Abstract:
The present invention concerns a process for making a polyareneazole multifilament yarn comprising: a) extruding a solution comprising polyareneazole polymer and polyphosphoric acid through a plurality of orifices to produce filaments; b) forming a multifilament yarn from said filaments; c) hydrolyzing at least some of the polyphosphoric acid in the yarn by heating the yarn to a temperature above about 120° C. for up to about two minutes; d) washing at least some of the hydrolyzed polyphosphoric acid from the yarn; e) drying the washed yarn; f) optionally, heating the yarn above about 300° C., and g) collecting the yarn at a speed of at least about 50 meters per minute.
Abstract:
In the preparation of poly(m-phenylene isophthalamide) filaments, hydrogen chloride is removed from as-produced amide solution of poly(m-phenylene isophthalamide) by contact with basic ion exchange resin.
Abstract:
Hydrogen chloride evolution is reduced in the distillation of chloroform from its admixture with an amide solvent when in contact with stainless steel, by incorporation of certain tertiary aliphatic amines.