Comparative study of three different kinetic models applied to the ageing of archaeological beeswax used as a paint medium

Kinetic evaluation of thermogravimetry data was used to understand the ageing behavior of beeswax used as an artists’ paint medium on ancient mummy shrouds and Fayum portraits. Individual components of beeswax were subjected to dynamic thermogravimetry to assess their evaporation rates, and three methods of kinetic analysis were evaluated for accuracy. The results showed that although it is impossible to accurately predict the volatility at room temperature for individual components of beeswax due mostly to their high molecular mass, relative trends and ranking of the volatility of the compounds can be obtained which may explain compositional changes over time.