Time-Temperature Superposition Principle Applied to Thermally Aged Composite Propellant

Aging of solid propellant is always a matter of concern, especially when the formulation is known to be sensitive to chemical degradation. In this study a propellant formulation containing an aziridine-type bonding agent and prone to hydrolysis was submitted to accelerated aging, to evaluate its possible effect on important events that may occur during the lifetime of solid rocket motors. To accomplish this aim, unaged and aged propellant was assayed by tension tests at different loadings, in order to apply the time-temperature superposition principle (TTSP) and raise the master curves, based on WLF equation. The results showed no effect of thermal aging on mechanical behavior during the time event correspondent to ignition, and only a slight change during flight acceleration. The most significant changes occurred for long-term events, thus implying careful handling of this propellant during storage.