Change of spherulitic structure in melt‐crystallized polymer fibers and films during uniaxial stretching

Abstract

As revealed by electron‐microscopic studies, the morphology of melt‐crystallized polymer films and fibers subjected to the ultimate degree of orientation, is characterized by layer‐like organization of lamellar crystals (paracrystalline structure). If the direction of the long axes of the macromolecules in crystallites coincides with the texture axis, the morphological orientation of paracrystalline layers is orthogonal to the stretching direction. Partial transformation of a spherulite into a “microneck” can lead to flattening of spherulites.

Heredity and difference of multiple‐scale microstructures in PAN‐based carbon fibers and their precursor fibers

“…This indicates lamellar structure has little relations with crystal/amorphous structure. A lot of literature suggests that it probably due to stretching or drawing during the production process, because similar lamellar structure was also found by earlier investigators in drawn polymers under conditions of flow 31–33. In addition, because the lamellar structure is nearly perpendicular to the fiber axis, it is disadvantageous to the tensile strength of carbon fibers.…”