Meso-Scale Observations of the Evolution of Matrix/Filler Interface Dewetting During NEPE Propellant Aging

To clarify the evolution of dewetting during the aging of NEPE propellant during long-term storage and more intuitively reveal the impact of aging on dewetting behavior, we used micro-CT to scan NEPE propellant samples subjected to 20% constant strain at different points during aging. After image processing, the internal pores of the samples were extracted, porosity was calculated, and the law of the variation in dewetting behavior at the matrix/filler interface during aging was analyzed. Additionally, we used SEM technology to scan the tensile fracture surfaces of the NEPE propellant samples, observing the aging evolution of the matrix and matrix/filler interface on the fracture surfaces. Along with conducting a micro-CT test, we further explored the changes in bonding performance at the matrix/filler interface during aging. The micro-CT scanning results indicated that dewetting was evident in unaged samples under constant-strain loading, resulting in numerous petal-shaped pores with a significant volume. As aging progressed, the number of petal-shaped pores gradually decreased, and porosity dropped significantly. The SEM scanning results show that the matrix gradually softened during aging, encapsulating solid particles more tightly. Based on all the experimental results, debonding in the NEPE propellants became progressively less pronounced with aging, and interfacial adhesion between the matrix and filler improved. These results provide support for enhancing NEPE propellants’ matrix/filler interfacial bonding strength and, consequently, improving their mechanical properties.