INFLUENCE OF AGEING ON THE STRUCTURAL INTEGRITY OF CARBOXYL-TERMINATED POLYBATUDIENE SOLID ROCKET PROPELLANT

The operability of a composite solid propellant is compromised by the presence of cracks, with origin in natural or mechanical ageings. These cracks may cause uneven burning of the propellant leading to a malfunction of the motor or in the worst scenario an overpressure burst. The propellants are characterised by an heterogeneous microstructure, due to many distinct components with very complex and different mechanical performance. Nevertheless, the mechanical behaviour of these propellants is mainly controlled by the elastomeric matrix, the properties of which exhibit a strong time dependence. Therefore, this paper uses Viscoelastic Fracture Mechanics analysis to establish the influence of the mechanical and oxidative ageings on the structural integrity of a booster composite solid propellant, based on a carboxyl-terminated polybutadiene binder reinforced with ammonium perchlorate oxidizer particles.
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