Process for forming filaments from polyamic acid

Abstract

A process for producing continuous filaments from polyamic acid suitable for conversion to polyimide filaments comprising providing a starting solution consisting essentially of equimolar amounts of P,P-diaminophenyl ether and bis-(3,4-dicarboxyphenyl) sulfone dianhydride, the remainder a solvent selected from the group consisting of dimethylformamide, methyl pyrrolidone and mixtures thereof, said starting solution having a viscosity ranging from 500 to 5,000 centipoises preferably 1,500 to 3,000 centipoises, and forming the starting solution into filaments by extruding it in a coagulating bath consisting essentially of a liquid selected from the group consisting of propanol, methyl alcohol, ethyl alcohol, butyl alcohol, a mixture of ethyl alcohol and propanol and a mixture of methyl alcohol and acetone.

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