Flame retardant, superhydrophobic, and superoleophilic reduced graphene oxide/orthoaminophenol polyurethane sponge for efficient oil/water separation

In this work, a novel recyclable, superhydrophobic with water contact angle of 179 +/- 0.35 degrees, superoleophilic, and flame-retardant graphene-based polyurethane (PU) sponge was prepared by functionalizing PU with reduced graphene oxide (RGO) and orthoaminophenol (OAP). RGO/OAP/PU sponge demonstrated high sorption capacity, achieving up to 80 times of its own weight for a wide range of organic solvent and oils. Also, the RGO/OAP/PU retained its sorption capacity even after 10 sorption cycles. The appearance and sorption capacity of RGO/OAP/PU sponge did not change after 60 s burning test where as the neat PU burned completely within 6 s. Themechanical test suggested that the RGO/OAP/PU sponge is not compressible with respect to PU sponge. The volume of PU decreased from 2.82 to 1.41 cm(3) while the RGO/OAP/PU volume (3.53 cm(3)) did not change. (C) 2020 Elsevier B.V. All rights reserved.