ESR Study of Free Radicals in Electrical Trees in Polyethylene

The electron spin resonance (ESR) spectrum of polyethylene samples containing electrical trees (or, where appropriate, breakdown channels) is found to be rich in structure. Much of this structure is correlated with the conditions under which the tree was produced, thus providing valuable information on the treeing phenomenon. However, in no case thus far has the paramagnetic center responsible for a given spectral component been identified.