Characterization of the orientation structure and distribution in rolled polypropylene

The polymer orientation structure in rolled polypropylene sheets was studied by polarized-light microscopy, scanning electron microscopy, and wide-angle x-ray diffraction. The initial spherulites became deformed to a pancake shape as rolling deformation proceeded and became more perfectly aligned as the rolling procedure continued. Most polymer crystallites were oriented with their b-axis nearly perpendicular to the rolling direction, as shown by x-ray pole figures. Even-order 〈Pn(cosX)〉c coefficients of the Legendre polynomial series (n = 2 to 10) describing the c-axis or orientation distribution of the molecular chains were determined from measurements of polar angle scan using the transmission technique. The 〈Pn〉c (n = 2 to 10) curves calculated from the pseudoaffine deformation theory agreed with the experimental data.