OXYLUMINESCENCE OF POLYAMIDE-12

The oxyluminescence of unstabilised samples of polyamide 12 was studie d in the temperature range 80-250-degrees-C. The chemiluminescence int ensity was first recorded at constant oxygen pressure and temperature. The kinetic curves reveal the existence of two kinetic stages. The fi rst one is a burst whose intensity is linked to the radical concentrat ion at the onset of oxygen admission. The second one corresponds to th e steady-state oxidation chain process in which an autoaccelerated cha racter attributed to branching is observed. A discontinuity is observe d in Arrhenius plots of maximum intensities at the melting point, T(f) . A possible explanation is that the peroxyl bimolecular terminating c ombination is governed by segmental motion at T < T(f) and by the radi cal intrinsic reactivity at T > T(f). Perturbed experiments in which o xygen is abruptly suppressed, and programmed temperature experiments i n which preoxidised samples are exposed in nitrogen reveal clearly tha t hydroperoxide decomposition contributes to oxyluminescence.