Modern Paints Exposed to Outdoor and Indoor Conditions: a Multi-Analytical Study

In order to preserve modern and contemporary art, it is important to understand the chemical behaviour of the synthetic organic materials such as acrylic, alkyds and polyvinyl acetate (PVAc) used for this field of art, when exposed to different light sources, such as sunlight found in outdoor conditions, as well as Light Emitting Diode (LED) lately widely used in museums. For such studies a multi-analytical approach based on reactive (THM-GC/MS) and non-reactive pyrolysis – gas chromatography / mass spectrometry (Py-GC/MS in the single and double-shot mode), Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIRATR), and colour measurements, were employed to investigate the stability of two types of acrylic binding media as well as alkyd and polyvinyl acetate (PVAc) to accelerated artificial sunlight ageing. Furthermore, an acrylic and alkyd binder type was exposed to three different types of illumination such as two newly developed LED-lighting systems – one based on a short wavelength blue LED and the other one on a long wavelength blue LED – and a halogen lamp. Particular attention was also paid to the influence of inorganic pigments on the photo-oxidative stability of the binding media. For this purpose, the binders in their pure form as well as mixed with different inorganic pigments were analyzed before and after exposure to ageing for different periods of time.