Pot life extension of isocyanate cured propellants by aziridine compounds

An isocyanate curable composite propellant composition having extended pot life, said composition comprised of hydroxy terminated polybutadiene, an isocyanate curing agent, and the inorganic oxidizer, ammonium perchlorate, that is less than 20 micron particle size and the is coated with an aziridine compound selected from compounds represented as follows:

• a reaction product formed from tri-aziridinylphosphine oxides or derivatives thereof reacted with monofunctional carboxylic acids, said tri-aziridinylphosphine oxides or derivatives thereof represented by the structure:
• ##STR15## wherein X.sub.1 represents an aziridine group of the structure:
• ##STR16## wherein Q.sub.1 and Q.sub.2 are selected from the group consisting of hydrogen or alkyl groups of one to four carbon atoms and said monofunctional carboxylic acid represented by the structure:
• ##STR17## wherein R is an organic entity containing one or more carbon atoms, said reactio product represented by the structure:
• ##STR18## wherein X.sub.1, Q.sub.1, Q.sub.2, and R are as defined above.