表层氟化环氧纳米复合材料表面的电荷动态特性

环氧树脂绝缘表面积聚的大量电荷是导致表面闪络的重要因素。在环氧树脂中掺杂TiO2无机纳米颗粒之后,可以增强其力学性能和抗电痕破坏性能,但对其表面电荷动态过程研究较少。同时,表层氟化可以保持原有有机聚合物的优良性能之外,还可使聚合物的本证缺陷得到改善。为此,制备了纯环氧试样以及含纳米TiO2质量分数分别为2%、4%、6%、8%的纳米复合试样,并对试样进行不同时间(0、30、60、90、120 min)的氟化处理,研究其在直流电场下纳米TiO2质量分数与氟化时间对表面电荷的积累与消散特性的综合影响。研究表明:纳米TiO2颗粒会减缓环氧树脂表面电荷消散的速度,6%纳米复合试样电荷消散最慢;表层氟化处理可以加速电荷消散速度,所以可以通过表层氟化处理来弥补纳米颗粒加入后对环氧树脂绝缘性能所带来的不利影响。

Effective Thermal Conductivity Analysis of Xonotlite-aerogel Composite Insulation Material

A 3-dimensional unit cell model is developed for analyzing effective thermal conductivity of xonotlite-aerogelcomposite insulation material based on its microstructure features. Effective thermal conductivity comparisonsbetween xonotlite-type calcium silicate and aerogel as well as xonotlite-aerogel composite insulation material arepresented. It is shown that the density of xonotlite-type calcium silicate is the key factor affecting the effectivethermal conductivity of xonotlite-aerogel composite insulation material, and the density of aerogel has little influence.The effective thermal conductivity can be lowered greatly by composite of the two materials at an elevatedtemperature.