The ageing kinetics and mechanisms of a composite solid rocket propellant were investigated by monitoring unstressed propellant samples during prolonged storage at elevated temperatures. For samples confined under air during ageing, it was determined that oxidative cross-linking of the propellant binder was the main degradation mechanism over time. Plasticizer loss was a significant ageing mechanism only for those samples aged unconfined. In addition, there was an indication that ambient humidity had a significant but reversible effect on propellant mechanical properties. Arrhenius mathematical relationships were derived in order to ascertain the extent to which ageing was accelerated by increased propellant temperature. An activation energy for binder oxidation of between 71 and 74 kJ/mol was determined.

A solid rocket propellant based on glycidyl azide polymer (GAP) binder plasticized with nitrate esters and oxidized with a mixture of ammonium nitrate (AN) and triaminoguanidine nitrate (TAGN) was formulated and characterized. Non‐lead ballistic modifiers were also included in order to obtain a propellant with non‐acidic and non‐toxic exhaust. This propellant was found to exhibit a burning rate approximately twice that of standard GAP/AN propellants. The exponent of the propellant is high compared to commonly used composite propellants but is still in the useable range at pressures below 13.8 MPa. This propellant may present a good compromise for applications requiring intermediate burn rate and impulse combined with low‐smoke and non‐toxic exhaust.

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A solid rocket propellant based on glycidyl azide polymer (GAP) binder plasticized with nitrate esters and oxidized with a mixture of ammonium nitrate (AN) and triaminoguanidine nitrate (TAGN) and including non-lead ballistic modifiers, was formulated. The propellant was designed so as to produce non-acidic and non-toxic exhaust products while still providing reasonably good burning rate and impulse. This propellant was characterized with respect to thermal and chemical stability and storage life by a variety of test methods. The data indicate that the propellant exhibits good stability and is suitably safe for prolonged storage. Characterization data for this propellant with regard to processing parameters, tensile properties, and ballistic performance are presented in a companion paper.

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