The Influence of Coagulation Variables on the Structure and Physical Properties of an Acrylic Fiber

Abstract

During the coagulation step in the wet spinning process, a concentrated, highly viscous polymer solution is transformed into protofibers which require further processing before they acquire textile fiber properties. The structure of these protofibers is strongly influenced by coagulation conditions, and this structure, in turn, influences the extent to which desirable properties can be developed in the finished product. In this study, the effect of several coagulation variables on the structure of protofibers preserved by freeze drying has been determined and related to the further processability and final properties of the fibers. Coagulation temperature, coagulation bath composition, extrusion rate, and take-up rate are shown to influence the cross-sectional shape, initial density, and void structure of the protofibers. Higher initial fiber density and more homogeneous internal structure permit the development of higher strength at lower stretches, higher elongation at a given strength level, high maximum strength and modulus at high stretch ratios, and improved fatigue and abrasion behavior.