Novel image analysis of two-dimensional X-ray fiber diffraction patterns: example of a polypropylene fiber drawing study

On-line studies of the structural development during continuous drawing of a polypropylene fiber were carried out using synchrotron wide-angle X-ray d iffraction. A unique image analysis method was introduced to extract quanti tative information on the crystal, amorphous and mesomorphic fractions. In addition, the unit-cell parameters and the crystal orientation were obtaine d under various draw conditions. It was found that the mesophase remained a bout constant during drawing. At draw ratios less than 6.0, the crystallini ty increased and the crystal density decreased as a result of the stress-in duced crystallization of crystals with a large degree of disordering. At dr aw ratios above 6.0, the crystallinity increased slowly and the decrease in crystal density was also retarded because of the draw-induced melting. The crystal orientation increased with increasing draw ratio up to a ratio of 6.0 and then decreased, probably because of chain breakage.