Study on properties of barium titanate/polyethersulfone dielectric composites prepared by physical dispersion method

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Composite materials applied to capacitors with high dielectric constant, low dielectric loss and outstanding thermal stability are concerned widely in the field of dielectrics. So committed to the development of dielectric materials with excellent performance is the key factor. In this work, the barium titanate/polyether sulfone (BaTiO3/PES) composite films were prepared by a physical dispersion technology, which utilized a ball milling machine by high-speed circulation, scattered the PES solution contained BaTiO3 in deionized water with the aid of a surfactant. Then, the BaTiO3/PES composite films were obtained through a series of operations, containing reclaimed organic solvent, washed with deionized water, filtered, dried and hot pressed. The morphology of the BaTiO3/PES emulsion was investigated by TEM and SEM. The results showed that the BaTiO3 particles were covered in the PES resin matrix homogeneously. For 50 wt% BaTiO3 reinforced PES composite film. The dielectric constant increased by ~ 227% compared with pure PES resin (4.1 at 1 kHz) and the dielectric loss maintained around 10−2 magnitude, which performed better dielectric properties. The tensile strength of 10 wt% BaTiO3/PES composite films (72 MPa) reached the highest value in comparison with those of pure PES (58 MPa) due to the strengthened interaction between particles and matrix. Further increase of BaTiO3 content, the tensile strength and elongation at break decreased slightly but remained an excellent flexibility from the PES matrix. The temperature at weight loss 5% (T5%) of composite film with 40 wt% of BaTiO3 content reached up to 503 °C in N2 atmosphere. All the BaTiO3/PES composite films performed the concentrated glass transition temperature (Tg) around 229 °C. In sum, excellent thermal stability and dielectric properties would make the BaTiO3/PES composite films become the fine potential candidates for dielectric composites in the capacitors.