Please cite this article in press as: K. ˇ Cíˇ zová, et al., Study of the degradation of beeswax taken from a real artefact, Journal of Cultural Heritage (2018), https://doi.org/10.1016/j.culher.2018.04.020 ARTICLE IN PRESS G Model CULHER-3413; No. of Pages 10 Journal of Cultural Heritage xxx (2018) xxx–xxx Available online at ScienceDirect www.sciencedirect.com Original article Study of the degradation of beeswax taken from a real artefact Katarína ˇ Cíˇ zová a,∗ , Katarína Vizárová a , Aleˇ s Ház a , Anna Vykydalová b , Zuzana Cibulková b , Peter ˇ Simon b a Slovak University of Technology, Faculty of Chemical and Food Technology, Institute of Natural and Synthetic Polymers, Department of Wood, Pulp and Paper, Radlinského 9, 831 07 Bratislava, Slovak Republic b Slovak University of Technology, Faculty of Chemical and Food Technology, Department of Physical Chemistry, Radlinského 9, 831 07 Bratislava, Slovak Republic a r t i c l e i n f o Article history: Received 22 December 2017 Accepted 20 April 2018 Available online xxx Keywords: Beeswax Natural ageing Degradation Sublimation Hydrolysis Oxidation a b s t r a c t This study is devoted to the statue of St. Ursula from the depositary to the Slovak National Museum– ˇ Cerven ´ y Kame ˇ n Castle. It is a heavily damaged, slightly under life-size seated female statue from the 2nd half of 19th century. The artefact is very heterogeneous and degraded. The wax parts have been examined with the aim of detecting and quantifying degradation products using FTIR spectroscopy, Py - GC/MS analysis and DSC measurement. The results obtained were compared with the degradation studies from available literary sources. The most important achievement is that the results support the theory of sublimation of n-alkanes from beeswax during ageing. The degradation mechanisms taking part during ageing are hydrolysis and oxidation. The suggested methods of accelerated ageing could be a suitable simulation of natural ageing. The experimental methods employed are complementary and enable to follow the progress of beeswax degradation. © 2018 Published by Elsevier Masson SAS. 1. Introduction Objects of cultural heritage in museum collections consist of various types of materials, mostly natural organic ones. Conserva- tors and restorers need information about the material composition and degree of degradation of the objects they are treating. They also need to know which materials were used in previous interven- tions and their impact on cultural heritage objects before making a decision which treating method to apply [1]. Natural waxes belong to materials that are significant in terms of occurrence in differ- ent cultural heritage sites, as well as in preservation/restoration applications. The available literature resources show that physico- chemical changes taking place during ageing of natural waxes are not satisfactorily explored. Also, there exist no standards for their accelerated ageing as an instrument of experimental verification of proposed preventive and preservative protection procedures such as exist, e.g., for paper. Natural waxes form a group of materials of various origins, differing in chemical composition and physical properties such as color, stickiness, hardness, flexibility, etc. In general, they are complex mixtures with numerous substances including saturated ∗ Corresponding author. Tel.: +421 907 642 128. E-mail address: katie.cizova@gmail.sk (K. ˇ Cíˇ zová). and unsaturated n-alkanes, long chain wax monoesters, diesters, hydroxy esters, fatty acids and many other components in small amounts, such as flavonoids [2,3]. Due to its properties and avail- ability, beeswax has been widely used in daily life as well as artwork since the neolithic period [4,5]. The composition of several kinds of beeswax taken from literature is shown in Table 1. Although the beeswax is generally considered to be stable and chemically resistant, there are several factors that affect its prop- erties. It contains many components, that is why it can undergo various physical and chemical processes causing its ageing and reducing overall stability. During natural ageing of waxes, basic mechanisms of degradation of individual components such as hydrolysis and oxidation take place. The degradation mechanism depends on external conditions. Significant changes have been identified comparing the fresh unaged material with the archaeological beeswax. The changes are attributable to the partial hydrolysis of esters to form palmitic and stearic acids and long chain alcohols. Also, a partial reduction of the content of odd-numbered hydrocarbons occurs which is explained by their sublimation either in warm and dry storage conditions or as a result of heating during beeswax processing. Hydrocarbon chain lengths shorten, preferably low carbon number hydrocarbons, or they decompose completely [5]. Exposing wax to sunlight, especially to its UV component and mainly at higher temperature, waxes undergo an oxidative https://doi.org/10.1016/j.culher.2018.04.020 1296-2074/© 2018 Published by Elsevier Masson SAS.