Enhanced flame retardancy of polyamide 6 composites via containing melamine polyphosphate modified boron nitride

Abstract In this study, melamine polyphosphate (MPP) was grafted onto the surface of hexagonal boron nitride (BN) particles by ball milling. Infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy tests confirmed the successful grafting of MPP onto BN, resulting in functional particles BN-MPP (BNM). Flame retardant modified PA6/BNM slices were prepared by formulating and adding BN-MPP into polyamide 6 (PA6) matrix by melt blending using a twin-screw extruder. Then the PA6/BNM composites were shaped by compression molding. The flame retardancy of the composites PA6/BNM was evaluated using cone calorimeter, limiting oxygen index, and horizontal-vertical combustion. Meanwhile, the tensile and bending properties of PA6/BNM composites were tested by using a universal tensile testing machine. The results showed that when the content of BNM of the composites PA6/BNM was 10 wt%, the composites PA6/BNM10 had excellent flame retardancy with UL94 V-1 rating and lower peak heat release rate 515 kW/m 2 . The purpose of this design scheme is to solve the problems of migration, leakage and exudation of flame retardant MPP in polyamide 6 matrix.