Control the strain-induced crystallization of polyethylene terephthalate by temporally varying deformation rates: A mechano-optical study

All three regimes observed in Linear profile are also observed in Logarithmic and Exponential cases. However, Sigmoidal deformation shows only the first two regimes even though the film was stretched to the same total engineering strain as applied to all profiles. Logarithmic profile was found to induce early strain crystallization leading to early development of strain hardening. Exponential profile on the other hand retards the formation of “potentially constraining” long-range physical networks. This allowed the development of higher birefringence and crystallinity levels using this mode. A logarithmic birefringence-work relationship with two distinct stages was found to apply to all temporally varying profiles.