Molecular simulations of hybrid cross-linked membranes for H2S gas separation at very high temperatures and pressure: Binary 90%/10% N2/H2S and CH4/H2S, ternary 90%/9%/1% N2/CO2/H2S and CH4/CO2/H2S mixtures

Neyertz, Sylvie; Benes, Nieck E.; Brown, David

doi:10.1016/j.memsci.2023.122092

Cited by 2 publications

(2 citation statements)

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“…Fe + ion irradiation resulted in the elimination of CO, C–O–C, and C–N bonds, and the generation of phenyl, phenoxyl, and ketone radicals. In addition, Neyertz’s group − utilized MD simulation techniques to conduct a series of significant research on gas separation in glassy polymer membranes. They systematically explored the sorption, diffusion, and permeation mechanisms of single (e.g., CO 2 , CH 4 , N 2 ), binary (e.g., CH 4 /N 2 , N 2 /H 2 S, CH 4 /H 2 S), and ternary (e.g., CH 4 /N 2 /CO 2 , N 2 /CO 2 /H 2 S, CH 4 /CO 2 /H 2 S) gas systems in 6FDA-based PIs.…”

Section: Introductionmentioning

confidence: 99%

“…The authors probed the structure of shocked PI specimens in the range of 28−163 GPa using X-ray diffraction, noting shock-induced melting below a shock pressure of 32 GPa. Huber et al 21 subjected the PI material to decomposition pressures (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), tracking the shock wave with embedded electromagnetic velocity gauges. They directly observed the attenuation of the leading shock wave and argued that the change in the PI Hugoniot curve originates from shockinduced chemical reactions rather than shock melting.…”

Section: Introductionmentioning

confidence: 99%

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Atomic Insight into Multilevel Microstructure Evolution and Energy Variation Mechanisms of Polyimide under Shock Compression

Liu,

Chen,

Zhu

et al. 2024

Macromolecules

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Polyimide (PI) stands as a foundational material in the aerospace industry and high-energy-density science, and its shock response under extreme conditions constitutes an increasing focus within the academic community. However, given the sophisticated molecular structure and stacking state of chains, the understanding of how PI mobilizes multiple micromechanisms in response to external shock loading remains incomplete. To fill this knowledge gap, aided by the multiscale shock technique (MSST), the dynamic behaviors of pyromellitic dianhydride (PMDA)/4,4′oxidianiline (ODA) PI over shock pressure range of 0−20 GPa are systematically studied through all-atom molecular dynamics (MD) simulations. The multilevel microstructures evolution (spanning from the covalent bond to molecular chain and to aggregation structures) and the diverse energy variation mechanisms are comprehensively analyzed. The results indicate a favorable agreement between the MD-calculated Hugoniot relations of PI and the experimental data in literature. The shock response of PI reveals two distinct stages: low shock strength (0 < P < 5 GPa, I) and high shock strength (5 < P < 20 GPa, II). In the low shock strength stage, diverse energy mechanisms engage in competitive interactions, with their sensitivity to shock pressure determined by the interaction intensities, wherein the relatively weak interchain energy emerges as the most active mechanism. In the high shock strength stage, energy mechanisms transform to coordinate with each other, maintaining consistent contributions to the total energy at a specified proportion. Microstructure analysis identifies the linkage between PMDA and ODA, as well as the ether linkage in ODA, as the most changeable bonded sites. Correspondingly, the C p −N, C p −O−C p, and C p −C p −O c −C p are the most changed bond length, bond angle, and dihedral angle, respectively. The rearrangement of rigid segments between the ether linkages is the primary reason for chain conformation, resulting in the topological structure of the entire molecular chain remaining constant, exhibiting self-similarity under varying shock pressure. Concurrently, X-ray diffraction (XRD) examinations on aggregation structure reveal a 42.6% reduction in d-spacing, indicating that the contraction of free volume is responsible for the observed shock compressibility of PI materials. This study offers insights into the molecular-level mechanisms of shocked polymers, which may serve as a blueprint for the development of advanced polymers in extreme conditions.

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