Pore Characteristics of NEPE Solid Propellant under Pressure Cure

ABSTRACT This study investigated the influence of the pressure‐cure process on the pore characteristics of nitrate ester‐plasticized polyether (NEPE) propellant using micro‐computed tomography technology. The mesostructure characteristics of the NEPE propellant were obtained under various curing pressures, including atmospheric pressure (0 MPa), 1, 1.5, and 2 MPa. The results demonstrated that the pore characteristics of the NEPE propellant exhibited significant changes under pressure cure. Specifically, the number of pores with a sphericity ranging from 0.61 to 1, indicating a more rounded morphology, increased, while the proportion of micro‐pores with a volume below 0.5 µm decreased. The micro‐pores coalesced into larger voids, and the pore distribution exhibited a distinct clustering tendency. The NEPE propellant produced by the pressure cure process exhibited an increased elongation rate, along with enhanced tensile strength and elastic modulus, as well as a significant reduction in porosity. However, when the applied pressure exceeded a certain threshold, like 2 MPa, the mechanical properties of the pressurized‐cured propellant no longer improved but instead decreased. When the pressure applied during the pressure cure process was in the range of 1–1.5 MPa, the porosity of the propellant decreased, the numerical distributions of pore sphericity and volume became more concentrated, and the mechanical properties were optimized to the greatest extent. Analysis of the pore characteristics and mechanical properties of NEPE propellant produced via pressure cure provides a guiding foundation for optimizing the solid rocket engine propellant manufacturing process in the aerospace industry.