Dynamical, morphological and mechanical properties of poly(ethylene terephthalate) deformed by plane strain compression

Dynamic, morphological and mechanical properties of poly(ethylene terephthalate) (PET) samples, submitted to plane strain compression, were evaluated in relation to the final applied stress through stress relaxation, small angle X-ray scattering and impact resistance experiments, respectively. The stress relaxation is well described by a bimodal exponential decay, indicating a fast relaxation process with characteristic times between 2 and 8 s, and a slow one with relaxation in the range between 65 and 105 s. The SAXS experiments confirm the increase of the amorphous phase with increasing of the final applied stress. The lamellar long period tends to decrease with increasing applied stress, resulting in the stacking across the compression direction and orientation along the flow direction. The impact resistance increases with final applied stress.