Work

Molecular dynamics simulation study on the aging process of RDX/HTPB propellants at different temperatures

Year: 2026

Type: article

Abstract: During long-term storage of HTPB-based high-energy solid propellants, slow aging often occurs and leads to irreversible changes, such as internal structural distortion, reduced stability, degraded mechanical properties, and abrupt changes in the burning rate. In severe cases, it may cause unintended ignition or spontaneous combustion and bring about safety risks during use. The decomposition reactions of the binder HTPB and the high-energy component RDX play a significant role, and a deep understanding of the microscopic decomposition mechanisms of RDX/HTPB propellants is crucial for ensuring operational stability and reliability. Using the ReaxFF/lg reactive force field, molecular dynamics simulations of the RDX/HTPB propellant aging process at different temperatures were conducted. Changes in the potential energy, species evolution, reaction pathways, and product distribution patterns were analyzed. The MD results indicate that the lower the temperature is, the lower the aging rate. When the temperature exceeds 1000 K, the aging rate exponentially increases with increasing temperature. The aging process begins with cleavage of N−NO2 bonds in RDX. The reaction products primarily consist of intermediates, final products, and some large carbon-containing clusters. The fitted activation energy was determined to be 85.59 kJ/mol, with a storage lifespan of 23.56 years at 20 °C predicted. The storage lifespan of the propellant is negatively correlated with temperature, indicating that low-temperature environments are beneficial for extending the storage duration of the propellant.

Source: Fuel Communications

DOI: 10.1016/j.jfueco.2026.100156