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The conservation of polymer-based cultural heritage is a major concern for collecting institutions internationally. Collections include a range of different polymers, each with its own degradation processes and preservation needs, however, they are frequently unidentified in collection catalogues. Fourier transform infrared (FTIR) spectroscopy is a useful analytical tool for identifying polymers, which is vital for determining storage, exhibition, loan and treatment conditions. Attenuated Total Reflection (ATR), and External Reflection (ER) are proven effective FTIR sampling techniques for polymer identification and are beginning to appear in conservation labs. This paper evaluates and optimises the application of these two FTIR techniques to three-dimensional plastic objects in the museum context. Elements of the FTIR measurement process are investigated for 15 common polymers found in museum collections using both authentic reference sheets, and case study objects to model for surface characteristics. Including: use of the ATR and ER modules, the difference between clamping and manually holding objects in contact with the ATR crystal, use of the Kramers-Kronig Transformation, signal-to-noise ratios for increasing number of co-added scans, resultant time taken to collect each measurement, associated professional, health and safety considerations, and the use and availability of reference materials for polymer identify verification. Utilising this information, a flowchart for applying FTIR spectroscopy to three-dimensional historic plastic objects during museum collection surveys is proposed to guide the conservation profession.

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Characterisation and deterioration of mineral papersMineral paper, also known as rich mineral paper, is a paper-like material manufactured from calcium carbonate with a small amount of high-density polyethylene (HDPE), instead of traditional cellulose-based fibres. For environmental reasons, mineral paper was designed to degrade when exposed to sunlight. It was the aim of this study to address the research gap in conservation literature describing the properties and degradation patterns of mineral paper.Three mineral paper samples were characterised using visual examination techniques and analysed using Fourier transform infrared spectroscopy with attenuated total reflectance (ATR-FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Calcium carbonate, talc, kaolin, high-density polyethylene and an unknown trace material(s) were identified in these mineral papers. Under accelerated ageing conditions, the mineral paper samples consistently demonstrated a higher rate of chemical and physical degradation compared to a cellulose paper standard when exposed to visible light and ultraviolet radiation. Through this, a greater understanding was obtained of mineral paper composition, its ageing trajectory, and response to environmental factors. Further research is required to identify the unknown trace element(s) and whether photo-sensitive additives are present. These results should help to inform the identification, storage, display and treatment of mineral paper-based collections.