Exploring the foundation of bond dissociation theory for elastomeric failure

Crosslinked polymer networks such as elastomers undergo rupture and fracture when chain scission takes place under high bond tension [1]. This paradigm-shifting assertion is supported by an extensive analysis of experimental data, including results obtained from spatially and temporally resolved polarized optical microscopy (str-POM). In the absence of a notch, rupture occurs during continuous stretching when the elastomeric lifetime – associated with the covalent bond lifetime –decreases with increasing strain and eventually matches the increasing stretch time. To test this theory, we measure the elastomeric lifetime as a function of strain (stretch ratio) using a series of stepwise stretch tests at different strain levels. The incubation time for delayed rupture is found to vary with the imposed strain in a manner comparable to the variation of stretch time with rupture strain. Furthermore, we apply srt-POM to elucidate the nature of crack propagation within the same theoretical framework.

[1] Perspective, Fracture behavior of polymers in Macromolecules, 57, 3875-3900 (2024).