| abstract |
The present invention concerns methods for producing a yarn comprising the steps of: (a) producing a plurality of dope filaments by spinning a polymer solution in sulfuric acid through a multi-hole spinneret, the polymer comprising imidazole groups; (b) coagulating the plurality of dope filaments into an as-spun yarn; (c) contacting the yarn with an aqueous base having a pKa less than or equal to 11; and (d) rinsing the yarn. |