USE OF EPR TO IMAGE NITROXYL RADICALS IN HALS STABILIZED POLYMERS

An X-band EPR-Imaging apparatus which allowed us to determine the dist ribution of nitroxyl radicals within solid samples of polymeric materi als containing hindered amine stabilizers, is described. It is shown t hat EPR Imaging represents a powerful tool for investigating the growt h and decay of nitroxyls formed in polymers irradiated under air for l ong periods. Since the variations of the radical concentration can be monitored both in time and in the space, this technique provides valua ble information not easily attainable by means of other methods.