Dielectric Properties Of Polypyrrole Spheres/Low Density Polyethylene Composites

In recent years,with the development of China’s high-voltage,ultra-high-voltage and ultra-high-voltage power transmission technologies,the large-scale use and integration of new energy sources.In order to further meet the needs of China ’s power industry,high-voltage insulation materials have become the focus of attention.Therefore,how to improve the performance of dielectric materials by modifying polymers based on ordinary polymer materials is one of the current research hotspots in the field of dielectric materials.In this paper,polypyrrole submicron spheres and polypyrrole nanospheres were first prepared by soft template method,and their morphology and structure were characterized by scanning electron microscopy and nitrogen adsorption.Nanosphere material.Next,using low density polyethylene(LDPE)as a matrix,polypyrrole submicron spheres and polypyrrole nanospheres were mixed into LDPE by melt blending to prepare polypyrrole submicron spheres/LDPE composites and Polypyrrole nanospheres/LDPE composites were analyzed by infrared spectroscopy.It was confirmed that polypyrrole submicron spheres and polypyrrole nanospheres were successfully added to LDPE.From the differential scanning calorimetry(DSC)analysis,it can be seen that the crystallinity of the composites increased with the addition of polypyrrole submicron spheres and polypyrrole nanospheres.X-ray diffraction analysis(XRD)showed that the presence of polypyrrole submicron spheres and polypyrrole nanospheres did not change the crystal structure of LDPE.Electroacoustic pulse method was used to test the space charge distribution of LDPE,polypyrrole submicron spheres/LDPE composites and polypyrrole nanospheres/LDPE composites.The test results show that the addition of polypyrrole submicron spheres and polypyrrole nanospheres can suppress the space charge accumulation in the composite material and the addition of polypyrrole nanospheres have a more obvious effect on the suppression of the space charge of the composite material.The TSC test results show that the addition of polypyrrole spheres will introduce a large number of deeper energy traps into the LDPE matrix,which effectively improves the ability to suppress space charge accumulation.DC conductivity and DC breakdown strength experiments were performed on polypyrrole submicron spheres and polypyrrole nanosphere composites with different concentrations at different test temperatures.The conductance results showed that the addition of polypyrrole submicron spheres and polypyrrole nanospheres significantly reduced the electrical conductivity of the composite.The DC breakdown test shows that with the increase of the amount of addition,the breakdown field strength of the polypyrrole spheres/LDPE composite material has a downward trend,and the size of the polypyrrole spheres has little effect on the breakdown characteristics of the composite material.Dielectric frequency experiments show that when a certain concentration of polypyrrole spheres are added,the dielectric constant of the composite material decreases,and the dielectric loss also increases with the addition of polypyrrole spheres.