Effects of Colloidal Nanosilica on Epoxy-based Nanocomposite Coatings

Epoxy-based nanocomposites were fabricated with different content of colloidal silica nanoparticles such as 10.0, 20.0 and 30.0 wt %, through solution casting. The covalent bonding interfaces, resulting from a ring-opening reaction between silica nanoparticles and epoxy matrix were confirmed by the Fourier transform (FT-IR) infrared spectroscopy. These nanocomposites were characterized for thermal stability, glass transition temperature and adhesive properties using thermogravimetric analyzer (TGA), differential scanning calorimeter (DSC) and cross-cut tape test. In addition, chemical resistance was assessed by immersing the films in different chemical solution (acid, alkali and salt solution) for 21 days. It was found that the properties of the nanocomposites were increased proportionally to the content of silica nanoparticles up to a certain amount of loading. After that the properties were decreased. The surface morphology of the nanocomposites was observed by scanning electron microscopy (SEM), which showed that the silica nanoparticles distributed uniformly. In addition, the nanocomposites were studied on UV radiation absorption by UV-Vis spectrophotometer. Excellent UV radiation was noticed by the nanocomposite films. The oxygen transmission rate (OTR) and water contact angle (WCA) testing of the nanocomposite films was also impressive.