Dolores Julia Yusá-Marco

Study of behaviour on simulated daylight ageing of artists’ acrylic and poly(vinyl acetate) paint films

AbstractThis work proposes a multi-method approach that combines advanced microscopy (SEM/EDX, AFM) and spectroscopy (UV-vis and FTIR) techniques. This approach not only characterises the behaviour of the additives of two commercial poly(vinyl acetate) (PVAc) and acrylic emulsion paints but also simultaneously characterises the changes in chemical composition and morphology observed in the paint films as a result of ageing due to the paints being exposed to an intense source of simulated daylight. In parallel, a series of mechanical tests were performed that correlate the chemical changes in composition and the changes observed in the films’ mechanical properties. This work was a comparative study between both types of acrylic and PVAc paints. The results obtained are of great interest for the modern paint conservation field as they provide valuable information on the mid- and long-term behaviours of these synthetic paints. FigureTensile test of phthalocianyne blue Liquitex® paint film

Study of ageing of ketone resins used as picture varnishes by FTIR spectroscopy, UV-Vis spectrophotometry, atomic force microscopy and scanning electron microscopy X-ray microanalysis.

This paper presents a study of thin films of the commercial ketone resins Laropal K80, Keton N and MS2A, attempting to reproduce the pictorial layers and protective finishes commonly present in contemporary paintings. Chemical and morphological changes due to the degradation effect of environmental agents have been specially considered. For this purpose, three different accelerated ageing processes were applied to a series of specimens prepared from the studied commercial products: thermal, UV light and ageing in an SO2-polluted chamber. Spectroscopic techniques such as FTIR spectroscopy and UV–Vis spectrophotometry were applied in combination with microscopic examination techniques, namely, AFM and scanning electron microscopy energy dispersive X-ray microanalysis (SEM-EDX). Chemical changes due to UV light and thermal ageing are in good agreement with those previously reported in the literature. Bleaching exhibited by the three commercial products after exposure to a SO2-saturated atmosphere has been related to the diffusion of SO2-rich water vapour into the film. This effect was particularly strong in the MS2A resin due to the higher content of hydroxyl groups in this product.

Multimethod analysis of Iranian Ilkhanate ceramics from the Takht-e Soleyman palace

AbstractThe present work describes an analytical study performed on several pieces of Iranian Ilkhanate glazed ceramics from the Takht-e Soleyman palace (Iran, thirteenth century). Several advanced instrumental techniques, including pyrolysis–gas chromatography–mass spectrometry, Fourier transform IR spectroscopy, light microscopy, X-ray diffraction, scanning electron microscopy–X-ray microanalysis and voltammetry of microparticles, were used. The results obtained led to identification of the chemical and mineralogical composition of the pastes and glazes and the colouring agents. Corrosion processes associated with the extreme burial conditions in which the pieces remained for centuries were characterized in some areas of the glazes. A drying oil was identified as the main component of the organic material that was used as the adhesive for the decorative gold sheets applied on the glazes. This finding is in good agreement with traditional recipes. Interestingly, this drying oil exhibits an unusual composition as the gold sheet preserved it from external ageing agents (light, atmosphere, etc.). FigureTiles with cobalt blue glaze from the indoor decoration of the Takht-e Soleyman Palace (13th-15th centuries, Iran). a: 20986-8, b: 20986-10 and c:21300a