Nanofilled dielectrics for high voltage electrical insulation

在高压应用中使用微米级填料的复合材料的进一步改进是不可能的，因为粘性组合物的混合已经达到了当前材料加工技术的极限。然而，纳米颗粒填充电介质的初步研究结果显示，在相当少的填料添加情况下，材料也有类似的改进；因此，进一步改进电介质材料的希望是有可能与现有的加工技术。大多数研究人员都认为纳米颗粒在有机材料（纳米复合材料）中的分散是纳米颗粒的主要问题，而均匀混合是纳米复合材料发展的关键。其中一个问题是，由于纳米颗粒的高表面能，纳米颗粒容易团聚，而传统的混合技术不能使纳米颗粒团聚。另一个问题是疏水聚合物与亲水纳米颗粒不相容，导致界面相互作用差。因此，有很大的需要发现替代的方法来获得更好的分散的纳米颗粒。研究重点是利用表面活性剂对纳米颗粒进行物理和化学改性。虽然表面活性剂通常应用于液体，但它们在形成固体介电材料的组合物中分散纳米颗粒的应用尚未见报道。使用表面活性剂的主要优点是它降低了纳米颗粒的表面和界面张力，从而减少了团聚，使颗粒更容易分散。初步研究表明，表面活性剂triton有助于纳米二氧化硅和纳米氧化铝在硅橡胶中的分散。该研究将集中于了解表面活性剂如何改善纳米介电材料的性能，以及哪种复合系统适合优化这些复合材料的介电性能，以用于高压电绝缘。

Further improvements to composite materials for use in high voltage applications using micron size fillers are not likely, as mixing of the viscous compositions has reached the limitation of current material processing technology. However, initial findings of nano-size particle (nanoparticle) filled dielectrics show similar improvements to materials at considerably reduced filler additions; thereby, the promise of further improvements to dielectric materials are likely with the existing processing technology. Most researchers agree that the problem with nanoparticles in organic materials (nanocomposites) is the dispersion of particles and uniform mixing is critical in the development of nanocomposites. One of the problems is that the nanoparticles agglomerate easily because of the high surface energy of the particles and conventional mixing techniques do not break apart the nanoparticle agglomerates. Another problem is the incompatibility of the hydrophobic polymer with hydrophilic nanoparticles, resulting in poor interfacial interactions. Thus, there is a great need to discover alternative ways to obtain a better dispersion of the nanoparticles. The reseach focuses on the surface modification of the nanoparticles by physical and chemical methods using surfactants. Although surfactants are commonly applied to liquids, their application to disperse nanoparticles in compositions forming solid dielectric materials has not yet been reported. The main advantage of using a surfactant is that it lowers the surface and interfacial tensions of the nanoparticles resulting in reduced agglomeration and makes it easier to disperse the particles. Preliminary findings have shown that triton, a common surfactant, aids in the dispersion of nanosilica and nanoalumina in silicone rubber. The research will concentrate on the understanding of how surfactants can improve the properties of nanodielectrics and which composite systems are appropriate to optimize the dielectric properties of these composites for high voltage electrical insulation.