PES-g-BST/PEEK composites modified by surface grafting with high dielectric tunability

Ceramic/polymer composites have been widely utilized due to their outstanding dielectric and mechanical properties. The interfacial bonding between ceramic and organic phases has a significant effect on the properties of composites. Therefore, enhancing the interfacial bond strength has become a hot issue. In this work, a chemically modified PES-g-BST/PEEK composite was prepared via cold-pressing sintering. The chemical bond was constructed to connect one end of PES (polyether sulfone) with BST (barium strontium titanate) and the other end with PEEK (polyether ether ketone) by using 4,4′-Diaminodiphenylsulfone (DDS), which enhanced the interface combination between ceramic fillers and organic phase. The influence of the surface grafting method and the amount of DDS on the microstructure and dielectric characteristics of the PES-g-BST/PEEK composite was investigated, and the amount of DDS was optimized. The permittivity, dielectric tunable efficiency, and dielectric tunability of the composites were improved. A chemically modified PES-g-BST/PEEK composite with improved dielectric properties and high dielectric tunability was obtained. The dielectric tunability amounts to 38.16 % under a 7 kV/mm bias, accompanied by a low dielectric constant of 14.5 and a dielectric loss of 0.076 (1 kHz). This work provides a way of enhancing the interface bonding of ceramic/polymer composites to improve dielectric tunability.