In this work, nano-titanium oxide (TiO2) is encapsulated into boron nitride nanosheets (BNNS) by the calcination process to fabricate core-shell structured TiO2@BNNS nanofillers. The effects of TiO2@BNNS fillers on the DC conductivity, space charge and breakdown strength of polypropylene (PP) composites are investigated. Experimental results show that PP/TiO2@BNNS composites have a lower temperature-dependent conductivity with an activation energy of 0.64 eV, which is much lower than that of PP, 0.95 eV. The DC breakdown strength of PP/TiO2@BNNS samples is 22.2% higher than that of PP at 90 °C. The average space charge density and electric field distortion rate of PP/TiO2@BNNS are reduced by 6.6 C/m3 and 23.3%, respectively, compared with PP, under a polarization electric field of 40 kV/mm at 90 °C. It is proven that TiO2@BNNS nanofillers form numbers of electrical potential wells for charge carriers, thereby, inhibiting the hot electron transport and their damage to polymer molecules. This work provides an effective method to improve the dielectric performance of PP cable insulation.

中文翻译：

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BNNS 封装的 TiO2 纳米填料赋予聚丙烯电缆绝缘层增强的介电性能


在这项工作中，通过煅烧过程将纳米二氧化钛（TiO2）封装到氮化硼纳米片（BNNS）中，制备核壳结构的TiO2@BNNS纳米填料。研究了TiO2@BNNS填料对聚丙烯(PP)复合材料的直流电导率、空间电荷和击穿强度的影响。实验结果表明，PP/TiO2@BNNS复合材料具有较低的温度依赖性电导率，活化能为0.64 eV，远低于PP的0.95 eV。 PP/TiO2@BNNS样品在90℃下的直流击穿强度比PP高22.2%。在90℃、40 kV/mm极化电场下，PP/TiO2@BNNS的平均空间电荷密度和电场畸变率比PP分别降低了6.6 C/m3和23.3%。事实证明，TiO2@BNNS纳米填料为载流子形成多个势阱，从而抑制热电子传输及其对聚合物分子的损害。该工作为提高PP电缆绝缘介电性能提供了有效方法。