抄録
A layer structure was observed by a scanning electron microscope on the surface of uniaxially- or biaxially-drawn high-density polyethylene films treated with low temperature oxygen plasma. The long axis of the layer structure was almost perpendicular to the drawing direction of the uniaxially drawn films. The spacing between layers expanded explicitly with increasing the electric power of discharge even at the same stage of the weight loss. There was not so much change in the surface morphology when the treatment time was longer than 20min at any discharge power, but the weight of the samples decreased linearly after 20min treatment. It was found by comparing the surface morphology with the micro X-ray diffraction patterns for the biaxially drawn samples that the layer structure was related to the orientation of the crystallites and that the layer laid perpendicular to the molecular chains in each region. As the appearance mechanism of the layer structure, it was suggested that the structural relaxation of the molecular chains was caused by the plasma radiation, and the partial-melting and epitaxial recrystallization processes occured continuously on the substrate crystal.
