Engineering Ce/P-functionalized g-C3N4 for advanced ABS nanocomposites exhibiting unparalleled fire retardancy, enhanced thermal and mechanical properties

The nanomaterials have been deeply explored as flame retardants for various polymeric materials due to their multifunctionality, but they often fail to significantly increase the limiting oxygen index (LOI) and vertical burning UL-94 rating, thus unable to meet industrial needs (LOI>27.0 % and UL-94 V-0 rating). Herein, we fabricated a cerium/phosphorus-doped g-C3N4 (Ce/P-CN) nanohybrid as a multifunctional high-efficiency fire retardant for acrylonitrile–butadiene–styrene (ABS). The Ce/P-CN nanoflakes featured a strengthening effect towards ABS, 10 wt% of which increased the tensile strength of ABS/(Ce/P-CN) by 33.8 %. Meanwhile, the ABS/(Ce/P-CN) nanocomposites showed remarkably enhanced high-temperature stability and carbonization performances relative to virgin ABS. Ce/P-CN simultaneously improved the anti-ignition, fire retardancy and smoke suppression of ABS due to the barrier effect of g-C3N4 nanoflakes and the catalytic carbonization effect of cerium and phosphorus. Notably, adding 10 wt% Ce/P-CN increased the LOI and UL-94 rating of ABS to 28.6 % and V-0, respectively, demonstrating its high flame-retardant efficiency. Thus, the high flame-retardant efficiency and multifunctionality enable Ce/P-CN to outperform previous flame retardants for ABS. This work offers a novel strategy for the development of high-efficiency g-C3N4 nanoflakes, which endow ABS with improved mechanical robustness and fire retardancy and show broad industrial prospects.