Figure 5.

Hexagonal boron nitride nanosheet flame−retardant coating. (a) Cross−sectional image of the PEI/h−BN−coated PUF after torch testing with the positions of the four parts (A−D) of the residue studied by (b) thermogravimetric analysis compared to uncoated and PEI/h−BN unburnt coated PUF. (c) EPMA B X−ray mapping, (d) SEM image, and (e) TEM cross−sectional micrograph of the charred portion of PEI/h−BN−coated PUF after torch testing. Aging results from (f) the natural environment and (g) under UV light. Reprinted with permission from Ref. [61] Copyright 2019 American Chemical Society.