High-temperature-resistant and flame-retardant polyamide-imide-based filament and green preparation and in-situ reinforcement method thereof

The invention belongs to the technical field of fiber materials, and discloses a high-temperature-resistant and flame-retardant polyamide-imide based filament and a green preparation and in-situ reinforcement method thereof. The proportion of PAI in the filament is greater than or equal to 90%, the diameter is 0.1-2mm, and the limit oxygen index is 40-50%; the filament is prepared in coagulating bath water in a green mode through a wet spinning technology, another component of polymer is introduced in the spinning process to serve as an elastomer, in-situ heating is conducted to enable the elastomer to be molten, and in-situ enhancement of the mechanical tensile property of the filament is achieved on the basis of the principle of rigid/flexible polymer network complementation. The filament is high-temperature-resistant, flame-retardant and excellent in mechanical property, the preparation method is simple, convenient, easy to operate and low in cost, and the filament has wide application prospects in the fie