Study On The Preparation And Performance Of Rare Earth Element Modified Barium Ferrite/PVDF Composite Film

Polyvinylidene fluoride?PVDF?materials have excellent ferroelectric and piezoelectric properties,and can be used to make sensors,memories,and multi-functional membrane devices.Therefore,polyvinylidene fluoride is widely used in medical,communications,new energy and environmental protection fields.Ferroelectric ceramic/polymer composite material is a new type of polymer composite material with good endurance and wide operating temperature range.The PVDF composite film prepared by doping magnetic materials?such as barium ferrite?,etc.The dielectric and thermodynamic properties have been greatly improved,and ferroelectric and ferromagnetic coexistence can be achieved.This material is expected to be used to manufacture new energy conversion materials,high-performance sensors and high-density data storage devices in the future.Therefore,carrying out relevant research is of great significance both in basic theory and practical application.In this paper,PVDF is used to be ferroelectric substrate.Two inorganic powders Ba_0.8Ce_0.2Fe₁₂O₁₉?BCFO?and Ba_0.8La_0.2Fe₁₂O₁₉?BLFO?were doped by rare-earth element lanthanum and cerium-modified barium ferrite,and they are prepared by high-temperature solid-phase method.BLFO/PVDF and BCFO/PVDF composite films were prepared by casting method.This paper studied the effect of changes in inorganic powder content on the multiferroicity of the composite film,as well as the effect of temperature changes and magnetic fields on the stability of the composite film.The study found that we have obtained composite films whose magnetic properties,dielectric properties and mechanical properties has improved.At the same time,the influence of the magnetic field on the dielectric properties was investigated.Under the condition of the magnetic field,the dielectric constant of the composite film increased significantly,and the dielectric loss was relatively decreased.The tensile strength of BLFO/PVDF composite film is greatly enhanced than that of pure PVDF film.In the study,the microstructure and thermodynamic properties of the composite film were observed and characterized using electron scanning microscope,atomic force microscope,X-ray diffractometer,DSC and Fourier infrared spectroscopy,etc.,and the mechanism was preliminary discussed with analysis.The DSC test results show that the enthalpy change value of the BLFO/PVDF composite film sample is higher than that of pure PVDF,indicating that a new connection and coupling method may be formed in the PVDF molecule due to the addition of magnetic elements.The disclosure and understanding of related mechanisms will help to further explore the magnetic,electrical and mechanical properties of these composite membranes and their coupling effects in the future.These results provides new ways and methods for developing and inventing new multiferroic polymers with multiple functions,and developing and exploiting a wider range of practical applications.