Uncovering the decomposition mechanism of nitrate ester plasticized polyether (NEPE): a neural network potential simulation

MJ Wen and JT Shi and XY Chang and JH Han and KH Pang and DP Chen and QZ Chu, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 26, 25719-25730 (2024).

DOI: 10.1039/d4cp02223h

Nitrate ester plasticized polyether (NEPE) propellants have attracted widespread attention due to their high energy density and excellent low- temperature mechanical properties. However, little is known about the thermal decomposition process of the NEPE propellant, particularly lacking microscale models and interaction mechanisms. This work aims to establish a high-precision and efficient neural network potential (NNP) model covering the NEPE matrix, describing its mechanical behavior and detailed thermal decomposition mechanisms. The model accuracy, including atomic energies and forces, was validated through density functional theory (DFT) results, and the NEPE propellant decomposition model was verified via molecular dynamics (MD) simulations with DFT precision. The results demonstrate that the NNP model accurately predicts the energies and forces of the NEPE matrix for single and mixed systems at the DFT- level precision, and reproduces the mechanical properties consistent with DFT calculations. Meanwhile, the thermal decomposition order of the NEPE matrix predicted by NNP is consistent with the experimental results, accurately capturing complex physical phenomena and detailed decomposition processes among components. It is also revealed that the addition of a binder can improve the stability of the propellant and extend its energy release time. This study applies innovative machine learning algorithms to develop an NNP computational model for the NEPE matrix with DFT precision, which is crucial for practical propellant formulation design. The developed NNP model for the NEPE matrix captures mechanical and thermal behaviors with DFT accuracy. Time-resolved 3D reconstruction of the decomposition process demonstrates that binders enhance stability and extend energy release time.

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