Polymer nanocomposites are more and more researched and employed as dielectrics in electrical power equipment. However, the bad dispersion and distribution of particles are often reported to deteriorate the dielectric properties of polymer nanocomposites. In most cases, researchers tend to use SEM/TEM images with imprecise descriptions to describe these two factors, and there was still no clear relationship between their quantified particle dispersion characteristics and dielectric properties of polymer nanocomposites. This work is to, first, propose a combined quantification method to estimate the dispersion and distribution of spherical/ellipsoidal particles/aggregates in polymer nanocomposites based on SEM images of epoxy SiO2 nanocomposites. Based on the proposed quantification method, epoxy nanocomposite with surface treated SiO2 shows overall better dispersion and distribution of particles/aggregates than those with untreated ones. The presence of agglomerations would lead to the enhancement of mobility of charge carriers and thus reduction of breakdown strength, which become more obvious with the growth of filler loadings. It is found that, in AC breakdown tests, dispersion and distribution of particles/aggregates show little influence on the reduction of AC breakdown strength. However, those should be the main factor which influences the DC breakdown strength in epoxy nanocomposites with a variation of filler loading concentrations.

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聚合物纳米复合材料中球形颗粒分散分布的量化方法及其与交直流击穿强度的关系研究

聚合物纳米复合材料越来越多地被研究并用作电力设备中的电介质。然而，据报道，颗粒的分散和分布不良会降低聚合物纳米复合材料的介电性能。在大多数情况下，研究人员倾向于使用描述不准确的 SEM/TEM 图像来描述这两个因素，并且它们的量化粒子分散特性与聚合物纳米复合材料的介电性能之间仍然没有明确的关系。这项工作首先提出了一种组合量化方法，以基于环氧 SiO2 纳米复合材料的 SEM 图像估计聚合物纳米复合材料中球形/椭圆体颗粒/聚集体的分散和分布。基于提出的量化方法，具有表面处理过的 SiO2 的环氧纳米复合材料总体上比未经处理的纳米复合材料表现出更好的颗粒/聚集体分散和分布。团聚的存在会导致电荷载流子迁移率的提高，从而降低击穿强度，随着填料负载量的增加，这一点变得更加明显。发现在交流击穿试验中，粒子/聚集体的分散和分布对交流击穿强度的降低影响不大。然而，随着填料负载浓度的变化，这些应该是影响环氧纳米复合材料直流击穿强度的主要因素。团聚的存在会导致电荷载流子迁移率的提高，从而降低击穿强度，随着填料负载量的增加，这一点变得更加明显。发现在交流击穿试验中，粒子/聚集体的分散和分布对交流击穿强度的降低影响不大。然而，随着填料负载浓度的变化，这些应该是影响环氧纳米复合材料直流击穿强度的主要因素。团聚的存在会导致电荷载流子迁移率的提高，从而降低击穿强度，随着填料负载量的增加，这一点变得更加明显。发现在交流击穿试验中，粒子/聚集体的分散和分布对交流击穿强度的降低影响不大。然而，随着填料负载浓度的变化，这些应该是影响环氧纳米复合材料直流击穿强度的主要因素。