Silvia Vicini

Physical-chemical characterisation of acrylic polymers grafted on cellulose

An oxidative reaction of cellulose with sodium metaperiodate was performed. The oxidised groups were decomposed by treatment with UV light into free macroradicals. In the presence of acrylic monomers, in the vapour phase, these reactive sites become the starting points for the graft copolymerisation of the cellulose substrate. In this study we examined the graft yield as a function of the polymerisation time and the oxidation degree of cellulose. The grafted polymer was characterised using several analytical techniques, DSC analysis, GPC analysis, viscosity, FTIR and 13C CP-MAS. Information on the morphology of grafted chains with respect to the bulk cellulose was obtained, measuring the dynamic parameters in a careful 13C CP-MAS NMR study. All proposed chemical reactions, if properly conducted, do not affect the crystallinity of cellulose and introduce only a very modest amount of oligomers, therefore they seem suitable for the consolidation and protection of precious cellulose based materials, which are of historical interest.

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.

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.

In situ copolymerisation of ethylmethacrylate and methylacrylate for the restoration of stone artefacts

Abstract In this paper the consolidating and protective products used in the restoration of stone manufactured objects of artistic interest are discussed; advantages of the different products and the relevant properties of the polymeric materials are underlined. The penetration of polymeric consolidating materials is very small and the in situ polymerisation of the monomers is suggested as an alternative technique to using macromolecular solutions. Some experimental results are presented showing that the in situ polymerisation improves the consolidating and the protective properties of polymers.

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.

CALORIMETRIC ANALYSIS OF THE POLYMERISATION PROCESS OF LINSEED OIL

In this paper the polymerisation of linseed oil is studied in order to prove the catalytic action of some inorganic pigments. The results show that the calorimetric technique is able to monitor the polymerisation process in the temperature range between 130 and220°C; reproducible values for isothermal analysis are obtained between 130 and 150°C;finally the results are quantitative and can be justified by kinetic equations.

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.

The influence of camphorquinone on the photochemical stability of cellulose

Abstract The photochemical stability of pure cellulose fibres and cellulose fibres with camphorquinone (CQ) has been studied by Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TG), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). The initial decomposition temperature T o , temperature of the maximum rate of the process T max and specific enthalpy Δ H were higher for cellulose fibres before UV irradiation than for those UV irradiated in either N 2 or air. The weight loss was higher for the samples after UV irradiation. In the presence of CQ the initial decomposition temperature T o for cellulose fibres was the same before and after UV irradiation, but much lower than for pure non-irradiated cellulose fibres. The specific enthalpy of the process is much lower after UV irradiation. The weight loss was smaller for the samples with CQ than for pure cellulose fibres. Comparison of the shape of the derivatographic, DSC and FTIR curves before and after UV irradiation suggests that photodegradation of cellulose occurs during irradiation of this biopolymer and that this process is faster in the presence of camphorquinone (CQ). The camphorquinone is photo-excited by UV light to the reactive triplet state and causes more efficient photodegradation of the cellulose.

Thermodynamics of polymer mixtures: study on the mixing process of the poly(styrene)/poly(vinylmethylether) system

Abstract The miscibility of poly(styrene) and poly(vinylmethylether) is studied both by measuring the glass transition temperatures of the mixture and with the application of the Flory–Prigogine theory in the approximated form due to Patterson. For these calculations, the enthalpy of mixing of the two polymers is evaluated by measuring the enthalpies of solution of the pure polymers and of the mixture. The trend of the interaction parameters with the temperature for two samples of poly(styrene) of different molecular weight is discussed.