Morphological aspects of water treeingin Co/sup 60/ gamma -ray irradiated polyethylene

To understand the effect of crosslinking in polyethylene on the water tree propagation, low-density polyethylene (LDPE) and Co/sup 60/ gamma -ray irradiated polyethylene were used for water treeing tests. Injection molded samples were made of LDPE using the CNRS laboratory model, and some of them were irradiated at different dose rates to produce crosslinking. The aged specimens were subjected to microscopic investigation, using scanning electron microscopy to study the morphology of the fractured surface and polarizing microscopy to study the structure of spherulite. It appears that the different structures found in the irradiated and nonirradiated materials polyethylene could account for the different water tree propagation in these materials.<
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