Preperation and investigation of epoxy nanocomposite coating

Objective: The main objective of this study is to develop novel epoxy-based nanocomposite coatings applicable to aluminum-based metallic surfaces and to investigate their structural, thermal, and mechanical properties. Materials and Methods: Initially, epoxy–amine coatings were synthesized by the ring-opening reaction of glycidoxypropyltrimethoxysilane (GPTMS) with various aromatic amines (2-amino-6-methoxybenzothiazole, 2-methylbenzothiazole, 3-amino-5-methylthio-1H- 1,2,4-triazole, and aniline) in the presence of 2,4,6-tris(dimethylaminomethyl)phenol as a catalyst. The ring-opening reactions led to crosslinking between the epoxy resin (GPTMS) and aromatic amines. In the second stage, Fe₃O₄ and graphene nanoparticles were incorporated into the epoxy–amine systems to obtain nanocomposite coatings. The coatings were cured at 25°C, 80°C, and 120°C. Findings: The chemical structures of the coatings were characterized by IR spectroscopy; their thermal properties were determined by DSC analysis, and their mechanical properties were evaluated through pendulum hardness, pencil hardness, cross-cut adhesion, pull-off adhesion, and impact resistance tests. DSC analyses revealed that the thermal stability of the new epoxy-nanocomposite coatings increased to above 300 °C, while optimum mechanical performance was achieved in systems cured at 80 °C and reinforced with graphene. These samples exhibited high hardness (2H–3H), good adhesion (4A–5B), and high pendulum hardness values (~75–78 P). Conclusion: Fe₃O₄ enhances the thermal stability of epoxy–amine coatings through a chemical mechanism, while graphene acts through a physical reinforcement mechanism. Mechanical testing demonstrated that nanoparticle-modified coatings exhibit significant improvements in parameters such as pendulum hardness, pencil hardness, adhesion, and impact resistance.