{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T05:45:40Z","timestamp":1782452740874,"version":"3.54.5"},"reference-count":36,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T00:00:00Z","timestamp":1781827200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"State Grid Jiangsu Electric Power Co., Ltd. Science and Technology Project","award":["J2024114"],"award-info":[{"award-number":["J2024114"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Silicone rubber is an important external insulating material for composite bushings, composite insulators, and other power equipment. During long-term service, it is inevitably exposed to coupled environmental and electrical stresses, such as elevated temperature, moisture ingress, strong electric fields, and partial discharge, which may lead to hydrophobicity loss, surface chalking, crack propagation, and particle shedding. To reveal the microscopic degradation mechanism of silicone rubber under complex operating conditions, a molecular model of methyl vinyl silicone rubber was constructed using Materials Studio. A stable silicone rubber molecular structure was obtained through crosslinking, geometry optimization, and ensemble relaxation. Subsequently, a reactive molecular dynamics simulation system under coupled temperature\u2013humidity\u2013electric field conditions was established using LAMMPS and the ReaxFF reactive force field. Different temperature gradients, electric field intensities, and aging\u2013recovery stages were designed to investigate the degradation behavior of silicone rubber. The evolution of the maximum carbon content, maximum silicon content, carbon-containing decomposition products, and typical small-molecule products, including H2, H2O, CH4, C2H2, C2H4, and C2H6, was statistically analyzed. In addition, atomic trajectory tracking was performed to clarify the processes of methyl group detachment, Si-O bond cleavage, water molecule participation, and molecular chain reconstruction. The results show that high temperature mainly promotes methyl group detachment from side chains and fracture of the siloxane main chain, while a strong electric field accelerates the decomposition process and induces the transformation of long siloxane chains into shorter chains. Water molecules can react with broken siloxane chains to form hydroxyl-containing structures, making the structural degradation partially irreversible. The degradation process of silicone rubber under coupled temperature\u2013humidity\u2013electric field stress can be summarized as side-chain detachment, main-chain scission, water-assisted reactions, free-radical recombination, and local molecular aggregation. This study provides a molecular-level theoretical basis for aging mechanism analysis, condition assessment, and lifetime prediction of composite external insulating materials.<\/jats:p>","DOI":"10.3390\/polym18121530","type":"journal-article","created":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T13:04:04Z","timestamp":1781874244000},"page":"1530","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Atomistic Mechanisms of Silicone Rubber Degradation Under Coupled Temperature\u2013Humidity\u2013Electric Field Conditions"],"prefix":"10.3390","volume":"18","author":[{"given":"Yiheng","family":"Zhou","sequence":"first","affiliation":[{"name":"School of Information and Control Engineering, School of Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhijun","family":"An","sequence":"additional","affiliation":[{"name":"School of Information and Control Engineering, School of Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yixin","family":"He","sequence":"additional","affiliation":[{"name":"School of Information and Control Engineering, School of Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cong","family":"Qian","sequence":"additional","affiliation":[{"name":"State Grid Jiangsu Electric Power Co., Ltd., Nantong Power Supply Branch, Nantong 226007, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiuhua","family":"Zhou","sequence":"additional","affiliation":[{"name":"State Grid Jiangsu Electric Power Co., Ltd., Nantong Power Supply Branch, Nantong 226007, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wentian","family":"Zeng","sequence":"additional","affiliation":[{"name":"School of Information and Control Engineering, School of Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7544-8721","authenticated-orcid":false,"given":"Xinhan","family":"Qiao","sequence":"additional","affiliation":[{"name":"School of Information and Control Engineering, School of Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4164-7762","authenticated-orcid":false,"given":"Wenyu","family":"Ye","sequence":"additional","affiliation":[{"name":"School of Information and Control Engineering, School of Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Wei, X., Lu, W., Zhang, J., Li, J., Xu, C., and Jia, Z. 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