Preparation and microwave absorbing properties of polyaniline/NiFe2O4/graphite nanosheet composites via sol-gel reaction and in situ polymerization

Excellent microwave absorption of polyaniline composites with NiFe2O4/graphite nanosheet was prepared via sol-gel method and in situ polymerization reaction. The obtained composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analyzer, vibrating sample magnetometer and a vector network analyzer. The results indicated that the graphite nanosheet was completely covered by NiFe2O4 particles and NiFe2O4/ graphite nanosheet is wrapped by polyaniline. Polyaniline /NiFe2O4/ graphite nanosheet has better thermal stability than polyaniline, and its conductivity and Ms are 0.2 S/cm and 10 emu/g, respectively. Measurement of the vector network analyzer indicates that the microwave absorbing properties of polyaniline /NiFe2O4/ graphite nanosheet are better than those of graphite nanosheet, NiFe2O4, polyaniline and polyaniline / graphite nanosheet. Its maximum reflection loss value is -21 dB at 11.5 GHz when the thickness is 2.0 mm, and polyaniline /NiFe2O4/ graphite nanosheet's best match thickness is 2.5 mm, its reflection loss value can reach -30 dB at 9.1 GHz in the X band.