Fibers from a soluble, fluorinated polyimide

Polyimide fibers have been produced from both polyamic acid and polyimide resins, derived from 2, 2‐bis (3,4‐dicarboxyphenyl) hexafluoropropane dianhydride and 2, 2‐bis (4‐4‐aminophenoxy) phenyl) hexafluoropropane, by extrusion into various aqueous organic media. Polyimide fibers obtained from polyamic acid fibers after thermal imidization exhibited round or oval cross‐sections, while fibers obtained directly from a polyimide resin had dogbone, C‐shaped, or oval cross‐sections. The effect of polymer inherent viscosity and filament production parameters on the formation of macropores within the filament will be discussed. Tensile properties of fibers, produced under various conditions, are listed and compared. © 1993 John Wiley & Sons, Inc.