Modification with boehmite-derived alumina nanoparticles enhances mechanical properties of resin

Abstract

Nanostructured γ-Al₂O₃ with an average particle size of 90 nm was synthesized by coated silica in solution. As a type of hard template, the coated silica shell layer could decrease the sinter of alumina particles during the phase transition process at 550 °C. The average particle size of γ-Al₂O₃ is significantly affected by boehmite concentration, amount of sodium silicate, and layers of silica. The mechanical properties of waterborne acrylic resin were enhanced significantly after the addition of γ-Al₂O₃ nanoparticles with dispersant (SK-5040). For solvent-based polyurethane resin, the surface of γ-Al₂O₃ nanoparticles needed to be modified by stearic acid to achieve proper dispersion and stability. For comparison, the effect of different fillers (including ZnO, TiO₂ and SiO₂) was also tested under the same conditions.