Participation of the charge-transfer complexes in the radiation-induced chain oxidation of aromatic amines in polymer films

Abstract

The chain redox reaction in γ-irradiated solid films of poly(vinyl chloride) (PVC), containing N,N,N′,N′-tetramethyl-4,4′-diaminodifenylmethane (Am) and CBr4, was studied. The formation of charge-transfer complexes between Am and CBr4 and also between Am radicals and CBr4, the participation of these complexes in the chain oxidation of Am were investigated by ESR, spectrophotometry and luminescence methods. The spectral-luminescent properties of Am radicals both isolated and interacting with the PVC matrix were discussed. It was discovered the quenching of luminescence of Am radicals by molecules of CBr4. The effects of annealing temperature and concentration of CBr4 on the quenching of luminescence of Am radicals were observed. Stern–Folmer’s equation was used for the description of the static quenching of Am radical fluorescence. It was shown that this quenching could be due to the formation of ground-state charge-transfer complexes between Am radicals and CBr4. The kinetic features and mechanism of the radiation-induced chain oxidation of Am with the participation of the charge-transfer complexes were investigated.