Service Life Assessment of Hydroxyl‐Terminated Polybutadiene ( HTPB ) Based Self‐Healing Polyurethane Composite

ABSTRACT This work reports the development of a robust, antiaging, extended service life, and ambient self‐healing polyurethane (SHPU) composite formulation based on hydroxyl‐terminated polybutadiene (HTPB), incorporating synergistic dynamic thiourethane, disulfide, and Zn 2+ coordination chemistries together with micro‐sized cerium oxide (CeO 2 ). The service life of the composite formulation was assessed through accelerated thermal aging at 60°C–80°C. For each temperature, comprehensive physical, chemical, and mechanical testing has been employed to evaluate the performance of this composite formulation. The formulation displayed an excellent antiaging performance, enabling ≥ 80 healing efficiency in terms of retention in tensile strength and tensile strain at break throughout aging. FTIR difference spectroscopy revealed progressive hydroxyl formation, carbonyl accumulation, and depletion of polybutadiene unsaturation consistent with thermo‐oxidative degradation. Swelling analysis confirmed temperature‐dependent network densification, with decreasing soluble fraction and increasing cross‐link density. Mechanical data showed a monotonic reduction in tensile strain at break following first‐order degradation kinetics. An Arrhenius analysis yielded an activation energy of 87.2 kJ mol −1 , enabling extrapolation of failure time (defined as 40% loss in tensile strain at break). The predicted service life of the composite at 25°C was approximately 28 years, demonstrating the significant durability enhancement imparted by CeO 2 and the multiple dynamic bonding strategy.