Nitrate ester functionalized ionic liquid as energetic plasticizer for HTPB propellant

Energetic plasticizers are rarely used in HTPB propellants due to compatibility issues; one strategy is usually adopted is to introduce energetic substituents. In this study, the synthesized high-energy ionic liquids were comprehensively characterized, and showed that they possess extremely low melting points (IL-3h, T m = –70 °C), good thermal stability (ILs, T p > 370 °C), and high densities (IL-3a, ρ = 1.637 g/cm 3 ). The high-energy performance exhibited by high detonation velocity ( D v ) and pressure ( D P ) of ionic liquids ( D v : 6600–6800 m/s; D p : 17–19 MPa) contributes to improved specific impulse in propellant formulations, which significantly surpasses that of conventional triethylene glycol dinitrate (TEGDN). Furthermore, HTPB elastomer cured with TDI were plasticized with ionic liquids, and the results of tensile and dynamic mechanical tests were showed that the HTPB elastomer plasticized with ionic liquids had a maximum tensile strength of 0.883 MPa and a maximum elongation at break of 539.2%, which were comparable to DOA ( σ t = 0.587 MPa, ε t = 479.1%). This work provides an innovative approach for the design of energetic ionic liquid plasticizers in HTPB propellants.