Investigation on the chemical structure and ageing transformations of the cycloaliphatic epoxy resin EP2101 used as stone consolidant

The commercial cycloaliphatic epoxy resin EP2101, frequently used as a structural stone strengthening agent in monuments, was tested to ascertain the related chemical nature, the mechanisms involved in the polymerization reaction and the stability under degradative environments. After a preliminary chemical characterization in the laboratory by means of GC/MS and FTIR, the resin was applied by brushing to the surface of veined Carrara marble and Vicenza white limestone specimens, and subjected to three different typologies of degradation: natural weathering, artificial accelerated ageing and resistance to mould growth. The resin's stability was monitored by microscopic observations, FTIR and SEM-EDX analysis, colorimetric and water absorption measurements. The results prompted a number of considerations, which were confirmed by those obtained from the examination of samples taken from a granite column in Murano (Venice) and a laboratory specimen of Proconnesian marble, treated in 1985 and 1984 respectively.