Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement
This study systematically examines the effect of the morphology of cerium oxide (CeO<sub>2</sub>) on the flame retardancy, thermal stability, and mechanical properties of polypropylene composites with intumescent flame retardant (PP/IFR). Layer-CeO<sub>2</sub> (L-CeO<sub&g...
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MDPI AG
2025-05-01
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| Online Access: | https://www.mdpi.com/1420-3049/30/10/2102 |
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| author | Bangmin Li Wayne Hsu Tingyi Zheng Yincai Wu Shenglong Wang Fenglong Lin Lijun Song Xianfa Rao |
| author_facet | Bangmin Li Wayne Hsu Tingyi Zheng Yincai Wu Shenglong Wang Fenglong Lin Lijun Song Xianfa Rao |
| author_sort | Bangmin Li |
| collection | DOAJ |
| description | This study systematically examines the effect of the morphology of cerium oxide (CeO<sub>2</sub>) on the flame retardancy, thermal stability, and mechanical properties of polypropylene composites with intumescent flame retardant (PP/IFR). Layer-CeO<sub>2</sub> (L-CeO<sub>2</sub>) outperforms Particulate-CeO<sub>2</sub> (P-CeO<sub>2</sub>) in enhancing the flame retardancy of PP/IFR composites, showing higher limiting oxygen index (LOI) and greater reductions in the total heat release rate (THR) and total smoke production (TSR). The substitution of 1% IFR with 1% L-CeO<sub>2</sub> significantly increased the LOI from 29.4% to 32.6%, while reducing the THR and TSR by 38.9% and 74.3%, respectively. L-CeO<sub>2</sub> incorporation improves thermal stability, increasing the residual char yield to 8.53% at 800 °C under air (vs. 3.87% for PP/IFR). Additionally, L-CeO<sub>2</sub> improved the mechanical properties of the composites, increasing tensile strength and rigidity. The synergistic flame-retardant mechanism is hypothesized to involve CeO<sub>2</sub> catalyzing the formation of a P-O-C crosslinked network in the carbon layer, leading to a denser carbon structure and improved flame-retardant performance in the PP/IFR composites. These findings demonstrate the efficacy of L-CeO<sub>2</sub> as a flame-retardant synergist, providing a foundation for developing fire-safe polymeric materials. |
| format | Article |
| id | doaj-art-32edad8996c44097bb749b4fbeef2b15 |
| institution | OA Journals |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | MDPI AG |
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| series | Molecules |
| spelling | doaj-art-32edad8996c44097bb749b4fbeef2b152025-08-20T02:33:58ZengMDPI AGMolecules1420-30492025-05-013010210210.3390/molecules30102102Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance EnhancementBangmin Li0Wayne Hsu1Tingyi Zheng2Yincai Wu3Shenglong Wang4Fenglong Lin5Lijun Song6Xianfa Rao7JiangXi University of Science and Technology, Ganzhou 341000, ChinaXiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361021, ChinaXiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361021, ChinaXiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361021, ChinaXiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361021, ChinaXiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361021, ChinaXiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361021, ChinaJiangXi University of Science and Technology, Ganzhou 341000, ChinaThis study systematically examines the effect of the morphology of cerium oxide (CeO<sub>2</sub>) on the flame retardancy, thermal stability, and mechanical properties of polypropylene composites with intumescent flame retardant (PP/IFR). Layer-CeO<sub>2</sub> (L-CeO<sub>2</sub>) outperforms Particulate-CeO<sub>2</sub> (P-CeO<sub>2</sub>) in enhancing the flame retardancy of PP/IFR composites, showing higher limiting oxygen index (LOI) and greater reductions in the total heat release rate (THR) and total smoke production (TSR). The substitution of 1% IFR with 1% L-CeO<sub>2</sub> significantly increased the LOI from 29.4% to 32.6%, while reducing the THR and TSR by 38.9% and 74.3%, respectively. L-CeO<sub>2</sub> incorporation improves thermal stability, increasing the residual char yield to 8.53% at 800 °C under air (vs. 3.87% for PP/IFR). Additionally, L-CeO<sub>2</sub> improved the mechanical properties of the composites, increasing tensile strength and rigidity. The synergistic flame-retardant mechanism is hypothesized to involve CeO<sub>2</sub> catalyzing the formation of a P-O-C crosslinked network in the carbon layer, leading to a denser carbon structure and improved flame-retardant performance in the PP/IFR composites. These findings demonstrate the efficacy of L-CeO<sub>2</sub> as a flame-retardant synergist, providing a foundation for developing fire-safe polymeric materials.https://www.mdpi.com/1420-3049/30/10/2102cerium oxidemorphologyintumescent flame retardantpolypropylenesynergistic effect |
| spellingShingle | Bangmin Li Wayne Hsu Tingyi Zheng Yincai Wu Shenglong Wang Fenglong Lin Lijun Song Xianfa Rao Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement Molecules cerium oxide morphology intumescent flame retardant polypropylene synergistic effect |
| title | Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement |
| title_full | Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement |
| title_fullStr | Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement |
| title_full_unstemmed | Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement |
| title_short | Morphology-Engineered CeO<sub>2</sub> as a Synergistic Flame Retardant in Polypropylene/Intumescent Systems: Mechanisms and Performance Enhancement |
| title_sort | morphology engineered ceo sub 2 sub as a synergistic flame retardant in polypropylene intumescent systems mechanisms and performance enhancement |
| topic | cerium oxide morphology intumescent flame retardant polypropylene synergistic effect |
| url | https://www.mdpi.com/1420-3049/30/10/2102 |
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