Assessing the Use of Supercritical Carbon Dioxide as a Carrier for Alkoxysilanes to Consolidate Degraded PUR Ester Foams: An Alternative to Traditional Methods

Inês Soares (), Carolina Viana, Angelica Bartoletti, Susana França de Sá, Anita Quye, Yvonne Shashoua, Teresa Casimiro and Joana Lia Ferreira ()
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Inês Soares: Laboratório Associado para a Química Verde (LAQV-REQUIMTE), Department of Conservation and Restoration, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Carolina Viana: Laboratório Associado para a Química Verde (LAQV-REQUIMTE), Department of Conservation and Restoration, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Angelica Bartoletti: Laboratório Associado para a Química Verde (LAQV-REQUIMTE), Department of Conservation and Restoration, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Susana França de Sá: Laboratório Associado para a Química Verde (LAQV-REQUIMTE), Department of Conservation and Restoration, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Anita Quye: Kelvin Centre for Conservation and Cultural Heritage Research, School of Culture and Creative Arts, University of Glasgow, Glasgow G12 8QH, UK
Yvonne Shashoua: Environmental Archaeology and Materials Science, National Museum of Denmark, 2800 Kongens Lyngby, Denmark
Teresa Casimiro: Laboratório Associado para a Química Verde (LAQV-REQUIMTE), Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
Joana Lia Ferreira: CIUHCT—Interuniversity Center for the History of Sciences and Technology, Department of Conservation and Restoration, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal

Sustainability, 2024, vol. 16, issue 11, 1-17

Abstract: Degradation of ester-based polyurethane (PUR) foams results in extensive fragmentation, stickiness, and brittleness both at surfaces and in the bulk. Current methods to conserve museum objects comprising PUR foams include consolidation with solvent-based polymeric solutions. Besides the limitations of spray and brush application for deep consolidant penetration and the impracticality of immersing large-scale objects in solutions, these methods often require large amounts of toxic solvents that are harmful for both the user and environment. Carbon dioxide can be employed as a green solvent as it can be recovered, recycled, and reused without contributing to the greenhouse effect. Supercritical carbon dioxide (scCO 2 )-assisted consolidation premises are that it may carry the consolidant deeper and deposit it consistently throughout the foam, whilst ensuring minimal interaction with the surface and avoiding material losses in severely degraded objects and the use of toxic solvents. The suitability of scCO 2 as a carrier is studied, and the results compared with spray application, a commonly used traditional method. Previous studies have shown that a mixture of alkoxysilanes has great potential for reinforcing the foam’s structure and hydrophobicity when applied by immersion and other impregnation techniques. In this study, scCO 2 -assisted consolidation has proven to be an effective and green alternative to consolidation by spray, reducing hazardous solvent emissions. After treatment, no visual changes were detected, the samples became less sticky, and the foam flexibility improved significantly. Analytical techniques confirmed the presence of the consolidant in all tested samples, both on the top surface and in-depth layers, in contrast to foams treated by spray.

Keywords: supercritical CO 2; sustainable conservation; polyurethane foam; consolidation; alkoxysilanes (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2024
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