Highly compressible, heat-insulating and self-extinguishing cellulose nanofiber/aramid nanofiber nanocomposite foams.

Foam as a kind of burgeoning materials with laminated porous 3D structure was realized multifunctional application in diversified fields. In this work, we aimed to prepare a highly compressible and self-extinguishing multifunctional nanocomposite foam with anisotropic porous 3D structure through a green aqueous freeze-drying method. In order to address the inflammable property and brittleness issue of high-loading cellulose nanofiber foam, aramid nanofiber was incorporated into cellulose nanofiber framework, forming the multicomponent and multilevel honeycomb structure of the nanocomposite foam. Herein, the compression cycle properties of the nanocomposite foam could be significantly improved by adding 50 wt.% aramid nanofiber and at 20% stress recovered by 100 % even if cyclically compressed 200 times. The total heat release of the nanocomposite foam was as low as 2.12 MJ/m which also had low thermal conductivity about 28.8 mW/m · K. The ANF improved the flame retardancy of the composite foam.