Quantifying dielectric and microwave absorption properties of barium titanate and strontium ferrite filled polymer composites

Abstract

In the present study, dielectric and microwave absorbing properties of barium titanate (BaTiO 3 ) and strontium ferrite (SrFe 12 O 19 ) filled thermoplastic polyurethane composites were investigated. The variations of the dielectric parameters of the BaTiO 3 filled composite samples with filler concentration were also modeled and simulated by the power-law model to predict dielectric coefficients of the samples for higher filler concentrations. Comparing the prediction of the Power-law model and experimental measured dielectric values indicate that the Power-law model predicts dielectric parameters of the composite with acceptable accuracy. Microwave absorption analyses of the composite samples showed that SrFe 12 O 19 is more effective than BaTiO 3 on the enhancement of microwave absorption capability of TPU. The hybrid composite samples that contained both SrFe 12 O 19 and BaTiO 3 were also prepared, and their microwave absorption performance was evaluated. It was observed that much lower RL values than that of the composite samples, which were filled SrFe 12 O 19 or BaTiO 3 could be obtained by the hybrid composites. However, absorption bandwidth of them was narrower than counterparts that contained the same amount of SrFe 12 O 19 .