Ionic liquid modified boron nitride nanosheets for interface engineering of epoxy resin nanocomposites: Improving thermal stability, flame retardancy, and smoke suppression

Hexagonal boron nitride (h-BN) is more challenging to exfoliate into fewer layers than graphene due to the ionic bond between B and N atoms (lip-lip interaction) from adjacent layers. In this paper, boron nitride was exfoliated and hydroxylated by thermal oxidation in air. Hydroxylated boron nitride nanosheets (BNO) were modified by ionic liquids and added to epoxy resin to prepare epoxy matrix nanocomposites (EP/[email protected]). The SEM results of EP/[email protected] nanocomposites suggested that the introduction of ionic liquids enhanced the interfacial interaction between boron nitride nanosheets and epoxy resin (EP). Thermogravimetric (TG) results showed that introducing 2 wt% [email protected] nanosheets improved the thermal stability of EP. In addition, cone calorimeter test (CCT) results showed that [email protected] nanosheets enormously improved the fire safety performance of the epoxy resin. The peak heat release rate, total heat release, peak smoke release rate, and total smoke release of epoxy resin nanocomposites with 2 wt% [email protected] nanosheets decreased significantly. In this work, the realization of ionic liquid modified boron nitride nanosheets ([email protected]) provides new possibilities for improving the fire safety performance of EP.