Influence of Nanoparticle Surfaces on the Electrical Breakdown Strength of Nanoparticle-Filled Low-Density Polyethylene

The electrical breakdown strength of TiO₂nanoparticle-filled low-density polyethylene (LDPE) nanocomposites was investigated. It was found that the surface water on the nanoparticles played a very important role in determining the breakdown strength. The breakdown strength at 63.2% cumulative failure probability (E₀) for the composites filled with dried nanoscale TiO₂was similar to that of neat LDPE and 50% higher than that for the samples filled with as-received nanoscale TiO₂. This increase was due to a better dispersion, a better interface, and a morphology change of the matrix. It was also found that surface modification of nanoscale TiO₂had a significant influence on the breakdown strength.N-(2-aminoethyl) 3-aminopropyl-trimethoxysilane (AEAPS)-coated TiO₂-filled samples showed about 40% higherE₀than that of uncoated, as-received TiO₂-filled samples. This was mainly due to enhanced electron scattering because of the presence of polar groups in AEAPS.