Study of the stability of siloxane stone strengthening agents

The commercial organosilicone compounds Rhodorsil Consolidante RC90 and Rhodorsil Consolidante RC80, commonly used as stone strengthening agents for the conservation of artefacts, were tested to ascertain their chemical nature, the mechanisms involved in the polymerization reactions and their stability under oxidative stress. The resins were first chemically characterized by means of GC/MS, FTIR and EDXRF techniques, then applied to slides and subjected to controlled photo-oxidative and thermo-oxidative weathering. The film's morphology was observed by SEM determinations, while DTA-TG techniques were used to determine polymer thermal stability. The features examined prompted a number of considerations on the effects of the resins applied on stone materials and were the reference point for speculation on the chemical nature and the performance of Sogesil XR893, a silicon resin which is no longer available on the market.