Small‐angle x‐ray scattering by nylon 6

Small‐angle x‐ray scattering (SAXS) of isotropic or uniaxially oriented nylon 6 was investigated as a function of thermal and mechanical history. In addition to the peak position and linewidth of the SAXS maximum, the integrated SAXS intensity was measured. It was found that the radial intensity distributions of isotropic or arced patterns are controlled to some extent by the small width of the semicrystalline macrolattice, rendering the conventional long period and line shape analysis inapplicable to these patterns. A two‐dimensional analysis is possible with well‐oriented fibers; the major structural changes which are seen in fibers after annealing above 190°C are associated with melting and recrystallization. Extensive cold drawing and subsequent annealing cause rather modest (ca. ∼30%) changes in the integrated SAXS intensity. These effects are consistent with the generation of homogeneous interfibrillar regions during the latter stages of plastic deformation. On annealing a quenched film on nylon 6, the transformation of the crystals from a pseudohexagonal to a monoclinic habit occurs above 170°C.