Dielectric and pyroelectric properties of BaTiO3-PVC composites

Dielectric relaxation and pyroelectric response of the barium titanate-poly (vinyl chloride) BaTiO3-PVC composites of 0-3 connectivity and volume fraction of ceramics phi from 0.0 to 0.4 were investigated. Dielectric properties of the composites were found to be a combination of those of pure PVC polymer and BaTiO3 ceramics: the value of dielectric permittivity increases with increasing volume fraction of the ceramics but the temperature dependence is determined by two relaxation processes in the polymer (at similar to 270 K - the local motion of the small groups in the chain and at similar to 350 K - the segmental molecular motion) and in the ceramics (dielectric anomaly at the phase transitions). The value of the pyroelectric coefficient p of poled composites increases with 0 and depends on the light modulation frequency f. as p similar to f(m)(-n) with n approximate to 0.9 to 1.1, dependently on phi.