Trabalho apresentado no XV CBECIMAT, Natal- RN, Novembro de 2002. Study of Pyroelectric Activity of PZT/PVDF-HFP Composite

Flexible, free-standing piezo and pyroelectric composite with 0 to 3 connectivity was made up from Lead Zirconate Titanate (PZT) powder and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) copolymer. The pyroelectric and the piezoelectric longitudinal (d33) coefficients were measured. A 50/50 vol. % PZT/PVDF-HFP composite resulted in piezo and pyroelectric coeffi-cients of d33 = 25.0 pC/N and p = 4.5 × 10-4 C/m2K at 70 °C, respectively. Analysis of the complex permittivity in a wide range of frequency was carried out indicating lower permittivity of the composite in comparison with a permittivity of the PZT ceramic. The low value of the permittivity gives a high pyroelectric figure of merit indicating that this material can be used to build a tem-perature sensor in spite of the lower pyroelectric coefficient compared with PZT