Polyphosphazene-Functionalized Boron Nitride Nanosheets as a Multifunctional Synergist for Enhanced Thermal-Oxidative Stability and Fire Safety of EPDM Composites

作者：Fangshan Li, K. X. Zhao, Yuchao Ke, Chun Yang, Bibo Wang, Fukai Chu, Weizhao Hu, Lei Song, Yuan Hu · 发表于：ACS Applied Nano Materials · 年份：2025 · DOI：10.1021/acsanm.5c02043 · 被引用次数：7 · 研究领域：Flame retardant materials and properties、Synthesis and properties of polymers、Polymer Nanocomposites and Properties

Ethylene propylene diene monomer (EPDM) is widely used in automotive and HVAC sealing systems, where its long-term thermal-oxidative stability and fire safety are critical, yet challenged by high-temperature operation and flammability risks. To address these limitations, this work develops a surface-engineered boron nitride synergist (h-BN@PDT) through NaOH-assisted hydroxylation and subsequent functionalization with hexachlorocyclotriphosphazene and tannic acid. The modified h-BN@PDT integrates phosphorus/nitrogen flame-retardant groups and radical-scavenging phenolic hydroxyls, achieving multifunctional enhancements in EPDM composites. Thermal-oxidative aging tests (125 °C, 168 h) demonstrated exceptional stability, with 11.12 MPa of tensile strength for aged h-BN@PDT/EPDM, compared to 2.78 MPa of traditional flame-retardant EPDM without BN fillers. Doubling oxidation induction time was attributed to enhanced thermal conductivity and pyrolysis activation energy, which contributed to BN’s oriented heat-transfer pathways and phenolic hydroxyl-mediated radical quenching. Flame retardancy evaluations revealed that h-BN@PDT can effectively replace partial conventional flame retardants while enabling the composite to achieve a UL-94 V-0 rating with only 25 phr of flame-retardant loading. Cone calorimetry tests demonstrated a significantly reduced heat and smoke release rate. Mechanistic studies identified that h-BN@PDT enhances flame retardancy through the synergistic effects of ...