Aminoxyl radicals as crosslinks for macromolecules of polyvinylpyrrolidone

Abstract

Using polyvinylpyrrolidone as an example, it has been shown that photolysis of ceric ammonium nitrate at room temperature can result in crosslinking of macromolecules. This process correlates with the formation of stable aminoxyl radicals, which are registered by EPR. The mechanism involves photodissociation of nitrate radicals produced in the primary reaction into nitric oxide or nitrogen dioxide depending on the wavelength of the light, and simultaneous formation of macroradicals. The accumulation of aminoxyl radicals occurs owing to the acceptance of macroradicals by nitroso or nitro groups according to which mechanism of the nitrate radical photodissociation prevails. Similar radical reactions are observed in N-methyl-2-pyrrolidone.

Polymers in polluted atmosphere. Free radical and ion-radical conversions initiated by nitrogen oxides

“…Macroradicals formed by the action of atoms O on polymers can be converted in the presence of NO into stable aminoxyl radicals. The use of these processes for the purposes of chemical modification of polymers is considered by the example of polyvinylpyrrolidone (PVP) in the work [28].…”