Abstract
A series of polyethylenes developed for use as high voltage electric cable insulation have been studied. All crosslinked polyethylene materials show similar thermal aging characteristics, whereas linear low‐density polyethylene is susceptible to thermal aging at higher annealing temperatues. Tree‐retardant additives are soluble in xylene, but some are also attached to the gel network. They function both as enhanced antioxidants and as enhancers of electric breakdown strength. Biaxially oriented film shows the greatest resistance to electric breakdown.