Drawing and tensile properties of polyamide 6/calcium chloride composite fibers

The influence of calcium chloride (CaCl2) contents on the drawing and tensile properties of polyamide 6 (PA6)/CaCl2 composite fibers prepared at varying drawing temperatures were investigated. At any fixed drawing temperature, the achievable draw ratio (Dra) values of PA6x(CaCl2)y as-spun fiber specimens approach a maximum value, as their CaCl2 contents are close to the 3 wt% optimum value. The maximum Dra values obtained for PA6x(CaCl2)y as-spun fiber specimens prepared at the optimum CaCl2 content reach another maximum as their drawing temperatures approach the optimum drawing temperature at 120 °C. The initial modulus, tensile strength and birefringence values of the PA6 and PA6x(CaCl2)y fiber specimens were found to improve consistently with Dra or with drawing temperatures when they were stretched to a fixed Dra. Similar to those found for their achievable drawing properties, the ultimate initial modulus, tensile strength and birefringence values of PA6x(CaCl2)y fiber specimens approach a maximum value, as their CaCl2 contents and drawing temperatures approach the 3 wt% and 120 °C optimum values, respectively. Experiments including thermal, FTIR, melt shear viscosity and wide angle X-ray diffraction experiments were performed on the PA6x(CaCl2)y resin and/or fiber specimens to clarify the possible reasons accounting for the interesting drawing, tensile and birefringence properties found for the PA6x(CaCl2)y fiber specimens.