Sugar-derived bio-based resins as platforms for the development of multifunctional hybrids with potential application for stone conservation

This research is focused on the design of a bio-based epoxy-silica hybrid, enriched with SiO2 nanoparticles, to be used in stone conservation. For this purpose, isosorbide, a sugar derivative coming from renewable sources, was selected for the development of epoxy thermosets that were functionalized adding fixed amounts of silica-forming mixtures, to gain hybrid organic-inorganic networks. Fourier Transform Infrared (FTIR), Attenuated Total Reflection Infrared (ATR-FTIR) and Raman spectroscopies were exploited to follow the synthetic procedures, whereas the homogeneity of the networks was ascertained by scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS). The materials were investigated by thermogravimetric (TG-DTA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and contact angle measurements. Once the proper epoxy-silica product was identified, specifically synthesized nanoparticles were incorporated. The obtained nanocomposite showed excellent thermo-mechanical (Tonset, Tg and Tα of 327, 55.9 and 70.1 °C, respectively) and hydrophobic (105°) properties making it a potential candidate for stone conservation.