Interactions Between Polyethyleneimine Xerogels and Acetic Acid Vapor from Degraded Cellulose Acetate. A Novel Therapy for Motion Picture Films Affected by the Vinegar Syndrome

Year: 2025

Authors: Porpora F., Dei L., Forcellini C., D’Aleo C., Lisi L., De Sanctis M., Carretti E.

Autors Affiliation: Univ Florence & CSGI Consortium, Dept Chem Ugo Schiff, via Lastruccia 3-13, I-50019 Florence, Italy; Film Restorat Lab Immagine Ritrovata, via Riva Reno 72, I-40122 Bologna, Italy; Natl Inst Opt CNR INO, Natl Res Council, Largo E Fermi 6, I-50125 Florence, Italy.

Abstract: Motion picture films made of cellulose acetate (CA) are subjected to degradation mainly due to the vinegar syndrome. The goal of this study is to investigate the absorption of acetic acid vapor by some polyethyleneimine (PEI) xerogels, aim at developing innovative, inexpensive, reusable, and easy-to-produce and handle chemical inhibitors for the vinegar syndrome. PEI-based xerogels (SPEI) are obtained through cryo-polymerization via epoxy-amine reaction between PEI and 1,4-Butanediol di-glycidyl ether (BDDE). The intent is to enhance the absorption of the acetic acid vapor by the porous and high-specific surface area network of the obtained PEI xerogel, allowing its neutralization through the free amino groups present in the gel. A chemical-physical, morphological, and rheological characterization of the SPEIs is performed and their behavior in the absorption and desorption of acetic acid is also studied. The efficacy of the SPEI in inhibiting the vinegar syndrome is evaluated on both CA-based real motion picture films, on which the deacetylation process is artificially and naturally induced. The characterization of degraded CA films stored with and without the inhibitor is evaluated using an already validated multi-analytical protocol. The excellent results achieved open interesting perspectives for the conservation of these 20th-century cultural heritage objects.

Journal/Review: MACROMOLECULAR RAPID COMMUNICATIONS

Volume: 46 (14)      Pages from:   to:

More Information: Thanks are due to the University of Florence for financial support, PhD Course funds, and University Research funds provided to the Chemistry Department Ugo Schiff. L’Immagine Ritrovata Institute (Bologna, Italy) is gratefully acknowledged. Special thanks go to Dr. Maura Pischedda and Dr. Zoe Rodriguez for their support in setting up the experiments with real motion picture films and to Dr. Rita Gelli for her assistance during SEM analysis. It is also worth noting that this paper presents part of the scientific results from the PhD Thesis of one of the authors (FP), defended on June 18th, 2024. This work was recognized at the 3rd International Summer School of Science-based Formulation (Florence, July 1-3, 2024), where the author received an award for the best-presented poster.Open access publishing facilitated by Universita degli Studi di Firenze,as part of the Wiley – CRUI-CARE agreement.
KeyWords: acidity; cultural heritage conservation; gas absorption; gels; motion picture films
DOI: 10.1002/marc.202500075