Fundamental research on characteristics of hydrophobicity disappearance of silicone rubber surface in Dynamic Drop Test

A study on the development of deterioration / performance evaluation method for outdoor electric insulation of polymer materials is pushed forward now in the International Council on Large Electric Systems (CIGRE). The small scale docimasy (Dynamic Drop Test) which could evaluate a disappearance characteristic of the hydrophobicity easily was suggested [1]. This test method is to evaluate the loss of hydrophobicity to drop electrically-charged water droplets on the sample surface continuously. We applied this dynamic drop test (DDT) to polymer materials which differ in the amount of Alumina Tri-Hydrate (ATH) filled and investigated factors about the change of hydrophobicity, in which the surface roughness and difference of the quantity of migration of the low molecular weight (LMW) were examined.