Inelastic response of thermo-oxidatively aged carbon black filled polychloroprene rubber. Part I: Viscoelasticity. (November 2022) - Kittur, M.I.
Highlights: Thermo-oxidative (TO) aging causes evolution of crosslinks and chain scissions. Evolution of elastomer network significantly affects the stress relaxation behavior. Multi-step loading causes strain-induced crystallization that is strongly affected by TO aging. Maxwell-Wiechert model is used to predict the time to reach the state of equilibrium. The effect of thermo-oxidative aging on Mullins effect is investigated. Mullins softening increases with thermo-oxidative aging durations. The evolution of elastomer network significantly affects the Mullins effect and its recovery. Abstract: The first part of a two parts study focuses on the inelastic response of carbon black-filled polychloroprene rubber undergoing thermo-oxidative aging. More precisely, the prominence of the present work is laid on the attempt to provide a better understanding of the network modification due to thermo-oxidative aging and its consequences on the macroscopic mechanical responses including viscoelasticity (in Part I) and Mullins effect (in Part II). For this purpose, the polychloroprene rubber specimens are exposed to a temperature of 120 °C for a duration of 2, 3, and 4 days to induce three different aging levels before undergoing various tests. Results indicated that during thermo-oxidative aging, crosslinking dominates chain scission, and the strain-induced crystallization becomes more pronounced. Furthermore, it is observed that the inelastic responses such as stress relaxation and strain-induced crystallization are strongly affected by this thermo-oxidative aging-induced network alteration.