Energetic plasticizers for GAP-based formulations with ADN: compatibility and performance evaluation of a nitrofurazanyl ether

Abstract

Glycidyl azide polymer (GAP) diol is an energetic binder with azide-functionalized side chains that offer a high enthalpy of formation. When formulated with ammonium dinitramide (ADN), GAP-based systems exhibit promising energetic and ballistic performance. However, GAP suffers from poor mechanical properties compared to inert binders such as hydroxyl-terminated polybutadiene (HTPB). As a result, plasticization is essential to lower the glass transition temperature of GAP. Energetic plasticizers can enhance both mechanical and energetic performance. In this study, we evaluated the compatibility of a novel nitrofurazanyl ether-based energetic plasticizer, NFPEG3N3, with key formulation components: GAP diol, HMX, Desmodur N100, and ADN. Compatibility was assessed using heat-flow microcalorimetry (HFMC) and thermogravimetry (TG), in accordance with STANAG 4147. NFPEG3N3 was found to be compatible with GAP diol, HMX, and N100. Although the NFPEG3N3–ADN mixture passed the HFMC (remaining below the 1% heat of explosion threshold), it failed TG, indicating potential concerns with long-term thermal stability. Performance calculations showed that replacing 15 wt% of GAP with NFPEG3N3 in a composite propellant increased the volume-specific impulse by 77 N s dm⁻³. Additionally, formulations incorporating NFPEG3N3 demonstrated a superior oxygen balance and higher volume-specific impulse compared to those using the widely adopted energetic plasticizer Bu-NENA.