In situ self-assembly of zeolitic imidazolate frameworks on the surface of flexible polyurethane foam: Towards for highly efficient oil spill cleanup and fire safety

In this work, a hydrophobic and oleophilic flexible polyurethane foam modified with metal organic framework (MFPU) was successfully fabricated through in situ self-assembly method. The structure and morphology of MFPU foams were characterized by X-ray diffraction, Fourier transform infrared spectra, Scanning electron microscopy and Energy dispersive X-Ray spectroscopy measurements. The growth of metal organic frameworks improved the surface roughness of FPU foams, leading to the highly increased water contact angle, which could provide well ameliorated hydrophobicity and lipophilicity properties. The modified FPU foams exhibited extraordinary absorption capacity and recyclability for various kinds of oils and organic solvents. The maximum absorption capacity could achieve 33 times of its own weight. The flammability of MFPU foams was evaluated by cone calorimeter test, vertical burning test and limited oxygen index test, the peak heat release rate and smoke production rate both decreased dramatically, indicating the coating of ZIF-8 was significantly conducive to improve the flame retardancy of FPU foams. These improvements made MFPU foams become an excellent absorbent with remarkable fire safety, and offered it with potential application in oil/water separation.