Preparation and characterization of CNTs/CaCu₃Ti₄O₁₂/silicone rubber composites with improved dielectric and mechanical properties

The dielectric performance of Silicone rubber (SR) composites can be significantly enhanced by carbon nanotubes. However, carbon nanotubes are easy to agglomerate in the polymer matrix. Adding low-dimensional materials of different dimensions may be a solution. In this article, one-dimensional multiwall carbon nanotubes (CNTs) and zero-dimensional copper calcium titanate (CaCu3Ti4O12, CCTO) ceramic fillers were simultaneously added to prepare silicone dielectric elastomer composites. SEM results showed that the CNTs were distributed uniformly in the SR matrix due to the addition of CCTO. When 2 wt% CNTs and 10 wt% CCTO were added, the dielectric constant of the composite increased from 2.79 (pure silicone rubber) to 5.72, with a low loss tangent of 0.0012. Due to the uniform dispersion of CNTs with the addition of CCTO particles, dielectric performance of the composites were enhanced. The tensile stress was 986 kPa, the elongation at break was 333%, while the elastic modulus was not more than 613 kPa (2 wt% CNTs and 5 wt% CCTO in the SR composite). In addition, the composites had a wide temperature range up to 400 degrees C. Therefore, the prepared CNTs/CCTO/SR composites have good dielectric and mechanical properties, and good thermal stability. It has a good reference value for this kind of composites as dielectric elastomer materials.