Thermal aging behavior and mechanism of an RDX-based aluminized thermobaric explosive

The aging characteristics of polymer bonded explosives (PBXs) directly affects long-term storage reliability and operational safety. This study combined multiple characterization techniques and molecular dynamics (MD) simulations to systematically investigate the microstructure, thermal response, and mechanical properties of cyclotrimethylenetrinitramine (RDX)-based aluminized thermobaric explosives (TBXs) under accelerated aging at 95°C for 42 days. Results showed thermal aging induced paraffin wax (PW) melting migration and butadiene rubber (BR) secondary crosslinking, increasing porosity and altering compressive strength. A strong positive correlation function relationship between compressive strength and crosslinking density was established (R 2 =0.9550), specifically, a 73.9% increase in crosslinking density during aging contributed to a 189.3% enhancement in compressive strength. Mean square displacement (MSD) analysis from MD simulations further confirmed that elevated temperature enhances the molecular mobility of the BR/PW system, thereby promoting PW migration and BR crosslinking. Owing to the retained chemical stability of RDX, the self-regulation of the BR/PW, and the nearly unchanged mechanical sensitivity and energy output, the explosive demonstrates excellent overall stability under the experimental conditions. This work provides experimental evidence and theoretical insights for aging assessment, lifetime prediction, and safety control of similar PBXs. • This study combined multiple characterization techniques and MD simulations. • Crosslink density is correlated with compressive strength during aging. • The reversible migration/crosslinking of BR/PW governs thermal aging of TBXs.