Polyimide fiber is one of the best fibers with high temperature resistance at present. It is widely used in aerospace

flexible electronic equipment and other fields. It can be prepared by one-step or two-step method. However

the polyimide fiber prepared by one-step method has the problems of high solvent toxicity

low solubility in most low toxic organic solvents and poor fiber forming; The polyimide fiber prepared by two-step method has the defects of surface porosity and poor mechanical properties. Because these two preparation methods have several problems

the further application and development of polyimide fiber are limited. This paper first reviews the relative references home and abroad

starting from the contradiction that it is difficult to balance the fiber forming properties of polyimide and fiber properties. The molecular structure of polyimide main chain

the orientation degree of main chain and the design principle of sequence degree of side chain are described

which provides a new idea for the preparation of high-performance polyimide fiber. In addition

the future development trend and application prospect of polyimide fiber are prospected.