Synthesis and characterization of Fe 3 O 4 /polypyrrole/carbon nanotube composites with tunable microwave absorption properties: Role of carbon nanotube and polypyrrole content
2015; Elsevier BV; Volume: 285; Linguagem: Inglês
10.1016/j.cej.2015.10.031
ISSN1873-3212
AutoresRuey‐Bin Yang, P. Madhusudhana Reddy, Chi–Jung Chang, Po-An Chen, Jem-Kun Chen, Chung-Chieh Chang,
Tópico(s)Metamaterials and Metasurfaces Applications
ResumoTwo different sizes of Fe3O4 nanoparticles were synthesized by hydrothermal (H-Fe3O4, ≈100 nm) and co-precipitation (C-Fe3O4, ≈20 nm) methods. Further, Fe3O4/polypyrrole (Ppy) composites were prepared by polymerizing the conductive monomer, pyrrole on the surface of Fe3O4. In addition, we also synthesized Fe3O4/Ppy/carbon nanotube (CNT) composites by blending the CNTs with Fe3O4/Ppy composites. Epoxy resin-based microwave absorbers were prepared at different thicknesses (1, 2 and 3 mm) by mixing 20% by weight of the as-prepared composites and the complex permittivity (ε′ − jε″) and permeability (μ′ − jμ″) were measured in the 2–18 GHz frequency range. The composites exhibited significant improvement in microwave absorption (reflection loss ⩽ −10 dB) with a bandwidth from 8 to 12.5 GHz (X-band) by matching the magnetic properties of Fe3O4 and the dielectric properties of Ppy and CNTs for 20 wt% of fillers in 3-mm thickness absorbers. The addition of CNTs into H-Fe3O4/Ppy composites further enhances the minimum reflection loss from −15.8 to −25.9 dB. The present results can pave the way to construct microwave absorbers with a desired reflection loss at a target frequency and thus, the efficient complementarities between complex permittivity and permeability of the nanocomposites can be achieved.
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