Experimental investigation of mechanical, thermal, and flame‐retardant property of polyamide 6/phenoxyphosphazene fibers

Abstract

ABSTRACTIn this study, flame‐retardant polyamide 6 (PA6) fibers incorporated with hexaphenoxycyclotriphosphazene (HPCP) were prepared by melt spinning. The effects of HPCP on the mechanical, thermal, and flame‐retardant property of PA6 fibers were investigated. The results indicated that PA6 fibers containing less than 15 wt % of HPCP possessed acceptable spinnability. HPCP resulted in a slight decrease in tensile strength and tensile modulus, however, an enhancement of the flexibility. Thermal decomposition temperature of PA6 fibers reduced about 22 °C but the residue at 800 °C increased. At the loading of 10 wt %, PA6 fibers reached a limiting oxygen index value of 28.6% and had no smoldering time in the vertical oriented burning. Residue analysis by Fourier‐transform infrared and scanning electron microscope revealed that a condensed phase mechanism was involved in the decomposition of PA6/HPCP system. Pyrolysis‐gas chromatography–mass spectrometry results demonstrated that HPCP not affected the composition of the pyrolysis gases, but mainly intensified the effusion of nonflammable gases, which is positive to flame retardancy. Therefore, the PA6/HPCP composite fibers would get access to satisfactory applications as flame‐retardant materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48458.