The mechanism of gamma-radiolysis of polymethylene, polypropylene and poly-n-butylene oxides: An ESR investigation

Abstract

The basic features of the mechanism of the solid state radiolysis of the title polyethers have been elucidated with an ESR study using the matrix isolation and spin-trapping techniques. The species identified at 77 K are α-alkoxy radicals arising from hydrogen abstractions probably involving the primary ether cation-radicals; chain scission radicals are formed on warming as a consequence of the thermal decomposition of the α-alkoxy radical precursors. The formation of acyl and α-keto radicals, which is observed on warming near room temperature, is identified with cage hydrogen abstraction reactions taking place between the products of the β-scission of the α-alkoxy radicals. Direct information on the stability and ESR properties of the polymeric ether cation-radicals, which are thought to be important intermediates in the radiolysis mechanism, have been obtained by irradiation in the CFCl₃ matrix.