Properties Comparison of Composite Solid Propellants Based on HTPB and NHTPB/HTPB

Hydroxyl terminated polybutadiene (HTPB) is the most commonly used binder in composite solid propellants. However, due to its non-energetic characteristic, it is recognized as a dead weight in practice. Therefore, replacing HTPB with an energetic polymer is essential. In this research,
nitrated hydroxyl terminated polybutadiene resin (NHTPB) with 12.2% nitration rate, in combination with HTPB resin was used as binder . Thus, the HTPB propellant base formulation (HB) was prepared as a reference sample and its physical-mechanical properties, burning rate, and sensitivity were compared with two other cured formulations: the propellant formulation with binder ratio of 5% NHTPB and 95% HTPB (NH5) and the other with binder ratio of 10% NHTPB and 90% HTPB (NH 10). The results showed that, with increasing NHTPB to HTPB ratio from 5% to 10%, Young's modulus, burning rate, impact, and friction sensitivities were increased in comparison to reference propellant. In addition, the cross-linking density, hardness, and tension were decreased