Mattel's Barbie: Investigation of a Symbol-Analysis of Polymeric Matrices and Degradation Phenomena for Sixteen Dolls from 1959 to 1976.

Mattel's Barbie dolls are the most famous and iconic dolls since 1959. Today, they are being collected by individuals and often conserved in museum environments due to their cultural and historical significance reflecting everyday life and historical events. However, just like most museum objects made of plastics, both historical and more recent Barbies show evident degradation phenomena. Firstly, Barbies were made of plasticized polyvinyl chloride (PVC), affected by the migration of additives-mostly the plasticizers-from the bulk phase to the outermost layer, appearing as a tacky and glossy exudate. Over the years, Barbies' polymeric constituents were replaced with more stable ones, whose additives migration is limited compared to PVC, even though still occurring. Multispectral photography in visible (VIS) and ultraviolet (UV) light, microscopical observations in VIS and UV light, and Fourier Transform Infrared spectroscopy in the Attenuated Total Reflectance mode (FT-IR ATR) were performed to characterize the constituent materials of 15 Barbies produced between 1959 and 1976, bridging the information gap on their processing over the years. The micro-invasive multi-analytical approach also allowed for the characterization of the degradation products, permitting the reference of the exudated compound to the specific bulk polymer.

Cytotoxicity inhibition of catechol's type molecules by grafting on TiO2 and Fe2O3 nanoparticles surface.

The potential toxicity deriving from the interaction between chemicals and manufactured nanoparticles (NPs) represents an emerging threat to the environment and human health. Several studies have focused on the risks and (eco)toxicity of manufactured NPs as a consequence of their extensive use in recent years, however, there is still a limited understanding of the combined effects caused by manufactured NPs in the presence of other environmental contaminants. This is particularly relevant to aquatic environments, where many types of pollutants are inevitably released and can be involved in many kinds of reactions. In this context, the interaction between catecholate type ligands and two different nanomaterials, namely TiO2 and Fe2O3 NPs, was investigated by performing cytotoxicity assays with the topminnow fish hepatoma cell line (PLHC-1) using: i) the original organic molecules, ii) pristine NPs alone, and iii) modified NPs obtained by grafting the ligands on the NPs surface. Cytotoxic effects were explored at three different levels, specifically on cellular metabolism, membrane integrity and lysosomal activity. The outcomes from these assays showed cytotoxicity only for the free catechol type ligands, while in general no significant decrease in cell viability was observed for pristine NPs, as well as for the modified NPs, regardless the initial cytotoxicity level of the organic ligands These results suggest that the binding of catechols on the NPs' surface inhibited their cytotoxicity, indicating that TiO2 and Fe2O3 NPs may act as sorbents of these contaminants, thus reducing their possible detrimental effects.

Data Fusion Approach to Simultaneously Evaluate the Degradation Process Caused by Ozone and Humidity on Modern Paint Materials.

The knowledge of the atmospheric degradation reactions affecting the stability of modern materials is still of current interest. In fact, environmental parameters, such as relative humidity (RH), temperature, and pollutant agents, often fluctuate due to natural or anthropogenic climatic changes. This study focuses on evaluating analytical and statistical strategies to investigate the degradation processes of acrylic and styrene-acrylic paints after exposure to ozone (O3) and RH. A first comparison of FTIR and Py-GC/MS results allowed to obtain qualitative information on the degradation products and the influence of the pigments on the paints' stability. The combination of these results represents a significant potential for the use of data fusion methods. Specifically, the datasets obtained by FTIR and Py-GC/MS were combined using a low-level data fusion approach and subsequently processed by principal component analysis (PCA). It allowed to evaluate the different chemical impact of the variables for the characterization of unaged and aged samples, understanding which paint is more prone to ozone degradation, and which aging variables most compromise their stability. The advantage of this method consists in simultaneously evaluating all the FTIR and Py-GC/MS variables and describing common degradation patterns. From these combined results, specific information was obtained for further suitable conservation practices for modern and contemporary painted films.

How Can Ozone and Relative Humidity Affect Artists' Alkyd Paints? A FT-IR and Py-GC/MS Systematic Study.

Knowledge of the chemical-physical reactions that determine the main degradation behaviour of artists' alkyd paints represents one of the main problems within the museum exhibitions. The collection and interpretation of these data on degradation phenomena, especially after ozone exposure at different relative humidity values, can be useful for their conservation needs. Therefore, a systematic investigation of these materials may help achieve this goal. Firstly, surface-level identification of the main functional groups of ad hoc created and aged alkyd paints was performed using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Subsequently, these paints were investigated by pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS), allowing for precise bulk identification of the organic compounds before and after accelerated ageing. A first successful attempt to provide quantitative Py-GC/MS data on alkyd-based paints is here presented and discussed. Comparing the results, it was possible to obtain new insights into the degradation behaviour of alkyd paints when exposed to ozone, allowing us to devise specific preventive and conservation strategies for these artistic materials.

The role of bio-pollutants in the indoor air quality of old museum buildings: artworks biodeterioration as preview of human diseases.

