Structure development in the melt spinning of nylon 6

It is known that nylon 6 (poly-E-aminocaproamide) assumes a variety of crystal structures, namely, the a form [1, 2] the y form [3–7], and a series of intermediate hexagonal structures [8–13]. The different types of crystal form appear under different crystalli-zation conditions. It has been reported that a metastable hexagonal structure is observed in as-spun nylon 6 fibers [8–13]. However, the mechanism by which this structure forms during the melt spinning process has not been examined systematically.