Electrochemical treeing in XLPE/silica nanocomposites

Ashcraft-type samples have been used to grow vented water trees in crosslinked polyethylene and crosslinked polyethylene based nanocomposites with 5 wt% and 12.5 wt% functionalized silica. Tree growths are reported at a range of stresses by sectioning the samples destructively. A nondestructive method is also introduced which allows visualization of electrochemical trees without sectioning. Nanocomposites are found to have higher resistance to water tree growth and this trend becomes clear with larger loading. Due to the high interface/volume ratio in nanocomposites, it is believed that scattering in the interfacial region inhibits tree growth.