Azide-bearing polymer-based solid composite propellant prepared by a dual curing system consisting of a urethane-forming reaction and a dipolar addition reaction

•Azide-bearing polymer-based solid propellants were prepared by using the urethane, the triazole, or dual curing systems.•The dual curing system offered the best mechanical properties as well as high burn rate and low pressure exponent.•The dual curing system also produced excellent adhesion between the GAP-based solid propellant and the HTPB liner.

Solid composite propellants based on a polymer bearing azide pendent groups, glycidyl azide polymer (GAP), were prepared by urethane- or triazole-forming reactions and their combination. Dipolarophiles featuring diacetylenic groups, such as bispropargyl succinate (BPS) and 1,4-bis(1-hydroxypropargyl)benzene (BHPB), were used as the curatives in the triazole curing system. Among the three types of curing systems used for the preparation of GAP-based solid composite propellants, dual curing systems provided the best mechanical properties, regardless of the oxidizer type included in the solid composite propellant. The dual curing system produced GAP-based solid composite propellants that exhibited a higher burn rate and a lower pressure exponent compared to propellants obtained from a single triazole curing system. Finally, good adhesion to the hydroxyl-terminated polybutadiene (HTPB)-based liner was observed in the GAP-based solid propellants prepared from the dual curing system.