Characterization of the Dynamic Stretching Stages of Polymeric Fibers using Dispersion Measurements

In this article, we intend to characterize the dynamics of the molecular chains at different stages of stretching polymeric monofilament fibers. The stages characterized in this work are; undrawn, shear-bands, necking, drawn, crazes, cracks and fracture regions. We used the lookup table technique to calculate the dispersion curves of the stretched polymeric fibers at different deformed stages from one interferogram. This technique is suitable for dynamic stretching experiment of fibers. Digital photoelasticity and white-light two-beam interferometry are utilized to study each phenomenon by finding the dispersion curves and the 3D birefringence profiles using a single-shot pattern, which is performed for the first time, as far as we know. This study gives us clear vision on the behavior of the polymeric fibers at a molecular level during dynamic stretching until reaching its fracture point. Patterns of each deformation stage are given for illustration.