Structure, nonisothermal decomposition kinetics, thermal safety and mechanisms of improving stability and sensitivity of RDX/expanded graphite embedment composite

To understand structure, properties and mechanisms of improving safety of RDX/expanded graphite (EG) embedment composite further and promote the application of EG in energetic materials, embedment stability, formability, detonation velocity, thermal stability, thermal safety and microscopic mechanisms of improving stability and sensitivity of the composite were studied in depth as a supplement to our previous work. Embedment stability was good. Formability (charge density of 1.76 gcm^-3) and detonation velocity (7577 ms^-1) were acceptable considering the content of EG was 13 wt%. Thermal stability and safety were proved to be improved by kinetics parameters and self-accelerating decomposition temperature. The former was obtained by forty-one kinds of kinetics model functions and six kinetics equations from nonisothermal thermolysis process of RDX. Molecular dynamics were employed to understand microscopic mechanisms for improving safety. Results showed that after being embedded in EG, strength and number of intermolecular forces in RDX crystal increased by 5.45 % and 14.38 %, and N-NO2 maximum bond length of RDX molecule was shorted from 1.60 to 1.56 Å indicating a stronger intermolecular interaction and a safer trigger bond. All these results suggested that RDX/EG embedment composite was a more stable and insensitive system with a certain practical value.