Small-Angle X-ray Scattering on Melt-Spun Polypropylene Fibers: Modeling and Data Reduction

We present a method for the evaluation of SAXS data of highly oriented semicrystalline polymers, allowing us to determine up to seven structural parameters from the measurements. The utilized samples were polypropylenes with varied distributions of the molecular weight, which were spun with different take-up velocities to alter the spinline stress, thus influencing the structural properties. We were able to determine the degree of orientation, lamella radius, long spacing, lattice distortion, and lamella height simultaneously. The microscopic orientation was compared with the crystalline orientation evaluated by Herman’s orientation function from WAXS.