ESTIMATION OF THE ACTIVATION-ENERGY FOR T HERMOOXIDATIVE DEGRADATION OF POLYETHYLENE IN THE PRESENCE OF INHIBITORS

The results of comparative analysis of the data on thermal and radiati on-initiated oxidative aging of polyethylene at 60, 80, and 140 degree s C are presented. Thermooxidative aging was studied under usual worki ng conditions employed in practice. Radiation-initiated oxidative agin g was performed under the conditions when pure radiation effects on th e degradation of material could be ignored. At each particular tempera ture, the time of attaining the critical level of damage was determine d for both aging methods. Comparative analysis of data on radiation-in itiated and thermooxidative degradation allowed the activation energy for the initiation of inhibited thermooxidative degradation of polyeth ylene in the temperature interval 60 - 140 degrees C to be evaluated ( E = 60 kJ/mol). It was suggested that this quantity is a universal val ue characterizing the temperature-dependent effect of surrounding medi um.