10 research outputs found
Estudio comparativo de tratamientos de consolidaciòn. Aplicaciòn a rocas calcarenìticas y calizas
The paper deals with the effectiveness of different protective treatments on porous stones used in the architecture and monuments in Spain and Sicily
Hybrid sol-gel based coatings for the protection of historical window glass
Medieval glass is commonly attacked by atmospheric pollutants conveyed by water, triggering the corrosion process. Current conservation strategies aim to maintain
window glass in its original context, and so it is necessary to
protect it from further degradation. Sol–gel technology is
very effective for the preparation of protective films, using
Si-alkoxide precursors chemically similar to the substrate.
The present work discusses water-repellent hybrid sol–gel
coatings made from tetra-ethyl-ortho-silicate with different
quantities of Si-alkoxides, functionalized with various alkyl
groups. The coatings were deposited using the dip-coating
technique and characterized by UV–VIS and FT-IR spectroscopy. Static and dynamic contact angle measurements
showed an overall homogeneity of the coatings and indicated
improved water-repellency when functionalized by long
alkyl chains. The coatings with best performance in terms of
transparency and contact angle, and with the lowest organic
content, were selected and applied to medieval-like glass
samples. Colorimetric characterization was carried out using a spectrophotometric scanner before and after application of
the coatings and no significant color changes were found.
The electron microscopy images revealed relatively even,
crack-free coatings, especially with higher organic contents.
Contact angle and colorimetric measurements were repeated
after accelerated ageing by exposure to UV light and an SO2-saturated atmosphere. A significant decrease in the contact
angle was observed only for the samples treated at the highest
SO2concentration. The silica-based materials did not give
reaction by-products, were water-repellent, compatible with
the substrate, colorless, transparent, and stable under exposure to chemicals and light, thereby satisfying the main
requirements for the conservation of Cultural Heritage