1,721,048 research outputs found
Rapid initial dimensional changes in wooden panel paintings due to simulated climate-induced alterations monitored by digital coherent out-of-plane interferometry
No full textMulti-Analytical Assessment of Bodied Drying Oil Varnishes and Their Use as Binders in Armour Paints
Full text linkThe characteristics of commercially available refined and bodied linseed and tung oils, used as binders in the production of armour paints after historic recipes, are explored. Employed as anticorrosive paints mainly from the 1920s to 1960s, armour paints are greener alternatives that can be used for protection in industrial heritage conservation. Using a multi-analytical approach, chemical and physical properties of the fresh oils and solid films before and after accelerated ageing (ISO 16474-2:2013) were investigated to better understand which features are beneficial for the technical function of armour paints. Tests included measurements of density, the refractive index, insoluble impurities, alkaline impurities, the water content, the iodine value, the saponification value, the free fatty acid concentration, the acid value, the peroxide value and colour (Lovibond) and cold tests. The characterisation of the fresh oils using molecular analysis with FTIR and GC-MS revealed the complexity of the commercial formulations, for which additions of semi- and non-drying oils were detected. The results show that organic paint binders follow complex chemical reactions (such as oxidation and decrease of unsaturation being variable or swelling following water-immersion tests), with implications for their suitability for use in protection
The influence of visible light and inorganic pigments on fluorescence excitation emission spectra of egg-, casein- and collagen-based painting media
No full textTotal Synchronous Fluorescence Spectroscopy Combined with Multivariate Analysis: Method for the Classification of Selected Resins, Oils, and Protein-Based Media Used in Paintings
No full textRecent interest in the fluorescence of binding media and varnishes (proteins, oils, and resins) commonly used in paintings is based on the potential for discriminating these organic materials. A useful way of studying the presence of the broad-band fluorescence emissions found in these complex organic materials is fluorescence excitation emission spectroscopy. However, due to the presence of Raman and Rayleigh scattering which may necessitate correction or preprocessing for statistical analysis and visualization, an alternative approach has been adopted for the analysis of different samples of artist materials based on total synchronous fluorescence spectroscopy. Films of selected drying oils, glue, egg, and casein and the resins mastic, dammar, copal, and shellac were analyzed using total synchronous fluorescence spectroscopy, and an interpretation of the differences between spectra is given. A data reduction method based on the transformation of fluorescence contours extracted from total synchronous fluorescence from Cartesian to polar coordinates is presented and is followed by the comparison of data using multivariate analysis and hierarchical cluster analysis. Results suggest that the new method can be used to classify samples on the basis of their fluorescence spectra, clearly differentiating oils, resins, and protein-based media into groups
Analysis of protein-based media commonly found in paintings using synchronous fluorescence spectroscopy combined with multivariate statistical analysis
No full textAdvanced imaging and spectroscopy for the conservation and monitoring of cultural heritage
No full textStratigraphic analysis of organic materials in wall painting samples using micro-FTIR attenuated total reflectance and a novel sample preparation technique
No full textA Critical Review on the Analysis of Metal Soaps in Oil Paintings
Full text linkUp to 70 % of the oil paintings conserved in collections present metal soaps, which result from the chemical reaction between metal ions present in the painted layers and free fatty acids from the lipidic binders. In recent decades, conservators and conservation scientists have been systematically identifying various and frequent conservation problems that can be linked to the formation of metal soaps. It is also increasingly recognized that metal soap formation may not compromise the integrity of paint so there is a need for careful assessment of the implications of metal soaps for conservation. This review aims to critically assess scientific literature related to commonly adopted analytical techniques for the analysis of metal soaps in oil paintings. A comparison of different analytical methods is provided, highlighting advantages associated with each, as well as limitations identified through the analysis of reference materials and applications to the analysis of samples from historical paintings
Multianalytical Assessment of Armour Paints—The Ageing Characteristics of Historic Drying Oil Varnish Paints for Protection of Steel and Iron Surfaces in Sweden
Full text linkThe characteristics of armour paints, historically used to protect ferrous industrial heritage, are explored. Amour paints contain lamellar and highly reflexive pigments of micaceous iron oxide (MIO) and metallic, leafing aluminium, bound in linseed oil and linseed oil–tung oil mixtures, on an inhibitive and soap-forming linseed oil primer (red lead). It is the first study of the binding media used for historical armour paints and investigates the chemical and physical ageing of armour paints using a multianalytical approach. Naturally aged examples are compared to accelerated aged replica armour paint, and to historical paints. The ageing and degradation reactions are assessed by complementary GC–MS and FTIR, together with measurements of wettability, hardness and surface colour. The historical paint formulations include linseed oils and alkyd binders. The results confirm that the leafing effect of aluminium pigments results in only a small concentration of binder at the surface: the paints studied reflect light and form a strong chemical and physical barrier. Linseed oils and tung oil mixtures have been proven to be suitable for the production of armour paints, but the evaluation of ageing and assessment of physical changes will require further investigation
The degradation of poly(vinyl acetate) as a material for design objects: A multi-analytical study of the effect of dibutyl phthalate plasticizer. Part 1
No full textThe influence of dibutyl phthalate (DBP) plasticizer on poly(vinyl acetate) (PVAc) degradation was investigated. A multi-analytical approach (combining FTIR and Fluorescence spectroscopy, NMR and DSC analyses) was used to study how thermal- and photo-oxidative ageing treatments act on the polymer and assess the role of the additive in the degradation pattern. Standard and plasticized PVAc films were artificially aged at 60 °C in a thermal regime and irradiated at wavelengths above 290 nm in a photo-oxidative ageing regime, with exposure between 100 and 2000 h. The two types of ageing differ mainly in the formation of C{double bond, long}C double bonds along the polymer backbone, enhanced by thermal ageing, and the formation of aldehydic structures, following photo-oxidative treatment and in the degree to which plasticizer is lost. The integration of results from different analytical methods highlights the utility in combining complementary analyses for the study of PVAc degradation
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