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International Journal of Polymer Science
Volume 2014, Article ID 102946, 9 pages
http://dx.doi.org/10.1155/2014/102946
Research Article

Controlling Dielectric and Magnetic Properties of PVdF/Magnetite Nanocomposite Fibre Webs

1Nonwovens Research Group, Centre for Technical Textiles, School of Design, University of Leeds, Leeds LS2 9JT, UK
2Condensed Matter Physics Group, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK

Received 9 September 2013; Revised 26 March 2014; Accepted 26 March 2014; Published 27 April 2014

Academic Editor: Yulin Deng

Copyright © 2014 A. P. Venugopal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The ability of filtration and separation media containing fibres to remove impurities from oil, water, and blood can be enhanced using magnetic fields. The ability to regulate the dielectric and magnetic behaviour of fibrous webs in terms of superparamagnetic or ferromagnetic properties by adjusting material composition is fundamental to meeting end-use requirements. Electrospun fibres were produced from PVdF (polyvinylidene fluoride) and nanomagnetite (Fe3O4 nanoparticles) from solutions of PVdF in dimethylacetamide containing Fe3O4 nanoparticle contents ranging from 3 to 10 wt%. Fibre dimensions, morphology, and nanoparticle agglomeration were characterised by environmental scanning electron microscopy (ESEM) and field emission gun transmission electron microscopy (FEGTEM). Dielectric behaviour of the fibre webs was influenced by web porosity and the Fe3O4 nanoparticle content. Impedance analysis of the webs indicated an increase in dielectric constant of 80% by the addition of 10 wt% Fe3O4 nanoparticles compared to 100 wt% PVdF. The dielectric constants of the webs were compared with those obtained from the theoretical mixing models of Maxwell and Lichtenecker. Vibrating sample magnetometer (VSM) magnetisation measurements indicated a blocking temperature above 300 K suggesting ferrimagnetic rather than superparamagnetic behaviour as a result of Fe3O4 nanoparticle agglomeration within fibres.