A study of the mechanism of decay of allyl macroradicals in crosslinked polyethylene

Free radicals were generated in peroxide-crosslinked polyethylene with different gel fraction contents by exposition to a gamma dose of 20 kGy at 293 K. The decay of allyl macroradicals was examined by the ESR method in dependence on the crosslinking concentration. The rate constants of the allyl radical decay decreased with increasing gel content of the samples, and the activation energies, determined from the temperature dependences of the rate constants, increased with increasing extent of crosslinking. The results are discussed from the energy aspect of the conformational motions dominating in the temperature region used and controlling the allyl radical decay in crosslinked polyethylene.