The Preparation And The Properties Study Of PZT/PVDF Piezocomposite

PVDF/PZT piezocomposite consisting of piezoelectric ceramic and polymer was made according the connection mode, volume fraction ratio or geometric distribution mode. This kind piezocomposite not only possesses properties of the piezoelectric ceramic and the polymer, but also overcomes the disadvantage of each single material. It contains many fine properties such as the high piezoelectricity, low brittleness, density and dielectric constant. And it also can be easy made into various shape products and thin slice. But the disperse degree of PZT ceramic particle in the PVDF is an exigent problem to be solved. The disperse degree of the ceramic can greatly affect uniformity of the composite, which limit the poling voltage and affect the piezoelectricity. In this paper, the relationships among constitutes, microstructures, dielectric and piezoelectric properties were calculated by employing the Banno Unit Cell mode; PZT ceramic were synthesized by the hydrothermal method and the appropriate solution was selected according the adsorption of PVDF on the ceramic particle surface; Then, relationships between the disperse degree and the fabrication process were studied. Base on these, the PZT/PVDF composites intermingled some PAn were prepared and the microstructures were investigated. At last, the Banno Unit Cell mode was proved and improved by the experimental data in order that the design of piezocomposite was more scientific and accurate.The research results show that the PZT ceramic particle with high purity, narrow granularity disperse, so this kind PZT ceramic particle is suitable to prepare the piezocomposite. Then the ethanol was selected to mix the PZT and PVDF. The mixed solution was ultrasonically dispersed to improve the dispersion degree. After that, the sample was pressed into shape and annealed. And it also found that the relative densities of the samples annealed under lOOMpa were 10 percent above those of the samples annealed without pressure. Based on this fabrication process, the PAn was introduced to enhance the uniformity of the composite, thus the piezoelectricity was greatly improved and the poling voltage can be lowered. At the same time, the dielectric propertiesunder different temperature were investigated, it was found that the dielectric properties of PZT/PVDF piezocomposite with some PAn changed slowly from 25C to 250C. The maximum of the piezoelectric constant d33 is 68pc/N when the volume fraction of PZT, PVDF, PAn is 0.55, 0.45, and 0.05 respectively. Finally, ,when the n , a , p are 6, 0.6, 0.3 respectively, the calculation value can agree well with the experimental data.