Wenchao Zhang,Kuo Zhao,Feng Guan,Jinghua Yin,Yu Feng,Jialong Li,Yanpeng Li
As a new type of dielectric material, the low dielectric constant and corona resistance life of fluorene polyester (FPE) restricts the range of its applications. In order to simultaneously achieve a high dielectric constant and the long corona aging lifetime of FPE, SiO2nanoparticles were chosen as additive to prepare FPE-based composite films. The microstructure of the composite film was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectroscopy (IR) and small-angle X-ray scattering (SAXS). The dielectric performances of the composites, including the dielectric constant, breakdown strength and corona resistance lifetime, were investigated. The results show that the introduced SiO2does not destroy the structure of the FPE molecular chain and that it increases the thickness of the filler-matrix interface. The dielectric constant of SiO2/FPE composites increased from 3.54 to 7.30 at 1 Hz. Importantly, the corona resistance lifetime increased by about 12 times compared with the pure FPE matrix. In brief, this work shows what possibilities there might be when considering the potential applications of high-strength insulating materials.Keywords:dielectric;fluorene polyester;composite film;corona aging lifetime
Polymer is the dielectric material of choice for dielectric capacitors. However, the low dielectric constant limits the polymer from achieving a satisfactory energy density. Therefore, researchers synergistically integrate a variety of components to effectively improve the energy storage performance. In this paper, Polyetherimide (PEI) and Fluorene Polyester (FPE) hybrid composite films are prepared by a linear/linear blending strategy. The dielectric constants of PEI and FPE are 3.38 and 3.45 at 10 Hz, and the dielectric constant is increased to 4.02 when the mass fraction of FPE is 10%. The breakdown field strength of PEI and FPE is 553.51 and 589.34 kV/mm, and the breakdown field strength reaches 746.51 kV/mm after blending. At 800 kV/mm, the energy storage density and energy storage efficiency of the hybrid composite film reach 11.38 J/cm 3 and 86.14%. Compared with PEI, the performance of the prepared blended composite film has been comprehensively improved, which provides a corresponding theoretical analysis and experimental strategy for the preparation of high-performance all-organic blended composite dielectric and also has potential application prospects in energy storage devices.
Polymer dielectrics, as a crucial role in electrostatic capacitors used in transport, oil exploration, the manufacturing industry, avionics domain, reach operating temperatures of 120 °C or more. However, the significant reduction in the capacity of energy storage at high temperatures greatly restricts polymer dielectrics used in such environments. By adjusting the distribution of functional layers, has designed all-organic multilayer composite dielectrics that can significantly inhibit carrier conduction at high temperatures, thereby enhancing the energy storage density. Among them, highly insulating polycarbonate (PC) is the outer layer, and highly heat-resistant fluorene polyester (FPE) forms the inner layer. The various distribution ratios that impacted the performance of these composite dielectrics have been thoroughly investigated. The research finds that the five-layer structured composite dielectric with PC and FPE layers composite dielectrics (PFPFP) have superior temperature stability and energy storage capabilities. In particular, they are able to withstand up to 350 kV/mm electric field strength ( E b ) at 150 °C, and the energy storage density of 2.15 J/cm 2 and the efficiency of 90.1 % is 3.98 times that of pure PC. It is suggested that the method of using the merits of different function layers to increase the dielectric energy density is suitable for different polymer films under severe conditions.
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