A UV-cured functional coating to prevent glass stress corrosion

Annealed glass suffers from stress corrosion, i.e., the decrease of the tensile strength over time, under load. The classical theory to account for this phenomenology involves the chemical reaction of water with silica which replaces strong chemical bonds with weaker ones, thus leading to sub-critical growth of the superficial flaws. In the present work, an innovative polymeric coating produced with the UV-curing technology is developed to protect glass surfaces against stress corrosion. The new coating is tailored to have a very good adhesion with glass, and an excellent hydrophobic behavior and a very low permeability on the side exposed to the environment. In such a way, it creates a barrier to water and water vapour. The effectiveness of the coating is assessed experimentally on new and naturally aged glass. To this aim, the coating is applied to glass specimens, that are afterwards tested with the coaxial double ring setup. The results are very encouraging, since an increase of about 75% of the mean tensile strength is obtained compared to uncoated specimens. Further steps, needed to definitely prove the effectiveness of the coating, consist in assessing the durability of the strengthened glass with respect to mechanical actions and weathering effects.