Comparative electromagnetic properties of polypropylene composites loaded with cobalt ferrites by melt mixing

Abstract

Polypropylene (PP) was investigated as a polymeric matrix of functional composites by melt mixing in a compression mould. The sample with 15 wt.% loading of cobalt ferrite (CoFe2O4) increases the electrical permittivity as a result of Maxwell-Wagner effect and induces ferrimagnetic properties in PP composites. By increasing the CoFe2O4 loading to 55 wt.%, the magnetization and relative permittivity were substantially raised. Interestingly, this high loading which was comparable to the percolation threshold, did not affect the coercivity. Both low and high CoFe2O4 loadings have insignificant effects on magnetic permeability spectra. The results suggest that the melt mixing is a facile route to incorporate high loading of magnetic powder into plastics, leading to composites of enhanced electromagnetic properties.