Irradiation temperature effect upon crosslinks induced by gamma-irradiations of polycrystalline n-alkanes, n-undecane to n-heptadecane

Abstract Even-odd alternation of dimer isomers distribution of a series of irradiated normal alkanes starting from n -undecane is found to be due to prominent crosslinks at the ends of monomers in odd members of the series irradiated at 77 K. However, penultimate sites are also favoured in opposition to ESR results. By increasing the temperature of the irradiation to 195 K, crosslinks in the central part of chains (H-links) are enhanced particularly for even homologues. The temperature dependence explains that none of the free radicals are found at the terminal position after irradiation of n -eicosane at room temperature.