Past work using hBN as a flame-retardant composite filler has required chemical functionalization of the hBN. For instance, Yu et al. modified hBN with (3-isocyanatopropyl)triethoxysilane to prepare epoxy resin nanocomposites by a sol-gel process, and the material showed flame retardant properties, such as 53.1% reduction in peak heat release rate. Cai et al. modified hBN with dopamine chloride and SnCl2 and observed that the fire-retardant performance of the modified hBN material increased as the SnO2 content increased. BN was modified by Qiu et al. with phytic acid and dicyandiamide for use as a flame retardant. Li et al. modified hBN with a phosphorus-based ionic liquid, namely [bmim], suggesting that the modified hBN exerted its flame-retardant effect both in the condensed phase via enhanced char formation and in the gas phase as a radical scavenger. Zhang et al. modified hBN with cobalt nitrate hexahydrate and ferrous sulfate heptahydrate and observed that orderly aligned hBN showed better flame-retardant performance than randomly oriented material. In another study, Zhang et al. showed that hexagonal boron nitride modified with iron(III) chloride hexahydrate and zinc chloride via solvothermal method gave a nanofiller with improved flame retardant performance. The same group modified hBN with iron (III)chloride hexahydrate and bismuth nitrate pentahydrate , proposing that hBN created a barrier effect in the condensed phase and the metallic component catalyzed the char formation.