Abstract: A high-strength high-modulus polyimide fiber and its preparation method pertain to the technical field of high-performance organic fiber. This fiber includes the polyimide (PI) fiber made from 3,3?,4,4?-biphenyl tetracarboxylic diandhydride (BPDA), p-phenylenediamine (pPDA) and 2-(4-aminophenyl)-1H-benzimidazol-5-amine (BIA), wherein the molar ratio between PPDA and BIA is 1:10˜3:1. During the synthesis, other diamine and diandhydride monomers may also be added. In the preparation process, the gradient temperature reaction method and one-step continuous preparation method are adopted, the synthesis and processing difficulty caused by the increase of the content of BIA is overcome, the problem of poor uniformity and stability of fiber is solved and PI fiber with high strength and high modulus is obtained. Its strength may reach 4.5 GPa and modulus may reach 201 GPa.

Abstract: Methods for making high quality polyimide fibers suitable for continuous industrial production are described. Polyimide fibers are continuously prepared from a polyamic acid solution through sequentially spinning the polyamic acid solution by either a wet or a dry-wet process, coagulating, drying or drying after washing, thermally treating and stretching the resulting polyamic acid fibers to obtain polyimide fibers, and winding polyimide fibers as prepared into rolls.

Abstract: Methods for making high quality polyimide fibers suitable for continuous industrial production are described. Polyimide fibers are continuously prepared from a polyamic acid solution through sequentially spinning the polyamic acid solution by either a wet or a dry-wet process, coagulating, drying or drying after washing, thermally treating and stretching the resulting polyamic acid fibers to obtain polyimide fibers, and winding polyimide fibers as prepared into rolls.