RAPID STABILIZATION OF ACRYLIC FIBERS USING AMMONIA - EFFECT ON STRUCTURE AND MORPHOLOGY

Acrylic fibers were stabilized, for subsequent carbonization, in oxidizing, inert, ammonia and mixed environments and the stabilized fibers were characterized using several techniques to determine the extent of reactions as well as the morphological changes. Ammonia was shown to accelerate stabilization of acrylic precursors that did not contain other effective initiators, such as acid comonomers. Two effects of ammonia-nucleophilic attack in initiating polymerization of nitrile groups and, possibly, the rapid disruption of lateral order in precursor morphology-combine to produce a significant enhancement in the rate of this intermediate step in the formation of carbon fibers. (C) 1993 John Wiley & Sons, Inc.