Development of techniques and research on plastic and nanostructured materials have provided a wide variety of formulations with versatile uses, such as binding and retouching media, adhesives, consolidants, coating materials, varnishes, or fillers for missing parts. However, the compatibility between artwork and applied products and their durability are tested only in very limited cases before application. In recent years, the awareness of the fact that conservative treatments applied without preliminary tests can cause damages or promote degradations processes, had leads to a growing interest towards the stability and durability of the materials used in conservation practices. In this work were studied and compared the degrading mechanisms occurring in different polymeric and nanostructured commercial products, in particular two acrylic co-polymers (Acril33 and Acril ME), two synthetic resins (Aquazol 500 and Laropal A81), a silicate consolidant (Estel 1000) and two nanoparticles dispersions (NanoEstel and NanoRestore), chosen for their widespread use and different physical-chemical characteristics and applications. The potentiality as consolidants or retouching materials was determined by means of Thermogravimetric Analysis (TGA), Dynamic Light Scattering (DLS), Centrifugal Separation Analysis (CSA), Viscometry, Size Exclusion Chromatography (SEC) and Fourier Transform Infrared Spectroscopy (FT-IR). Afterwards, thermal (80, 100, 120 and 140°C up to 15000 hours) and photo-oxidative (UVA λ=254 nm, UVC λ=366 nm up to 2000 hours) accelerated aging tests allowed to define behaviours, long-lasting performances, degradation kinetic parameters as well as degradation mechanisms of each commercial product by means of SEC, FT-IR, colorimetric and gloss measurements. Finally, luminescent materials were synthesized and tested with the aim to discriminate between original and retouched or consolidated areas. The visible emitting lanthanide complexes Eu(NO3)3(phen)2 and Tb(NO3)3(phen)2 were prepared and embedded in the commercial polymeric and nanostructured products herein tested. Appreciable photoluminescence was observed for the complexes once dispersed in the different matrices and after photo-oxidative aging (UVA λ=254 nm up to 2000 hours) tests.

La ricerca e lo sviluppo di nuove tecnologie riguardanti materiali plastici e nanostrutturati hanno fornito un'ampia varietà di formulazioni a Restauratori e Conservatori, le quali possono essere utilizzate in modo versatile come leganti pittorici e da ritocco, adesivi, consolidanti, materiali di rivestimento, vernici o riempitivi per parti mancanti. Tuttavia, le prestazioni e la durata dei trattamenti a lungo termine, nonché la compatibilità tra l'opera d'arte e il prodotto applicato, vengono testate solo in casi molto limitati prima che il prodotto sia utilizzato nell’intervento conservativo. Negli ultimi anni, invece, la consapevolezza che trattamenti conservativi effettuati senza test preliminari possono causare danni o accelerare processi di degradazione, ha portato a un crescente interesse verso lo studio della stabilità e della durata dei materiali. In questo lavoro sono stati studiati e confrontati i meccanismi di degrado di diversi prodotti commerciali polimerici e nanostrutturati, in particolare due copolimeri acrilici (Acril33 e Acril ME), due resine sintetiche (Aquazol 500 e Laropal A81), un consolidante a base di silice (Estel 1000) e due dispersioni di nanoparticelle (NanoEstel e NanoRestore), scelti per il loro diffuso utilizzo e per le loro diverse caratteristiche fisico-chimiche e applicazioni. Le potenzialità come consolidanti o materiali da ritocco sono state determinate in seguito alla caratterizzazione dei prodotti commerciali mediante Analisi Termogravimetrica (TGA), Dynamic Light Scattering (DLS), Analisi in Campo Centrifugale (CSA), Viscosimetria, Cromatografia ad Esclusione Dimensionale (SEC) e Spettroscopia Infrarossa in Trasformata di Fourier (FT-IR). Successivamente, gli invecchiamenti accelerati di tipo termo-ossidativo, effettuati alle temperature di 80, 100, 120 e 140 ° C per un massimo di 15000 ore e gli invecchiamenti di tipo foto-ossidativo UVA λ=254 nm e UVC λ=366 nm, effettuati per un massimo di 2000 ore, hanno permesso, mediante analisi SEC, FT-IR, misure colorimetriche e di gloss, di definire i comportamenti prestazionali a lungo termine, i parametri cinetici di degradazione e i meccanismi di degradazione di ciascun prodotto commerciale studiato. Infine, sono stati sintetizzati e testati materiali luminescenti con lo scopo di ottenere una facile discriminazione tra aree originali e ritoccate o consolidate del manufatto. A tale fine, i complessi luminescenti Eu(NO3)3(phen)2 e Tb(NO3)3(phen)2 sono stati preparati e dispersi nei prodotti commerciali polimerici e nanostrutturati qui studiati. Apprezzabile fotoluminescenza è stata osservata per entrambi i complessi dispersi nelle singole matrici e in seguito a loro invecchiamento foto-ossidativo UVA (λ=254 nm) per un massimo di 2000 ore.

Advanced polymeric and nanostructured coatings for Cultural Heritage conservation and restoration / Gheno, Giulia. - (2018 Jul 10).

Advanced polymeric and nanostructured coatings for Cultural Heritage conservation and restoration

GHENO, GIULIA
2018-07-10

Abstract

Development of techniques and research on plastic and nanostructured materials have provided a wide variety of formulations with versatile uses, such as binding and retouching media, adhesives, consolidants, coating materials, varnishes, or fillers for missing parts. However, the compatibility between artwork and applied products and their durability are tested only in very limited cases before application. In recent years, the awareness of the fact that conservative treatments applied without preliminary tests can cause damages or promote degradations processes, had leads to a growing interest towards the stability and durability of the materials used in conservation practices. In this work were studied and compared the degrading mechanisms occurring in different polymeric and nanostructured commercial products, in particular two acrylic co-polymers (Acril33 and Acril ME), two synthetic resins (Aquazol 500 and Laropal A81), a silicate consolidant (Estel 1000) and two nanoparticles dispersions (NanoEstel and NanoRestore), chosen for their widespread use and different physical-chemical characteristics and applications. The potentiality as consolidants or retouching materials was determined by means of Thermogravimetric Analysis (TGA), Dynamic Light Scattering (DLS), Centrifugal Separation Analysis (CSA), Viscometry, Size Exclusion Chromatography (SEC) and Fourier Transform Infrared Spectroscopy (FT-IR). Afterwards, thermal (80, 100, 120 and 140°C up to 15000 hours) and photo-oxidative (UVA λ=254 nm, UVC λ=366 nm up to 2000 hours) accelerated aging tests allowed to define behaviours, long-lasting performances, degradation kinetic parameters as well as degradation mechanisms of each commercial product by means of SEC, FT-IR, colorimetric and gloss measurements. Finally, luminescent materials were synthesized and tested with the aim to discriminate between original and retouched or consolidated areas. The visible emitting lanthanide complexes Eu(NO3)3(phen)2 and Tb(NO3)3(phen)2 were prepared and embedded in the commercial polymeric and nanostructured products herein tested. Appreciable photoluminescence was observed for the complexes once dispersed in the different matrices and after photo-oxidative aging (UVA λ=254 nm up to 2000 hours) tests.
10-lug-2018
30
2016/2017
Settore CHIM/03 - Chimica Generale e Inorganica
Università degli Studi di Trieste
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2927592
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