Synthesis-and Characterization of Nanocomposite Hybrid Coatings Based on 3-Glycidoxypropyl-trimethoxysilane and Bisphenol A

Organic-inorganic hybrids were prepared using 3-glycidoxypropyl-trimethoxysilane (GPTMS) and bisphenol A (SPA) as a cross-linking agent, via the sol-gel process. The cross-linking agent was used to prevent brittleness and the formation of cracks in hybrid coatings. Attenuated total reflectance infrared (ATR-IR) spectroscopy was used to characterize the structure of the hybrids. The morphology of the hybrid coatings was examined by scanning electron microscopy and Si mapping. The hybrid systems have a uniform network structure and inorganic phases have a size of less than 100 nm. In addition, the effect of SPAlGPTMS molar ratio on cross-linking was investigated by ATR-IR and corrosion protection properties of hybrid coatings were evaluated by linear sweep voltametry (LSV) and 2000-h salt spray test methods. The results of these experiments show that the increasing of cross-linking between silica-network and SPA, would prevent the formation of cracks and decrease the brittleness. Increasing SPA content in organic-inorganic hybrid coatings or nanocomposites led to the formation of an efficient barrier to water and corrosion initiators such as chloride and oxygen.