A study on the dielectric properties of SBS/conductive filler/ dielectrics composites for phantom model

Dielectric properties and shape memory characteristics of SBS composites filled with carbon black as conductive filler and (Ba, Ca)(Sn, Ti)O₃ or SrTiO₃ as dielectrics were investigated for the development of phantom model. SBS/ carbon black composite showed an increment of complex dielectric constant with increasing the content of carbon black and the frequency dependence that the dielectric constant decreases with the frequency. The complex dielectric constant and the conductivity of SBS/carbon black/dielectrics composites increased with the increase of dielectrics and the characteristics of the frequency dependence also occurred by the effect of carbon black. Phantom materials with the dielectric properties and the conductivity corresponding to human tissues for the measurement of specific absorption rate (SAR) within the frequency range of current mobile phones (775 MHz-2 GHz) could be developed by adjusting the composition ratios of carbon black, dielectrics and SBS and by controlling the characteristic of frequency dependence of composite. From thermomechanical cycling test good shape recoverability could be obtained in SBS composite even though the residual strain was increased by the effect of filler.