Fabrication and characterization of orientation in skew stretched polyethylene terephthalate films
Skew stretched films were prepared by first unaxial stretching and subsequently skew stretching at 30 and 60 angles to various stretch ratios. The films were characterized by refractive index (birefringence), infrared absorption (dichroism) and wide-angle x-ray diffraction measurements. The data are represented in terms of ellipsoids and symmetry axes were determined. The results from the different methods are compared. Biaxial orientation factors are computed based on the experimentally determined axes.
Wu, J. P.; White, J. L.; and Cakmak, Mukerrem, "Fabrication and characterization of orientation in skew stretched polyethylene terephthalate films" (1989). Polymer Engineering Faculty Research. 297.