Mechanism study on the interface enhancement effect of NPBA functional groups on NPBA-HMX

ZK Feng and ZC Wen and HP Li and CT Li and F Wang, MATERIALS TODAY COMMUNICATIONS, 40, 110052 (2024).

DOI: 10.1016/j.mtcomm.2024.110052

The incorporation of NPBA has significantly enhanced the mechanical properties of NEPE propellants. Further investigation is warranted into the micro mechanisms through which functional groups enhance interfacial mechanics. This study utilizes molecular dynamics simulations and quantum chemical calculations to explore the interface enhancement effect of NPBA functional groups on NPBA-HMX. The molecular dynamics simulations reveal that NPBA, enriched in CN functional groups, displays superior mechanical properties, showcasing stability across various stretching rates, improved yield strength, ductility, and flexibility. Notably, as temperature decreases, its yield strength increases while the critical normal separation distance decreases. Better mechanical properties attributed to stronger affinity between HMX and fragments with CN group. Quantum chemical calculations (based on electrostatic potential analysis) indicate that the fragment with CN group has a stronger binding energy with HMX (23.50 kJ/mol). The long-range force distance between the OH group of NPBA and HMX is also found by rigidity scanning of quantum chemistry. This study reveals the in-depth mechanics enhancement mechanism of NPBA. NPBA enhances propellant mechanics through its strong interaction with HMX via fragments with CN group and through cross-linking with curing agents like N100/TDI via OH group. This is crucial for accurately constructing complex curing cross-linking models that are close to reality and simulating their mechanical properties.

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