An Experimental Study on Small Angle Dynamic Light-Scattering from Polyethylene Films by the Photographic-Method Using Stroboscope Technique

Abstract

The Hv small angle light-scattering from polyethylene films gives a sort of diffraction pattern like a four-leaf clover type. This suggests that there might be a kind of regularity for the presence of optical heterogeneity within the films.The change in distribution of scattered intensity with static elongations was observed in two kinds of polyethylene films, a slowly cooled film of medium density polyethylene, Lupolen KR 1051, and the same irradiated by electron bombard using a high-tension electron microscope. Moreover, the dynamic response to the distribution of scattered intensity with sinusoidal tensile strain was observed by the photographic method using stroboscope technique.The dynamic response to scattered intensity at given scattering and azimuthal angles was usually in advance of the dynamic strain by the phase angle γ and represented bywhere Is is the static level of the scattered intensity and Id is its dynamic amplitude. The amplitude can be represented by the in-phase and out-of-phase components, ΔI' and ΔI", with respect to the dynamic strain, and the phase angle γ may be defined by ΔI"/ΔI'=tanγ.The frequency dependence of these parameters, Is, ΔI', ΔI" was investigated at temperatures, both room and elevated near 60°C, over the frequency range from 0.05 to 10cps. A frequency dispersion of Is was definitely found around 0.7cps, which shift to higher frequencies with increase of temperature, whereas those of ΔI' and ΔI" were not definite because of much scattering of the data.