Dielectric properties of CaCu₃Ti₄O₁₂–silicone rubber composites

CCTO–silicone rubber composites with different CCTO mass fractions have been prepared. SEM images show that CCTO particles distribute evenly in silicone rubber matrix. The experimental results reveal that the composites possess excellent mechanical and dielectric properties. The dielectric constant of the composites has been simulated in the light of two different theoretical models which can almost properly predict the experimental values for the composites except when the mass fraction of CCTO increases beyond 30 %, the experimental values begin to slightly deviate down from the predicted ones. Both the dielectric constant and loss values increase with the increase of uniaxial pressure applied on the composites. For the composite with CCTO mass fraction of 50 % under the pressure of 4 MPa, its dielectric constant value has been improved by about three times, but its loss value has been raised by less than twice that of the composites without pressure. Therefore, the dependence of dielectric constant on pressure makes it a new promising material in practical applications as capacitance sensors and other electronic devices.