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

Acrylic fibers were stabilized, for subsequent carbonization, in oxidi zing, 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 ot her effective initiators, such as acid comonomers. Two effects of ammo nia-nucleophilic attack in initiating polymerization of nitrile groups and, possibly, the rapid disruption of lateral order in precursor mor phology-combine to produce a significant enhancement in the rate of th is intermediate step in the formation of carbon fibers. (C) 1993 John Wiley & Sons, Inc.