Free radicals and photo-oxidation of an alternating copolymer of ethylene and carbon monoxide

Reactions of formations of free radicals on photolysis of low-molecular alternating ethylene-carbon monoxide copolymer and its photo-oxidation are investigated. It is found that the photolysis occurs by the Norrish 1 type mechanism with terminations of the polymer chain and formation of acyl and alkyl terminal radicals (quantum yield ϕR≃2×10−4 at 77 K and ∼10−3 at 300 K). The copolymer photo-oxidation is characterized by high efficiency. In the case of doses of up to ∼5 × 1017 quanta/cm2, there is a correspondence between the amount of absorbed O2 and the formation of gaseous products of oxidation, H2O and CO2 (ϕO2≃ϕgas≃7). At doses >1018 quanta/cm2 the yield of gaseous products is retarded, and the yield of O2 absorption decreases by an order of 10. The gaseous products of the photolysis and photo-oxidation involve (among H2O and CO2) also carbon monoxide, methane, ethane, propane, ethylene, acetone and hydrogen peroxide (ϕ=10−2–10−4).