Thermal degradation of chlorosulfonated polyethylene rubber and ethylene propylene diene terpolymer

In this work, the thermal degradation of chlorosulfonated polyethylene rubber (CSM) and ethylene propylene diene terpolymer (EPDM) were studied. The thermogravimetry of CSM and EPDM were firstly analyzed, and the loss in elongation and fatigue strength of CSM and EPDM due to thermal and humidity conditions was measured. To evaluate the degradation of these properties, the Arrhenius equation was used to confirm the relationship between temperature and exposure time. From these evaluation methods, the thermal reduction of fatigue strength can be predicted by taking into account the temperature and exposure time. The acceleration in the thermal degradation of elongation and fatigue strength were almost equal. In addition, the activation energy of thermogravimetry agreed well with that of fatigue strength. Next, the viscoelastic behavior of virgin CSM, EPDM and their thermal degradation were measured. The thermal degradations of mechanical loss tangent were evaluated by using the Arrhenius equation to confirm the relationship between the temperature and the exposure time. The acceleration in the thermal degradation of a mechanical loss tangent agreed well with the acceleration in the thermal degradation of elongation and of fatigue strength.

► Thermal degradations for CSM and EPDM were estimated.
► The degradation of elongation and fatigue strength were evaluated.
► The degradation shift factor of elongation agreed with that of fatigue strength.
► The activation energy was almost equal between the shift factor and TGA.
► The degradation of viscoelastic tan δ had the same shift factor.