Efficiency of antioxidants in thick-walled natural rubber samples evaluated by differential scanning calorimetry and compression stress–relaxation

The effect ot two antioxidants, IPPD and DENA, on the aging properties of TMTD-vulcanized natural rubber was studied by DSC. In the case of IPPD, the results were compared with mechanical measurements. The DSC measurements were carried out on specimens taken at different depths from cylindrical samples. The decrease in oxidative induction time was less pronounced for IPPD than for DENA at the edge of the samples. In the interior, the opposite behaviour was observed.