Preparation, flame retardancy, and phase-change kinetics of OMMT/chitosan composite phase-change capsules
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Qing Cao
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Wenjie Guo
Abstract
Double-shell phase change capsules composed of organically modified montmorillonite (OMMT), chitosan (CS), and paraffin wax (PCM) were fabricated using complex coacervation and dry mixing methods. Paraffin served as the core material, CS as the organic shell, and OMMT as the inorganic flame-retardant component. The morphology, thermal stability, flame retardancy, and phase transition kinetics of the capsules were systematically examined. Results indicated that when the mass ratio of OMMT to CS/PCM was 1:1, OMMT was uniformly dispersed on the capsule surface, leading to optimal performance. Thermogravimetric (TG) and microscale combustion calorimetry (MCC) analyses revealed that the incorporation of OMMT significantly improved the thermal stability of the capsules, increased char residue, and markedly reduced both the peak heat release rate (PHRR) and total heat release (THR). The phase change behavior was elucidated through differential scanning calorimetry (DSC). Furthermore, Kissinger’s kinetic model was applied to determine the activation energy, which was found to be higher in the OMMT-containing capsules, suggesting that OMMT addition restricts molecular thermal motion. This study offers both theoretical insights and practical guidelines for designing composite phase change materials that combine high energy storage efficiency with enhanced flame retardancy.
Funding source: The National Natural Science Foundation of China
Award Identifier / Grant number: NO. 52204224
Award Identifier / Grant number: NO. 51904032
Funding source: The Doctoral Scientific Research Launch Fund Project of Shandong University of Aeronautics
Award Identifier / Grant number: NO.2024Y35
Funding source: The National Natural Science Foundation of Shandong Province
Award Identifier / Grant number: ZR2025MS955
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Research ethics: Not applicable.
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Informed consent: Not applicable.
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Use of Large Language Models, AI and Machine Learning Tools: None declared.
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Conflict of interest: The authors state no conflict of interest.
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Research funding: This work was supported by the National Natural Science Foundation of China, grant number NO. 52204224 and NO. 51904032; the National Natural Science Foundation of Shandong Province, grant number NO.ZR2025MS955; the Doctoral Scientific Research Launch Fund Project of Shandong University of Aeronautics, grant number NO.2024Y35.
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Data availability: The datasets used and/or analyzed during the current study available from the corresponding author on reasonable request.
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