DSC AND TGA TO EVALUATE THE SELECTIVE IMPREGNATION OF WATERLOGGED ARCHAEOLOGICAL WOODS WITH POLY(ETHYLENE) GLYCOLS MIXTURES

Abstract

Within the cultural heritage field the wood conservation of waterlogged archaeological objects aims at preventing the collapsing of the wooden structure (upon drying) the degradation of which is related to the Taxon but also to the chemical and biological nature of the site. The refilling of the wood cavities with a consolidant, which confers robustness and stability, is an interesting strategy for the conservation methods of waterlogged archaeological objects. To this purpose, using different impregnation methods, waterlogged archaeological woods were consolidated by using aqueous mixtures of poly(ethylene) glycols with different molecular weights (PEG 400 and PEG 4000) as well as mixtures of these pure polymers. Of course the effectiveness of these treatments depends on the amount of polymers entrapped within the wood pores. In this work we proved that the DSC technique is suitable for the investigation of the selective consolidation of waterlogged archaeological woods by using PEGs polymer mixtures. The amount of each polymer (PEG 400 and PEG 4000) entrapped into the pores was quantitatively determined. The total content of the consolidant obtained from DSC was in a good agreement with that calculated from TGA. The successful DSC and TGA techniques corroborate their relevance within the cultural heritage issue. Therefore, one may envisage that they can be combined to obtain a profile of concentration (of all the consolidant and of the single components) at different depths of the sample without damaging the object being small the weight of the sample (a few mg) required for the measurements.