Electric Field Assisted Morphology Regulation, Moisture and Water Treeing Resistance of Cross-Linked Polyethylene

Moisture penetration causes the degradation of cross-linked polyethylene (XLPE). To explore the effects of morphology on moisture and water treeing resistance, in this work, the XLPE samples were prepared under an assisted electric field, and their morphology, moisture resistance, and antiwater treeing performance were investigated. The scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) measurement results indicated that the assisted electric field reduced the spherulite size and enhanced the crystallinity of XLPE. Molecular dynamics simulations further demonstrated that the assisted electric field reduced the free volume, which consequently lowered the water diffusion coefficient. These morphological modifications effectively impeded water molecule migration, led to a reduction in moisture absorption, and further enhanced the moisture and water tree resistance. This work provides a novel strategy for the enhancement of the moisture and water treeing resistance of polymers, which helps improve the long-term reliability of terrestrial and submarine cables.