Comparative Assessment of Energetic Plasticizers Including NFPEG3N3 in a GAP/HMX Formulation: Mechanics, Stability, Combustion, and Performance

ABSTRACT We examine the new energetic plasticizer 3‐(2‐(2‐(2‐azidoethoxy)ethoxy)ethoxy)‐4‐nitro‐1,2,5‐oxadiazole (NFPEG3N3), three reference compounds (BDNPA/F, Bu‐NENA, and DNDA‐57), and a plasticizer‐free control in a fixed HMX/GAP composite. NFPEG3N3 provides the strongest low‐temperature properties, yielding the lowest formulation glass transition temperature of −50.9°C. In tensile testing, NFPEG3N3, Bu‐NENA, and DNDA‐57 show comparable peak strengths (0.36–0.38 MPa), while BDNPA/F is higher (0.50 MPa). NFPEG3N3 achieves the highest ductility (3.8% strain at maximum stress) and the lowest elastic modulus (16.7 MPa), indicating superior compliance without a penalty in peak load capacity relative to the other energetic plasticizers. All formulations meet STANAG‐referenced stability criteria in vacuum stability, heat‐flow microcalorimetry, and mass loss. Consistent with its nitrate ester‐free structure, NFPEG3N3 exhibits distinctly lower heat release and mass loss than BDNPA/F and Bu‐NENA. Burning‐rate regression shows NFPEG3N3 does not significantly change the burn rate at 7 MPa, while reducing the Vieille pressure exponent by 16.5% to 0.792. As polymer‐bonded explosives, DNDA‐57 and BDNPA/F yield the highest detonation velocity and pressure, while NFPEG3N3 is slightly above the control in detonation velocity and notably higher in pressure and temperature of detonation. As composite propellants, NFPEG3N3 matches Bu‐NENA in mass‐specific impulse and exceeds it in volume‐specific impulse. Overall, NFPEG3N3 has balanced properties: enhanced toughness, acceptable strength, favorable stability, and improved combustion characteristics. These properties make it a promising alternative to nitrate ester plasticizers in GAP/HMX systems.