The preparation and wide frequency microwave absorbing properties of tri-substituted-bisphthalonitrile/Fe3O4 magnetic hybrid microspheres

A novel tri-substituted-bisphthalonitrile/magnetite (TPH/Fe3O4) magnetic hybrid microspheres were synthesized from tri-substituted-bisphthalonitrile (TPH) and FeCl3 center dot 6H(2)O via a facile one-step solvent-thermal crystallization route. The morphology and structure of the magnetic hybrid microspheres were monitored by SEM, FTIR and XRD. The results displayed that the as-prepared TPH/Fe3O4 magnetic hybrid microspheres were regular spheres and the average particle size was about 137 rim in a narrow dispersion. Besides, the particle size and size distribution can be controlled by subtle variation of the ratio of TPH to ferric ions in the microspheres. The TPH/Fe3O4 hybrid microspheres maintained good saturation magnetization (58.16 emu g(-1)) and novel microwave electromagnetic properties: The dielectric loss was less at low frequency and was multimodal at high frequency; the magnetic loss was enhanced obviously with the increasing amount of TPH. Additionally, the microwave absorption properties were detected, and the results demonstrated that the strong reflection loss (RL) and multimodal bands appeared in the wide frequency for the TPH/Fe3O4 magnetic hybrid microspheres. When the matching thickness was 5.0 mm, the effective RL values of -31 dB, -33 dB and -37 dB were obtained in the wide microwave frequency range from 2 GHz to 16 GHz by adjusting the content of TPH. The wide frequency microwave absorption properties, together with the regular sphere and excellent magnetism, enable TPH/Fe3O4 magnetic hybrid microspheres to be further applied in the areas of functional materials. (C) 2013 Elsevier B.V. All rights reserved.