Comparative Study of Barium Titanate-filled Polyurethane and Hydrogenated Nitrile Butadiene Rubber as Electroactive Polymer Composites

As a ferroelectric material with high permittivity, barium titanate (BaTiO 3 ) is an appropriate filler to modify the dielectric constant of polymer composites for the use in dielectric actuators, both in research as well as for emerging industrial applications such as adaptive grippers. In this work, BaTiO 3 powder in different concentrations was dispersed in polyurethane rubber (PUR) and hydrogenated nitrile butadiene rubber (HNBR) matrices, respectively. The rubber compounds were compression-molded into elastomer films and their dielectric response as a function of the $\mathrm{B}\mathrm{a}\mathrm{T}\mathrm{i}\mathrm{O}_{3}$ concentration was characterized using impedance spectroscopy. Planar dielectric elastomer actuators (DEA) were fabricated from PUR and HNBR films to investigate the electric field-induced response of composites. Both strain and force measurements were used to evaluate the performance of DEAs. The results show the advantage of incorporating BaTiO 3 particles into dielectric elastomers to increase the relative permittivity and thereby enhance DEA performance.