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 (D-ra) values of PA6(x)(CaCl2)(y) as-spun fiber specimens approach a maximum value, as their CaCl2 contents are close to the 3 wt% optimum value. The maximum D-ra values obtained for PA6(x)(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 A degrees C. The initial modulus, tensile strength and birefringence values of the PA6 and PA6(x)(CaCl2)(y) fiber specimens were found to improve consistently with D-ra or with drawing temperatures when they were stretched to a fixed D-ra. Similar to those found for their achievable drawing properties, the ultimate initial modulus, tensile strength and birefringence values of PA6(x)(CaCl2)(y) fiber specimens approach a maximum value, as their CaCl2 contents and drawing temperatures approach the 3 wt% and 120 A degrees C optimum values, respectively. Experiments including thermal, FTIR, melt shear viscosity and wide angle X-ray diffraction experiments were performed on the PA6(x)(CaCl2)(y) resin and/or fiber specimens to clarify the possible reasons accounting for the interesting drawing, tensile and birefringence properties found for the PA6(x)(CaCl2)(y) fiber specimens.