Abstract: To enhance the puncture resistance of aramid fabric, a self-synthesized polyurethane with intrinsic flame-retardant properties and a slow reaction rate was used as the coating matrix in the finishing treatment. The polyurea/aramid composite fabric was prepared using a coating method. The chemical structures of the latent curing agent and flame-retardant polyurea were characterized by Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance spectroscopy. The thermal stability, flame-retardant properties, microstructure, and puncture resistance of the composite fabric were analyzed using thermogravimetric analysis, vertical burning tests, limiting oxygen index tests, polarizing microscopy, puncture testing instruments, and a universal testing machine. The results indicated that while the aramid/polyurea fabric was initially flammable, its flame-retardant performance improved with an increasing proportion of phosphorus-containing polyols in the polyurea matrix. When the proportion of phosphorus-containing polyols reached 21%, the polyurea/aramid composite fabric self-extinguished in the vertical burning test, with a char length of only 2.1 cm and a limiting oxygen index of 28.5%, qualifying it as a flame-retardant fabric. Moreover, the polyurea coating significantly enhanced the puncture resistance of the aramid fabric.

Key words: polyurea, aramid fiber, flame retardant, puncture resistance