THE DEFORMATION BEHAVIOR OF POLYETHYLENE SPHERULITE

Abstract

The deformation behavior of polyethylene spherulite composed of spherical shells (extinction bands) was studied by polarized microscope. The spherulitic films were drawn with various ratios at 20°C and 100°C, and the elongation ratios of each shell were evaluated.
The results obtained are as follows;
(1) The elongation ratio of the outermost shell, being the same as that of spherulite, is less than that of the sample. This indicates that the relative motion occurs between spherulites. The deviation from affine deformation is less for the hot drawn film than for the cold drawn film.
(2) The thickness of each elemental shell is almost uniform for the homogeneously deformed two-dimensional spherulite. Consequently the elongation ratios of outer shells are less than that of inner shells.
(3) Similarly a spherical shell in three-dimensional spherulite deform to an ellipsoidal shell, though the thickness of an elemental shell is not uniform. The crystal lamellae constituting these deformed shells must be disrupted to fullfil the geometric requirement.
(4) Deformation modes within a three-dimensional spherulite, which are generally deviated from affine deformation, depend on elongation ratios and deformation temperatures.