THE CONSTRUCTION OF A PHASE-DIAGRAM FOR A TERNARY-SYSTEM USED FOR THEWET SPINNING OF ACRYLIC FIBERS BASED ON A LINEARIZED CLOUDPOINT CURVECORRELATION

A phase diagram for the commercially significant ternary system poly(a crylonitrile-co-methylacrylate-co-sulfonic acid), sodium thiocyanate, and water, used to wet-spin textile acrylic fibers, was constructed fr om a linearized cloudpoint curve correlation. Experimental cloudpoints in the accessible low polymer content range were evaluated and used t o extrapolate to higher polymer concentrations to produce a full-phase diagram. Although the correlation only holds for systems undergoing l iquid/liquid demixing, the fact that the relation holds for this syste m despite evidence for PAN crystallization is discussed. (C) 1997 John Wiley & Sons, Inc.