ABSTRACT
As an emerging two-dimensional nanomaterial, black phosphorus (BP) nanosheets have attracted wide attention in the field of fire-safe polymer nanocomposites. Due to the high phosphorus content and layer structure, the advantages of phosphorus-based flame retardants and two-dimensional nanomaterials are presented simultaneously in BP nanosheets. To further promote the flame retardant application of BP nanosheets, this chapter first introduces the preparation approaches of BP crystals and nanosheets. Next, functionalization methods that are adopted to enhance the interfacial interaction and dispersion state of BP nanosheets are summarized, in terms of coordination bonds, electron transfer, electrostatic interactions, in situ hydrothermal/solvothermal, and mechanical force. The flame retardant effect of BP nanosheets is analyzed specifically in different polymer resins, including polyurethane, epoxy, polycarbonate, and polylactic acid. Meanwhile, the inherent relation among functionalization methods, flame retardancy mechanism, and mechanical property improvement is revealed from multiple angles and aspects. It is believed that the summary of the preparation, exfoliation, flame retardancy, and mechanism of BP nanosheets is capable of promoting the development of BP-based flame retardants and polymer/BP nanocomposites.
