A differential scanning calorimetry method to study polymer photoperoxidation

A main challenge in the field of polymer aging is the detection of extremel y small amounts of peroxide formed in the primary steps of oxidation. This is a necessary condition to be able to predict physical changes and to reme dy the resulting loss of proper-ties. All experiments carried out to assess the properties of peroxide species are generally based on direct or indire ct chemical titration. However, all of these techniques are limited by the molecular accessibility of chemical reagents in the macromolecular medium. As the decomposition of these species is known to be strongly exothermic, w e used differential scanning calorimetry (DSC) measurements to quantify the level of peroxides formed from the photo-oxidation carried out under accel erated conditions. This method appears to be more sensitive than chemical t itration in the detection of small amounts of peroxide structures. Moreover , it gives additional information such as their thermal range and kinetics of decomposition. (C) 2001 Elsevier Science Ltd. All rights reserved.