Electrical tree and deteriorated region in polyethylene

In polyethylene subjected to high electric fields, a deteriorated region is formed before tree initiation. The chemical analysis of the deteriorated region by FT-IR and Raman spectroscopy showed that it contains excess carbonyl groups (C=O) and double bonds (C=C) compared to normal polyethylene. Scanning electron microscope observation found in the deteriorated region a number of voids with diameter>