The invention discloses a modified nylon composite
flame retardant and a preparation method thereof, and the preparation method comprises the following steps: mixing
agmatine and
sulfuric acid according to a ratio of 1: 1, adding
ethanol, heating and stirring, and carrying out rotary
evaporation to remove a
solvent to obtain
agmatine sulfate; then, 4, 4 '-diaminodiphenyl
sulfone and phenylphosphoryl dichloride are dissolved in
acetonitrile, and after a reaction, a
phosphorus-
sulfur composite
flame retardant is obtained; then mixing brominated
polystyrene and
antimony trioxide according to a ratio of 3: 1, adding a
dimethyl sulfoxide solvent, and stirring to obtain a
bromine-
antimony composite
flame retardant; and finally, mixing all the components with the long
glass fiber, performing high-speed stirring and twin-screw
extrusion melt blending, and performing cooling and
pelletizing molding. The
agmatine sulfate can provide gas-phase flame retardance, the
phosphorus-
sulfur composite flame retardant generates a
carbon layer to enhance
solid-phase flame retardance, and the
bromine-
antimony composite flame retardant synergistically delays
flame propagation, so that the flame retardance stability and durability of the nylon composite flame retardant are improved, and the long-term use safety in a high-temperature environment is ensured.