Effect of trap level density on breakdown strength and space charge distribution of polypropylene/low‐density polyethylene composites

Yan, Hongda; Zhang, Chong; Li, Wei‐Kang; Zha, Jun‐Wei

doi:10.1002/pc.25408

Cited by 20 publications

(14 citation statements)

References 33 publications

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“…The formation of electrical treeing was inhibited [17]. Additionally, the space charge distribution [18,19], the polymers' crystalline morphology [20,21], the mechanical properties and flame resistance were all improved [22]. Throughout the former studies on nanocomposites' dielectric properties, the research focus mainly concentrated on three aspects: (1) The inorganic nanofiller changed the polymers' crystalline morphology.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nano-MgO Particles Doping on Breakdown Characteristics of Polypropylene

Guang

Cheng

2020

Coatings

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In this article, the nano-MgO particles were used as inorganic fillers, and polypropylene (PP) polymer was used as a matrix. The nano-MgO/PP composites were prepared by double melt blending. Using the polarization microscope (PLM) test and hot-stage microscope test, the crystalline morphology of PP and nano-MgO/PP with different mass fraction were observed. Using the differential scanning calorimetry (DSC) test, the parameters and crystallinity in the process of isothermal crystallization could be obtained. Additionally, the samples of pure PP and nano-MgO/PP composites were dealt with using a breakdown test and a dielectric frequency spectra test. From the experimental results, nano-MgO particle doping decreased the samples’ crystal size, and the crystalline structure was converted from large spherulites to fascicled crystallization. Additionally, the crystallization rate became fast and crystallinity increased. According to the breakdown test, the nano-MgO particle doping made the composites form small, dense spherulites. The breakdown developed through a longer path, so the composites’ breakdown strength rose greatly. When the mass fraction of nano-MgO particles was 3%, the shape parameter of the composites’ Weibull distribution β was larger, which illustrated that the nano-MgO particles were dispersed uniformly in the PP matrix. According to the dielectric frequency spectra test, the dielectric constant of different nanocomposites were all lower than which of pure PP, but the loss angle tangent values were all higher than which of pure PP.

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Section: Introductionmentioning

confidence: 99%

Effect of Nano-MgO Particles Doping on Breakdown Characteristics of Polypropylene

Guang

Cheng

2020

Coatings

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“…At 1800 s, the charges peak around the negative electrode and the positive electrode both increased, but the charge peak in sample A2 decreased. This illustrated that rapid air cooling changed the crystalline morphology of LDPE, and the attenuation characteristics of space charges were also affected [29]. From the space charge attenuation of samples W3 and O4 in short-circuiting, the space charge distributions of samples W3 and O4 were identical with those of sample A1.…”

Section: Change Density/cm -3mentioning

confidence: 90%

The Effect of the Cooling Process on the Crystalline Morphology and Dielectric Properties of Polythene

Guang

2020

Materials

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In this study, LDPE samples were prepared by melt blending with different cooling processes, which were natural air cooling, rapid air cooling, water cooling and oil cooling, respectively. According to polarization microscope (PLM) and differential scanning calorimeter (DSC) tests of these four low-density polyethylene (LDPE) samples, the effect of different cooling processes on polythene crystalline morphology could be studied. According to conductivity, dielectric frequency spectra and space charge tests, the effect of crystalline morphology on dielectric macroscopic properties could be explored. The microstructure characteristic results indicated the cooling medium significantly affected polythene crystalline morphology. When the samples were produced with natural air cooling, the crystalline grain size was large. On the other hand, after rapid air cooling, water cooling and oil cooling processes, the samples’ crystalline grain dispersed uniformly, and the grain sizes were lower. The space charge testing results indicate the samples produced with water cooling and oil cooling processes restrained the electrode injection in the process of pressurization. During short-circuits, the rates of charge release of these two samples were fast, and the remaining space charges were fewer. The conductivity and dielectric frequency spectra testing results indicated the conductivities of samples produced with water cooling and oil cooling processes were both less than those of samples produced with a natural air cooling process. Besides, with increasing experimental frequency, the relative dielectric constants of all testing samples decreased. Among them, the relative dielectric constant of the LDPE sample with the natural air cooling process was the largest. However, the crystalline structures of samples produced with rapid air cooling and water cooling processes were close, which restrained the movement of polymer macromolecule chains. Thus, the dielectric constants were lower. Additionally, because of the influence of relaxation polarization and dipole polarization, the dielectric losses of LDPE with water cooling and oil cooling processes increased to varying degrees.

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“…The space charge inside the material was redistributed under DC electric field, leading to the local field distortion, which was harmful to the bulk insulation strength. [33][34][35] The space charge characteristics [36][37][38] of the samples were tested by the PEA method. During the test, the sample was polarized with a DC 10 kV/mm of electric field for 20 min.…”

Section: Materials Instruments and Methodsmentioning

confidence: 99%

Enhanced direct‐current breakdown strength of Al₂O₃/epoxy resin composites through plasma fluoridation of fillers interface

et al. 2021

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Herein, a method for improving the direct-current (DC) breakdown strength of the epoxy resin (ER) was proposed. Nano-Al 2 O 3 was treated with CF 4 /Ar plasma and doped into the epoxy resin matrix to obtain epoxy composites with high DC breakdown strength in both extremely uneven and slightly uneven electric fields. The reaction essence of plasma fluoridation was characterized, and the dielectric spectrum, volume conductivity, space charge, and carrier trap characteristics of the modified composites were studied. The plasma fluoridation at the fillersmatrices interface is an effective pretreatment method to enhance insulation, exhibiting good applicability to ceramic/polymer composites.

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Effect of trap level density on breakdown strength and space charge distribution of polypropylene/low‐density polyethylene composites

Cited by 20 publications

References 33 publications

Effect of Nano-MgO Particles Doping on Breakdown Characteristics of Polypropylene

Effect of Nano-MgO Particles Doping on Breakdown Characteristics of Polypropylene

The Effect of the Cooling Process on the Crystalline Morphology and Dielectric Properties of Polythene

Enhanced direct‐current breakdown strength of Al₂O₃/epoxy resin composites through plasma fluoridation of fillers interface

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Effect of trap level density on breakdown strength and space charge distribution of polypropylene/low‐density polyethylene composites

Cited by 20 publications

References 33 publications

Effect of Nano-MgO Particles Doping on Breakdown Characteristics of Polypropylene

Effect of Nano-MgO Particles Doping on Breakdown Characteristics of Polypropylene

The Effect of the Cooling Process on the Crystalline Morphology and Dielectric Properties of Polythene

Enhanced direct‐current breakdown strength of Al2O3/epoxy resin composites through plasma fluoridation of fillers interface

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Enhanced direct‐current breakdown strength of Al₂O₃/epoxy resin composites through plasma fluoridation of fillers interface