The influence of structure on water treeing in crosslinked polyethylene: tree morphology and the influence of organic contaminants

Trace amounts of ethylene glycol present in crosslinked polyethylene during thermal aging are shown in experiments on miniature cables to exert a major accelerating effect on water-tree populations and growth. The morphology is changed from bow-tie to acicular. Few water trees grown under these conditions show foreign particles or bubbles as initiation sites. Vented trees are shown to be fan-shaped and occur in parallel arrays along the miniature cable axis under all conditions studied