Multimodal spectroscopic assessment of mechanical and chemical properties of ABS objects in cultural heritage preservation

¹ Department of Chemistry, Biology and Biotechnology, University of Perugia via Elce di Sotto, 8 06123, Italy
² CNR – Istituto di Scienze e Tecnologie Chimiche “Giulio Natta” (SCITEC), via Elce di Sotto, 8 06123 Perugia, Italy
³ CNR – Istituto di Scienze del Patrimonio (ISPC), Strada Provinciale 35d, n. 9, 00010, Montelibretti (Roma), Italy
⁴ Dipartimento di Fisica e Geologia Università di Perugia, via Pascoli 8 06123 Perugia
⁵ CNR - Istituto Officina dei Materiali (IOM), Via Pascoli, 06123 Perugia, Italy
⁶ CNR – Istituto di Scienze del Patrimonio (ISPC), Via Guglielmo Sanfelice, 8 80134 Napoli, Italy
⁷ Fondazione Museo Kartell, Via delle Industrie 3, 20082 Noviglio Milano, Italy
⁸ Università degli Studi di Firenze, Dipartimento di Storia, Archeologia, Geografia, Arte e Spettacolo, Via S. Gallo, 10 - 50129 Firenze, Italy
⁹ Triennale Milano, Conservazione e restauro, viale Emilio Alemagna 6, 20121 Milano, Italy

^* Corresponding author: martina.alunnicardinali@unipg.it
^† Present address: Department of Earth and Environmental Sciences, University of Milano‐Bicocca, Piazza della Scienza 1, 20126 Milan, Italy

Published online: 31 October 2024

Abstract

The 1960s saw the emergence of plastic as an indispensable component in various fields, including art and design. Acrylonitrile-butadiene-styrene (ABS) is widely used by artists and designers for a range of applications including sculptures and decorative pieces. Consequently, the necessity to conserve ABS from deterioration is a crucial issue in the field of cultural heritage preservation. Many studies have highlighted the criticality of the stability of the polybutadiene component when exposed to light. We propose a new multimodal spectroscopic approach to assess the conservation status of plastic design objects. This non-destructive approach combines correlative Brillouin and Raman micro-spectroscopy (BRaMS), external reflection IR spectroscopy and portable NMR relaxometry. BRaMS is a novel non-destructive technique in the field of heritage conservation, allowing simultaneous monitoring of chemical and mechanical changes occurring at the sample surface. The present study focused on photochemically aged LEGO® bricks made of ABS and aimed to i) correlate chemical and mechanical changes induced by light exposure and ii) introduce a surface degradation index (SDI), measurable in situ by external reflection IR spectroscopy, to assess the state of conservation of plastic artefacts. Finally, non-invasive investigations were carried out on real design objects using the MObile LABoratory (MOLAB) platform.