whose aggregation is known to be induced by hydrophobic interactions. On the other hand, in aged OVA paint replicas, we observed the formation of new intermolecular β-sheets and an increase in thermostability. In addition FTIR showed oxidation of the side chains of the aged OVA/hematite sample and aged casein pigment samples, and SEC highlighted hydrolysis phenomena in aged carbonate, azurite and red lead/OVA complexes and in aged casein/calcium carbonate and casein/azurite samples.

Graphical abstract: Interactions between inorganic pigments and proteinaceous binders in reference paint reconstructions

Back to tab navigation

Publication details

The article was received on 21 Sep 2012, accepted on 30 Nov 2012 and first published on 30 Nov 2012


Article type: Paper
DOI: 10.1039/C2DT32203J
Citation: Dalton Trans., 2013,42, 5975-5984
  •   Request permissions

    Interactions between inorganic pigments and proteinaceous binders in reference paint reconstructions

    C. Duce, E. Bramanti, L. Ghezzi, L. Bernazzani, I. Bonaduce, M. P. Colombini, A. Spepi, S. Biagi and M. R. Tine, Dalton Trans., 2013, 42, 5975
    DOI: 10.1039/C2DT32203J

Search articles by author

Spotlight

Advertisements