Elisabetta Princi

Noninvasive and nondestructive NMR, Raman and XRF analysis of a Blaeu coloured map from the seventeenth century

A complete multianalytical study of a hand-coloured map from the seventeenth century is presented. The pigments atacamite, massicot, minium, gypsum, carbon black and vermilion were determined by means of XRF and Raman spectroscopy. The state of conservation of the cellulosic support was monitored by means of unilateral NMR. The analysis was nondestructive and noninvasive, and thus several spectra were collected from the same areas, yielding more reliable results without damaging the artwork. The role of copper pigments in the oxidation processes observed in the cellulosic support is discussed, as well as the possible provenance of atacamite as a raw material instead of as a degradation product of malachite.

Analysis of a coloured Dutch map from the eighteenth century: the need for a multi-analytical spectroscopic approach using portable instrumentation.

A Dutch map from the eighteenth century was multi-analytically analysed making use of energy dispersive X-ray fluorescence (EDXRF), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), Raman and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The cellulosic support was characterised and its state of conservation was evaluated. Besides, paramagnetic impurities were detected together with copper metallic chips. The colours present in some areas of the map were also analysed. Vermilion, carbon black and organic pigments were found. Surprisingly, in the green areas, the rare presence of the mineral moolooite (copper oxalate) was detected. A possible biological attack is discussed in order to explain the presence of such compound. Almost all of the techniques used in the analysis were portable, non-destructive and non-invasive, which is very desirable when analysing objects belonging to Cultural Heritage. The need for a multi-analytical approach using portable instrumentation is also discussed.

13C NMR Study of the Effect of Coordinating Solvents on Zirconocene-Catalyzed Propene/1-Hexene Copolymerization

The solvent effect observed in propene/1- hexene copolymerizations performed with the isospecific catalyst rac-Et(Ind) 2 ZrCl 2 /MAO is studied, A range of solvents with increasing donor character and steric hindrance has been tested, and their effect on copolymer yield, composition, and microstructure has been thoroughly analyzed. Our results demonstrate that the solvent can have a significant influence on the comonomer reactivities, even though the solvent polarity is not the relevant factor. At the same comonomer compositions in solution, polymerizations carried out in coordinating solvents (e.g., aromatic solvents), lead to the formation of products with considerably decreased content of 1-hexene. The reduced incorporation of the higher a-olefin is explained in terms of competition between the nucleophilic medium and the olefin monomer for coordination to the active polymerization site. These results give us valuable information regarding the mechanism of polymerization at the active centers.

In situ copolymerization for the consolidation of stone artefacts

In this paper, the properties of some polymeric materials used as consolidating and protective products in the restoration field of stone manufactured objects of artistic interest are discussed. The penetration of polymeric consolidating products is very small because of their macromolecular nature, and in situ polymerization of the monomers is suggested as an alternative technique to the use of macromolecular solutions. The effects of plasticizer agents in the reaction system have been investigated, in order to decrease T g and make the products more elastic.

Investigation of the Composition of Historical and Modern Italian Papers by Energy Dispersive X-ray Fluorescence (EDXRF), X-ray Diffraction (XRD), and Scanning Electron Microscopy Energy Dispersive Spectrometry (SEM-EDS)

In this work, a study concerning the composition of Italian papers from the seventeenth to the twentieth centuries was carried out using energy dispersive X-ray fluorescence spectrometry (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The analyzed samples consisted of papers employed for drawing, writing, printing, and absorbance. Observations carried out by SEM magnified the typical paper morphology. EDXRF in combination with XRD and SEM-EDS allowed the determination of calcite, gypsum, kaolin, talc, magnesite, and dolomite, used as fillers in the production of the papers studied herein. The inks present in the handwritten and printed papers, investigated by SEM-EDS and μ-EDXRF, were synthetic, Fe based, and iron gall inks.

The nanostructured morphology of linear polyurethanes observed by transmission electron microscopy

The morphology of polyester-based polyurethanes was observed by transmission electron microscopy, which highlighted a nanostructured system made by a continuous distribution of hard domains with size equal to few nanometres in the soft matrix.

Fibre width measurement and quantification of filler size distribution in paper-based materials by SEM and image analysis

In this paper the development of image processing and analysis routines for acquiring information about the paper structure from images obtained by scanning electron microscopy (SEM) is described. A new method to measure the fibre width based on the processing of superficial SEM observation is herein proposed and successfully applied to some commercial paper-based materials. The quantification of fillers in the Z-direction of paper was based on paper cross-sectional SEM images. The results obtained by image processing demonstrated the excellent performance and suitability of the proposed method to quantify exactly information concerning fraction and size distribution of digital fillers. The fraction of digital fillers was correlated with the surface roughness of a given paper grade.

Evaluation of enthalpy of mixing by calorimetric method: effect of hydrogen bonding in poly(4-hydroxy styrene)-based blends

To verify the effect of hydrogen bonding on the polymer mixing, blends of poly(vinyl methyl ether) (PVME) and poly(methyl methacrylate) (PMMA) with poly(4-hydroxy styrene) (PHS), respectively, have been prepared. The effect of hydrogen bond strength on the enthalpy of mixing, ΔHM, was investigated by microcalorimetric measurements and FTIR spectroscopy. Infrared analysis allowed to measure the amount of hydrogen bonding by a curve fitting procedure in PHS/PMMA blends, looking to the change in the characteristic bands of carbonyl group of PMMA. In the case of PHS/PMVE, the hydroxyl-stretching region has been investigated to have only a qualitative estimation of hydrogen bonding. For both PHS/PMVE and PHS/PMMA systems, the measured exothermic (negative) ΔHM decreases with the increase in the PHS content, indicating that the presence of strong specific intermolecular interactions, such as hydrogen bonding, favours the polymer blending.