DEFORMATION MECHANISM OF POLYETHYLENE SPHERULITES AS OBSERVED BY WIDE-ANGLE LIGHT-SCATTERING

The deformation mechanism of polyethylene spherulites was studied by analyzing the change in wide angle “ring” scattering arising from the helicoidal twisting of lamellae with applied uniaxial stretching. It was verified by numerical calculations of the ring scattering that the scattering angles θ giving rise to maximum ring intensity at azimuthal angle μ are independent of the polarization conditions (V, H, H, and etc.) and orientation of the optical axes of the scattering elements with respect to spherulite radii (i.e., independent of the internal reorientation processes of the optical axes within the deformed spherulites). These angles are dependent entirely on the ring spacing in a particular angular region of the spherulite in accordance with the Bragg’s equation. Thus the studies of the ring spacing as a function of the azimuthal angles between the stretching direction and the scanning plane give information on angular dependence of the spherulite deformation. These results indicated, for a special polyethylene studied, that the spherulites deform affinely at least up to 60-% elongation. It was also indicated that the spherulite deformation model of the multiple concentric-shell deformation is not appropriate for describing the observed ring scattering patterns. © 1979 The Society of Polymer Science, Japan.