<p>The growing demand for high-performance coatings prompts researchers to develop multifaceted and low-cost polymeric nanocomposite coatings to meet stringent industrial and domestic requirements. In this study, a dual crosslinking strategy, such as interchain urethane hydrogen bonding and metal–ligand coordination between cerium oxide (CeO₂) and carbamate linkages, was used to synthesize hydroxyl-terminated polybutadiene-based nanocomposite coatings with enhanced mechanical properties, thermal stability, flame retardancy, adhesion, and heat insulation, making them suitable for aerospace, automotive, and protective applications. The nanocomposite coatings were synthesized through the solvent-assisted dispersion of CeO₂ (0.5–2.0 wt%) in tetrahydrofuran and incorporated into the polyurethane (PU)&#xa0;matrix, followed by curing at 60°C for 72 h. The Fourier transform infrared spectroscopy (FTIR) confirms the formation of urethane bonds and CeO₂ interactions. The synthesized PU nanocomposites were characterized through adhesion tests, X-ray diffraction, atomic force microscopy, thermogravimetric analysis (TGA), mechanical testing, linear ablation rate, and flame retardancy studies. The optimal performance has been observed at a 1.5% CeO₂ loading, where the balance of mechanical properties (tensile strength increased by 215% with an acceptable elongation at break of 590%) and thermal stability (T5% increased by 24°C) is achieved, along with enhanced flame retardancy (%LOI increased by 78%).</p>