Study On High Temperature Dielectric Energy Storage Performance Of Linear Polymer And Its Composite Materials

The dielectric in commercial film capacitors is dominated by bi-oriented polypropylene(BOPP).Compared with traditional ceramic materials,polymers have the advantages of high breakdown,low density,but they are relatively low as energy storage materials.The dielectric constant often means lower energy storage density.Because PVDF and its copolymers have high dielectric properties,they far surpass other polymers in energy storage and have become a research hotspot.However,their low efficiency is destined to be unfavorable for high-temperature applications.Studies have found that some linear polymers such as PMMA,ABS,etc.have higher T_g and still have higher efficiency at high temperatures,but the lower dielectric of linear polymers leads to generally lower energy storage density.Add a certain amount of PVDF It can effectively improve the energy storage density and energy storage efficiency of the polymer.This paper mainly studies the electrical properties of the composite material with PVDF as the additive and linear polymer as the substrate.The main contents are as follows:(1)PVDF was added to the linear polymer PMMA.Starting from room temperature,the energy storage and efficiency of PVDF/PMMA films were studied,and it was found that the energy storage of composite materials was improved compared with PMMA.Then at 90 ~oC,the composite material was tested and analyzed for ferroelectricity,and it was found that the energy storage and efficiency of the composite material were improved at the test temperature of 90 ~oC.In the fatigue test,the performance of the composite material is stable,indicating that the material has good durability and stability.(2)Then the linear polymers ABS is discussed.From the analysis of the structure of ABS,it is concluded that the higher Tg of ABS is beneficial to improve its stability at high temperatures,and the polar cyano group is beneficial to improve the overall polarization of the polymer,indicating that ABS can be used for high-temperature energy storage.The stable dielectric and ferroelectric properties at different temperatures indicate the reliability of ABS.Finally,the fatigue and curling of ABS were studied,and the performance comparison before and after showed that the performance of ABS was stable.(3)Using ABS as the base polymer and PVDF as the additive,The performance of the composite material has been effectively improved at room temperature and high temperature.It is found that the composite material of 40 vol%PVDF still maintains a high energy storage 11.42 J/cm~3(425MV/m)at 100 ~oC,and the efficiency is 75.8%.Finally,the cyclic fatigue test shows that the composite material can maintain stable energy storage performance regardless of room temperature or 100 ~oC.