Damp-Heat Ageing of Resin Insulation Materials (Epoxy Resin and Phenolic Resin as Examples) and Their Effects on Flame Retardancy.
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| Title: | Damp-Heat Ageing of Resin Insulation Materials (Epoxy Resin and Phenolic Resin as Examples) and Their Effects on Flame Retardancy. |
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| Authors: | Ming, Yue1 (AUTHOR), Qiao, Xinhan2 (AUTHOR) 18086799908@189.cn, Meng, Haoran2,3 (AUTHOR), Zeng, Wentian2,4 (AUTHOR), Xia, Xiaolei1 (AUTHOR), Yang, Feng1,2 (AUTHOR), Xu, Ke3 (AUTHOR), Zhang, Zhijin4 (AUTHOR), Huang, Chuanhui1 (AUTHOR) huangch2008@xzit.edu.cn |
| Source: | Polymers (20734360). May2026, Vol. 18 Issue 10, p1200. 15p. |
| Subjects: | Flammability, Deterioration of materials, Epoxy resins, Insulating materials, Phenolic resins, Microstructure, Fire testing |
| Abstract: | As power equipment insulation materials, epoxy resin and phenolic resin are inevitably exposed to damp-heat environments during long-term operation, leading to ageing degradation. This study systematically investigates the effects of damp-heat ageing (85 °C, 90% RH, 0–56 days) on the flame retardancy of both resins through oxygen index tests, vertical combustion experiments, and microstructural analysis (SEM/EDS). Results indicate that ageing unexpectedly enhances flame retardancy: Epoxy resin: Oxygen index rapidly increased from 64.4% (0 days) to 76.5% (21 days), then stabilised at 75–76%. Afterflame time decreased from 143 s to 109 s after 56 days. Phenolic resin: Oxygen index rose continuously with ageing; afterflame time dropped sharply from 211 s (0 days) to 0 s (56 days). Mechanistic analysis reveals that ageing promotes surface enrichment of flame-retardant elements (Ca, Mg, Si in epoxy; Al, Mg in phenolic) and structural changes (e.g., porous carbonisation), which facilitate barrier effects against heat/oxygen diffusion. This work challenges conventional views on ageing-induced degradation, providing new insights for evaluating insulation safety in humid environments. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | As power equipment insulation materials, epoxy resin and phenolic resin are inevitably exposed to damp-heat environments during long-term operation, leading to ageing degradation. This study systematically investigates the effects of damp-heat ageing (85 °C, 90% RH, 0–56 days) on the flame retardancy of both resins through oxygen index tests, vertical combustion experiments, and microstructural analysis (SEM/EDS). Results indicate that ageing unexpectedly enhances flame retardancy: Epoxy resin: Oxygen index rapidly increased from 64.4% (0 days) to 76.5% (21 days), then stabilised at 75–76%. Afterflame time decreased from 143 s to 109 s after 56 days. Phenolic resin: Oxygen index rose continuously with ageing; afterflame time dropped sharply from 211 s (0 days) to 0 s (56 days). Mechanistic analysis reveals that ageing promotes surface enrichment of flame-retardant elements (Ca, Mg, Si in epoxy; Al, Mg in phenolic) and structural changes (e.g., porous carbonisation), which facilitate barrier effects against heat/oxygen diffusion. This work challenges conventional views on ageing-induced degradation, providing new insights for evaluating insulation safety in humid environments. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 20734360 |
| DOI: | 10.3390/polym18101200 |
