Open Access

ARTICLE

Synergistic Effect of Silicone Macromolecular Charring Agent and Ammonium Polyphosphate on Improving Flame Retardancy and Mechanical Properties of Ethylene-Butyl Acrylate Copolymer Composites

Xuan Huo¹, Bingchen Wu¹, Yuanmeng Lou¹, Junlin Zhu¹, Cui Li¹, Lili Ma¹, Ye-Tang Pan², Chuncheng Hao^1,*, Xin Wen^1,*

1 College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China
2 National Engineering Research Center of Flame Retardant Materials, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, 100081, China

* Corresponding Authors: Chuncheng Hao. Email: ; Xin Wen. Email:

Journal of Polymer Materials 2025, 42(2), 517-530. https://doi.org/10.32604/jpm.2025.065320

Received 10 March 2025; Accepted 27 May 2025; Issue published 14 July 2025

Abstract

Power cables are important pieces of equipment for energy transmission, but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge. In this work, a novel intumescent flame retardant (IFR) system containing silicone-containing macromolecular charring agent (Si-MCA) and ammonium polyphosphate (APP) was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer (EBA) composites. The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites (EBA/APP-Si-31), corresponding to the best flame retardancy with 31.2% of limited oxygen index (LOI), V-0 rating in UL-94 vertical burning test, and 76.4% reduction on the peak of heat release rate (PHRR) in cone calorimeter test. The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion, including the radical-trapping effect, the dilution effect of non-flammable gases, and the barrier effect of the intumescent char layer. Meanwhile, the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene (PE-g-MA) as the compatibilizer. Thus, the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites, and it will promote their applications as cable sheath materials.

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