Evidence for non-Arrhenius behavior of EPDM rubber by combining Arrhenius and time–temperature superposition (TTS) extrapolations

Studying the non-Arrhenius behavior of rubber is crucial to ensure appropriate lifetime prediction and reduce ineffective acceleration experiments. In this paper, accelerated thermal aging from 70 °C to 130 °C is conducted on an ethylene propylene diene monomer (EPDM) rubber and the tensile characteristics of the rubber are tested. Further, the popular Mooney-Rivlin equation is employed to analyze the influence of aging temperature and time on the effective crosslink densities. The enormous increase in the physical crosslinking density when the aging temperature reaches 115 °C demonstrates that the activation energy varied during the degradation process. By combining the Arrhenius extrapolation with the time-temperature superposition (TTS) extrapolation, a novel method to prove the non-Arrhenius behavior of EPDM rubber is provided. Based on the method proposed in this study, the activation energies for the high- and low-temperature processing of rubber can be determined.