Thermal Aging Behavior of Polymers under 110℃ Air Oxidative Conditions

Abstract

In this study, five types of polymers fluoroelastomer (FKM), ethylene propylene diene monomer (EPDM) rubber, ethylene propylene rubber (EPR), chloroprene rubber (CR), and silicone rubber (SR) were subjected to thermal aging in air at 110°C for up to 30 days to comparatively evaluate their aging behaviors. Changes in key functional groups were monitored using Fourier-transform infrared (FT-IR) spectroscopy, with peak intensities normalized to those of unaged reference specimens. Element analysis (EA) was employed to quantify variations in carbon, hydrogen, nitrogen, and oxygen contents, and these results were systematically correlated with observed variation in hardness values. The results revealed distinct differences in thermal-oxidative durability among the tested materials. EPR and CR exhibited pronounced oxidative degradation, as evidenced by significant increases in both the carbonyl FT-IR peak and oxygen content, accompanied by marked increases in hardness. In contrast, FKM, EPDM, and SR demonstrated comparatively high stability, showing minimal variation in hardness values under the same conditions.