Abstract: An improved process for the production of ultralow denier, high-strength polybenzimidazole filaments is provided. A solution of the polymer is extruded vertically downward through a plurality of extrusion orifices into a gaseous atmosphere before being passed through a liquid coagulation bath. During their passage from the extrusion orifices to the exit from the coagulation bath, the filaments are drawn at an initial draw ratio of approximately 2:1 to 50:1. After being passed through the coagulaton bath, the filaments are washed, dried, and heat drawn at a heat draw ratio of approximately 1.5:1 to 10:1. The resulting filaments, having a denier per filament of approximately 0.05 to 0.50 and a tenacity of at least 4 grams per denier, are collected.

Abstract: High performance wholly aromatic polyamide fibers are provided possessing a novel chemical structure. The fibers of the present invention have chain extending bonds from the aromatic nuclei thereof which are coaxial or parallel and oppositely directed, and have a sulfur content of about 0.5 to 10 percent by weight (e.g. 0.5 to 3 percent by weight) as sulfonic acid and/or sulfonate groups attached to the aromatic nuclei. Not only do the fibers exhibit highly satisfactory tenacity (at least 15 grams per denier), elongation (at least 1.5 percent), and initial modulus (at least 400 grams per denier), but they exhibit an increased resistance to burning when compared to conventional unsubstituted aromatic polyamides. The fibers also exhibit particularly good resistance to organic solvents.

Abstract: Anisotropic dopes having a polymer content of at least about 20% by weight of the dope are provided. The dope may be spun into fibers, extruded as films or utilized as a fracturing agent in subterranean formations. The preparation of the dope involves dissolving a polymer selected from the group consisting of polyacryloyloxybenzoic acid, polymethacryloyloxybenzoic acid, polyacryloylaminobenzoic acid, polymethacryloylaminobenzoic acid, and mixtures thereof in an aqueous solution containing a compound selected from the group consisting of Group I metal compounds and compounds containing a protonated amine group.

Abstract: An improved process for preparing wholly aromatic polyamide fibers of high performance charcteristics is provided. The process includes the steps of providing a spinning solution of a wholly aromatic polyamide, the polyamide having a sulfur content as sulfonic acid and/or sulfonate groups attached to the aromatic nuclei of at least 0.5 percent by weight based on the weight of the polyamide; spinning the spinning solution of the wholly aromatic polyamide to produce an as-spun fiber having an inherent viscosity of at least 1.0; and heat treating the as-spun fiber under sufficient tension to maintain a constant length or to elongate the fiber up to about 5 percent of the as-spun length while heating within a range of about 150.degree. C. to about 650.degree. C. The resulting fibers have a tenacity of at least 15 grams per denier, an elongation of at least 1.5 percent, and an initial modulus of at least 400 grams per denier.