Fabrication of Ultrahigh‐Strength Polybenzimidazole Fibers via a Novel and Green Integrated Liquid Crystal Spinning Process

Abstract Herein, the first example of ultrahigh‐strength polybenzimidazole (PBI) fibers using a PBI solution in liquid crystal state is reported via a novel and green integrated spinning technology. Microwave‐assisted polycondensation is utilized to synthesize the polybenzimidazole/polyphosphoric acid liquid crystal spinning solution and pure water is employed as the coagulating and washing bath to afford a green fabrication process. The green integrated spinning technology is eco‐friendly, cheap, and conducive for the large‐scale production of PBI fibers. The as‐prepared PBI fibers display superb flame retardancy, and the outstanding thermal stability of PBI fiber enables it to preserve structural integrity at temperatures as high as 600 °C. More significantly, it prepared the ultrahigh‐strength of PBI fiber up to 0.91 GPa, which is two times than that of the reported PBI fibers, marking a significant breakthrough for the high‐performance PBI fibers.