Crosslinking influence on water tree resistance in polyethylene

In this study water tree resistance of crosslinked polyethylene and of low density polyethylene were compared in order to elucidate whether the crosslinking influences or not the water tree propagation in polymer insulation. The experiments were carried out on plane samples made of low density polyethylene. Polyethylene crosslinking was obtained by irradiating the samples with high energy electron beams, in order to avoid the possible errors due to byproducts used for chemical crosslinking. The samples, irradiated or not, were analyzed by determining the crosslinking degree and the oxidation profile as resulting from Fourier transform infrared (FTIR) cartography. By comparing the water tree lengths with the modifications produced by irradiation it can be concluded that crosslinking does not seem to affect the water tree propagation.