Tensile Properties-Microstructure Correlations in the Hot-Drawn Nylon 6 Fiber

In the present work, nylon 6 fibers were hot-drawn with different number of drawing steps with a fixed total draw ratio of 4.63. FTIR spectroscopy, wide-angle x-ray diffraction, differential scanning calorimetry and birefringence measurements were used to explain the relationship between structure and tensile properties of the drawn fibers. The results show that gamma crystalline phase converts to alpha crystalline phase upon the drawing process. For three-stage drawn fibers, a higher initial modulus is achieved as compared to single and two-stage drawn fibers. The tensile properties (e.g. initial modulus) and shrinkage behavior of three-stage drawn fibers cannot be simply explained only with the crystalline structure and orientation. For understanding the relation, the interfibrillar taut tie molecules fraction should be considered.