Effect of a neutral polymeric bonding agent on damage evolution and mechanical properties of highly filled polymer composites

Abstract

Neutral polymeric bonding agents (NPBAs) are widely used to improve particle/binder interfacial properties and the mechanical performance of nitrate ester plasticized polyether (NEPE) propellants. However, their effects on mesoscopic damage evolution under external loading remain insufficiently understood. In this study, atomic force microscopy (AFM), in-situ scanning electron microscopy (SEM), numerical simulation, and uniaxial tensile testing were used to investigate the effects of NPBA on the mesoscopic damage and macroscopic mechanical properties of NEPE propellants. AFM results showed a continuous apparent modulus transition region at the HMX/binder interface, with the modulus increasing gradually from the binder to the HMX particle. After NPBA addition, the transition width tended to decrease, while the average modulus gradient tended to increase. In-situ SEM observations showed that HMX/binder debonding occurred earlier in the absence of NPBA. After NPBA addition, HMX/binder debonding was delayed, while AP/binder debonding was also observed. Combined experimental and numerical results suggest that NPBA has a greater influence on the HMX/binder interface than on the AP/binder interface. Interfacial damage tended to occur at the weaker particle/binder interface, and the relative strengths of the HMX/binder and AP/binder interfaces affected the location and subsequent evolution of damage. Tensile tests showed that NPBA increased the tensile strength and elastic modulus but substantially reduced the elongation at maximum load. Further increasing the NPBA content from 0.5 to 1.0 wt.% resulted in relatively small changes in the mechanical properties.

The authors' abstract, as published at the source. Polymer Testing, 2026 · DOI ↗