Flame retardation of glass-fiber-reinforced polyamide 6 by combination of aluminum phenylphosphinate with melamine pyrophosphate

The aluminum phenylphosphinate (BPA-Al) was synthesized and its chemical structure was confirmed by FT-IR, 1H NMR, and inductively coupled plasma-atomic emission spectrometry (ICP-AES). BPA-Al was used to prepare a series of flame-retardant glass-fiber-reinforced polyamide 6 (GFPA6) composites together with melamine pyrophosphate (MPyP) and sodium tungstate (ST) via melt compounding. The flame retardancy of the composites was investigated by vertical burning test and cone calorimeter test. The thermal behaviors and decomposition kinetics were investigated by thermogravimetric analysis (TGA). BPA-Al alone could not improve the flame retardancy of GFPA6 composites, but the combination of BPA-Al and MPyP resulted in a UL-94 V-2 rating, and the addition of a small amount of ST to the flame retardant system could endow the composites a V-0 rating. The flame retardant systems also resulted in a decrease in PHRR and THR in cone calorimeter test. The analysis of thermal decomposition kinetics showed that the activation energies (Eα) of the flame-retardant composites dramatically decreased compared with that of GFPA6. Copyright © 2011 John Wiley & Sons, Ltd.