Thermal degradation chemistry of archaeological pine pitch containing beeswax as an additive

Abstract

Thermo analytical techniques and gas chromatography/mass spectrometry (GC/MS) were used to evaluate the presence of chemical-physical interactions between pine pitch and beeswax used as additive The mixtures found in several archaeological objects demonstrate that by modifying the physical and chemical properties of pitch and tar, our ancestors were able to add a variety of organic materials, such as waxes or animal fats.Westudied pine pitch replicas from Pinus sylvestris prepared following a test from the field of experimental archaeology. Varying proportions of beeswax were added and then the resulting pitches were studied by a multi-analytical approach comprising the use of thermo analytical techniques (DSC, TG and TG-FTIR) and GC/MS, which provides molecular information. The same approach was also used to study a mixture of pitch from Pinus sylvestris L. and beeswax ("Zopissa"), whose relative proportions were unknown, and two archaeological adhesives collected from glass opus sectile fragments found in the northern necropolis of Antinoopolis (Egypt, 4th-5th century AD). Our thermo-analytical techniques managed to determine the relative proportion of pine pitch and additives, such as beeswax, in unknown archeological mixtures, and to evaluate the presence of interactions between pitch and additive

Thermal and dynamic mechanical properties of beeswax-halloysite nanocomposites for consolidating waterlogged archaeological woods

“…In agreement with the literature [31], the principal peak can be ascribed to the solideliquid transition and the other to a solidesolid transition. The separation of the peaks depends on the kind of wax and the experimental procedure [17,30]. The thermal parameters are shown in Table 1.…”

“…Wax slows down the wood photodegradation [16]. Recently, interactions between pine pitch and beeswax were studied keeping in mind that these mixtures (in the presence of other additives) discovered in archaeological finds were used as adhesives [17].…”

Recent Advances in Analytical Pyrolysis to Investigate Organic Materials in Heritage Science

“…Several studies have been performed by TG-FTIR analysis in the field of heritage science to overcome this limitation. [26] Despite this,t he interpretation of the FTIR spectra of the evolved species can be complex, and often benefits from the aid of mass spectrometry,asdemonstrated in the characterization of pine pitch containing beeswax as an additive,o ri ns tudying the effects of pigments in paint materials. [26] When data obtained by thermal analysis are integrated with those achieved by mass spectrometric systems,m ore satisfactory results are obtained, since acombination of mass spectrometry with thermal analyses provides profiles of the evolved/pyrolyzed species in relation to temperature increase.…”

“…[26] Despite this,t he interpretation of the FTIR spectra of the evolved species can be complex, and often benefits from the aid of mass spectrometry,asdemonstrated in the characterization of pine pitch containing beeswax as an additive,o ri ns tudying the effects of pigments in paint materials. [26] When data obtained by thermal analysis are integrated with those achieved by mass spectrometric systems,m ore satisfactory results are obtained, since acombination of mass spectrometry with thermal analyses provides profiles of the evolved/pyrolyzed species in relation to temperature increase. [6f] Ther ange of possible applications of analytical pyrolysis and the type of information that can be gained from asingle instrumental run has been widened by using pyrolysers in ad ifferent mode,t hat is,b yr amping the temperature from ambient to thermodesorption temperatures and finally to pyrolysis conditions,c ombined with mass spectrometric detection (with or without ag as chromatographic separation in between).…”

Halloysite Nanotubes for Cleaning, Consolidation and Protection

“…Namely, the latter hybrid behaved as a solid‐like material even at a temperature above the melting point because of the inorganic skeleton conferred to wax by the nanotubes. These features are promising for the use of beeswax/HNTs composites provided tht beeswax was reported as consolidant of waterlogged archaeological woods with the limiting factor of wax relatively low melting point.…”