Preparation And Electromagnetic Wave-absorbing Properties Of Fe₃O₄/Conducting Polymer Microspheres

Polypyrrole/Fe₃O₄?PPy/Fe₃O₄?and Fe₃O₄@polypyrrole@polyaniline?Fe₃O₄@PPy@PANI?composites were synthesized with in-situ polymerization method.T he morphology,magnetic properties,phase composition and electromagnetic microwave absorbing propert ies of PPy/Fe₃O₄ and Fe₃O₄@PPy@PANI composites were characterized by transmission electron microscopy?TEM?,X-ray diffraction?XRD?,fourier transform infrared spectroscopy?FT-IR?,vibrating sample magnetometer?VSM?and vector network analyzer?VNA?.The main contents show as follows:?1?PPy/Fe₃O₄ nanospheres were synthesized successfully via one-pot process.The influences of the mass ratio of polyvinyl alcohol?PVA?to pyrrole on performance of the PPy/Fe₃O₄ composites were investigated.T he results showed that: PPy/Fe₃O₄ nanospheres became more disperse and regular nanoparticles due to the addition of PVA.PVA caused pyrrole to form polypyrrole nanospheres,and Fe3+ ions were used as oxidant and Fe₃O₄ formed in situ consequently on the surface of PPy nanospheres.When the mass ratio of PVA/pyrrole was 3/4,the minimum reflection loss?RLmin?value of PPy/Fe₃O₄ composites reached-41.3 d B at 7.7 GHz with the thickness of 3.0 mm.The microwave interference cancellation of interface reflection,nature resonance loss and current loss are the main reasons for the loss of electromagnetic microwave for as-prepared PPy/Fe₃O₄ composites.?2?Fe₃O₄ which prepared via solvothermal method was bedecked by PPy firstly.The electromagnetic proportion of Fe 3O4@PPy@PANI composites were controlled by the dosage of PANI.The influences of the mass ratio of aniline to Fe 3O4@PPy on microwave absorption performance of the Fe₃O₄@PPy@PANI composites were also investigated.When the mass ratio of aniline to Fe₃O₄@PPy is 1/4,the minimum reflection loss value of Fe₃O₄@PPy@PANI composites reached-39.2 d B at 6.7 GHz,and the absorption bandwidths exceeding-10 d B are 2.0 GHz with a thickness of 4.0 mm.When the mass ratio of aniline to Fe 3O4@PPy is 1/2,the absorption bandwidths exceeding-10 d B are 4.6 GHz with a thickness of 2.0 mm.