Degradation Products Assessment of the Wooden Painted Surfaces from a XVIIth Heritage Monastery

Currently, approximately 70% of paintings in museum collections are affected by the presence of metallic soaps, evidenced by spherical globules visible on the surface of the paintings. They are responsible for altering the paintings’ surface through processes such as exfoliation and cracking, or even in the form of surface “skins” that appear in the pictorial layers. The objective of this study is the investigation of the icon paintings from Saint Mary Monastery, Techirghiol, Romania, which underwent some restoration procedures. This study is so important/significant, due to the presence of efflorescence that is correlated with the conversion of some fatty acids, as palmitic acid, stearic acid and azelaic acid, in the so-called metallic soaps through the reaction of the metals contained in the pigments from the painting layer and the binder. The investigated paintings are strongly affected by zinc carboxylate aggregation, and for this, the sample was embedded in polyester resin and the obtained cross-section, after polishing, was investigated by microscopic techniques (optical microscopy (OM), stereomicroscopy, and scanning electron microscopy with electronic dispersion spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and gas-chromatography with mass spectrometry (GC-MS) in good agreement with data from the literature. The potential result of this study is the identification and quantification of the metallic soap generated as a white deposit (probably salts, a kind of white efflorescence), from the binding medium of the metal carboxylate ionomer, by the crystallization of saturated fatty acids, through polymerization in oil. Six pigments (calcite, lithopone, carbon black, red ochre, vermilion, and ultramarine), present in the sublayers of the samples were identified

Degradation Products Assessment of the Wooden Painted Surfaces from a XVIIth Heritage Monastery

Currently, approximately 70% of paintings in museum collections are affected by the presence of metallic soaps, evidenced by spherical globules visible on the surface of the paintings. They are responsible for altering the paintings’ surface through processes such as exfoliation and cracking, or even in the form of surface “skins” that appear in the pictorial layers. The objective of this study is the investigation of the icon paintings from Saint Mary Monastery, Techirghiol, Romania, which underwent some restoration procedures. This study is so important/significant, due to the presence of efflorescence that is correlated with the conversion of some fatty acids, as palmitic acid, stearic acid and azelaic acid, in the so-called metallic soaps through the reaction of the metals contained in the pigments from the painting layer and the binder. The investigated paintings are strongly affected by zinc carboxylate aggregation, and for this, the sample was embedded in polyester resin and the obtained cross-section, after polishing, was investigated by microscopic techniques (optical microscopy (OM), stereomicroscopy, and scanning electron microscopy with electronic dispersion spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and gas-chromatography with mass spectrometry (GC-MS) in good agreement with data from the literature. The potential result of this study is the identification and quantification of the metallic soap generated as a white deposit (probably salts, a kind of white efflorescence), from the binding medium of the metal carboxylate ionomer, by the crystallization of saturated fatty acids, through polymerization in oil. Six pigments (calcite, lithopone, carbon black, red ochre, vermilion, and ultramarine), present in the sublayers of the samples were identified

ASSESSMENT OF MICROPLASTICS IN PERSONAL CARE PRODUCTS BY MICROSCOPIC METHODS AND VIBRATIONAL SPECTROSCOPY

Primary microplastics, known as microbeads (μBs), are found in personal care and cosmetic products (PCCPs) being used as an ingredient for physical abrasion on human body surface. Due to the fact that μBs has sizes less than 0.8 mm, sometimes even less than 0.1 mm, they can be ingested by many organisms, being transmitted in the food chain. The development of a method for isolating the microplastics from the matrix of branded PCCPs samples (i.e., shower gel, body spray) using ultrasound technique at constant temperature and pressure, high-performance vacuum filtration method with various high-purity filtration membranes (e.g., cellulose) was the first objective of this study. The second objective was to combine vibrational spectroscopy techniques (i.e., Fourier-transform infrared μ-spectroscopy) with optical microscopy, to investigate the morphology and chemical composition of MPs. Microplastics were identified in all five brands of analyzed products. Thus, an average value of 420 μBs/100 g in shower gel and 200 μBs/100 mL in body sprays was determined; the identified colors were black (mostly), blue, yellow, brown, green, and red. The observed sizes varied from tens of micrometers to a few centimeters in some cases and the thickness reached 10 μm. From visual (microscopy) and chemical (μ-FTIR spectroscopy) point of view the structure was mostly like polypropylene fibers, smaller and having glossy mate appearance

Non-Destructive and Micro-Invasive Techniques for Characterizing the Ancient Roman Mosaic Fragments

The color characteristics, vibration spectra, phase and mineral composition, internal structural organization of several fragments of the ancient Roman mosaics from the Roman Mosaic Museum, Constanta, Romania were studied by non-destructive (Chromatic analysis, Neutron Diffraction, Neutron Tomography) and micro-invasive techniques (Optical Microscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy, Raman Spectroscopy, Wavelength Dispersion X-ray Fluorescence). These investigations were performed in order to characterize the original Roman mosaic fragments. The major and minor phase components of the studied mosaic fragments were determined, the crystal structure of the main phases was analyzed, and their three-dimension spatial arrangement was reconstructed. The similar composition of the major phases of all mosaic fragments can indicate a generic recipe for making mosaic elements, but minor phases were presumably added for coloring of mosaic pieces. Some degradation areas inside the volume of the mosaic fragments were found by means of neutron diffraction and neutron tomography methods. These degradation areas are probably related to the formation of iron hydroxides during chemical interactions of mosaic fragments with the sea and urban polluted atmosphere

Novel Structures of Functionalized Graphene Oxide with Hydrazide: Characterization and Bioevaluation of Antimicrobial and Cytocompatibility Features

Graphite was oxidized to graphene oxide and activated by thionyl chloride, for further covalently linking three hydrazides with potential biological activity. The obtained materials were characterized by scanning electron microscopy with energy dispersive spectroscopy, Fourier-transform infrared and Raman spectroscopies. The presence of various functional groups specific to graphene oxide (GO) functionalized with different hydrazides was confirmed by spectral data. The ratio between D- and G-bands, observed in Raman spectra, allowed for an evaluation of the disorder degree and the mean crystallite size of the samples. The micrographs highlighted that the samples lead to the occurrence of disorders, probably caused by the sp3 carbons, the formation of oxygen-containing functional groups in the basal planes, and by various structural defects. The new graphene oxide–hydrazide derivatives were tested for their antimicrobial and cytotoxicity activity. Their antimicrobial activity against planktonic and biofilm-embedded cells was inferior to that of free hydrazides, except for GO-3 against planktonic Escherichia coli and GO-2 against Pseudomonas aeruginosa biofilm, demonstrating that further optimization is needed to be able to exploit the huge potential of GO for developing potent antimicrobials