Electron spin resonance study of the radiation-induced chain oxidation of aromatic amines in poly(vinyl chloride)

The quantitative analysis of ESR spectra of poly(vinyl chloride) (PVC), gam ma-irradiated at 77 K, has been made by a computer subtraction. The ESR spe ctra of alkyl, allyl and polyenyl macroradicals were separated. These spect ra were used for separation of the spectra of radicals trapped in solid sol utions of N,N,N',N'-tetramethyl-4,4'-diamino-difenylmethane (Am) and CBr4 i n PVC. It has been established that Am inhibites PVC chain dehydrochlorinat ion, interacting with alkyl macroradicals and resulting in Am-. free radica ls. The effects of radiation dose and annealing temperature on the generati on and transformations of Am-. and other radicals were investigated, and th e radiation-chemical yields of radicals were determined. It has been shown that Am-. radicals have high thermal stability and initiate chain oxidation of amine with a chain length of 100. (C) 1999 Elsevier Science B.V. All ri ghts reserved.