Annealing of Polypropylene Films Crystallized from a Highly Extended Melt,
OAK RIDGE NATIONAL LAB TN
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The crystalline microstructure of thin films of isotactic polypropylene drawn from melt at a very high rate of extension transmission micrography was examined by dark-field micrography and X-ray scattering. Annealing at temperatures below 100 degrees C produced no qualitative change in the electron microscope observations, but between 110 and 150 degrees C produced gradual dominance of lamellar crystals, oriented normal to the drawn direction. Small angle x-ray scattering data exhibited a strong streaking normal to the fiber axis in broad agreement with the observed fibrosity. Author, modified-PL .