An iron phenylphosphinate@graphene oxide nanohybrid enabled flame-retardant, mechanically reinforced, and thermally conductive epoxy nanocomposites

• Multifunctional nanohybrid (FeHP@GO) has been prepared via a facile and scalable approach. • Adding 1 wt% FeHP@GO significantly improves fire retardancy and mechanical properties of EP. • The EP/FeHP@GO sample shows superior flame retardancy and mechanical property to previous work. • The thermal conductivity of EP/FeHP@GO nanocomposites are also dramatically improved. The epoxy (EP) resin is being intensively applied in electronics packaging, the 5th generation communication technology (5G) and composite tanks for pressurized hydrogen fuel storage. For these applications, to date it has remained a grand challenge for EP to achieve a demanding property portfolio, e.g., the combination of satisfactory fire retardancy, high thermal conductivity (λ) and excellent mechanical properties. Herein, we report an iron phenylphosphinate-functionalized graphene oxide (FeHP@GO) nanohybrid by a facile yet scalable in-situ self-assembly method. Compared to the virgin EP, the EP nanocomposite with 2.0wt% of FeHP@GO shows 42.5% improvement in the limiting oxygen index (LOI), 46.2% and 23.5% reductions in the peak heat release rate (PHRR) and total heat release rate (THR), respectively, and a desired UL-94 V-0 rating. In addition, the resultant EP nanocomposite also exhibits improved tensile strength and λ (increased by 32.6% and 96.0%, respectively) relative to virgin EP. Such desirable integrated performances outperform those of the previously-reported EP counterparts, because of the multiple synergistic effects between FeHP and GO. This work provides an innovative strategy for the design of multifunctional EP nanocomposites, which holds the great promise for many industrial applications.