Synthesis and microwave absorption enhancement of BaTiO 3 nanoparticle/polyvinylbutyral composites

Abstract

Barium titanate (BaTiO₃)-polyvinyl butyral (PVB) composites at various weight concentrations were prepared via ultrasonic probe sonicator. The sonication was carried out at 20 kHz and 70% amplitude for about 2 h and BaTiO₃ nanoparticles were dispersed well in the mixture of PVB/ethanol under probe sonication. As a microwave absorbent, the microwave absorbing properties of the BaTiO₃ nanoparticle-PVB composites with different mixture ratios of 5 wt.% (RAM1), 10 wt.% (RAM2) and 15 wt.% (RAM3) BaTiO₃ were investigated based on transmission line theory in the frequency range from 1 GHz to 14 GHz. The minimum reflection loss (R_L) of the RAM1 reaches −3.47 dB at 5.57 GHz with a matching thickness of only 7.0 mm. For RAM2 with 4 mm and 4.2 mm thickness (t_m), the R_L values are less than −10 dB obtained in the frequency 10.3–13.4 GHz. The RAM3 composite with 15 wt.% BaTiO₃ mixture ratio shows a minimum reflection loss of −43.8 dB at 11.01 GHz with a −15 dB bandwidth over the extended frequency range of 10.2–13.2 GHz for a thickness of 2.8 mm and −44.2 dB at 4.77 GHz for a thickness of 6.5 mm.