Flame retardancy of polyamide 6 hybrid fibers: Combined effects of α-zirconium phosphate and ammonium sulfamate

Synergistic effect between alpha-zirconium phosphate (alpha-ZrP) and ammonium sulfamate (AS) for enhanced flame retardant properties of Polyamide 6 (PA6) was investigated by using oxygen index instrument, cone calorimeter, thermogravimetric analyzer (TGA), Instron universal test machine and scanning electron microscopy (SEM). PA6/AS/alpha-ZrP ternary hybrid materials with various contents of alpha-ZrP and AS were fabricated by melt-mixing method. The result from flammability indicated that the Limiting oxygen index (LOI) and Underwriters Laboratories-94 (UL-94) rating of PA6/AS/alpha-ZrP were significantly accelerated under the coordinating function of alpha-ZrP and AS. Moreover, the thermal stability for PA6/AS/alpha-ZrP studied by TGA also demonstrated this synergistic effect between alpha-ZrP and AS on the heat resistance. The effects of the usage amount of alpha-ZrP and AS on mechanical properties were analyzed by using uniaxial tensile test. It was found that the addition of AS provided negative effects on the tensile strength of PA6/AS/alpha-ZrP, however, the adverse trends that mentioned above could be overcome by using the well dispersed alpha-ZrP.