MODEL OF STABILIZATION FOR PAN-BASED CARBON-FIBER PRECURSOR BUNDLES

A combination of theoretical modeling and confirmation experiments has resulted in a model of the complex stabilization process in the manufacture of carbon fibers from polyacrylonitrile precursors. The model describes the temperatures and compositions inside large bundles during stabilization. The bundle is modeled as a homogeneous solid, with the many chemical reactions grouped into the three most important: cyclization of the nitrile groups, dehydrogenation of saturated carbon-carbon bonds, and oxidation. Experiments showed that the resulting mathematical model describes well the measured temperatures and compositions for bundles with 12,000 to 60,000 filaments. The heat-transfer and reaction-kinetics parameters required by the model were estimated experimentally. The model and experiments show that the fiber bundle temperature can be as much as 15-degrees-C above the stabilization oven temperature. A series of case studies with the model demonstrates key points about the stabilization process and shows how oven temperature profiles may be used to reduce the time required for stabilization.