Abstract: Fibers of an alternating carbon monoxide-ethylene polymer having a molecular weight of at least 100,000 g/mole and a birefringence of at least 650.times.10.sup.-4 can be formed by first extruding a solution of the polymer in a mixed solvent system comprising an aromatic alcohol which is free of alkyl substituents on the aromatic nucleus and another solvent which is a liquid and is other than an aromatic alcohol. The extrusion into the solvent is at an extrusion rate of at least 1 m/min and forms a solvent-containing article which is then cooled or coagulated in a non-solvent for the polymer. The solvent is removed by extraction with a non-solvent for the polymer which is soluble in the mixture of solvents and the resulting article is drawn at a temperature of at least 180.degree. C.

Abstract: In a process for preparing a polyvinyl alcohol yarn of high tenacity, a solution of polyvinyl alcohol in an organic solvent is extruded from a spinneret into a coagulation bath through an air gap or inert gas gap, and the extruded solution is drawn. The spinneret has capillaries which are at least five times their diameter in length and the concentration of the polyvinyl solution is at least 30-(M.sub.v /20,000) in percent by weight of the polyvinyl alcohol solution.