Fabrication and wet spinning of a fully aromatic meta-polybenzimidazole

Abstract

High reduced viscosity meta-polybenzimidazole (mPBI) as well as high-strength fibers of this polymer were fabricated via solution polycondensation and wet spinning, and the content of phosphorus pentoxide (P₂O₅) in the solvent, the reaction period and the draw ratio were altered. The results indicate that the reduced viscosity of the polymer reached a maximum of 2.75 dL g⁻¹ with 82 wt% P₂O₅ in the solvent, and the reaction period was 8 h. The polymer displayed good solubility and excellent thermal stability. At a coagulation bath concentration, polymer reduced viscosity and stretch ratio of 61.5 wt%, 2.75 dL g⁻¹ and 1.87, respectively, mPBI fibers that had relatively smooth surfaces and almost circular cross sections were formed (minimum diameter of 138 μm and maximum breaking strength of 306 MPa). In addition, the fibers exhibited good dimensional and chemical stability.