Exploring the Theoretical Foundation with Rupture and Delayed Rupture Experiments

TL;DR

This paper explores how polymer networks rupture under different stretching conditions to support a new theory of bond dissociation in elastomers.

Contribution

The study introduces a new time-temperature equivalence principle derived from rupture experiments in polymer networks.

Findings

Network lifetime depends on temperature in an Arrhenius-like manner and is exponentially sensitive to stretching.

Rupture time during continuous stretching is inversely proportional to the stretch rate.

A new time-temperature equivalence is demonstrated where different rate-temperature pairs produce the same rupture behavior.

Abstract

We carry out uniaxial continuous and step stretching
of various
cross-linked polymer networks to demonstrate how characteristics of
rupture during continuous stretching and delayed rupture after step
stretching can be used to probe the structure of the emergent kinetic
activation theory of bond dissociation (KATBD) for elastomeric failure.
Based on delayed rupture experiments, we show that the network lifetime t
ntw, taken as the incubation time t
del‑rupt for delayed rupture, depends on temperature
in an Arrhenius like manner and is exponentially sensitive to the
degree of network stretching (depicted by the step-stretch ratio λss). Rupture at λb during continuous stretching
for a wide range of stretch rates takes place on time scales inversely
proportional to the stretch rate. The elapsed time t
rupt at rupture is found to be comparable to t
del‑rupt at various values of λb = λss in a wide range of temperature, affording
the experimental basis for the premise of the KATBD. Having identified
the hidden internal clock t
ntw, continuous
stretching tests at different temperatures are performed to show the
existence of a new time temperature equivalence (TTE): fast stretching
at higher temperatures is equivalent to slow stretching at lower temperatures:
different pairs of rate and temperature can produce the rupture at
the same tensile strength and strain.

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