Quantitative characterization of deformation in polypropylene fibers

A modus operandi is developed for characterizing, in quantitative morphological terms, the structural changes occurring during the preparation (spinning, drawing, and heat setting) and testing (tensile modulus) of isotactic polypropylene fiber. This involves the application of the following eight different physical techniques: wide‐angle x‐ray diffraction, birefringence, density, sonic modulus, small‐angle x‐ray diffraction, dark‐field microscopy, small‐angle light scattering, and tensile modulus. Structural changes on several organizational levels, the spherulitic, the interlamellar, and the molecular, are determined in this manner and related to the processes involved.