Uniformity of Electron Beam Crosslinking of Polyethylene Depending on the Distribution of Absorbed Radiation Dose

The crosslinking of polyethylene of pipe grades under irradiation with 900-keV electrons at absorbed doses of 50 to 400 kGy in the presence of antioxidants and a crosslinking agent has been studied. The degree of crosslinking of polyethylene has been measured based on the concentration of a gel fraction determined by its extraction in xylene. It has been shown that a 60% degree of crosslinking was achieved at a dose of about 100 kGy in all cases. It is reasonable to combine a standard method for determining the gel fraction with visual inspection of samples to identify the conditions for the formation of an excessively low-melting material. It has been shown that the nonuniformity of the crosslinking degree at a level of ±7% can be achieved at a dose nonuniformity of up to ±50%.