Indoor air quality in buildings is strongly affected by chemical, physical, and biological agents. Long exposure to inadequate indoor air quality can be very dangerous for the building occupants and can lead to chronic diseases associated with the sick building syndrome (SBS). In this paper, the large presence of biological pollutants in the indoor rooms of an old building and its strict relationship with the outdoor/indoor air conditions were investigated studying Coronini Cronberg Palace Foundation, a historic house museum of the sixteenth century in Gorizia (Italy), where biological contamination affecting the artworks can soon become potentially harmful also for operators and visitors. Detailed aerobiological and microbiological analyses on organic natural materials, combined with a microclimate monitoring, were conducted to evaluate the influence of temperature and relative humidity levels within the Palace in the conspicuous growth and diffusion of microorganisms. Fungal and bacterial colonies damaging materials, mainly affected by the sudden fluctuations of hygrothermal values, were found to widely exceed Italian and international recommended levels for good air quality for both artworks and human beings. Understand their impact on human health would be strictly necessary to reduce biological risks for museum staff and cultural heritage users, but consequently to improve indoor air quality.

A Critical Review on the Analysis of Metal Soaps in Oil Paintings.

Up 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.

Disclosing the composition of unknown historical drug formulations: an emblematic case from the Spezieria of St. Maria della Scala in Rome.

This paper reports a pioneering study of an unknown historical drug formulation preserved in the Spezieria of Santa Maria della Scala in Rome, founded at the end of the seventeenth century by the Discalced Carmelites. Due to limited literature related to pharmaceutical remedies and drugs of the Early Modern Era (between the XV and XVIII centuries) and the complexity in their formulations, the study of these drugs represents a great challenge. The untargeted nature of the selected drug required a multi-analytical approach with complementary techniques to formulate a compositional hypothesis: FT-IR spectroscopy, gas chromatography-associated/mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) were successfully employed to identify different organic compounds. Systematic archaeobotanical research was performed as well, allowing us to acquire data related to the possible genus of plants from which these natural compounds derive and their geographical origin. The unknown drug formulation turned out to be a complex mixture used as an ointment with an anti-inflammatory purpose. It mainly contains a mixture of Venetian turpentine; a Pine resin (colophony) from the Pinaceae family; an exudate of a plant from South America, whose identified components are triterpenic compounds such as alpha- and beta-amyrins, betulin and lupeol; and saturated fatty acids which act as carriers and/or to reduce the viscosity of abovementioned exudates and resins. The study of historical drugs is important not only in order to know the practices handed down by the speziali in the past but also to reconstruct historical recipes, which can inspire new dermatological, cosmetic, hygienic and current healing products.Graphical abstract.

Accelerated Ageing Procedures to Assess the Stability of an Unconventional Acrylic-Wax Polymeric Emulsion for Contemporary Art.

This research evaluates the stability of an aqueous emulsion of acrylic copolymers and waxes. Edelwachs, generally applied on wood, has been recently used as an unconventional medium in contemporary painting. Through Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) and Fourier Transformed Infrared Attenuated Total Reflectance (FT-IR-ATR) analyses, the composition of Edelwachs was defined as a mixture of acrylic polymers (MA, MMA, nBA, nBMA), Carnauba and microcrystalline waxes and additives. Mock-ups-obtained mixing Edelwachs with titanium white, zinc white and ultramarine blue were subjected to UV, high temperatures, and high relative humidity accelerated ageing. The effect of the ageing procedures was evaluated through optical microscopy, colourimetric measurements, FT-IR-ATR, Thermogravimetry and Differential Scanning Calorimetry (TG-DSC) and wettability measures. FT-IR-ATR spectra do not show significant variations in terms of chemical stability, indicating a fair stability of Edelwachs as a painting binder. UV and high temperature treatments show the most relevant effects in terms of colorimetric changes (increasing of b*) and thermal stability. The TG-DSC highlights the influence of the pigments (specifically zinc white) mainly on the thermal behaviour of the acrylates. The unexpected decrease of wettability of the paint films, registered after ageing, may indicate a possible phase separation among acrylates and waxes.

Investigation of modern oil paints through a physico-chemical integrated approach. Emblematic cases from Valencia, Spain.

The study and the characterisation of modern and contemporary oil paintings is still a challenging issue, in particular considering the significant changes in paint production across the 19th and 20th centuries. This paper presents the results of the first physico-chemical integrated study of the artistic materials used in six paintings from the School of Art and Higher Design of Valencia (Escola d'Art i Superior de Disseny, EASD-Valencia), artworks created between 1871 and 1943 by four famous Valencian artists: Salustiano Asenso Arozarena, Salvador Abril I Blasco, Enrique Navas Escuriet and José Bellver Delmás. A wide range of inorganic and organic compounds was identified through a multi-analytical approach by means of visible reflectance spectroscopy, XRF, µ-Raman, FTIR and GC-MS. The investigation on the binding media suggests the use of commercial paint formulations including mixtures of drying, slow- and non-drying oils and the presence of Gum Arabic as well. Traditional pigments (such as vermillion, earth pigments, lead white) and modern pigments (such as zinc white, cobalt and chromium-based pigments) were identified together with fillers and extenders. Degradation products, in particular zinc and lead soaps having strong conservation implications, were also detected. This work, focusing on the identification of the palettes and the binding media used by the selected artists, aims at providing meaningful data and interesting case studies that are useful beyond the Valencian painters solely. This study provides new insight into the use of 19th-20th century commercial oil paints and the selection of painters' palette and their artistic production techniques. Besides, this work highlights the necessity of a multi-analytical approach to obtain valuable information for documentation and preventive conservation.