FREE-RADICALS FORMED UPON THE PHOTOLYSIS AND RADIOLYSIS OF POLYMERS .2. PHOTOLYSIS AND PHOTOOXIDATION OF POLYETHYLENE IN THE PRESENCE OF FERROCENIC ADDITIVES
Si. Kuzina et al., FREE-RADICALS FORMED UPON THE PHOTOLYSIS AND RADIOLYSIS OF POLYMERS .2. PHOTOLYSIS AND PHOTOOXIDATION OF POLYETHYLENE IN THE PRESENCE OF FERROCENIC ADDITIVES, High energy chemistry, 31(5), 1997, pp. 333-337
The steps of initiation, propagation, and termination of kinetic chain
s in photooxidation of polyethylene and its composites with ferrocenic
additives were examined. An increase in the stabilizing ability of th
e additives with a rise in their concentration was observed in polyeth
ylene photolysis at 77 K. Dual behavior was exhibited by 2,2-bis(1,1'-
diethylferrocenyl)propane (FEP) additives at 315 K in the presence of
oxygen: they act as sensitizers at a low concentration (0.003 mol/kg)
and as inhibitors of initiation and photooxidation processes in polyet
hylene at 0.010 mol/kg. The inhibiting effect of FEP additives is asso
ciated not only with shielding and quenching of excited states of carb
onyl groups in polyethylene, but also with their ability to decompose
peroxide radicals. The sensitization is due to an increase in the ligh
t absorption because of the presence of FEP additives in polyethylene.