| Abstract: | Examination of longitudinal, cross, and skew sections of extruded polycaprolactam filaments with the polarizing light microscope reveal morphological features not previously described. In cross-sectional view, three distinct layers enclose a “homogeneous” central matrix. The outermost layer is characterized by large, birefringent, truncated cones extending upward from the surface. Associated with the cones and an entity in its own right is what appears to be a second layer of ultrafibrils. Below the latter is a fine-structured layer of submicroscopic spherulites. A combination of the above features forms the transcrystalline region of stressed melts. Row nucleation is evident on the surface of the filaments. |
