System for in situ observation of three-dimensional structural changes in polymer films during uniaxial deformation

A simple three-dimensional structural evaluation system for a film during uniaxial deformation has been developed. The system is realized with an automatic film stretching machine, which allows the horizontally symmetric stretching of a film, and a synchrotron radiation X-ray scattering apparatus. Using this system, two-dimensional patterns of small-angle X-ray scattering and wide-angle X-ray diffraction can be obtained simultaneously during film stretching in the so-called edge and end views, together with stress–strain data. As cylindrical symmetry of the structure can be expected for a uniaxially stretched film, the two-dimensional patterns in the through view are identical to those in the edge view, indicating that three-dimensional structural characterization can be performed with a combination of edge and end views during film stretching. For amorphous poly(ethylene terephthalate) and crystalline poly(vinyl alcohol) films, the preliminary results of three-dimensional structural characterization during film stretching are shown.