Enhanced Historical Limestone Protection by New Organic/Inorganic Additive-Modified Resins

The Cultural Heritage deterioration is a spontaneous decay process due to water percolation and air pollutant deposition. In this context, novel acrylic (Twinswet, TW) siloxane-based (Alpha®SI30) resins were exploited starting from commercial products then modified by adding either polysiloxane-based additive (TegoPhobe 1500N) or precursor of SiO2 nanoparticles (Tetraethyl ortosilicate, TEOS) improve the Vicenza stone surface hydrophobicity. Properties coated materials studied using different techniques such as contact angle (WCA), capillary absorption, colorimetric vapor permeability measurements. Accelerated UV aging eight-month outdoor exposure tests (at Milan University campus) also performed determine coatings durability. Notably, addition both additives slightly enhanced hydrophobicity resulting in WCAs about 140°, decreased absorption especially for Alpha-based resins. Conversely, reduction was observed, even if within threshold value 50%. Concerning color variation, Alpha®SI30 preserved external aspect; instead, TW smoothly color. All stable exposure. Hence, present revealed be very promising protection historical monuments.