Chemiluminescence of polyamides III. Luminescence accompanying thermooxidation of lactam-based polyamides stabilized by antioxidants

Abstract

Chemiluminescence accompanying oxidation of lactam-based polyamides stabilized with phenols and secondary aromatic amines as well as with a hindered nitroxy radical was measured. The yields of chemiluminescence per mol of oxygen absorbed were found to be higher for oxidation of polyamide in the presence of antioxidants than in their absence depending on the content of amino and carboxylic end-groups. Because antioxidants react with peroxy radicals by several consecutive inhibition reactions with different yields of chemiluminescence, the intensity of chemiluminiscence also depends on the rate of initiation of the oxidation. The relation between the intensity of chemiluminescence and the rate of oxygen consumption during oxidation of stabilized polyamides differed profoundly for various polyamides depending on their end-group content, on the concentration of antioxidant and also on the conditions of oxidation, especially on the rate of initiation determining the rate of antioxidant consumption. Redox inhibition reactions were found to be the predominant source of chemiluminescence accompanying the oxidation of N-alkylamides in the presence of antioxidants.