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

Abstract

Thermal and mechanical properties were determined for the halloysite nanotubes (HNT)/beeswax composites at various compositions. The beeswax degradation temperatures and time course, provided by thermogravimetry (TG), evidenced the improvement of the thermal properties operated by HNT. Differential scanning calorimetry (DSC) allowed us to determine the enthalpy of melting as well as the time course of the melting process for beeswax. A slight loss of beeswax crystallinity was observed upon HNT addition. The dynamical mechanical analysis (DMA) provided the loss and the storage modulus for the nanocomposites upon heating and it was shown that the nanoclays create an inorganic framework which enhances the mechanical properties keeping unaltered the beeswax shape even above the melting temperature. To the light of these insights, samples of waterlogged archaeological wood were consolidated with the HNT/beeswax nanomaterial. The amount of HNT entrapped into the pores as well as the shrinkage volume of wood samples were determined. The HNT/beeswax mixtures can be considered a promising consolidant material for archaeological wood.