PHOTOOXIDATION OF LINEAR LOW-DENSITY POLYETHYLENE - A COMPARISON OF PHOTOPRODUCTS FORMATION UNDER NATURAL AND ACCELERATED EXPOSURE

Some samples of LLDPE have been photo-oxidized under natural and accelerated exposure. The structural changes have been studied using infrared spectroscopy combined with chemical derivatization. Some stoichiometry differences under the two modes of exposure have been found. The comparison of the extent of photoproduct formation during natural and accelerated exposure allowed us to address some controversial issues such as the mechanisms for the build up of ketone, ester and alcohol species. Our study proved that acid and vinyl groups may form from hydroperoxide groups. Finally, the importance of the UV accelerated device used to run laboratory tests is discussed.