Stamatina Theochari

This study aims to propose a multidisciplinary methodology for the assessment of raw papers made of fibres from annual plants, and to investigate their sheet-forming behaviour and potential for packaging materials for cultural heritage objects or archive collections. The study highlights the effects of dry heating artificial ageing on the mechanical and optical properties of the papers. Their morphology was examined through non-destructive spectral imaging in visible (VIS) and ultraviolet-induced visible luminescence (UVL), colourimetry and glossimetry. SEM and Dino Lite handheld digital microscopy have also been employed. The evaluated raw papers presented durability after ageing, with minor changes in pH, visual characteristics (colour/gloss), and mechanical properties (tensile strength), pointing to the usability of non wood packaging materials. The study can serve as a guide for a multi-faceted diagnostic methodology and in-situ testing for the assessment of newly developed and possibly sustainable packaging materials for sensitive archive collections and cultural heritage objects.

Green organic coatings are developed to be deposited on and protect metallic cultural heritage artefacts from environmental degradation. This research work is carried out through a comparative study of under-development green organic and commercial coatings for indoor and outdoor applications against an artificial ageing environment. Non-destructive techniques, such as Colorimetry, Glossimetry, Eddy-current thickness measurements, and SEM-EDS investigation, are employed to assess the studied bronze substrate-coating mock-up systems’ behavior. The results showed some correlations among the studied parameters, such as the thickness–colour (namely ΔΕ parameter) relationship, while comparative conclusions provide consultant suggestions for cultural heritage conservation applications.

Packaging materials made from polypropylene (PP) can be used to protect cultural heritage objects from damage ensuring their long-life preservation. This research work concerns the assessment of recycled polypropylene hollow chamber sheets as potential packaging materials for archival collections and cultural heritage objects. It was carried out through a multidisciplinary diagnostic methodology combining mechanical methods, non-destructive imaging techniques in visible light (VIS), and ultraviolet-induced visible luminescence (UVL), as well as handheld digital microscopy, colorimetry, glossimetry, and SEM microanalysis. The results showed that the condition and mechanical performance of the specimens are affected by the ageing process.

The role of Crocin, which is a natural organic substance from the Greek plant Crocus sativus, is investigated as a green corrosion inhibitor for the AA 1050 commercial aluminum alloy in 0.01 M sodium chloride solution. Its action was assessed by Linear and Tafel Polarization, as well as by mass loss measurements and confirmed by observation and analysis of the surface morphology of the specimens by Scanning Electron Microscopy. Corrosion inhibition efficiency of Crocin improves with concentration and at 1.25 mM was estimated in the range of 90-95%, which indicates the formation of an adsorbed layer that isolates and protects the surface. Experimental results showed that Crocin acts as a mixed-type inhibitor with predominantly anodic effectiveness, also retarding pitting corrosion process. The inhibitive action of Crocin was explained by theoretical calculations employing density functional theory, semiempirical PM6 and molecular mechanics methodologies, showing good agreement with experimental results. The reactivity of Crocin is attributed to chemisorption on the Al₂O₃ surface through its vicinal hydroxyls of the sugar moiety. This process is assisted by the π-conjugated system of the polyene chain together with the extended electron delocalization over the oxygen atoms of the esterified carboxyl groups, as well as by the intense electrostatic potential regions located on the sugar moiety of the Crocin molecule.

Adhesion, colorimetric analysis, and lightfastness of acrylate resin-based inks printed on an anodized aluminium substrate were studied. Samples of AA1050 alloy were chemically pretreated and anodized to appropriately modify the surface morphology in order to be printable. Printing inks with different compositions and two types of printing plates were used in the deposition of coatings by the screen printing technique. Surface morphology analyses, contact angle measurements, and surface free energy calculations were performed on the treated aluminium samples. The properties in terms of ink viscosity, thickness and surface characteristics of the printed unaged and aged coatings were observed. The results of the measurements performed on the coatings showed that different compositions of the inks lead to differences in the adhesion of the coatings to the aluminium substrate and affect the changes in the lightfastness of the coatings. The use of printing plates with different properties had a significant impact on the thickness and lightfastness of the printed coatings. The scientific results of this study have shown that it is possible to profile the printing influencing parameters depending on the application requirements.

The effect of anodizing temperature (10–50°C) at each particular stage of the anodizing process of the commercial AA5052 in 0.4 M H3PO4 at 30 V