Polydopamine-bridged synthesis of ternary h-BN@PDA@SnO₂ as nanoenhancers for flame retardant and smoke suppression of epoxy composites

The potential prospect of hexagonal boron nitride (h-BN) in the fields of polymer composites is severely limited by undesirable exfoliation efficiency and chemical inertness. Herein, bio-based dopamine was employed toward exfoliating bulk h-BN with hydrogen bond action and imparting a highly-active surface. With assistance of polypodamine, SnO₂ nanoparticles were in-situ synthesized and strengthened the interfacial interaction between h-BN and epoxy (EP) matrix. The integrated function of metal oxide/h-BN toward flame retardant and smoke suppression of polymer materials was firstly studied and obtained, in term of reduced peak heat release rate (decreased by 41.1%), lower total heat release (decreased by 30.1%), and suppressed total smoke production (decreased by 21.6%). In addition, the mechanism for enhancements on flame retardant and smoke suppression of EP composites was systematically investigated. Such a design route simultaneously achieves the exfoliation and functionalization of h-BN, thus offering an active platform for further functionalization modification.