Abstract
Ferrites are generally used to obtain soft magnets for domestic or industrial applications but their use in this direction had generated an increasing interest in modifying the polymer properties by dispersing in their volume certain amounts of these ceramic compounds. Of course one issue of each researcher is to find a way or a technique to orientate the ferrites particles inside the polymer matrix to obtain structures able to respond to application of an external magnetic field. The use of ferrites nano-sized particles is facilitating their uniform distribution inside the polymer and, because of the viscous properties of pre-polymer mixture, is avoiding their aggregation. One way to create oriented distributions of the nano-particles is to use external magnetic fields during polymerization such as, at the end of process, they will be kept in fixed position inside the polymer network. The current study is about electrical properties induced by the presence of nano-sized strontium ferrite and barium ferrite in an epoxy matrix. Three types of epoxy resins had been used with 5% weight ratio of each type of ferrite and 10% weight ratio when both ferrites were used to modify the properties of the same polymer matrix. Electric conductivity had been studied by two methods – one on steady-state regime and one in variable regime. Using the variable measurement of electromagnetic properties the dielectric permittivity and the magnetic permeability were also determined.
Keywords: epoxy resin; nano-sized ferrites; electromagnetic properties