Thermal aging mechanism of PBT energetic elastomer based on the evolution of microstructure

Chen, C.; Pan, Hongjiang; Tu, J.P.; Chen, Jingxiang; Zhang, X.G.; Mao, Chenyu; Zhou, Xing

doi:10.1016/j.mtchem.2023.101655

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…In addition, the experimental results also show that TMP has a low melting point and contains three –OH groups in its molecular structure, which is easy to react with –NCO groups, promote the formation of three-dimensional network of elastomers, and can improve the cross-linking degree of cured products. 41 Hence, the presence of TMP molecules facilitates the formation of the cross-linking network structure for the PBT/TDI system.…”

Section: Resultsmentioning

confidence: 99%

Curing and Cross-Linking Processes in the Poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran/Toluene Diisocyanate/Trimethylolpropane System: A Density Functional Theory and Accelerated ReaxFF Molecular Dynamics Investigation

Qiu,

Chen,

Huan

et al. 2024

ACS Omega

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The physical and chemical properties of solid propellant are influenced by the composition and structure of the binder, with its network structure being formed through curing and cross-linking reactions. Therefore, understanding the mechanisms of these reactions is crucial. In this study, we investigated the curing and cross-linking mechanisms of poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran (PBT), toluene diisocyanate (TDI), and trimethylolpropane (TMP) using a combination of density functional theory (DFT) calculations and accelerated ReaxFF molecular dynamics (MD) simulations. DFT calculations revealed that the steric effect of the −CH 3 group in TDI exerts a significant influence on the curing reaction between TDI and PBT. Additionally, in the cross-linking process, the energy barrier for TDI reacting with TMP was found to be much lower than that for TDI reacting with the PBT-TDI intermediate. Subsequently, we conducted competing reaction processes of TMP/TDI-PBT-TDI cross-linking and TDI-PBT-TDI self-cross-linking using accelerated MD simulations within the fitted ReaxFF framework. The results showed that the successful frequency of TMP/TDI-PBT-TDI cross-linking was substantially higher than that of TDI-PBT-TDI self-cross-linking, consistent with the energy barrier results from DFT calculations. These findings deepen our understanding of the curing and cross-linking mechanisms of the PBT system, providing valuable insights for the optimization and design of solid propellants.

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Section: Resultsmentioning

confidence: 99%

Curing and Cross-Linking Processes in the Poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran/Toluene Diisocyanate/Trimethylolpropane System: A Density Functional Theory and Accelerated ReaxFF Molecular Dynamics Investigation

Qiu,

Chen,

Huan

et al. 2024

ACS Omega

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“…The degree of crosslinking is an important link in facilitating the communication between chemical aging and aged mechanical parameters [ 9 ]. Chen [ 10 ] investigated the aging mechanism of PET elastomers and established a mechanical property deterioration model of propellants based on microstructure evolution. Thus, by analyzing the changes in the physical and chemical properties of the elastic matrix, it is possible to determine the key reactions and degradation mechanisms during the aging process, which allows us to reveal the aging mechanism [ 11 ] and extend the service life of the propellants.…”

Section: Introductionmentioning

confidence: 99%

Research on the Thermal Aging Performance of a GAP-Based Polyurethane Elastomer

Liu,

Zhu,

Yang

et al. 2024

Polymers

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Glycidyl azide polymer (GAP)-based polyurethane is an ideal elastomeric matrix for high-energy, low-smoke, and insensitive solid propellants. As the skeleton structure of GAP propellants, changes in the structure and properties of GAP elastomers during aging lead to the deterioration of propellant performance (especially in relation to mechanical properties), which causes safety risks. A high-temperature-accelerated aging experiment (70 °C) on a GAP elastomer was conducted. The evolution of the microstructure of the GAP elastomer system was analyzed by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR), and variations in the macroscopic properties were analyzed by the hardness test and the uniaxial tensile test. The experimental results showed that thermal aging of the GAP elastomer is a coupled process of multiple chemical reactions. The azide groups, urethane groups, and ether bonds were the weak links in the network structure, breaking during the aging process, and the crosslinking density rose and then decreased. Macroscopic properties also showed segmented changes. The aging process was divided into three stages: post-curing (stage one); when the crosslinked network began to break (stage two), and when the crosslinked network was destroyed (stage three). Changes in the microstructure and macroscopic properties were consistent. This work is of great significance for exploring the aging mechanism of GAP propellants and extending their storage life.

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Molecular dynamics and experimental study of mechanical and tribological properties of graphene‐reinforced nitrile butadiene rubber–phenolic resin composites

Li,

Chen,

Qian

et al. 2024

Polymer Composites

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The mechanical and tribological properties as well as the microstructural characteristics of five groups of nitrile butadiene rubber (NBR)/graphene (GE)/phenolic resin (PF) composites were systematically investigated using a combination of experimental and molecular dynamics (MD) simulation methods. Experiments confirmed that PF effectively enhanced the mechanical properties of NBR, including the crosslinking density, hardness, and compression permanent deformation, along with its tribological performance under various working conditions. MD simulations further clarified the tribological mechanism of the NBR/GE/PF composites from a microscopic perspective, highlighting the pivotal role of the hydrogen‐bonding network. PF15 exhibited low wear and mobility during friction owing to its robust hydrogen‐bonding network.Highlights Combined experiments and simulation for NBR performance analysis. Investigated the tribological properties of NBR/GE/PF under various conditions. Hydrogen bonding in NBR/GE/PF was achieved via simulation. A good correlation was found between experimental results and simulation data.

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Thermal aging mechanism of PBT energetic elastomer based on the evolution of microstructure

Cited by 5 publications

References 24 publications

Curing and Cross-Linking Processes in the Poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran/Toluene Diisocyanate/Trimethylolpropane System: A Density Functional Theory and Accelerated ReaxFF Molecular Dynamics Investigation

Curing and Cross-Linking Processes in the Poly(3,3-bis-azidomethyl oxetane)-tetrahydrofuran/Toluene Diisocyanate/Trimethylolpropane System: A Density Functional Theory and Accelerated ReaxFF Molecular Dynamics Investigation

Research on the Thermal Aging Performance of a GAP-Based Polyurethane Elastomer

Molecular dynamics and experimental study of mechanical and tribological properties of graphene‐reinforced nitrile butadiene rubber–phenolic resin composites

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