New hydrophobic silica nanoparticles capped with petroleum paraffin wax embedded in epoxy networks as multifunctional steel epoxy coatings

The silane amide precursors were prepared by amidation of oleic and stearic acid with gamma-aminopropyl-triethoxysilane. The stearyl and oleyl amines were added to vinyl trimethoxy silane to synthesize aminosilane precursors. The chemical structures, surface morphology, thermal stability of the prepared hydrophobic silica nanoparticles were investigated. The wetting characteristics, mechanical properties, thermal stability and corrosion resistance of the prepared hydrophobic silica nanoparticles with epoxy composites coated on the steel panels were studied. The data confirm that the all the prepared hydrophobic silica show higher contact angles (100-110 degrees) when blended with epoxy up to 3Wt %. Moreover, the dispersion, hydrophobicity and paraffin wax contents of silica nanoparticles embedded into epoxy networks control the high corrosion resistivity of the composites as organic coatings of steel substrate. The salt spray resistance data elucidate that the epoxy modified with 1 Wt % of the hydrophobic silica/paraffin wax achieved higher salt spray resistances up to 1500 h with high rating.