<p>Polyhedral oligomeric silsesquioxane (POSS) nanoparticles are materials which consist of both inorganic and organic parts. An example of such materials is epoxy/POSS nanocomposites. POSS’s organic part and weight percentage in the epoxy matrix can affect the nanocomposite’s dispersion, interaction, and final properties. Epoxy/aminopropyl isobutyl-polyhedral oligomeric silsesquioxane (AI-POSS) nanocomposites were formulated with 0.5, 1, 3, and 5% (by wt) of AI-POSS nanoparticles. The AI-POSS acted as pendant groups to the epoxy chains due to the presence of one reactive agent. Therefore, it was possible to form agglomerations. Still, their dispersion and consistency increased in the epoxy matrix by performing the pre-reaction with an excess epoxy resin, which was observed in the SEM and EDX images. The corrosion properties of the scratched samples were reduced after 100&#xa0;days, due to the weak resistance of these coatings against scratches in the salt spray, which were also observed in the cross-cut. However, excellent corrosion resistance was observed in the samples without scratches after 100&#xa0;days. These nanocomposites were degraded at higher temperatures than pure epoxy in the TGA. Epoxy/aminopropyl isobutyl-POSS with 3% (by wt) AI-POSS (EAP 3) and neat epoxy or epoxy/aminopropyl isobutyl-POSS without nanoparticles (EAP 0) samples exhibited 90% weight loss at 594 and 505&#xa0;°C, respectively. The variance was attributed to the presence of inorganic groups in nanoparticles. Storage modulus, glass transition temperature, tensile strength, Young’s modulus, and toughness increased by increasing AI-POSS nanoparticles as high as 3% (by wt) in DMTA and tensile analysis. Therefore, the most optimal state for these nanocomposites was achieved when 3% (by wt) of AI-POSS nanoparticles were used in the epoxy matrix.</p> Graphical abstract <p></p>