Study of thermal behavior and molecular composition of mixtures of resinous materials and beeswax found as adhesives in archaeological finds

Beeswax and resinous materials have been used and combined since ancient times to obtain adhesives. In this work, we studied mixtures of these two materials under heating to investigate the effect of their interactions on the properties of the resulting adhesive. The results were then compared with those of archaeological samples, to obtain new insights into ancient technological knowledge. This study was performed by combining two different chemical-analytical techniques: evolved gas analysis coupled with mass spectrometry and flow injection analysis- high resolution mass spectrometry. Evolved gas analysis was used to investigate the thermal behavior of the mixtures and obtain information on production techniques and ageing processes. The data were processed by isoconversional method to estimate the activation energies associated with the thermal degradation of the ad- hesives. The results suggested that archaeological mixtures were subjected to a thermal pre-treatment before their use as adhesives and that heating led to a material with new chemical features, due to the formation of hybrid species between resin diterpenes and the beeswax compounds. The formation of these species was confirmed by high resolution mass spectrometry.