CRYSTALLINE-STRUCTURE AT SURFACES OF UNIAXIALLY DRAWN POLYPROPENE FILMS

A series of uniaxially drawn films of isotactic polypropene and ethene -propene random copolymer was prepared. The differences in the crystal orientation between the bulk and the surface layer were examined usin g wide-angle X-ray diffraction and grazing incidence X-ray diffraction techniques. It was found that the c-axis orientation of the surface l ayer is almost identical with that of the bulk. The magnitude in the b -axis of the polypropene films decreased with increasing draw ratio. T he changes in the b-axis at the bulk were found to be greater than tho se at the surface layer.