Dielectric and Electrical Insulation Performance of Polymer Nanocomposites Viewed from Mesoscopic Properties of Organic and Inorganic Nano-scale Interfaces

聚合物纳米复合材料是近年来在介电和电绝缘领域备受关注的一种先进的新型材料，我们在过去的14350171-2004财年研究计划的基础上进行了开创性的工作。它们的特点在于，只需在聚合物基质中分散少量的纳米填料，就可以将传统聚合物转化为性能优异的新材料，如介电材料和电绝缘材料。科学和工程挑战的重点是介观材料区域中纳米尺度界面的物理化学模型。提出了多核界面模型，并结合聚合物纳米复合材料的实验结果进行了研究。实验工作重点放在局部放电电阻和树枝电阻性能上，发现与其他性能相比，这两种性能发生了显著的有利变化。在《科学和植物保护公约》RES…中得出的结论17360145财年至2007财年的进一步研究项目如下：(1)通过粗粒度分子动力学模拟对多核界面模型进行了科学的深化。多核模型可以解释纳米复合材料的大部分介电和电绝缘性能，包括介电性能、导电性、高场电导、空间电荷注入、介电击穿、局部放电电阻、丁字形电阻和跟踪电阻。(3)如果聚合物是纳米结构的，那么局部放电(PD)的耐性会有显著的改善。这种现象是由于聚合物基质在纳米尺度上被三维分割而发生的，并用多核模型进行了分析。(4)树枝的阻力也有了很大的改善，特别是中等电场条件下树枝的寿命大大延长。这一性能被认为是由于局部放电电阻的改善而出现的，树状结构的起始电压通过抑制电荷注入而降低，这可以用多核模型来分析。树的传播分为两个过程，即被纳米尺度的障碍物减慢，和通过“多核纳米粒子”的电荷尾部引起的库仑排斥而加速。

Polymer nanocomposites are advanced new materials attracting much attention in the field of dielectric and electrical insulation, which we, the investigators, played a pioneering work based on our past JSPS Research Project 14350171(FY2002- FY2004). They are characteristic in the fact that conventional polymers could be transformed into new materials with superior performance as dielectrics and electrical insulating materials, by just dispersing a small amount of nano-fillers into polymer matrices. Scientific and engineering challenge was made focusing on a physico-chemical model for nano-scale interfaces in mesoscopic material regions. A multi-core interfacial model was proposed and investigated with experimental findings on polymer nanocomposites. Experimental work was especially focused on partial discharge resistance and treeing resistance performances that were found to be subject to remarkably favorable change as compared with other properties. Conclusion obtained in the JSPS Res … More earch Project 17360145(FY2005 -FY2007) is as follows :(1) The multi-core interfacial model was scientifically deepened by the coarse-grained molecular dynamics simulation. Polymer chains would interact with the surfaces of nano-fillers that are characterized by the multi-core model(2) The multi-core model would explain a majority of dielectric and electrical insulating properties of nanocomposites, including dielectric properties, electrical conductivity, high field electrical conduction, space charge injection, dielectric breakdown, partial discharge resistance, teeing resistance, and tracking resistance.(3) Partial discharge(PD) resistance was found to exhibit remarkable improvement, if polymers axe nano-structured. This phenomenon was considered to take place by the fact that the polymer matrices are segmented three-dimensionally in nano-scale, which was analyzed by the multi-core model.(4) Treeing resistance also showed much improvement Especially treeing lifetime is much extended under moderate electric field condition. This performance was considered to appear due to PD resistance improvement Tree initiation voltage is lowered by the suppression of charge injection that could be analyzed by the multi-core model. Tree propagation is divided into two processes, i.e. it is slowed down by nano-scale obstacles, and is speeded up through coulombic repulsion caused by the charge tails of“multi-cored nano-particles". Less