Thermal behavior of mercury carboxylates as paintings' degradation products

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388980%3A_____%2F24%3A00597749" target="_blank" >RIV/61388980:_____/24:00597749 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11310/24:10490480

Výsledek na webu

<a href="https://hdl.handle.net/11104/0359596" target="_blank" >https://hdl.handle.net/11104/0359596</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s10973-024-13463-3" target="_blank" >10.1007/s10973-024-13463-3</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Thermal behavior of mercury carboxylates as paintings' degradation products

Popis výsledku v původním jazyce

Mercury long-chain carboxylates have been identified recently as degradation products resulting from saponification occurring in painted artworks. Saponification belongs among the degradation processes endangering undesirably the appearance and stability of painted artworks, significant treasures of humanity. The mechanism of saponification has not been still fully understood because of the enormous complexity of both painting materials and factors triggering the deterioration. Moreover, the properties and stability of metal soaps resulting from this degradation are also poorly understood, complicating the choice of suitable conservation treatment. Relining, a heat-based restoration technique for reinforcing deteriorated canvases, can induce irreversible changes in paint layers, being applied inappropriately. Within this study, we report thermal behavior and stability of mercury palmitate (Hg(C16)2), mercury stearate (Hg(C18)2), and their respective mixtures with linseed oil in the temperature range of 25-150 degrees C, employing a combination of techniques, including DSC, TG-MS, FTIR, XRPD, and in situ high-temperature FTIR and XRPD. It was observed that while Hg(C16)2 and Hg(C18)2 undergo partial decomposition around 150 degrees C, in a mixture with linseed oil, they decompose rapidly at significantly lower temperature (around 100 degrees C). The decomposition of mercury carboxylates results in the formation of metallic mercury, a volatile toxic substance, and free fatty acids, reactants capable of further development of saponification in paint layers. In addition, a structural polymorph of Hg(C16)2 and Hg(C18)2 with a different arrangement of carboxylate groups around the mercury atom was formed after the heat treatment during the cooling down at ca 120 degrees C as documented by in situ high-temperature XRPD and FTIR.

Název v anglickém jazyce

Thermal behavior of mercury carboxylates as paintings' degradation products

Popis výsledku anglicky

Mercury long-chain carboxylates have been identified recently as degradation products resulting from saponification occurring in painted artworks. Saponification belongs among the degradation processes endangering undesirably the appearance and stability of painted artworks, significant treasures of humanity. The mechanism of saponification has not been still fully understood because of the enormous complexity of both painting materials and factors triggering the deterioration. Moreover, the properties and stability of metal soaps resulting from this degradation are also poorly understood, complicating the choice of suitable conservation treatment. Relining, a heat-based restoration technique for reinforcing deteriorated canvases, can induce irreversible changes in paint layers, being applied inappropriately. Within this study, we report thermal behavior and stability of mercury palmitate (Hg(C16)2), mercury stearate (Hg(C18)2), and their respective mixtures with linseed oil in the temperature range of 25-150 degrees C, employing a combination of techniques, including DSC, TG-MS, FTIR, XRPD, and in situ high-temperature FTIR and XRPD. It was observed that while Hg(C16)2 and Hg(C18)2 undergo partial decomposition around 150 degrees C, in a mixture with linseed oil, they decompose rapidly at significantly lower temperature (around 100 degrees C). The decomposition of mercury carboxylates results in the formation of metallic mercury, a volatile toxic substance, and free fatty acids, reactants capable of further development of saponification in paint layers. In addition, a structural polymorph of Hg(C16)2 and Hg(C18)2 with a different arrangement of carboxylate groups around the mercury atom was formed after the heat treatment during the cooling down at ca 120 degrees C as documented by in situ high-temperature XRPD and FTIR.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

<a href="/cs/project/LM2023066" target="_blank" >LM2023066: Nanomateriály a nanotechnologie pro ochranu životního prostředí a udržitelnou budoucnost</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Thermal Analysis and Calorimetry

ISSN

1388-6150

e-ISSN

1588-2926

Svazek periodika

149

Číslo periodika v rámci svazku

23

Stát vydavatele periodika

HU - Maďarsko

Počet stran výsledku

12

Strana od-do

13773-13784

Kód UT WoS článku

001291932700001

EID výsledku v databázi Scopus

2-s2.0-85201434852